Environment and Interdisciplinary Development

Correlation Between Microplastic Pollution and Potentially Toxic Elements in Surface Waters of the Southwestern Caspian Sea

Document Type : Original Article

Authors

Fereshteh Haji Aghaei Ghazi Mahalleh
Javid Imanpour Namin

Department of Fishery, Faculty of Natural Resource, University of Guilan, Sowmesara, Iran

https://doi.org/10.22034/envj.2025.520957.1498
Abstract
Introduction: Microplastic pollution and potentially toxic elements in aquatic environments pose significant environmental threats to marine ecosystems and human health. This study aimed to investigate the relationship between microplastic pollution and potentially toxic elements in the surface waters along the southwestern coasts of the Caspian Sea.
Materials and Methods: In this study, the elements arsenic (As), cadmium (Cd), cobalt (Co), chromium (Cr), copper (Cu), mercury (Hg), lead (Pb) and zinc (Zn) were selected due to their toxic potential, bioaccumulation ability and widespread presence in aquatic environments contaminated by industrial, agricultural and urban activities. To achieve this aim, sampling was conducted at three selected stations: Kiashahr, Anzali and Astara. These stations were chosen to assess the distribution and concentration of microplastics and potentially toxic elements in the region. For microplastic sampling in surface waters, a plankton net with a mesh size of 0.35 mm was used. The net was towed by a boat at a depth of 25 cm from the water surface at a constant speed of 5 km/h for 5 minutes. In the microplastic separation process, organic matter in the water samples was first digested using hydrogen peroxide (H₂O₂, 30%). Then, microplastics were separated from other suspended particles by density-based flotation in saturated NaCl solution. The concentrations of potentially toxic elements were measured using inductively coupled plasma mass spectrometry (ICP-MS). Data analysis was performed using SPSS version 27 at a 95% confidence level.
Results: The results showed that the highest mean concentrations of elements at the Kiashahr and Anzali stations were Cu > As > Hg and at the Astara station were As > Zn > Cu > Hg. The Anzali station showed the highest abundance of microplastics with 57.66 ± 5.50 particles per m³. The extracted microplastics were classified into two morphological types: fibres and fragments, appearing in six colors: blue, brown, red, transparent, black and green. Among them, blue was the dominant color with a frequency of 78%. The highest abundance of microplastics was observed in the size ranges of 4 to 5 mm and greater than 5 mm. FTIR-ATR spectroscopy identified four types of polymers in the microplastic samples: polyethylene, polypropylene, polyester and polystyrene, among which polyethylene was identified as the dominant polymer with the highest frequency.
Discussion: Comparison of the concentrations of potentially toxic elements against global standards revealed that the levels of the measured elements in the surface waters of the southwestern coasts of the Caspian Sea are generally within the established standard limits. However, the concentration of mercury in this region, considering the prohibition on discharging this element into marine ecosystems, exceeds the permissible environmental standards and pollution management principles. This result indicates the presence of mercury pollution in the coastal waters, which could have negative and long-term impacts on marine ecosystems and the health of aquatic organisms. Furthermore, correlation analysis revealed a significant positive correlation between the abundance of microplastics and mercury concentration at the Kiashahr station. These findings highlight the potential role of microplastics in the adsorption, transfer and accumulation of pollutants in aquatic environments. Overall, the results of this study emphasize the need for more precise monitoring and management of pollutant sources, as well as the evaluation of risks associated with the accumulation of microplastics in the coastal waters of the Caspian Sea. This is crucial for developing effective management strategies aimed at preserving ecosystem health and reducing pollution, particularly in coastal areas impacted by human activities.

Keywords

Southwestern Coast
Polyethylene
Mercury
FTIR-ATR
Subjects
1.  Abadi, M., Zamani, A., Parizanganeh, A., Khosravi, Y. and Badiee, H., 2018. Heavy metals and arsenic content in water along the southern Caspian coasts in Iran.  Environmental Science and Pollution Research, 25(24): 23725-23735. DOI:10.1007/s11356-018-2455-7. (In Persian with English abstract).
