farhank

• Palm, Ellen; Hansen, Steffen Foss; Farrelly, Trisia; Oturai, Nikoline Garner; Ramos, Tiffany Marilou & Khan, Farhan R. [Show all 7 contributors for this article] (2026). Regulations, International Negotiations and Transformative Approaches to Address Plastic Pollution. In Singh, Nisha; Walker, Tony R. & Hofmann, Thilo (Ed.), Microplastics and Nanoplastics in the Environment. Royal Society of Chemistry (RSC). ISSN 9781837678235. p. 345–378. doi: 10.1039/9781837678235-00345. Full text in Research Archive Show summary

  Micro- and nanoplastics in the environment are a growing global concern driven by the rising production and use of plastics in all sectors of society. This chapter explores measures to address the adverse impacts of plastic pollution through regulatory frameworks, initiatives and transformative approaches. It offers insights into two key strategies for reshaping the current plastic system, alongside a summary of regional and global governance efforts. By examining the current state of European Union regulations and the United Nations plastic treaty negotiations, as well as the opportunities and difficulties of circular economy and citizen science approaches, the chapter encourages readers to engage with a broad body of scientific literature on plastic pollution. Ultimately, it seeks to inspire more interdisciplinary thinking and foster collaborations on the pressing challenges society faces with the omnipresence of plastics.

• Khan, Farhan; Yusuph, Mamlo A.; Sørensen, Christina & Mayoma, Bahati S. (2026). Brand audit attribution of plastic litter in the African Great Lakes: dominance of national manufacturers and implications for extended producer responsibility. Environmental Science and Pollution Research. ISSN 0944-1344. 33(23), p. 11654–11664. doi: 10.1007/s11356-026-38019-w. Full text in Research Archive
• Flick, Helge Marius; Khan, Farhan R.; Bokor, Barbara; Vries, Frans P. de; Garrard, Samantha L. & Abate, Tenaw Gedefaw [Show all 7 contributors for this article] (2026). Governing microplastics in the North-East Atlantic: The importance of regional frameworks in the absence of a global treaty. Marine Policy. ISSN 0308-597X. 191. doi: 10.1016/j.marpol.2026.107173. Full text in Research Archive
• Khan, Farhan R.; Catarino, Ana I.; Syberg, Kristian; Belleghem, Frank G.A.J. Van & Clark, Nathaniel J. (2025). Microplastics as a Vector of Hazardous Contaminants: Plastic Chemicals, Digestive Physiology and the Need for Chemical Simplification. In Martín, Julia; Santos, Juan Luis; Aparicio, Irene & Alonso, Esteban (Ed.), Microplastic Pollution. Jenny Stanford Publishing. ISSN 9781003660064. p. 223–264. doi: 10.1201/9781003660064-8. Full text in Research Archive Show summary

  Microplastics are one of today’s major environmental problems, as they are a ubiquitous persistent pollutant group that has reached all parts of the environment. The chemical burden of microplastics results from the plastic-associated chemicals (chemical additives, monomers, and non-intentionally added substances) incorporated into the polymer matrix during manufacturing, and the environmental pollutants (e.g., hydrophobic organic compounds, trace metals or pharmaceuticals) that sorb to the plastic surfaces following release. Microplastics have also been shown to be readily ingested by a wide range of organisms across taxonomic groups, and it is this combination of biotic ingestion and chemical association that gives credence to the notion that microplastics may be vectors of hazardous contaminants. Therefore, the transfer of chemicals from microplastics has been the subject of much laboratory research, but owing to the complexity of exposure scenarios, results are often disparate. Moreover, while the relevance of microplastics as realworld vehicles for environmental pollutants has been questioned, recent analysis has shown that plastics can have as many as 16,000 chemicals added to them during manufacturing, many of which are of known toxicity. Furthermore, plastic-associated chemicals once released into the environment may be transformed into distinct substances that exhibit different toxicities compared to their parent compound. This chapter provides an overview of the current literature on microplastics as carriers of environmental pollutants and plastic-associated chemicals, and the emergence of transformation products as a topic of concern. The importance of digestive physiology is recognized as one of the main sites in which chemical release and desorption occurs resulting in chemicals being labile within an organism. Lastly, we explore how the wealth of literature linking microplastics and chemicals has heightened calls for chemical simplification to ensure better safety for environmental (and human) health.

• Khan, Farhan R.; Clark, Nathaniel & Xu, Elvis Genbo (2025). Micro(nano)plastics in the fish gastrointestinal tract: A mini review and relevance to One Health perspective. Current Opinion in Environmental Science & Health. 46. doi: 10.1016/j.coesh.2025.100645. Full text in Research Archive Show summary

  Micro(nano)plastics (MNPs) research in the piscine gastrointestinal tract has been a significant area of study. Understanding the environmental presence of microplastics, their potential for both localised and systemic effects, and their role as a gateway for MNPs and associated chemicals to enter the tissues and the food web, including the human food chain, is crucial. The fish gut, as a critical intersection between environmental, biotic, and human health, aligns with the One Health concept. We review the likely uptake mechanisms and toxicological damage caused by ingesting MNPs and their associated chemicals in fish, contextualised within the realms of digestive physiology and biological plausibility.

• Jaén-Gil, Adrián; Tisserand, Amandine Aline; Santos, Lúcia H. M. L. M.; Rodríguez-Mozaz, Sara; Gomiero, Alessio & Langeland, Eirik [Show all 7 contributors for this article] (2025). Legacy of Chemical Pollution from an Underwater Tire Dump in Alver Municipality, Norway: Implication for the Persistence of Tire-Derived Chemicals and Site Remediation. Environments. 12(10). doi: 10.3390/environments12100356. Full text in Research Archive Show summary

  Increasing attention has been given to the environmental impact of tire-derived chemicals in aquatic systems, but submerged whole tires remain an overlooked source. This study investigates a previously unexplored underwater tire dump in Hjelmås Bay, Alver Municipality (Norway) where a blast mat manufacturer discarded large quantities of tires into the bay in the 1970s. These tires have remained submerged for over 50 years. We conducted an initial site mapping and collected sediment and water samples to assess tire-related pollutants in comparison with control sites. Sediment analysis revealed elevated levels of Zn, Pb, and Cu, particularly near the tire dump center, with Zn being the most abundant. Bis(2-ethylhexyl) phthalate (DEHP) was the dominant phthalate detected in the sediments, though no clear spatial pattern emerged for phthalates. Non-target chemical screening of water samples identified 20 features potentially linked to tire degradation, with N,N′-Diphenylguanidine (DPG) being the most notable. Our study highlights the long-term environmental persistence of several tire-derived chemicals, which has ramifications for both the regulation of tire-derived chemicals and plans for remediation at Hjelmås. Our initial findings warrant the implementation of a comprehensive chemical and ecological baseline monitoring assessment prior to discussions on remediation.

• Khan, Farhan R.; Bury, Nicolas R.; Cooper, Christopher A.; Boyle, David; Middleton, Elizabeth & Herzog, Simon D. (2025). The impact of climate change on the flux and fate of metals in freshwater systems: Implications for metal exposure across different scales. Environmental Research. ISSN 0013-9351. 287, p. 123057–123057. doi: 10.1016/j.envres.2025.123057. Full text in Research Archive
• Mayoma, Bahati S.; Yusuph, Mamlo A.; Sailas, Hellena; Emanuel, Zagalo; Lukanga, Editrudith & Kitogo, Lawrence [Show all 14 contributors for this article] (2025). Abundance and characteristics of anthropogenic litter along the Tanzanian shores of the African Great Lakes: including volunteer involvement, outreach, and stakeholder engagement in a holistic approach. Environmental Science and Pollution Research. ISSN 0944-1344. doi: 10.1007/s11356-025-36528-8. Full text in Research Archive Show summary

