Department of Aquatic Environment Management, Fisheries College and Research Institute, Thoothukudi, Tamil Nadu, India.
Department of Fish Quality Assurance and Management, Fisheries College and Research Institute, Thoothukudi, Tamil Nadu, India.
Environ Sci Pollut Res Int. 2022 Oct;29(50):75525-75538. doi: 10.1007/s11356-022-21054-8. Epub 2022 Jun 3.
Microplastics accumulation on beaches raises a serious concern worldwide. Hence, the present study was conducted with the focus of investigating the abundance, characteristics, risk assessment, surface morphology and elemental composition of microplastics (MPs) in the beach sediments of the Thoothukudi region, situated on the south-east coast of India, Gulf of Mannar region. The MPs abundance ranged between 19 ± 18.62 and 78.55 ± 95.17 items/kg with a mean abundance of 33.82 ± 26.11 items/kg and the spatial distribution of MPs showed insignificant variation. Fragments (59.48%), 0.5-1 mm (43.66%) and blue-coloured MPs (45.61%) were highly predominant in the sediments. Attenuated total reflection - Fourier transform infrared (ATR-FTIR) spectroscopy showed the dominance of polyethylene polymers in sediments (52.26%) and their sources could be attributed to the direct inflow of sewage, recreational and fishing activities and accidental loss. The current study revealed that microplastics (< 5 mm) are ubiquitous along the Thoothukudi coast, posing a serious threat to the marine environment and marine organisms. The ecological risk assessment of MPs in sediments was calculated by adopting 3 models: the polymer hazard index (PHI), pollution load index (PLI) and potential ecological risk assessment (RI). The overall PHI = 698.96 exhibited a hazard level of IV, which was mainly due to the varying abundance of polymer composition in sediments. The value of PLI is 2.51, which mainly depends on the MPs abundance in sediments and yields the hazard level of I. The ecological risk posed by MPs in beach sediments along the Thoothukudi coast (RI = 241.06) falls into the medium category, indicating that steps must be taken to reduce the flow of plastics through management measures such as proper wastewater treatment practices, recycling of plastic waste and proper waste disposal. Field emission scanning electron microscopy (FESEM) images revealed that MPs surfaces were strongly weathered and energy dispersive X-ray (EDX) spectroscopy spectra showed that the presence of inorganic elements associated with the surface MPs might be derived from the surrounding environment or additives in plastics. Hence, further research has to be conducted in view of studying the combined effects of MPs pollution and organic pollutants, which will provide further understanding of the contamination of MPs in the marine environment.
海滩上的微塑料积累引起了全世界的严重关注。因此，本研究的重点是调查印度东南海岸马纳尔湾地区的图奥赫蒂鲁地区海滩沉积物中微塑料（MPs）的丰度、特征、风险评估、表面形态和元素组成。MPs 的丰度范围在 19±18.62 到 78.55±95.17 个/千克之间，平均值为 33.82±26.11 个/千克，空间分布没有明显变化。碎片（59.48%）、0.5-1 毫米（43.66%）和蓝色 MPs（45.61%）在沉积物中占主导地位。衰减全反射-傅里叶变换红外（ATR-FTIR）光谱显示，聚乙烯聚合物在沉积物中占主导地位（52.26%），其来源可归因于污水的直接流入、娱乐和渔业活动以及意外损失。本研究表明，微塑料（<5 毫米）在图奥赫蒂鲁海岸随处可见，对海洋环境和海洋生物构成严重威胁。采用 3 种模型对沉积物中 MPs 的生态风险进行评估：聚合物危害指数（PHI）、污染负荷指数（PLI）和潜在生态风险评估（RI）。聚合物危害指数的总和为 698.96，表现出 IV 级危害水平，主要是由于沉积物中聚合物组成的丰度不同。PLI 的值为 2.51，主要取决于沉积物中 MPs 的丰度，产生 I 级危害水平。图奥赫蒂鲁海岸海滩沉积物中 MPs 造成的生态风险（RI=241.06）属于中等类别，这表明必须采取措施减少通过管理措施（如适当的废水处理实践、塑料废物回收和适当的废物处置）流入的塑料量。场发射扫描电子显微镜（FESEM）图像显示，MPs 表面风化严重，能量色散 X 射线（EDX）能谱显示，与 MPs 表面相关的无机元素可能来自周围环境或塑料中的添加剂。因此，需要进一步研究 MPs 污染与有机污染物的综合影响，这将进一步了解海洋环境中 MPs 的污染情况。