2.     Abbasi, S., Soltani, N., Keshavarzi, B., Moore, F., Turner, A. and Hassanaghaei, M., 2018. Microplastics in different tissues of fish and prawn from the Musa Estuary, Persian Gulf. Chemosphere, 205: 80-87. DOI:10.1016/j.chemosphere.2018.04.076. (In Persian with English abstract).
3.     Akarsu, C., Kumbur, H., Gökdağ, K., Kıdeyş, A.E. and Sanchez-Vidal, A., 2020. Microplastics composition and load from three wastewater treatment plants discharging into Mersin Bay, north eastern Mediterranean Sea. Marine Pollution Bulletin, 150:110776. DOI:10.1016/j.marpolbul.2019.110776.
4.     Alharbi, T., Alfaifi, H. and El-Sorogy, A., 2017. Metal pollution in Al-Khobar seawater, Arabian Gulf, Saudi Arabia. Marine Pollution Bulletin, 119(1): 407–415. DOI:10.1016/j.marpolbul.2017.03.011.
5.     Amelia, T.S.M., Khalik, W.M.A.W.M., Ong, M.C., Shao, Y.T., Pan, H.J. and Bhubalan, K., 2021. Marine microplastics as vectors of major ocean pollutants and its hazards to the marine ecosystem and humans. Progress in Earth and Planetary Science, 8: 12. DOI:10.1186/s40645-020-00405-4. Assess 184:6903–6911.
6.     Barboza, L.G.A., Vieira, L.R., Branco, V., Figueiredo, N., Carvalho, F., Carvalho, C. and Guilhermino, L., 2018. Microplastics cause neurotoxicity, oxidative damage and energy-related changes and interact with the bioaccumulation of mercury in the European seabass, Dicentrarchus labrax (Linnaeus, 1758). Aquatic Toxicology, 195, 49-57. DOI:10.1016/j.aquatox.2017.12.008.
7.     Barrows, A.P.W., Neumann, C.A., Berger, M.L. and Shaw, S., 2017. Grab vs. neuston tow net: a microplastic sampling performance comparison and possible advances in the field. Analytical Methods, 9: 1446–1453. DOI:10.1039/C6AY02387H.
8.     Baztan, J., Carrasco, A., Chouinard, O., Cleaud, M., Gabaldon, J.E., Huck, T., Jaffres, L., Jorgensen, B., Miguelez, A., Paillard, C. and Vanderlinden, J.P., 2014. Protected areas in the Atlantic facing the hazards of micro-plastic pollution: first diagnosis of three islands in the Canary Current. Marine Pollution Bulletin, 80(1-2): 302–311. DOI:10.1016/j.marpolbul.2013.12.052.
9.     Biati, A. and Karbassi, A.R., 2012. Flocculation of metals during mixing of Siyahrud River water with Caspian Sea water. Environmental Monitoring and Assessment, 184(11): 6903-6911. DOI:10.1007/s10661-011-2466-z.
10. Brandon, A.M., Gao, SH., Tian, R., Ning, D., Yang, S.S., Zhou, J., Wu, W.M. and Criddle, C.S., 2018. Biodegradation of polyethylene and plastic mixtures in mealworms (larvae of Tenebrio molitor) and effects on the gut microbiome. Environmental Science and Technology, 52(11): 6526–6533. DOI:10.1021/acs.est.8b02301.
11. Browne, M.A., Galloway, T. and Thompson, R., 2008. Microplastic - an emerging contaminant of potential concern. Integrated Environmental Assessment and Management, 3(4): 559-561. DOI:10.1002/ieam.5630030412.
12. Browne, M.A., Galloway, T.S. and Thompson, R.C., 2011. Spatial patterns of plastic debris along estuarine shorelines. Environmental Science and Technology. 44(9): 3404-3409. DOI:10.1021/es903784e.
13. Carbery, M., MacFarlane, G.R., O’Connor, W., Afrose, S., Taylor, H. and Palanisami, T., 2020. Baseline analysis of metal(loid)s on microplastics collected from the Australian shoreline using citizen science. Marine Pollution Bulletin, 152: 110914. DOI:10.1016/j.marpolbul.2020.110914.