  Environmental pollution due to mismanaged anthropogenic litter is one of the most pressing issues facing the world today. To reduce existing environmental burdens of litter, clean-up events have increased in popularity. Here, we report on the results of the Clean Shores, Great Lakes project, in which we conducted 69 volunteer-based clean-ups along the Tanzanian shorelines of the African Great Lakes (Victoria, Tanganyika, and Nyasa (also known as Lake Malawi)). A total of 5483 volunteers engaged with the project across all clean-up sites, collecting 431,328 pieces (25,981 kg) of anthropogenic litter. Expressing the data as normalized to area (items m−2) or effort (items individual−1 h−1) revealed that the interpretation of a polluted site varies with units, highlighting the need for consistency in the field. Litter density varied from 0.06 to 13.89 items m−2 and 5.2–706 items individual−1 h−1. Plastics were the major litter type constituting 75% of all litter (mean = 74.2 ± 12.5% across all sites), while clothing (10.9 ± 9.5%) and fishing gear (3.7 ± 5.2%) were also prevalent. Two items constituted > 40% of all collected litter, namely plastic beverage bottles (average 23.7 ± 17.1%, range 0–72.9%) and plastic bags (average 19.7 ± 13.2%, range 1–50.3%). Prioritizing intervention measures on these two items could reduce litter leakage significantly. Furthermore, a holistic approach was undertaken through voluntary engagement, citizen science involvement, stakeholder dissemination, and school visits to increase public awareness. Clean-up data when disseminated to relevant policymakers and stakeholders can motivate activity for the environmental management of anthropogenic litter and plastic pollution.

• Khan, Farhan R.; Rødland, Elisabeth Støhle; Kole, Pieter Jan; Belleghem, Frank G.A.J. Van; Jaén-Gil, Adrián & Hansen, Steffen Foss [Show all 7 contributors for this article] (2024). An overview of the key topics related to the study of tire particles and their chemical leachates: From problems to solutions. TrAC. Trends in analytical chemistry. ISSN 0165-9936. 172. doi: 10.1016/j.trac.2024.117563. Full text in Research Archive Show summary

  The environmental contamination and biological impacts of tire particles and their associated chemicals is of great concern. Variously termed as tire wear particles (TWP), tire and road wear particles (TRWP), and end-of-life tires (ELTs) to differentiate between possible compositions and sources in the environment, these rubber particles are a major source of plastic pollution. The array of added chemicals that leach into the environment presents an additional environmental, toxicological and regulatory challenge. In this review, we define several topic areas that are relevant to the study of tire particles, outlining the current state and ongoing challenges. Emissions estimates needed to establish environmental loads are based on dated, summarized datasets rather than measured data, but determining the environmental presence of tire particles is hampered by a lack of standardised sampling methods. Several techniques for the analysis of tire rubber and associated chemicals are available, but the variability in tires model composition makes the selection of analytical markers challenging, as does a lack of commercial standards. Toxicologically, there remains a need to delineate particle and leachate effects and, in addition, to investigate emerging chemicals of concern and their transformation products. Such knowledge is required to feed into regulatory processes which currently regulate tire constituents separately rather than as the whole tire. Technological solutions to capture or replace tire rubber are progressing, often outside of academia, and it is important that the scientific community collaborate with those attempting to reduce the environmental impact of tires, including the tire industry.

• Snekkevik, Vilde Kloster; Cole, Matthew; Gomiero, Alessio; Haave, Marte; Khan, Farhan R. & Lusher, Amy L. (2024). Beyond the food on your plate: Investigating sources of microplastic contamination in home kitchens. Heliyon. 10(15). doi: 10.1016/j.heliyon.2024.e35022. Full text in Research Archive Show summary

  Given that a substantial amount of time is spent in kitchens preparing food, the kitchen equipment used may be relevant in determining the composition and amount of microplastics ending up on our dinner plate. While previous research has predominantly focused on foodstuffs as a source of microplastics, we emphasise that micro- and nanoplastics are ubiquitous and likely originate from diverse sources. To address the existing knowledge gap regarding additional sources contributing to microplastics on our dinner plates, this review investigates various kitchen processes, utensils and equipment (excluding single-use items and foodstuffs) to get a better understanding of potential microplastic sources within a home kitchen. Conducting a narrative literature review using terms related to kitchenware and kitchen-affiliated equipment and processes, this study underscores that the selection of preparation tools, storage, serving, cooking, and cleaning procedures in our kitchens may have a significant impact on microplastic exposure. Mechanical, physical, and chemical processes occurring during food preparation contribute to the release of microplastic particles, challenging the assumption that exposure to microplastics in food is solely tied to food products or packaging. This review highlights diverse sources of microplastics in home kitchens, posing concerns for food safety and human health.

• Aanesen, Margrethe; Ahi, Julide Ceren; Abate, Tenaw Gedefaw; Khan, Farhan R.; Vries, Frans P. de & Kite-Powell, Hauke [Show all 7 contributors for this article] (2024). Insights from international environmental legislation and protocols for the global plastic treaty. Scientific Reports. 14(1). doi: 10.1038/s41598-024-53099-9. Full text in Research Archive Show summary

  Plastic pollution has emerged as a global challenge necessitating collective efforts to mitigate its adverse environmental consequences. International negotiations are currently underway to establish a global plastic treaty. Emphasizing the need for solution-orientated research, rather than focusing on further defining the problems of widespread environmental occurrence and ecological impacts, this paper extracts insights and draws key patterns that are relevant for these international negotiations. The analysis reveals that (i) environmental rather than human health concerns have been the predominant driving force behind previous regulations targeting pollutants, and (ii) the decision to ban or discontinue the use of harmful pollutants is primarily affected by the availability of viable substitutes. These two key findings are relevant to the discussions of the ongoing Intergovernmental Negotiating Committee (INC) on the global plastic treaty and underscore the recognition of environmental consequences associated with plastic pollution while emphasizing the need to enhance the knowledge base of potential human health risks. Leveraging the availability of substitutes can significantly contribute to the development and implementation of effective strategies aimed at reducing plastic usage and corresponding pollution.

• Obanya, Henry E.; Khan, Farhan R.; Carrasco-Navarro, Victor; Rødland, Elisabeth Støhle; Walker-Franklin, Imari & Thomas, Jomin [Show all 21 contributors for this article] (2024). Priorities to inform research on tire particles and their chemical leachates: A collective perspective. Environmental Research. ISSN 0013-9351. 263(3). doi: 10.1016/j.envres.2024.120222. Full text in Research Archive Show summary

  Concerns over the ecological impacts of urban road runoff have increased, partly due to recent research into the harmful impacts of tire particles and their chemical leachates. This study aimed to help the community of researchers, regulators and policy advisers in scoping out the priority areas for further study. To improve our understanding of these issues an interdisciplinary, international network consisting of experts (United Kingdom, Norway, United States, Australia, South Korea, Finland, Austria, China and Canada) was formed. We synthesised the current state of the knowledge and highlighted priority research areas for tire particles (in their different forms) and their leachates. Ten priority research questions with high importance were identified under four themes (environmental presence and detection; chemicals of concern; biotic impacts; mitigation and regulation). The priority research questions include the importance of increasing the understanding of the fate and transport of these contaminants; better alignment of toxicity studies; obtaining the holistic understanding of the impacts; and risks they pose across different ecosystem services. These issues have to be addressed globally for a sustainable solution. We highlight how the establishment of the intergovernmental science-policy panel on chemicals, waste, and pollution prevention could further address these issues on a global level through coordinated knowledge transfer of car tire research and regulation. We hope that the outputs from this research paper will reduce scientific uncertainty in assessing and managing environmental risks from TP and their leachates and aid any potential future policy and regulatory development.

