Postgraduate in Animal Science (PPGCA/UEMA), Multi-User Laboratories in Postgraduate Research (LAMP), State University of Maranhão, São Luís, 65081-400, Brazil.
Center for Exact, Natural and Technological Sciences (CCENT), State University of the Tocantina Region of Maranhão (UEMASUL), Imperatriz, 65900-000, Brazil.
Sci Rep. 2024 Aug 4;14(1):18037. doi: 10.1038/s41598-024-66570-4.
The field study aims to address identified research gaps by providing valuable information on the concentration, spatial distribution, pollution levels, and source apportionment of toxic and essential elements in sediment samples from four sampling sites (P1: Beira Rio (urban area), P2: Bananal (rural area), P3: Embiral (rural area), P4: Cidelândia (rural area) distributed along the middle Tocantins River, Brazil. Samples were collected in 2023 from river sections and analyzed using various contamination índices (geoaccumulation index, contamination factor, enrichment factor, pollution load index, sediment pollution index, potential ecological risk coefficients, and integrated risk index). Results indicated that the levels of aluminum, iron, manganese, and selenium exceeded legal standards in that year. Chromium, nickel, copper, zinc, and lead exceeded guidelines, mainly in section P1 for aluminum and section P3 for nickel and lead. Rainy months showed increased presence, indicating seasonal variability. The geoaccumulation index indicated low pollution levels, with lead and nickel notably present near urban and industrial areas. The enrichment factor highlighted elevated concentrations of lead and zinc in industrial areas. Both PLI and SPI indices raise concerns regarding Pb (P4) and Zn (P3) concentrations at specific times of the year. Overall, potential ecological risks were deemed low for most sites. Continuous monitoring and interventions are crucial to preserve water and environmental quality in the region.
本野外研究旨在通过提供有关托坎廷斯河中四个采样点（P1：贝罗里奥（城市地区）、P2：巴纳纳尔（农村地区）、P3：恩比拉尔（农村地区）、P4：西德拉兰迪亚（农村地区））沉积物样品中有毒和必需元素浓度、空间分布、污染水平和来源分配的有价值信息，解决已确定的研究空白。这些样品是在 2023 年从河流部分采集的，并使用各种污染指数（地质累积指数、污染因子、富集因子、污染负荷指数、沉积物污染指数、潜在生态风险系数和综合风险指数）进行了分析。结果表明，当年铝、铁、锰和硒的含量超过了法定标准。铬、镍、铜、锌和铅超过了指导值，主要是在 P1 段的铝和 P3 段的镍和铅。雨季的存在增加，表明存在季节性变化。地质累积指数表明污染水平较低，主要是在城市和工业区附近存在铅和镍。富集因子突出了工业区铅和锌浓度的升高。PLI 和 SPI 指数都表明，在一年中的特定时间，Pb（P4）和 Zn（P3）的浓度存在问题。总体而言，大多数地点的潜在生态风险被认为较低。需要持续监测和干预，以保护该地区的水和环境质量。