14. Castillo, A.B., Al-Maslamani, I. and Obbard, J.P., 2016. Prevalence of microplastics in the marine waters of Qatar. Marine Pollution Bulletin, 111(1–2): 260–267. DOI:10.1016/j.marpulbull.2016.06.108.
15. Castro, R.O., Silva, M.L. and da Araújo, F.V., 2018. Review on microplastic stud-ies in Brazilian aquatic ecosystems. Ocean and Coastal Management, 165: 385-400. DOI: 10.1016/j.ocecoaman.2018.09.013.
16. Cesa, F.S., Turra, A. and Baruque-Ramos, J., 2017. Synthetic fibers as microplastics in the marine environment: a review from textile perspective with a focus on domestic washings. Science of The Total Environment 598: 1116-1129. DOI:10.1016/j.scitotenv.2017.04.172.
17. Claessens, M., De Meester, S., Van Landuyt, L., De Clerck, K. and Janssen, C.R., 2011. Occurrence and distribution of microplastics in marine sediments along the Belgian coast. Marine Pollution Bulletin, 62(10): 2199-2204. DOI:10.1016/j.marpolbul.2011.06.030.
18. Collignon, A., Hecq, J.H., Glagani, F., Voisin, P., Collard, F. and Goffart, A., 2012. Neustonic microplastic and zooplankton in the North Western Mediterranean Sea. Marine Pollution Bulletin, 64(4): 861-864. DOI:10.1016/j.marpolbul.2012.01.011.
19. Conley, K., Clum, A., Deepe, J., Lane, H. and Beckingham, B., 2019. Wastewater treatment plants as a source of microplastics to an urban estuary: removal efficiencies and loading per capita over one year. Water Research, 3:100030. DOI:10.1016/j.wroa.2019.100030.
20. Darvishnia, Z., Riahi Bakhtiari, A., Kamrani, E. and Sadjjadi, M.M., 2015. Bioaccumulation of Heavy Metals (Pb, Fe & Zn) in the Tissues of Skeletal Coral family, Faviidae and Surrounding Sediments in the South of Qeshm Island-The Persian Gulf. Journal of Aquatic Ecology, 5(1): 77-87. DOI:20.1001.1.23222751.1394.5.1.10.1. (In Persian with English abstract).
21. Doyle, M.J., Watson, W., Bowlin, N.M. and Sheavly, S.B., 2011. Plastic particles in coastal pelagic ecosystems of the Northeast Pacific Ocean. Marine Environmental Research, 71(1): 41-52. DOI:10.1016/j.marenvres.2010.10.001.
22. Éfendieva, I.M., 1994. Ecological problems of oil exploitation in the Caspian Sea area. Journal of Petroleum Science and Engineering, 28(4): 227-231. DOI:10.1016/S0920-4105(00)00081-4.
23. Elsagh, A. and Barmaki, M., 2014. Determination of pollution caused by heavy metals Cu, Zn, Ni and Pb in the Persian Gulf coastal sediments. Journal Environmental Science and Technology, 15(2). (In Persian with English abstract).
24. El-Sorogy, A.S. and Attiah, A., 2015. Assessment of metal contamination in coastal sediments, seawaters and bivalves of the Mediterranean Sea coast, Egypt. Marine Pollution Bulletin, 101(2): 867–871. DOI:10.1016/j.marpolbul.2015.11.017.
25. Golovanova, I.L., 2008. Effect of heavy metals on the physiological and biochemical status of fishes and aquatic invertebrates. Inland Water Biology, 1(1): 93–101. DOI:10.1007/s12212-008-1014-1.
26. Guzzetti, E., Sureda, A., Tejada, S. and Faggio, C., 2018. Microplastic in marine organism: Environmental and toxicological effects. Environmental Toxicology and Pharmacology, 64: 164–171. DOI:10.1016/j.etap.2018.10.009.
27. Haji Aghaei Ghazi Mahalleh, F. and Imanpour Namin, J., 2025. Microplastic contamination in the whitefish (Rutilus frisii) from the southwestern coasts of the Caspian Sea (Guilan Province). Iranian Scientific Fisheries Journal, 33(5): 55-68. DOI:10.22092/ISFJ.2025.132776. (In Persian with English abstract).