• Nchimbi, Amina Asiya; Shilla, Daniel Abel; Kosore, Charles Mitto; Shilla, Dativa Joseph; Shashoua, Yvonne & Sørensen, Christina [Show all 7 contributors for this article] (2024). Microplastic pollution in the Thumbprint emperor (Lethrinus harak) from Tanzanian coastal waters: Occurrence, abundance, characterization, and relevance as a monitoring species. Regional Studies in Marine Science. 76. doi: 10.1016/j.rsma.2024.103600. Full text in Research Archive Show summary

  In the present study we collected the Thumbprint emperor (Lethrinus harak) from seven landing sites from the coastal waters around Dar es Salaam and Zanzibar (Tanzania) to (i) quantify and characterize microplastics (MPs) in their digestive tracts and (ii) use previously assessed environmental levels in nearshore surface waters and seabed sediments to determine whether L. harak could be a relevant biomonitor for MP pollution in the region. L. harak (n=387) had an overall frequency of occurrence (FO%) of 48 % and displayed spatial variation between sites with Kunduchi (FO=66.7 %) and Mijimwena (FO=17.1 %) having the highest and lowest FO%, respectively. Fish from Mjimwema had a mean MP content of 0.17 ± 0.38 MPs individual-1 whilst fish from Kizimkazi had the highest MP abundance (1.75 ± 2.33 MPs individual-1). Fibers (overall 64.7 %, range across sites 48–86 %) and fragments (17.9 %, 5–25 %) were the most dominant MP types whilst black (46.9 %, 40–58 %) and blue (22.5%, 7–36 %) MPs were the most common colours. Fish length (ρ= -0.09, p=0.09) or weight (ρ=0.07, p=0.18) did not significantly correlate to MP abundance in fish (Spearman rank correlations). Neither MP occurrence nor abundance was linked to MP concentrations in either surface waters or seabed sediments (Spearman rank correlation), but MPs in the fish better reflected MPs in the sediment compared to surface water (two-way ANOVA on ranked data). Whilst L. harak presents as a promising candidate to monitor MP pollution along the East African coast due to its ecology, overall, it lacks reliability. Nonetheless, the present study fills important knowledge gaps both geographically on the East African Coast and with an underrepresented taxonomic family (Lethrinidae ‘Emporer fishes’).

• Mbugani, John J.; Shilla, Daniel A.; Kimaro, Wahabu; Shilla, Dativa Joseph & Khan, Farhan R. (2024). Effect of Microplastic Exposure to the Reproductive Energy and Fecundity of Female Wami Tilapia (Oreochromis urolepis, Norman 1922) Fish. Environmental Quality Management. ISSN 1088-1913. 34(2). doi: 10.1002/tqem.22330. Full text in Research Archive Show summary

  There is mounting evidence indicating that microplastics (MPs, < 5 mm) cause reproductive dysfunction in fish, yet information on the long-term effects of MP exposure remains scarce. In this study, Wami tilapia fries were exposed to 38–45 µm polyethylene (PE) MPs for their first 2 months in treatment groups of control (0 PE MPs/mL), 1, 10, and 100 PE MPs/mL (with 60 individuals per group in triplicates), and subsequently maintained in a ratio of 3 females to 1 male for an additional 5 months. Reproductive proxies and parameters of female fish health were calculated, and models were developed according to the Akaike information criterion (AIC) and no significant differences in fecundity, relative fecundity, hepatosomatic index (HSI), weight, length, gonadosomatic index, and oocyte packing density were found between treatment groups (one-Way ANOVA, p > 0.05). However, condition factors varied significantly between treatment groups (Kruskal–Wallis Test, p = 0.006), with the control group differing significantly from the groups exposed to 1 PE MPs/mL (p = 0.007), 10 PE MPs/mL (p = 0.03), and 100 PE MPs/mL (p = 0.001). Fecundity showed strong correlations with weight and length in all treatment groups except the group exposed to 10 PE MPs/mL (weight: r = 0.471, p = 0.346; length: r = 0.688, p = 0.131) and showed insignificant correlations with condition factors and HSI. Multiple regression models revealed that weight significantly contributed to fecundity in all treatment groups except the group exposed to 10 PE MPs/mL. Histopathological analysis indicated damage to livers and small intestines proportional to the dose of PE MPs. This study demonstrates that long-term exposure of fish to MPs has no significant effect on fecundity but impairs fish health, which could potentially jeopardize the quality of fish eggs and recruitment.

• Khan, Farhan R.; Oliveria, Miguel; Walker, Tony R.; Panti, Cristina & Hardiman, Gary (2023). Ecotoxicological Impacts of Micro(Nano)plastics in the Environment: Biotic and Abiotic Interactions. Microplastics. 2(3), p. 218–218. doi: 10.3390/microplastics2030017. Full text in Research Archive Show summary

  Plastic and microplastic pollution is a complex, muti-faceted challenge that has engaged a broad alliance of stakeholder groups who are concerned with environmental, biotic and human health [...]

• Helal, Mohamed; Hartmann, Nanna B.; Khan, Farhan & Xu, Elvis Genbo (2023). Time to integrate “One Health Approach” into nanoplastic research. Eco-Environment & Health. ISSN 2772-9850. 2(1), p. 18–20. doi: 10.1016/j.eehl.2023.01.001. Full text in Research Archive Show summary

  • High heterogeneity and small size make nanoplastics a challenging issue. • The One Health Approach is particularly relevant for nanoplastic research. • Current limitations in nanoplastic research should not hinder mitigation strategies. • Integrating nanoplastic data on humans, animals, and the environment is critical.

• Clark, Nathaniel J.; Khan, Farhan R.; Crowther, Charlotte; Mitrano, Denise & Thompson, Richard C. (2023). Uptake, distribution and elimination of palladium-doped polystyrene nanoplastics in rainbow trout (Oncorhynchus mykiss) following dietary exposure. Science of the Total Environment. ISSN 0048-9697. 854. doi: 10.1016/j.scitotenv.2022.158765. Full text in Research Archive Show summary

  The ingestion of nanoplastics (NPs) by fish has led to concerns regarding fish health and food chain transfer, but analytical constraints have hindered quantitative data collection on their uptake and depuration. We used palladium-doped polystyrene nanoplastics (PS-Pd NPs, ~200 nm) to track particle fate in rainbow trout (Oncorhynchus mykiss) during a week-long dietary exposure and subsequent 7-day depuration period on a control diet (no added PS-Pd NPs). At Day 3 and 7 of the exposure, and after depuration, the mid intestine, hind intestine, liver, gallbladder, kidney, gill and carcass were sampled. All organs and the carcass were analysed for total Pd content by inductively couple plasma mass spectrometry. After 3 days of exposure, the mid (32.5 ± 8.3 ng g−1) and hind (42.3 ± 8.2 ng g−1) intestine had significantly higher total Pd concentrations compared to the liver and carcass (1.3 ± 0.4 and 3.4 ± 1.1 ng g−1, respectively). At Day 7, there was no time-related difference in any organ (or the carcass) total Pd concentrations compared to Day 3. When the total Pd content was expressed as a body distribution based on mass of tissue, the carcass contained the highest fraction with 72.5 ± 5.2 % at Day 7, which could raise concerns over transfer to higher trophic levels. The total number of particles that entered the fish over the 7 days was 94.5 ± 13.5 × 106 particles, representing 0.07 ± 0.01 % of the Pd the fish had been fed. Following depuration, there was no detectable Pd in any organ or the carcass, indicating clearance from the fish. These data indicate that these NPs are taken into the internal organs and carcass of fish, yet removal of the exposure results in substantial excretion to below the limit of detection.

• KeChi-Okafor, Chimdia; Khan, Farhan R.; Al-Naimi, Usama; Béguerie, Victor; Bowen, Libby & Gallidabino, Matteo D. [Show all 8 contributors for this article] (2023). Prevalence and characterisation of microfibres along the Kenyan and Tanzanian coast. Frontiers in Ecology and Evolution. 11. doi: 10.3389/fevo.2023.1020919. Full text in Research Archive Show summary

  Microplastic pollution is ubiquitous, with textiles being a major source of one of the dominant microplastic types—microfibres. Microfibres have been discovered in the aquatic environment and marine biota, demonstrating direct infiltration in the environment. However, the impact of non-plastic microfibres has been overlooked until recently despite their prevalence and the ecotoxicological risk posed by chemical dyes and finishes used during processing. During an expedition from Lamu to Zanzibar (East Africa), a citizen science strategy was employed to innovate, educate and influence microfibre pollution reform through the Flipflopi project, a circular economy effort to stop the use of single-use plastic. Simple sampling methods were developed to replace costly equipment, which local citizens could use to partake in the collection and sampling of surface water samples from the previously understudied Kenyan and Tanzanian coast. To maintain the reliability of samples and to minimise contamination, a forensic science strategy was embedded throughout the methodology of the study, collection and analysis of the samples. A total of 2,403 microfibres from 37 sites were recovered and fully characterised with 55% found to be of natural origin, 8% regenerated cellulosic and 37% synthetic microfibres. Natural microfibres were in higher abundance in 33 of the 37 sampled sites. Congruent with recent studies, these findings further support the need for greater understanding of the anthropogenic impact of natural microfibres.

