Instituto de Química, Universidade Federal do Rio Grande do Sul (UFRGS), Av. Bento Gonçalves, 9500, Porto Alegre 91501-970, RS, Brazil.
Programa de Pós-graduação em Geociências, Instituto de Geociências, Universidade Federal do Rio Grande do Sul (UFRGS), Av. Bento Gonçalves, 9500, Porto Alegre 91501-970, RS, Brazil.
Sci Total Environ. 2021 Mar 10;759:143503. doi: 10.1016/j.scitotenv.2020.143503. Epub 2020 Nov 11.
The ubiquitous presence of microplastics in the aquatic environment has raised concern about their potential impacts on and risks to the biota. While the presence of microplastics in a marine environment has been well studied, the impact of microplastic contamination in freshwater bodies is understudied. In the present study, baseline data about contamination with microplastics in Lake Guaíba in southern Brazil are presented. The abundance, distribution, and composition of microplastics in the surface of this freshwater body were investigated, and these parameters were correlated with population density, land occupation, wind, and geohydrologic processes. The samples were collected with a manta net (60 μm mesh size). Microplastics were found in all the samples, with an average of 11.9 ± 0.6 to 61.2 ± 6.1 items m, which indicates the widespread contamination of the lake with plastic particles. The most frequent microplastic morphology was the fragment type in the size range of 100 to 250 μm, and the predominant colours were white/transparent and red. Measurement uncertainty of the visual microplastic counts showed that black colour microplastics is more susceptible to be mistaken, which might lead to an underestimation and/or overestimation of the total number of microplastics. Polypropylene and polyethylene together comprised most of the polymer types (98%). Micro-Fourier transform infrared (micro-FTIR) spectroscopy analyses showed that 58% of the analysed polymers were highly oxidised, indicating long residence of this particles in the water. In addition, our data show that the distribution of microplastics is strongly influenced by the geohydrological characteristics of the lake. Therefore, this research may provide information for further investigations of microplastic distribution in Lake Guaíba and can serve as a base to improve the regulations regarding waste management to effectively reduce microplastic pollution in freshwater systems. Additionally, the measurement uncertainty showed that black microplastics are more susceptible to variations in their measurements.
微塑料在水生环境中无处不在，这引起了人们对其对生物群潜在影响和风险的关注。虽然海洋环境中微塑料的存在已经得到了充分的研究，但淡水体中微塑料污染的影响还在研究中。本研究提出了巴西南部瓜伊巴湖微塑料污染的基线数据。研究了该淡水体表面微塑料的丰度、分布和组成，并将这些参数与人口密度、土地利用、风和地下水文过程进行了相关分析。样品是用曼塔网（60μm 网眼尺寸）采集的。所有样品中都发现了微塑料，平均每个样品中有 11.9±0.6 至 61.2±6.1 个微塑料，这表明该湖泊受到了广泛的塑料颗粒污染。最常见的微塑料形态是碎片型，尺寸在 100 至 250μm 之间，主要颜色是白色/透明和红色。视觉微塑料计数的测量不确定度表明，黑色微塑料更容易被误认，这可能导致对微塑料总数的低估和/或高估。聚丙烯和聚乙烯一起构成了大多数聚合物类型（98%）。微傅里叶变换红外（micro-FTIR）光谱分析表明，58%的分析聚合物高度氧化，表明这些颗粒在水中的停留时间很长。此外，我们的数据表明，微塑料的分布受到湖泊地下水文特征的强烈影响。因此，本研究可为进一步研究瓜伊巴湖微塑料分布提供信息，并可作为改进有关废物管理法规的基础，以有效减少淡水系统中的微塑料污染。此外，测量不确定度表明，黑色微塑料更容易受到测量变化的影响。