28. He, Z.P., Song, J.M., Zhang, N.X., Xu, Y.Y., Zheng, G.X. and Zhang, P., 2008. Variation characteristics and controlling factors of heavy metals in the South Yellow Sea surface seawaters. Huanjing Kexue/Environmental Science, 29(5): 1153-1162. DOI:10.1007/s10661-008-0552-7.
29. Hidalgo-Ruz, V. and Thiel, M., 2015. The contribution of citizen scientists to the monitoring of marine litter. Fate and Impact of Microplastics in Marine Ecosystems, 125. DOI:10.1016/B978-0-12-812271-6.00123-x.
30. Humbatov, F.Y., Ahmadov, M.M., Balayev, V.S. and Suleymanov, B.A., 2015. Trace metals in water samples taken from Azerbaijan sector of Caspian Sea. Journal of Chemistry and Chemical Engineering, 9(4): 288-295. DOI:10.17265/1934-7375/2015.04.007.
31. Imhof, H.K., Laforsch, C., Wiesheu, A.C., Schmid, J., Anger, P.M., Niessner, R. and Ivleva, N.P., 2016. Pigments and plastic in limnetic ecosystems: A qualitative and quantitative study on microparticles of different size classes. Water research, 98: 64-74. DOI:10.1016/j.watres.2016.03.015.
32. Jambeck, J.R., Geyer, R., Wilcox, C., Siegler, T.R., Perryman, M., Andrady, A., Narayan, R. and Law, K.L., 2015. Marine pollution. Plastic waste inputs from land into the ocean. Science, 347(6223): 768–771. DOI:10.1126/science.1260352.
33. Jang, Y.C., Lee, J., Hong, S., Lee, J.S., Shim, W.J. and Song, Y.K., 2014. Sources of plastic marine debris on beaches of Korea: more from the ocean than the land. Ocean Science Journal, 49: 151-162. DOI:10.1007/s12601-014-0015-8.
34. Jiang, C., Yin, L., Wen, X., Du, C., Wu, L., Long, Y., Liu, Y., Ma, Y., Yin, Q., Zhou, Z. and Pan, H., 2018. Microplastics in sediment and surface water of west dongting lake and south dongting lake: abundance, source and composition. International Journal of Environmental Research and Public Health, 15(10): 2164. DOI:10.3390/ijerph15102164.
35. Karbassi, A.R., Nouri, J., Bidhendi, Gh.R. and Ayaz, G.O., 2008. Behavior of Cu, Zn, Pb, Ni and Mn during mixing of freshwater with the Caspian Sea water. Desalination, 229: 118–124. DOI:10.1016/j.desal.2007.06.035. (In Persian with English abstract).
36. Kim, S., Sin, A., Nam, H., Park, Y., Lee, H. and Han, C., 2022. Advanced oxidation processes for microplastics degradation: A recent trend. Chemical Engineering Journal Advances, 9: 100213. DOI:10.1016/j.ceja.2021.100213.
37. Kostianoy Andrey, G., Aleksey, N. and Kosarev. A., 2005. The Handbook of Environmental Chemistry. Water Pollution, 205: 37. DOI:10.1016/02/3141YL-543210.
38. Kowalski, N., Reichardt, A.M. and Waniek, J.J., 2016. Sinking rates of microplastics and potential implications of their alteration by physical, biological, and chemical factors. Marine Pollution Bulletin, 109: 310-319. DOI:10.1016/j.marpolbul.2016.05.064.
39. Kühn, S., Van Oyen, A., Booth, A.M., Meijboom, A. and Van Franeker, J.A., 2018. Marine microplastic: Preparation of relevant test materials for laboratory assessment of ecosystem impacts. Chemosphere, 213: 103-113. DOI:10.1016/j.chemosphere.2018.09.032.
40. Kwon, J.H., Chang, S., Hong, S.H. and Shim, W.J., 2017. Microplastics as a vector of hydrophobic contaminants: importance of hydrophobic additives. Integrated Environmental Assessment and Management, 13(3): 494–499. DOI:10.1002/ieam.1906.