• Kosore, Charles Mitto; Ojwang, Loice; Maghanga, Justin; Kamau, Joseph; Shilla, Daniel & Everaert, Gert [Show all 8 contributors for this article] (2022). Microplastics in Kenya's marine nearshore surface waters: Current status. Marine Pollution Bulletin. ISSN 0025-326X. 179. doi: 10.1016/j.marpolbul.2022.113710. Full text in Research Archive Show summary

  Microplastics (MPs) were collected at six locations along Kenya's marine nearshore surface waters using a 300 μm mesh-size manta net. The samples were washed over a 125-μm mesh size sieve No.120 into a glass jar and preserved in 70% ethanol. MPs were sorted, counted visually under a dissecting microscope then identified using attenuated total reflection Fourier transform infrared (ATR-FTIR) spectroscopy. A total of 1473 particles with an overall mean concentration of 0.58 ± 1.29 MPs m−3, were collected. Fragments were the most common types representing 55% of the total MPs, followed by films (40%) and fibers (2%). Polypropylene (PP) was dominant (52%), high-density polyethylene (HDPE) comprised 38% and low density polyethylene (LDPE) 10% of the total MPs. This study provided baseline information, in which Malindi was identified as a hot spot for MPs pollution. Furthermore, the outcomes will assist policy formulations and management strategies aimed at controlling marine plastics.

• Mbugani, John J.; Machiwa, John F.; Shilla, Daniel Abel; Kimaro, Wahubu; Joseph, Dativa & Khan, Farhan R. (2022). Histomorphological Damage in the Small Intestine of Wami Tilapia (Oreochromis urolepis) (Norman, 1922) Exposed to Microplastics Remain Long after Depuration. Microplastics. 1(2), p. 240–253. doi: 10.3390/microplastics1020017. Full text in Research Archive Show summary

  The histopathological effects of microplastics (MPs) in the gastrointestinal tracts of fish following long-term exposure and depuration are relatively understudied. This study investigated histomorphological damage in the small intestine of Oreochromis urolepis larvae following 65 d exposure to 38–45 μm of polyethylene microspheres (PE MPs) and after a recovery period of 60 d. Larval fish were assigned to each treatment group (control, 1, 10 and 100 PE MPs), where ingestion and degenerative changes in the small intestine were examined using a routine hematoxylin and eosin staining technique. The results highlighted significant PE MPs ingestion and retention proportional to exposure dose (χ2 = 49.54; df = 2). Villi height and width and epithelial cell height were significantly affected and differed between treatment groups. Indices of damage to the small intestine organ (χ2 = 47.37; df = 2; p < 0.05) and reaction patterns of villi, epithelial, goblet and cryptic glandular cells, leucocytic infiltration and blood congestion revealed significant occurrence of alteration as PE MPs exposure dose increased. After the recovery period, no PE MPs were observed, and villi height, width and epithelial cells showed recovery with no significant difference between treatment groups. Organ indices declined (χ2 = 12; df = 2; p < 0.05) but remained significantly different between treatment groups, largely due to leucocytic infiltration (χ2 = 9.08; df = 2; p < 0.05). The study demonstrated that microplastics induced small intestinal wall degeneration, but recovery in young fish occurred slowly. The damage likely compromised its digestive function, which may affect growth and reproduction. This requires further research.

• Mbugani, John J.; Machiwa, John F.; Shilla, Daniel Abel; Joseph, Dativa; Kimaro, Wahubu & Khan, Farhan R. (2022). Impaired Growth Performance of Wami Tilapia Juveniles (Oreochromis urolepis) (Norman, 1922) Due to Microplastic Induced Degeneration of the Small Intestine. Microplastics. 1(3), p. 334–345. doi: 10.3390/microplastics1030025. Full text in Research Archive Show summary

  Microplastics-induced histopathological changes in gastrointestinal tracts of fish have been widely reported. However, the translation of adverse effects in the gut to impacts on growth are understudied. This study investigated the effect of MP-induced small intestinal histomorphological changes on growth performance of Oreochromis urolepis juveniles. Sixty larvae were exposed in control (0), 1, 10, and 100 polyethylene microplastic particles (PE MPs)/mL treatment groups. On day 65, juveniles were euthanized, dissected, and biometric data were taken. Small intestine histomorphological lesion index (HLI) was calculated following histological preparation using routine hematoxylin and eosin procedure. Results showed increase in HLI proportional to PE MPs exposure dose. These deteriorations equally reduced growth in final weight, weight gain and total length (One-Way ANOVA, p > 0.05), and Specific Growth Rate (SGR) (Kruskal–Wallis Test, p > 0.05), though there were insignificant differences between treatment groups. Condition factors of fishes in control and 1 PE MPs differed significantly and with other treatment groups (Tukey HSD, p < 0.05). Small intestines HLI correlated significantly with growth pattern (Spearman, r = 1.00, p = 0.01), condition factors (Pearson, r = −0.995, p < 0.05), final weight, weight gain, and total length (Spearman, r = −1.00, p = 0.01) but not with SGR. The allometric growth pattern changed towards isometric corresponding to increasing HLI. These findings suggest that MPs damaged small intestine structure and thus impaired digestion and nutrients absorption functions which disrupted growth. Such effects may impair juveniles’ ability to escape enemies, find food, and eventually reproduce, and therefore require further study.

• Trudsø, Louise Lynn; Nielsen, Maria Bille; Hansen, Steffen Foss; Syberg, Kristian; Kampmann, Kristoffer & Khan, Farhan [Show all 7 contributors for this article] (2022). The need for environmental regulation of tires: Challenges and recommendations. Environmental Pollution (1987). ISSN 0269-7491. 311. doi: 10.1016/j.envpol.2022.119974. Full text in Research Archive Show summary

  The interest in tire wear particles (TWPs), generated from abrasion of tires, have gained traction over the past few years, both in regards to quantifying particulate emissions, leaching of different compounds, toxicity, and analytical methods. The life of a tire, from cradle to end-of-life, crosses over different scenarios during its lifetime and transcends environmental compartments and legislative areas, underlining the need for a collective approach. Sustainability for a tire encompasses the use of raw materials, recycling of raw materials, circular economy and material sourcing. The tire industry is currently making significant efforts towards a greener and more sustainable production considering reduction of CO2-emissions, recycling, material sources and implementing the use of biomass from plants rather than oil-derived alternatives. In this paper, we aim to analyze and discuss the need for environmental regulation of tires in order to provide a series of targeted recommendations for future legislation. Our study shows that the numerous regulations related to tires focus on chemicals, manufacturing, raw materials, use of tires on roads, waste handling, safety and polycyclic aromatic hydrocarbons (PAHs) in different life cycle stages of a tire. However, none directly addresses the contribution of TWPs to the environment. Despite the overall good intentions of the existing regulations, there is a lack of focus on the compounds that partition from the tire and disperse in the environment, their mixture effects, and the transformative products from the parent compounds in the environment. Therefore, a renewed focus is needed on risk assessment of complex mixtures like TWPs. Thus, transparency in regard to use of chemicals in TWP, mixtures, minimization of emissions, and capture of particulate pollution should be a priority.

