School of Chemistry, University of the Witwatersrand, Johannesburg, Private Bag 3, WITS, 2050, South Africa.
School of Chemistry, University of the Witwatersrand, Johannesburg, Private Bag 3, WITS, 2050, South Africa.
Chemosphere. 2021 Dec;284:131407. doi: 10.1016/j.chemosphere.2021.131407. Epub 2021 Jul 2.
Agricultural pesticides threaten aquatic systems and biodiversity at a global scale, but limited information is available on the accumulation of current-use herbicides in tissues of aquatic organisms. Here, we examine the potential exposure and accumulation of currently used herbicides in two species of fish from Lake St Lucia, a global biodiversity hotspot located in South Africa. Muscle tissue samples were analysed for 11 widely used multi-residue and phenoxy-acid herbicides. Herbicide residues were detected in all samples analysed, with total concentrations ranging from 44.3 to 238 ng g (Clarias gariepinus) and 72.2-291 ng g dw (Oreochromis mossambicus). The most prominent herbicides detected included the two phenoxy-acid herbicides, MCPA (17.6 ± 12 ng g) and 2,4-D (28.9 ± 16 ng g), along with acetochlor (15.4 ± 5.8 ng g), atrazine (12.7 ± 7.1 ng g) and terbuthylazine (12.4 ± 12 ng g). Results indicate that fish at Lake St Lucia accumulate a complex mixture of herbicides, some previously unreported in tissue, highlighting the potential threat that agricultural runoff may pose to conservation areas. However, assessing the impact of herbicide accumulation on wild fish populations is difficult at present and urgent toxicological data are needed to better understand chronic exposure effects on aquatic organisms. A preliminary human health risk assessment indicated minimal risk associated with the consumption of local fish, but potential additive and synergistic effects of contaminant mixtures remain unknown.
农业农药在全球范围内威胁着水生系统和生物多样性，但关于当前使用的除草剂在水生生物组织中的积累，信息有限。在这里，我们研究了来自南非全球生物多样性热点的圣卢西亚湖的两种鱼类中当前使用的除草剂的潜在暴露和积累。肌肉组织样本分析了 11 种广泛使用的多残留和苯氧羧酸类除草剂。所有分析的样本中都检测到了除草剂残留，总浓度范围为 44.3 至 238ng g（Clarias gariepinus）和 72.2 至 291ng g dw（Oreochromis mossambicus）。检测到的最主要的除草剂包括两种苯氧羧酸类除草剂，MCPA（17.6 ± 12ng g）和 2,4-D（28.9 ± 16ng g），以及乙草胺（15.4 ± 5.8ng g）、莠去津（12.7 ± 7.1ng g）和特丁津（12.4 ± 12ng g）。结果表明，圣卢西亚湖的鱼类积累了复杂的除草剂混合物，其中一些以前在组织中没有报告过，这突出表明农业径流可能对保护区构成潜在威胁。然而，目前评估除草剂积累对野生鱼类种群的影响很困难，需要紧急的毒理学数据来更好地了解水生生物的慢性暴露效应。初步的人类健康风险评估表明，当地鱼类的食用风险很小，但污染物混合物的潜在附加和协同效应尚不清楚。