41. Law, K.L., Morét-Ferguson, S., Maximenko, N.A., Proskurowski, G., Peacock, E.E., Hafner, J. and Reddy, C.M., 2010. Plastic accumulation in the North Atlantic subtropical gyre. Science, 329(5996): 1185-1188. DOI:10.1126/science.1192321.
42. Lee, K.W., Shim, W.J., Kwon, O.Y. and Kang, J.H., 2013. Size-dependent effects of micro polystyrene particles in the marine copepod Tigriopus japonicus. Environmental science and technology, 47: 11278-11283. DOI:10.1021/es401932b.
43. Li, J., Song, Y. and Cai, Y., 2020. Focus topics on microplastics in soil: Analytical methods, occurrence, transport, and ecological risks. Environmental Pollution, 257: 113570. DOI:10.1016/j.envpol.2019.113570.
44. Lima, A.R., Costa, M.F. and Barletta, M., 2014. Distribution patterns of microplastics within the plankton of a tropical estuary. Environmental Research, 132, 146-155. DOI:10.1016/j.envres.2014.03.031.
45. Liu, G., Zhu, Z., Yang, Y., Sun, Y., Yu, F. and Ma, J., 2019. Sorption behavior and mechanism of hydrophilic organic chemicals to virgin and aged microplastics in freshwater and seawater. Environmental Pollution, 246: 26–33. DOI:10.1016/j.envpol.2018.11.100
46. Liu, X., Deng, Q., Zheng, Y., Wang, D. and Ni, B.J., 2022. Microplastics aging in wastewater treatment plants: Focusing on physicochemical characteristics changes and corresponding environmental risks. Water Research, 221: 118780. DOI:10.1016/j.watres.2022.118780.
47. Luo, W., Su, L., Craig, N.J., Du, F., Wu, C. and Shi, H., 2019. Comparison of microplastic pollution in different water bodies from urban creeks to coastal waters. Environmental pollution, 246: 174-182. DOI:10.1016/j.envpol.2018.11.081.
48. Masoudnik, M., Riyahi Bakhtiari, A. and Abdollahi, M., 2017. Investigating abundance, distribution and accumulation of plastic resin pellets and fragments in the Caspian Sea: A case study of noor shores. Journal of Oceanography, 8(29): 43–53. DOI:10.18869/acadpub.joc.8.29.43. (In Persian with English abstract).
49. Mataji, A., Taleshi, M.S. and Balimoghaddas, E., 2020. Distribution and Characterization of Microplastics in Surface Waters and the Southern Caspian Sea Coasts Sediments. Archives of Environmental Contamination and Toxicology, 78(1): 86-93. DOI:10.1007/s00244-019-00700-2. (In Persian with English abstract).
50. Morét-Ferguson, S., Law, K.L., Proskurowski, G., Murphy, E.K., Peacock, E.E. and Reddy, C.M., 2010. The size, mass, and composition of plastic debris in the western North Atlantic Ocean. Marine Pollution Bulletin, 60(10): 1873-1878. DOI:10.1016/j.marpolbul.2010.07.020.
51. Napper, I.E. and Thompson, R.C., 2016. Release of synthetic microplastic plastic fibres from domestic washing machines: Effects of fabric type and washing conditions. Marine Pollution Bulletin, 112(1-2): 39-45. DOI:10.1016/j.marpolbul.2016.09.025.
52. Nematollahi, M., Moore, F., Keshavarzi, B., Vogt, R.D., Nasrollahzadeh Saravi, H. and Busquets, R., 2020. Microplastic particles in sediments and waters, south of Caspian Sea: Frequency, distribution, characteristics, and chemical composition. Ecotoxicology and Environmental Safety, 206: 111137. DOI:10.1016/j.ecoenv.2020.111137. (In Persian with English abstract).
53. Neufeld, L., Stassen, F., Sheppard, R. and Gilman, T., 2016. The new plastics economy — rethinking the future of plastics. World economic forum, Ellen MacArthur Foundation, McKinsey & Company http://www.ellenmacarthurfoundation. org/publications.