• Nchimbi, Amina Asiya; Kosore, Charles Mitto; Oduor, Nancy; Shilla, Dativa Joseph; Shashoua, Yvonne & Khan, Farhan [Show all 7 contributors for this article] (2022). Microplastics in Marine Nearshore Surface Waters of Dar es Salaam and Zanzibar, East Africa. Bulletin of Environmental Contamination and Toxicology. ISSN 0007-4861. 109, p. 1037–1042. doi: 10.1007/s00128-022-03620-5. Full text in Research Archive Show summary

  Limited information exists on the occurrence of microplastics (MPs) in East African coastal waters. A 300 μm manta net was used to collect surface water from 8 sites in the regions Dar es Salaam (DES) and Zanzibar (ZZ) during low and high tides. DES had a higher (p < 0.05) abundance of MPs than ZZ. Fragments and fibers were the dominant MP types at all sites. The number of fibers was significantly higher (p = 0.002) in DES than in ZZ. MPs were more prevalent during high tide in both DES and ZZ. The MPs within the 2–5 mm size range were identified most often. White and blue MPs were the most common in study sites comprising 45% and 18% of the total MPs respectively. Three polymers polypropylene (PP) high-density polyethylene (HDPE) and low-density polyethylene (LDPE) were identified. The occurrence of MPs in nearshore waters of DES and ZZ is probably due to their proximity to industrial areas, poor solid waste management, and high population pressure.

• Nchimbi, Amina Asiya; Shilla, Daniel Abel; Kosore, Charles Mitto; Shilla, Dativa Joseph; Shashoua, Yvonne & Khan, Farhan (2022). Microplastics in marine beach and seabed sediments along the coasts of Dar es Salaam and Zanzibar in Tanzania. Marine Pollution Bulletin. ISSN 0025-326X. 185. doi: 10.1016/j.marpolbul.2022.114305. Full text in Research Archive Show summary

  Microplastics (MPs) pollution in the marine environment has been one of the biggest challenge in developing countries due to a lack of proper solid waste management strategies. This study reports the distribution and types of MPs in beach and seabed zones of the Dar es Salaam and Zanzibar coasts. A total of 641 MPs were identified across all sites, of which 84 % and 16 % originated from beach and seabed sediments, respectively. Fragment and fibers were the most common types in both seabed and beach zone confirming the secondary sources of the MPs. Attenuated Total Reflection Fourier Transform Infrared (ATR-FTIR), revealed four types of polymers with polyethylene (PE) (56%) and polyester (PS) (24 %) being the most common. Microplastics were more abundant on beaches than in seabed zone. A larger abundance of PE and PS reveals a wide range of MPs entering the Ocean.

• Khan, Farhan; Catarino, Ana I. & Clark, Nathaniel J. (2022). The ecotoxicological consequences of microplastics and co-contaminants in aquatic organisms: a mini-review. Emerging Topics in Life Sciences. ISSN 2397-8562. 6(4), p. 339–348. doi: 10.1042/ETLS20220014. Full text in Research Archive Show summary

  Microplastics (MPs, <5 mm in size) are a grave environmental concern. They are a ubiquitous persistent pollutant group that has reached into all parts of the environment — from the highest mountain tops to the depths of the ocean. During their production, plastics have added to them numerous chemicals in the form of plasticizers, colorants, fillers and stabilizers, some of which have known toxicity to biota. When released into the environments, MPs are also likely to encounter chemical contaminants, including hydrophobic organic contaminants, trace metals and pharmaceuticals, which can sorb to plastic surfaces. Additionally, MPs have been shown to be ingested by a wide range of organisms and it is this combination of ingestion and chemical association that gives weight to the notion that MPs may impact the bioavailability and toxicity of both endogenous and exogenous co-contaminants. In this mini-review, we set the recent literature within what has been previously published about MPs as chemical carriers to biota, with particular focus on aquatic invertebrates and fish. We then present a critical viewpoint on the validity of laboratory-to-field extrapolations in this area. Lastly, we highlight the expanding ‘microplastic universe’ with the addition of anthropogenic particles that have gained recent attention, namely, tire wear particles, nanoplastics and, bio-based or biodegradable MPs, and highlight the need for future research in their potential roles as vehicles of co-contaminant transfer.

• Mihai, Florin-Constantin; Gündoğdu, Sedat; Khan, Farhan; Olivelli, Arianna; Markley, Laura A. & Emmerik, Tim van (2022). Plastic pollution in marine and freshwater environments: abundance, sources, and mitigation. In Sarma, Hemen; Dominguez, Delfina C. & Lee, Wen-Yee (Ed.), Emerging Contaminants in the Environment: Challenges and Sustainable Practices. Elsevier. ISSN 9780323851602. p. 241–274. doi: 10.1016/B978-0-323-85160-2.00016-0. Full text in Research Archive Show summary

  Macro- and microplastics are critical emerging pollutants found in marine and freshwater environments around the world. Plastic consumption supported by a linear economy combined with exportation of plastic packaging materials to countries with deficient solid waste management practices causes massive plastic pollution in low and middle-income countries. This chapter examines the causes, distribution, and impacts of macroplastic and microplastic pollutants, each with particular characteristics in marine and freshwater environments in different parts of the world. The geographical dimension of plastic pollution is revealed and the impacts on natural habitats and human settlements are highlighted. This chapter provides an overview of environmental plastic abundance, sources and mitigation strategies. The circular economy is further presented as a key mitigation strategy in the prevention of plastics materials in the environment, improvement of the production sector, and providing better waste management practices to reduce this global environmental threat.

• Clark, Nathaniel J.; Khan, Farhan; Mitrano, Denise; Boyle, David & Thompson, Richard C. (2022). Demonstrating the translocation of nanoplastics across the fish intestine using palladium-doped polystyrene in a salmon gut-sac. Environment International. ISSN 0160-4120. 159. doi: 10.1016/j.envint.2021.106994. Full text in Research Archive Show summary

  Fish are widely reported to ingest microplastics with low levels accumulating in the tissues, but owing to analytical constraints, much less is known about the potential accumulation of nanoplastics via the gut. Recently, the labelling of plastics with inorganic metals (e.g., palladium) has allowed measurements of nanoplastic uptake. The aim of the current study was to quantitatively assess the uptake of nanoplastics by the fish gut using palladium-doped nanoplastics (with a mean hydrodynamic radius of 202 ± 7 nm). By using an ex vivo gut sac exposure system, we show that in 4 h between 200 and 700 million nanoplastics (representing 2.5–9.4% of the administered nanoplastics dose) can enter the mucosa and muscularis layers of the intestine of salmon. Of the particles taken up, up to 700,000 (representing 0.6% of that taken into the tissue) of the nanoplastics passed across the gut epithelium of the anterior intestine and exit into the serosal saline. These data, generated in highly controlled conditions provide a proof-of-concept study, suggesting the potential for nanoplastics to distribute throughout the body, indicating the potential for systemic exposure in fish.

• Stöfen-O′Brien, Aleke; Naji, Abolfazl; Brooks, Amy L.; Jambeck, Jenna R. & Khan, Farhan (2022). Marine plastic debris in the Arabian/Persian Gulf: Challenges, opportunities and recommendations from a transdisciplinary perspective. Marine Policy. ISSN 0308-597X. 136. doi: 10.1016/j.marpol.2021.104909. Full text in Research Archive Show summary

  In recent years, the amount of plastic waste entering the marine environment around the world has gained increasing attention. Yet certain areas and regions remain relatively undocumented. Research findings on this topic within the countries adjacent to the Arabian/Persian Gulf comprised of Iran, Iraq, Bahrain, Saudi Arabia, Kuwait, Qatar, Oman and the United Arab Emirates is relatively sparse. Significant gaps remain regarding the precise details on the quantity, sources and impacts of plastic marine debris as well as appropriate management responses. This article addresses these shortcomings from a transdisciplinary perspective, drawing on science, engineering and law. Based on an analysis and overview of the scientific research on plastic pollution in the region, an estimate of mismanaged waste is developed, both on a national level as well as for selected coastal cities. The article then explores the applicable international and regional regulatory framework to address marine debris in the Arabian/Persian Gulf region. It provides one of the first accounts of this regional sea from a comprehensive marine litter regulatory perspective, incorporating scientific findings as well as modelling techniques. The article suggests possible ways to achieve synergies and cooperation among actors and proposes novel approaches on methods to address the problem with a view to the transboundary nature of the issue. The key to success lies in dedicated cooperative efforts within the region, both between the public and private sector and between government and civil society.

