Postgraduate Program in Chemistry, Chemistry Institute, Federal University of Bahia (UFBA), Street Barão de Jeremoabo, s/n, 40170-270 Salvador, BA, Brazil.
Postgraduate Program in Geochemistry: Petroleum and Environment (POSPETRO), Geoscience Institute, Federal University of Bahia (UFBA), Street Barão de Jeremoabo, s/n, 40170-290 Salvador, BA, Brazil.
Mar Pollut Bull. 2020 Sep;158:111423. doi: 10.1016/j.marpolbul.2020.111423. Epub 2020 Jul 8.
Ten surface sediments collected from Joanes River, Bahia, Brazil in rainy and drought periods in 2019 were evaluated according to the enrichment factor (EF), potential ecological risk index (RI), potential contamination index (PCI), pollution load index (PLI), and index of geoaccumulation (I). Initially the dry sediment was subjected to granulometric analysis and determination of the concentration of organic matter. Then, the samples were digested in HNO and analyzed by Inductively Coupled Plasma Optical Emission Spectrometry (ICP OES) to determine the metals cadmium (Cd), copper (Cu), chromium (Cr), nickel (Ni), lead (Pb) and zinc (Zn). Zn and Cu were classified in that order as the most contaminated elements in most sediment. Comparison of the total metal concentrations with the threshold (TELs) and probable (PELs) effect levels in sediment quality guidelines suggested a more worrisome situation for Zn (648.83-1415.90 μg g; PEL = 315 μg g), of which concentrations were occasionally associated with adverse biological effects in four sediments, followed by Cu in five sediments during dry and rainy periods; while adverse effects were rarely associated with Cd, Cr, Ni, and Pb. In another evaluation, Cd, Cu, Cr, and Zn could be considered the most dangerous in the entire river, as they were classified in the high levels of contamination by the PCI, associated with serious adverse effects in most samples. In an assessment regarding the ecological risks in the study environment, the sediment samples remained below the limit established by the risk index (IR). The Zn presented moderately severe enrichment (6.78-11.83) in all the collection stations in the dry and rainy periods, followed by the Cd that presented moderate enrichment (2.23-4.17), whose values exceeded almost 1000 times the background at one site. Through the PCA it was possible to evidence the existing correlation between metals, organic matter, and silt and clay fraction. The results obtained in the PCA represented more than 80% of the variance between the data. The environmental risk assessment revealed a significant increase in the risk associated with metals during the rainy season. This is probably due to the greater supply of organic matter from the leaching of the margins.
2019 年，在巴西巴伊亚州的若阿内斯河（Joanes River）采集了 10 份表层沉积物，分别在雨季和旱季进行评估，评估指标包括富集因子（EF）、潜在生态风险指数（RI）、潜在污染指数（PCI）、污染负荷指数（PLI）和地积累指数（I）。首先，对干燥的沉积物进行粒度分析和有机质含量测定。然后，将样品在 HNO 中消解，并用电感耦合等离子体光学发射光谱法（ICP OES）进行分析，以测定金属镉（Cd）、铜（Cu）、铬（Cr）、镍（Ni）、铅（Pb）和锌（Zn）的浓度。在大多数沉积物中，Zn 和 Cu 依次被归类为污染最严重的元素。将金属总浓度与沉积物质量指南中的阈值（TELs）和可能效应水平（PELs）进行比较表明，Zn 的情况更令人担忧（648.83-1415.90μg/g；PEL=315μg/g），在四个沉积物中偶尔会与不利的生物效应相关，其次是在旱季和雨季的五个沉积物中与 Cu 相关；而 Cd、Cr、Ni 和 Pb 则很少与不利生物效应相关。在另一项评估中，Cd、Cu、Cr 和 Zn 可被视为整条河流中最危险的物质，因为它们根据 PCI 被归类为高污染水平，与大多数样品中的严重不利影响相关。在对研究环境中的生态风险进行评估时，沉积物样品仍低于风险指数（IR）设定的限值。在旱季和雨季的所有采样点，Zn 都表现出中度至重度富集（6.78-11.83），其次是 Cd，其表现出中度富集（2.23-4.17），在一个采样点，其值超过背景值的近 1000 倍。通过 PCA 可以证明金属、有机质和粉砂黏土之间存在相关性。PCA 得到的结果代表了数据之间超过 80%的方差。环境风险评估表明，雨季与金属相关的风险显著增加。这可能是由于边缘淋滤带来了更多的有机质。