54. Newman, M.C. and Clements, W.H., 2008. Ecotoxicology: a comprehensive treatment. CRC press, 882p. DOI:10.1201/9780849333576.
55. Pan, J., Pan, J.F. and Wang, M., 2014. Trace elements distribution and ecological risk assessment of seawater and sediments from Dingzi Bay, Shandong Peninsula, North China. Marine Pollution Bulletin, 89(1-2): 427-434. DOI:10.1016/j.marpolbul.2014.10.022.
56. Park, S.Y. and Kim, C.G., 2019. Biodegradation of micro-polyethylene particles by bacterial colonization of a mixed microbial consortium isolated from a landfill site. Chemosphere, 222: 527–533. DOI:10.1016/j.chemosphere.2019.01.159.
57. PlasticsEurope, 2019. Plastics – the facts 2019. An analysis of European plastics production, demand and waste data. PlasticsEurope Retrieved from https:// www.plasticseurope.org/en/resources/publications/1804-plastics-facts-2019. Accessed on 17 August 2020.
58. Rasta, M., Rahimibashar, M.R., Ershad, A., Jafroudi, H.T. and Kouhbane, S.T., 2021. Characteristics and seasonal distribution of microplastics in the surface waters of Southwest coast of the Caspian Sea (Guilan Province, Iran). Bulletin of Environmental Contamination and Toxicology, 107(4): 671-676. DOI:10.1007/s00128-021-03268-7. (In Persian with English abstract).
59. Rasta, M., Sattari, M., Taleshi, M.S. and Imanpour Namin, J., 2020. Identification and distribution of microplastics in the sediments and surface waters of Anzali Wetland in the Southwest Caspian Sea, Northern Iran. Marine Pollution Bulletin, 160: 111541. DOI:10.1016/j.marpolbull.2020.111541. (In Persian with English abstract).
60. Reddy, M.S., Basha, S., Adimurthy, S. and Ramachandraiah, G., 2006. Description of the small plastics fragments in marine sediments along the Alang-Sosiya ship-breaking yard, India. Estuarine Coastal and Shelf Science, 68(3-4): 656−660. DOI:10.1016/j.ecss.2006.03.018.
61. Reisser, J.W., Slat, B., Noble, K., du Plessis, K., Epp, M., Proietti, M.C., de Sonneville, J.D., Becker, T. and Pattiaratchi, C., 2015. The vertical distribution of buoyant plastics at sea: An observational study in the North Atlantic Gyre. Biogeosciences, 12(4): 1249-1256. DOI:10.5194/bg-12-1249-2015.
62. Rodrigues, P., Armando, J., Duarte, C. and Santos-Echeandía, J., 2022. Interaction of microplastics with metal(oid)s in aquatic environments: What is done so far?  Journal of Hazardous Materials Advances, 6: 100072. DOI:10.1016/j.hazadv.2022.100072.
63. Saeedi Saravi, S.S., Karami, B., Karami, S. and Shokrzadeh, M., 2012. Evaluation of metal pollution in fish and water collected from Gorgan coast of the Caspian Sea, Iran. Bulletin of Environmental Contamination and Toxicology, 89(2): 419-423. DOI:10.1007/s00128-012-0670-3. (In Persian with English abstract).
64. Shaw, E.J. and Turner, A., 2019. Recycled electronic plastic and marine litter. Science of the Total Environment, 694: 133644. DOI:10.1016/j.scitotenv.2019.133644.
65. Simonett, O., 2006. Vital Caspian Graphics; Challenges beyond caviar, United Nations Environment program and Caspian Environment program, Publishing by Andishe Pouya.
66. So, W.K., Chan, K. and Not, C., 2018. Abundance of plastic microbeads in Hong Kong coastal water. Marine Pollution Bulletin, 133: 500-505. DOI:10.1016/j. marpolbul.2018.05.066.
67. Stolte, A., Forster, S., Gerdts, G. and Schubert, H., 2015. Microplastic concentrations in beach sediments along the German Baltic coast. Marine Pollution Bulletin, 99(1-2): 216-229. DOI:10.1016/j.marpolbul.2015.07.022.