• Mihai, Florin-Constatin; Gündoğdu, Sedat; Markley, Laura A.; Olivelli, Arianna; Khan, Farhan & Gwinnett, Claire [Show all 15 contributors for this article] (2022). Plastic Pollution, Waste Management Issues, and Circular Economy Opportunities in Rural Communities. Sustainability. 14(1). doi: 10.3390/su14010020. Full text in Research Archive Show summary

  Rural areas are exposed to severe environmental pollution issues fed by industrial and agricultural activities combined with poor waste and sanitation management practices, struggling to achieve the United Nations’ Sustainable Development Goals (SDGs) in line with Agenda 2030. Rural communities are examined through a “dual approach” as both contributors and receivers of plastic pollution leakage into the natural environment (through the air–water–soil–biota nexus). Despite the emerging trend of plastic pollution research, in this paper, we identify few studies investigating rural communities. Therefore, proxy analysis of peer-reviewed literature is required to outline the significant gaps related to plastic pollution and plastic waste management issues in rural regions. This work focuses on key stages such as (i) plastic pollution effects on rural communities, (ii) plastic pollution generated by rural communities, (iii) the development of a rural waste management sector in low- and middle-income countries in line with the SDGs, and (iv) circular economy opportunities to reduce plastic pollution in rural areas. We conclude that rural communities must be involved in both future plastic pollution and circular economy research to help decision makers reduce environmental and public health threats, and to catalyze circular initiatives in rural areas around the world, including less developed communities.

• Naji, Abolfazl; Azadkhah, Sharifeh; Farahani, Hadi; Uddin, Saif & Khan, Farhan (2021). Microplastics in wastewater outlets of Bandar Abbas city (Iran): A potential point source of microplastics into the Persian Gulf. Chemosphere. ISSN 0045-6535. 262, p. 1–8. doi: 10.1016/j.chemosphere.2020.128039. Full text in Research Archive Show summary

  Wastewater discharge is considered to be a significant point source of microplastic (MPs) release into the marine environment. This study is the first attempt to quantify MPs released from the wastewater outfall from Bandar Abbas City into the Persian Gulf. Two wastewater discharge stations at Gursuzan and Suru were sampled. MPs were isolated by an oxidative procedure and subsequent density separation using ZnCl2 solution. The average MP concentration in wastewater and sludge were 70.66 (±14.12, SD) MP.35 L−1 and 6070 (±807.25) MPs.kg−1, respectively at Confidence Level (CL) (95.0%). The most commonly recovered polymers were polyethylene (PE) and polypropylene (PP) in all size classes. Our findings provides a baseline of MP concentration in wastewater streams and slurry that is discharged from the Bandar Abbas wastewater treatment facility into the Persian Gulf. This highlights the need to undertake more studies at water treatment plants in the region for a realistic assessment of MP discharge into the Persian Gulf.

• Halle, Louise L.; Palmqvist, Annemette; Kampmann, Kristoffer; Jensen, Anders; Hansen, Tobias & Khan, Farhan (2021). Tire wear particle and leachate exposures from a pristine and road-worn tire to Hyalella azteca: Comparison of chemical content and biological effects. Aquatic Toxicology. ISSN 0166-445X. 232, p. 1–9. doi: 10.1016/j.aquatox.2021.105769. Full text in Research Archive Show summary

  Tire emissions have emerged as an environmental contaminant of concern. To fully understand their effects to biota, research is needed from different stages of a tire’s lifecycle. In this study we exposed freshwater Hyalella azteca to tire wear particles (TWPs) as particle suspensions or their respective chemical leachates (the chemicals released from tire particles into water) from a pristine (P-TWP) and worn (W-TWP) tire of same make and model. Acute and long-term toxicity experiments on H. azteca showed that P-TWP suspensions were more toxic than W-TWP suspensions with estimated LC50 values of 364 ± 64 particles (0.19 ± 0.03 g L−1) and 3073 ± 211 particles (0.91 ± 0.06 g L−1), respectively. However, leachates from W- and P-TWPs appeared equally toxic, but did not conform to a sigmoidal dose-response pattern and LC50 values could not be derived. In long-term tests (21 d) P-TWP suspensions showed no significant effects on H. azteca mortality (p = 0.970) or reproduction (p = 0.123), but growth was significantly reduced (p = 0.003) at the highest concentration tested (250 particles mL−1 or 0.127 g L-1). Chemical analysis of both particle types and their leachates showed that four compounds, benzothiazole, 1-indanone, aluminum and zinc, consistently leached from TWPs into water. Analysis of the two TWPs showed a difference in the concentration of the various compounds. Specifically, P-TWPs contained significantly more 1-octanethiol, phenanthrene, anthracene and aluminum than W-TWPs, suggesting that they are possible candidates for the increased toxicity observed following P-TWP exposure.

• Khan, Farhan; Croft, Stephanie Storebjerg; Herrando, Elisa Escabia; Kandylas, Athanasios; Meyerjuergens, Tabea & Rayner, Dylan [Show all 8 contributors for this article] (2021). A Brief Perspective on Environmental Science in the Anthropocene: Recalibrating, Rethinking and Re-Evaluating to Meet the Challenge of Complexity. Environments. 8(10). doi: 10.3390/environments8100098. Full text in Research Archive Show summary

  A convincing case has been made that the scale of human activity has reached such pervasiveness that humans are akin to a force of nature. How environmental science responds to the many new challenges of the Anthropocene is at the forefront of the field. The aim of this perspective is to describe Anthropocene as a concept and a time period and discuss its relevance to the contemporary study of environmental science. Specifically, we consider areas in environmental science which may need to be revisited to adjust to complexity of the new era: (a) recalibrate the idea of environmental baselines as Anthropogenic baselines; (b) rethink multiple stressor approaches to recognize a system under flux; (c) re-evaluate the relationship of environmental science with other disciplines, particularly Earth Systems Science, but also social sciences and humanities. The all-encompassing nature of the Anthropocene necessitates the need to revise and reorganize to meet the challenge of complexity.

• Syberg, Kristian; Knudsen, Camilla M.H.; Tairova, Zhanna; Khan, Farhan R.; Shashoua, Yvonne & Geertz, Torsten [Show all 11 contributors for this article] (2020). Sorption of PCBs to environmental plastic pollution in the North Atlantic Ocean: Importance of size and polymer type. Case Studies in Chemical and Environmental Engineering (CSCEE). 2, p. 100062–100062. doi: 10.1016/j.cscee.2020.100062. Full text in Research Archive Show summary

  Plastic pollution is a great threat to the marine environment. Owing to its low density, a substantial fraction of plastic debris is transported across ocean surfaces by currents. Consequently, plastic debris has been concentrated in oceanic gyres such as the North Atlantic subtropical Gyre (NASG). This study presents data that describes plastic abundances and the concentrations of adhered PCBs (polychlorinated biphenyls) from 15 surface trawls conducted within and outside the NASG. Abundance of plastic pieces was significantly higher inside the gyre than outside supporting earlier findings about the importance of the gyres as accumulation zones for plastic debris. Concentrations of PCBs were comparable among different sizes fractions when measured per plastic piece but significantly higher on smaller pieces when measured per weight unit. Polyethylene pieces furthermore had higher concentrations of PCB than polypropylene pieces. These findings highlight the importance of accounting for particle size and polymer type when assessing sorbed contaminants to environmental plastic pollution.

• Syberg, Kristian; Palmqvist, Annemette; Khan, Farhan R.; Strand, Jakob; Vollertsen, Jes & Clausen, Lauge Peter Westergaard [Show all 13 contributors for this article] (2020). A nationwide assessment of plastic pollution in the Danish realm using citizen science. Scientific Reports. 10(1). doi: 10.1038/s41598-020-74768-5. Full text in Research Archive Show summary

  Abstract Plastic pollution is considered one of today’s major environmental problems. Current land-based monitoring programs typically rely on beach litter data and seldom include plastic pollution further inland. We initiated a citizen science project known as the Mass Experiment inviting schools throughout The Danish Realm (Denmark, Greenland and the Faeroe Islands) to collect litter samples of and document plastic pollution in 8 different nature types. In total approximately 57,000 students (6–19 years) collected 374,082 plastic items in 94 out of 98 Danish municipalities over three weeks during fall 2019. The Mass Experiment was the first scientific survey of plastic litter to cover an entire country. Here we show how citizen science, conducted by students, can be used to fill important knowledge gaps in plastic pollution research, increase public awareness, establish large scale clean-up activities and subsequently provide information to political decision-makers aiming for a more sustainable future.

