Department of Botany, Government College Women University, Sialkot, 51310, Pakistan.
State Key Laboratory of Grassland Agro-ecosystems, School of Life Sciences, Lanzhou University, Lanzhou, 730000, Gansu, PR China.
Environ Pollut. 2021 Dec 1;290:118104. doi: 10.1016/j.envpol.2021.118104. Epub 2021 Sep 3.
Contamination of waters and soils with microplastics (MPs) is an emerging environmental issue worldwide. MPs constitute a cocktail of various additives and polymers besides adsorbing toxic heavy metals from the environment. This co-occurrence of MPs with heavy metals poses a threat to the health of organisms and is poorly understood. Ingestion of MPs contaminated with heavy metals may also result in subsequent transfer of heavy metals up in the food chain. MPs surfaces play a crucial role in the adsorption of heavy metals. Aged/biofouled MPs facilitate greater adsorption of metals and certain microplastic (MP) polymers adsorb some metals more specifically. External factors involved in the process of adsorption/accumulation of heavy metals are the solution pH, salinity, and the concentration of relevant heavy metals in the media. Desorption greatly depends upon pH of the external solution. This is more concerning as the guts/digestive systems of organisms have low pH which could enhance the desorption of toxic metals and making them accumulate in their bodies. The aim of this article is to discuss the abundance, distribution, adsorption, and desorption behavior of MPs for heavy metals, and their combined toxic effects on flora and fauna based on the limited research on this topic in the literature. There is an overarching need to understand the interactions of MPs with heavy metals in different ecosystems so that the extent of ecotoxic effects they pose could be assessed which would help in the environmental regulation of these pollutants.
水和土壤中微塑料（MPs）的污染是一个全球性的新兴环境问题。MPs 除了吸附环境中的有毒重金属外，还构成了各种添加剂和聚合物的混合物。MPs 与重金属的共同存在对生物的健康构成了威胁，但人们对此了解甚少。摄入含有重金属的 MPs 也可能导致重金属在食物链中进一步转移。MPs 的表面在重金属的吸附中起着至关重要的作用。老化/生物污染的 MPs 促进了更多金属的吸附，某些微塑料（MP）聚合物更具体地吸附某些金属。重金属吸附/积累过程中涉及的外部因素是溶液 pH 值、盐度以及介质中相关重金属的浓度。解吸在很大程度上取决于外部溶液的 pH 值。这更令人担忧，因为生物体的肠道/消化系统的 pH 值较低，这可能会增强有毒金属的解吸，并使它们在体内积累。本文的目的是根据文献中对这一主题的有限研究，讨论 MPs 对重金属的丰度、分布、吸附和解吸行为，以及它们对动植物的联合毒性影响。人们迫切需要了解 MPs 与不同生态系统中重金属的相互作用，以便评估它们所造成的生态毒性影响，从而有助于对这些污染物进行环境监管。