68. Tabari, S., Saravi, S.S., Bandany, G.A., Dehghan, A. and Shokrzadeh, M., 2010. Heavy metals (Zn, Pb, Cd and Cr) in fish, water and sediments sampled form Southern Caspian Sea, Iran. Toxicology and Industrial Health, 26(10): 649–656. DOI:10.1177/0748233710377777. (In Persian with English abstract).
69. Thompson, R.C., Olsen, Y., Mitchell, R.P., Davis, A., Rowland, S.J., John, A.W.G., McGonigle, D. and Russell, A.E., 2004. Lost at sea: where is all the plastic? Science, 304: 838. DOI:10.1126/science.1094559.
70. Torres, F.G., Dioses-Salinas, D.C., Pizarro-Ortega, C.I. and De-la-Torre, G.E., 2021. Sorption of chemical contaminants on degradable and non-degradable microplastics: Recent progress and research trends. Science Total Environmental, 757: 143875. DOI:10.1016/j.scitotenv.2020.143875.
71. Tsang, Y.Y., Mak, C.W., Liebich, C., Lam, S.W., Sze, E.T. and Chan, K.M., 2017. Microplastic pollution in the marine waters and sediments of Hong Kong. Marine Pollution Bulletin, 115(1-2): 20-28. DOI:10.1016/j.marpolbul.2016.11.003.
72. U.S. Environmental Protection Agency (EPA). Quality Criteria for Water: 1986. EPA 440/5-86-001.
73. Wang, J., Liu, R.H., Yu, P., Tang, A.K., Xu, L.Q. and Wang, J.Y., 2012. Study on the pollution characteristics of heavy metals in seawater of Jinzhou Bay. Procedia Environmental Sciences, 13: 1507–1516. DOI:10.1016/j.proenv.2012.01.143.
74. Wang, J., Peng, J., Tan, Z., Gao, Y., Zhan, Z. and Chen, Q., 2016. Microplastics in the surface sediments from the Beijiang River littoral zone: composition, abundance, surface textures and interaction with heavy metals. Chemosphere, 171: 248–258. DOI:10.1016/j.chemosphere.2016.12.074.
75. Wang, W., Ge, J. and Yu, X., 2020. Bioavailability and toxicity of microplastics to fish species: A review. Ecotoxicology and Environmental Safety, 189:109913. DOI:10.1016/j.ecoenv.2019.109913.
76. Watson-Wright, W.M., Wells, P.G., Duce, R.A., Gilardi, K.V., Girvan, A.S.T., Hubar, M.E., Kershaw, P.J., Linders, J.B.H.J., Luit, R.J., Vivan, C.M.G. and Vousden, D.H., 2024. The UN Joint Group of Experts on the Scientific Aspects of Marine Environmental Protection (GESAMP) - An ocean science-policy interface standing the test of time. Marine Pollution Bulletin, 199: 115917. DOI:10.1016/j.marpolbul.2023.115917.
77. Yu, F., Yang, C., Zhu, Z., Bai, X. and Ma, J., 2019. Adsorption behavior of organic pollutants and metals on micro/nanoplastics in the aquatic environment. Science of the Total Environment, 694: 133643. DOI:10.1016/j.scitotenv.2019.133643.
78. Zeinolabedin, Y., Yahyapour, M.S. and Shirzad, Z., 2009. Geopolitics and Environmental Issues in the Caspian Sea, Caspian Journal of Environmental Sciences, 7(2): 113-121. DOI:10.1016.556508/en.
79. Zhang, B., Chen, L., Chao, J., Yang, X. and Wang, J., 2020. Research progress of microplastics in freshwater sediments in China. Environmental Science and Pollution Research, 27: 31046–31060. DOI:10.1007/s11356-020-09473-x.
80. Zhao, S., Zhu, L. and Li, D., 2015. Microplastic in three urban estuaries, China. Environmental Pollution, 206: 597–604. DOI:10.1016/j.envpol.2015.08.027.
Environment and Interdisciplinary Development
Volume 11, Issue 92
Spring 2026
Pages 121-138

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