• Khan, Farhan R. (2020). Prevalence, Fate and Effects of Plastic in Freshwater Environments: New Findings and Next Steps. Toxics. ISSN 2305-6304. 8(3), p. 72–72. doi: 10.3390/toxics8030072. Full text in Research Archive Show summary

  At a time when a global pandemic rightly holds our collective attention, environmental issues have taken a backseat to the ongoing battle against Covid-19. However, when normality resumes (or a new normal emerges), these environmental concerns will return to the fore and few issues are as tangible or emotive as plastic pollution. The presence of plastics in aquatic environments, particularly freshwater environments that are relied upon on a daily basis (e.g., for water and food supply, as well as recreation and tourism), is a constant reminder of the indelible mark that our species is leaving on the planet.

• Khan, Farhan R.; Shashoua, Yvonne; Crawford, Alex; Drury, Anna; Sheppard, Kevin & Stewart, Kenneth [Show all 7 contributors for this article] (2020). ‘The Plastic Nile’: First Evidence of Microplastic Contamination in Fish from the Nile River (Cairo, Egypt). Toxics. ISSN 2305-6304. 8(2), p. 22–22. doi: 10.3390/toxics8020022. Full text in Research Archive Show summary

  The presence of microplastics (MPs) in the world’s longest river, the Nile River, has yet to be reported. This small-scale study aimed to provide the first information about MPs in the Nile River by sampling the digestive tracts of two fish species, the Nile tilapia (Oreochromis niloticus, n = 29) and catfish (Bagrus bayad, n = 14). Fish were purchased from local sellers in Cairo, and then their gastrointestinal tracts were dissected and examined for MPs. Over 75% of the fish sampled contained MPs in their digestive tract (MP prevalence of 75.9% and 78.6% for Nile tilapia and catfish, respectively). The most abundant MP type was fibers (65%), the next most abundant type was films (26.5%), and the remaining MPs were fragments. Polyethylene (PE), polyethylene terephthalate (PET) and polypropylene (PP) were all non-destructively identified by attenuated total reflectance Fourier transform infrared spectroscopy. A comparison with similar studies from marine and freshwater environments shows that this high level of MP ingestion is rarely found and that fish sampled from the Nile River in Cairo are potentially among the most in danger of consuming MPs worldwide. Further research needs to be conducted, but, in order to mitigate microplastic pollution in the Nile River, we must act now.

• Halle, Louise L.; Palmqvist, Annemette; Kampmann, Kristoffer & Khan, Farhan R. (2020). Ecotoxicology of micronized tire rubber: Past, present and future considerations. Science of the Total Environment. ISSN 0048-9697. 706, p. 135694–135694. doi: 10.1016/j.scitotenv.2019.135694. Full text in Research Archive Show summary

  Micronized tire rubber has recently come into focus as black particles that are found in microplastic (MP) samples worldwide. These particles have been found in all environmental compartments with the most likely source being the abrasion of car tires on road surfaces. Thus, it is well founded that tires are a source of MPs and that tire abrasion is a primary source of anthropogenic particulates. Currently, the impact of tires has been viewed through the lens of particulate pollution together with MPs, but this is a relatively new direction for this topic. Previously ecotoxicological research into the environmental consequences of tires has primarily been related to the leached chemicals from tire particulates. This paper aims to (i) highlight similarities and differences of micronized rubber particles with the existing suite of polymer contaminants termed as ‘microplastics’ or ‘plastic debris’, (ii) survey the existing literature on environmental presence, fate, and interaction of micronized rubber particles with biota, and lastly (iii) present future research needs that require consideration in order to move this research area forward. Existing knowledge gaps that require attention include; determining the environmental presence and fate of micronized rubber within different environmental compartments, understanding the interaction of rubber particles with biota, particularly as potential impacts have so far been attributed solely to the leachate, and evaluating whether standard ecotoxicological protocols need to be adapted for particulate contaminants in general and specifically to suit rubber particulates and leachate.

• Mayoma, Bahati S; Sørensen, Christina; Shashoua, Yvonne & Khan, Farhan (2020). Microplastics in beach sediments and cockles (Anadara antiquata) along the Tanzanian coastline. Bulletin of Environmental Contamination and Toxicology. ISSN 0007-4861. 105, p. 513–521. doi: 10.1007/s00128-020-02991-x. Full text in Research Archive Show summary

  Little is known about the prevalence of microplastics (MPs) in East Africa. In the present study, sediments were sampled at 18 sites along the Tanzanian coast that exhibit different levels of anthropogenic activity and were extracted using floatation methodology. Cockles (Anadara antiquata) were collected only from eight sites and MPs were extracted following NaOH digestion. MPs were most abundant at Mtoni Kijichi Creek (MKC, 2972 ± 238 particles kg−1 dry sediment), an industrial port in Dar es Salaam, and significantly higher than all other sites where the abundance range was 15–214 particles kg−1 dry sediment (p < 0.05, one-way ANOVA). Fragments and fibers were found at all sites. Polypropylene and polyethylene were identified polymers. MPs were found in cockles from all sampled sites with both frequencies of occurrence and MPs per individual subject to site-specific variation. This study provides a baseline of MP data in a previously uninvestigated area.

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• Khan, Farhan R.; Rolsky, Charles; Catarino, Ana I. & Kelkar, Varun (2025). Microplastics Pollution in Aquatic Ecosystems: Challenges and Perspectives. Environments. 12(9), p. 315–315. doi: 10.3390/environments12090315. Full text in Research Archive Show summary

  Over the last 20 years, microplastics have emerged as a grave environmental concern owing to their ubiquitous presence and demonstrable toxic effects [...]

• Khan, Farhan R.; Molden, Nick & Booth, Andy M. (2025). As the “Wheels Come Off”, Including Tire Emissions in the Plastics Treaty Would Show Drive. Environmental Science and Technology. ISSN 0013-936X. doi: 10.1021/acs.est.5c13479. Full text in Research Archive Show summary

  Tire wear emissions are one of the biggest and most overlooked sources of microplastics pollution. If the Global Plastics Treaty leaves them out, it risks failing to meet its intended aims.

• Aanesen, Margrethe; Ahi, Julide Ceren; Abate, Tenaw G.; Khan, Farhan R.; Vries, Frans P. de & Kite-Powell, Hauke [Show all 7 contributors for this article] (2024). Correction to: Insights from international environmental legislation and protocols for the global plastic treaty (Scientific Reports, (2024), 14, 1, (2750), 10.1038/s41598-024-53099-9). Scientific Reports. 14(1). doi: 10.1038/s41598-024-57568-z. Full text in Research Archive
• Halsband, Claudia; Sørensen, Lisbet; Khan, Farhan R.; Herzke, Dorte & Wagner, Stephan (2023). Editorial: Environmental impacts and risks of car tire and styrene-butadiene rubber: microplastic pollution and contaminant transport. Frontiers in Environmental Science. 11. doi: 10.3389/fenvs.2023.1355263. Full text in Research Archive Show summary

  Every year, almost 2 billion new vehicle tires are produced world-wide. At the same time >1 billion tires reach their end of life. During use, tire wear particles (TWPs) form through abrasion of the rubber material, and in contact with the road surface composites of both materials form tire and road wear particles (TRWPs). These emissions represent a large fraction of total microplastic pollution, and thus a pressing environmental challenge that cannot be counteracted by “green” urbanization through the electrification of car, truck, and airplane fleets. In fact, heavier electric cars may emit even more TWPs and increase the frequency of tire replacements. In addition to TWPs and TRWPs, crumb rubber (CR) produced from end-of-life tires has been a popular low-cost product as infill on artificial grass for outdoor sports pitches, where it has become a substitute for natural grass, sand, or gravel, but is prone to runoff into the surrounding environment.

• Catarino, Ana Isabel; Asselman, Jana; Khan, Farhan R. & Everaert, Gert (2023). Editorial: Plastic pollution in a changing marine environment: effects and risk. Frontiers in Marine Science. 10. doi: 10.3389/fmars.2023.1213393. Full text in Research Archive
• Jaén-Gil, Adrián; Navrestad, Veslemøy; Andersen, Gidske Leknæs; Frapiccini, Emanuela; Santos, Lucia Helena & Khan, Farhan [Show all 7 contributors for this article] (2023). CHEMICAL DISTRIBUTION AND ECOTOXICOLOGICAL EFFECTS OF PLASTIC LEACHATES IN SOIL: A CASE STUDY OF LISLA LYNGØYNA ISLAND. Full text in Research Archive Show summary

  In the last decade, the environmental effects of plastic pollution in aquatic and terrestrial ecosystems have been reported worldwide, emphasizing the adverse effects of the generated microplastics after degradation under natural conditions. In particular, the distribution and accumulation of plastic waste at several sites along the West Coast of Norway have received special attention as “open lab” where large amounts of stranded marine litter have been buried over time and several ecological processes are still occurring. In this study, the occurrence and biological effects of the leachates generated from buried plastic waste on the so called Norwegian “plastic island” Lisla Lyngøyna have been investigated. Three soil layers have been collected at three different sampling sites containing high, medium, and low plastic pollution levels. The chemical composition of the leachates generated from soil samples was investigated using a chromatography system coupled to tandem mass spectrometry. The outcomes point out the occurrence of different type of additives in the investigated samples. The results of chemical analyses were compared with the ecotoxicity measurements on the same samples using standard testing based on Daphnia spp, Selenastrum spp and three plant seeds species. Overall, medium-to-absent toxicity was scored by the battery of adopted ecotoxicity bioassays. This study points out the need of an integrated chemical, ecotoxicological and ecological approach to define both the environmental risk and the appropriate action toward a sustainable management of plastic pollution.

• Khan, Farhan R.; Patsiou, Danae & Catarino, Ana I. (2021). Pollutants Bioavailability and Toxicological Risk from Microplastics. In Rocha-Santos, Teresa; Costa, Monica & Mouneyrac, Catherine (Ed.), Handbook of Microplastics in the Environment. Springer. ISSN 9783030106188. doi: 10.1007/978-3-030-10618-8_19-1. Full text in Research Archive Show summary

  Microplastics (MPs, <5 mm in size) are considered to be one of today’s major environmental problems. They are a ubiquitous persistent pollutant group that has reached into all parts of the environment – from the highest mountain tops to the lowest depths of the ocean. In their production, plastics have added to them a number of chemical additives in the form of plasticizers, colorants, fillers, and stabilizers, some of which with known toxicological effects to biota. When released into nature, MPs are also likely to encounter and sorb to their surfaces a variety of established pollutants including hydrophobic organic contaminants, trace metals, and pharmaceuticals. Importantly, MPs have been shown to be readily ingested by a wide range of organisms and it is this combination of biotic ingestion and chemical association that gives credence to the notion that MPs may impact the bioavailability and toxicity of both endogenous and exogenous pollutants. This chapter provides an overview of the literature that has examined the role of MPs as chemical carriers to biota, with particular focus on aquatic organisms. The influence and interactions of MPs with endogenous and exogenous chemicals are reviewed before a more critical view of the relative importance of MPs as pathway for chemical transfer is provided. Lastly, the current state of the literature is placed into context of the needs of risk assessment highlighting the challenges to assessing the risk of MPs as chemical vehicles.

• Halden, Rolf U.; Rolsky, Charles & Khan, Farhan (2021). Time: A Key Driver of Uncertainty When Assessing the Risk of Environmental Plastics to Human Health. Environmental Science and Technology. ISSN 0013-936X. doi: 10.1021/acs.est.1c02580. Full text in Research Archive Show summary

  The “shadow” of plastic pollution looms large over environmental and human health research, but time is an overlooked variable as we attempt to understand, assess and mitigate the adverse impacts of synthetic polymer ubiquity. Plastic debris has infiltrated the environment to a level where we find it in air, water, soil, and food; yet, we still have only a rudimentary understanding of how environmental plastics affect human health. Here, we argue that time is the principal but currently underappreciated determinant that is impeding a reliable assessment of human health risks posed by environmental plastics. Time changes plastics, impacting both their physicochemical properties and their role as environmental toxicants, thereby creating a barrier to performing reliable risk assessment (Figure1). However, the importance of time has yet to be realized and its impact integrated into the life-cycle and risk assessments of present-day plastic polymers.

• Gomiero, Alessio; Bødtker, Gunhild & Khan, Farhan R. (2025). A conceptual framework towards the risk assessment of plastic pollution. NORCE Research AS. ISSN 9788284084442. Full text in Research Archive Show summary

  Plastic pollution represents a pervasive, multifactorial environmental challenge with profound ecological, economic, and societal implications. Global plastic production exceeds 350 million metric tonnes annually, and inadequate waste management, fragmentation, and abrasion processes have resulted in widespread contamination by macro-, micro-, and nanoplastics across terrestrial, freshwater, and marine ecosystems. These particles act as both physical stressors and chemical vectors, introducing thousands of plastic-associated additives into the environment and sorbing existing environmental pollutants. Their persistence, heterogeneity, and capacity to interact with co-occurring stressors — including pathogens and resistance genes complicate remediation and necessitate integrated risk assessment approaches. This report introduces a Weight-of-Evidence (WoE) framework for ecological risk assessment (ERA) of plastic pollution, designed to synthesize heterogeneous data streams into a transparent and actionable Risk Index (RI). The framework aggregates four primary Lines of Evidence (LOEs): (1) chemical characterization of plastics and associated contaminants; (2) bioavailability of plastic-derived chemicals and pollutants; (3) sub-lethal stress biomarkers indicating physiological impairment; and (4) standardized laboratory bioassays assessing organism-level toxicity. Each LOE is evaluated through structured algorithms and hazard quotients, normalized and weighted to reflect ecological relevance. The composite RI enables prioritization of high-risk sites, supporting evidence-based management and policy decisions.

• Gomiero, Alessio; Gomes, Tânia; Michelangeli, M. Elisabetta; Almeida, Ana Catarina; Forsman, Emelie & Piarulli, Stefani [Show all 13 contributors for this article] (2024). Towards an environmental risk assessment of microplastic – Optimization of monitoring methods and test battery for ecotoxicology testing. NORCE Research AS. ISSN 9788284083711. Full text in Research Archive Show summary

  The project aimed to enhance Norway’s capacity to conduct microplastic (MP) toxicity assessments by standardizing testing methods and promoting collaboration among institutes. Assessing the biological effects of microplastics on marine organisms is essential for complementing existing plastic monitoring programs. While these programs effectively gather data on the occurrence of MPs across various environmental matrices, including biota, understanding the biological impacts may provide critical context in the future for interpreting data and formulate an effective environmental risk assessment. By examining how MPs affect the health and behaviour of marine species, we can identify potential ecological risks and inform management strategies aimed at mitigating plastic pollution. This integrated approach not only enhances our understanding of MP dynamics in marine ecosystems but also supports the development of evidence-based policies to protect marine life and preserve biodiversity. In this context, there is the necessity of a risk assessment framework which can be aligned with the efforts of achieving a Good Environmental Status (GES) assessment by defining threshold levels for MP exposure and identifying vulnerable marine species. Addressing data gaps highlighted by the Vitenskapskomitéen for Mat og Miljø (VKM, 2019), the Micro-Opt project aimed to strengthen Norway's role in global MP research supporting marine conservation and sustainable resource use. Through this collaboration, the MicroOpt consortium intended to support the combat of marine litter understanding its effects of organisms and thus aiming at protecting marine biodiversity.

• Khan, Farhan R.; Jaén-Gil, Adrián; Navrestad, Veslemøy; Tisserand, Amandine Aline & Gomiero, Alessio (2023). System for clearing marine litter from the seabed - pre-analysis and protocol: Analysis of the legacy of particle and chemical pollution from an underwater tire dump at Hjelmås, Alver Kommune (Norway). NORCE Research AS. Full text in Research Archive

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