Environmental and Nano Science Group, Department of Chemistry, University of the Western Cape, Cape Town, South Africa.
Environmental and Nano Science Group, Department of Chemistry, University of the Western Cape, Cape Town, South Africa; Department of Chemistry, Faculty of Science, Lagos State University, LASU, P.O. Box 0001, Ojo, Lagos, Nigeria.
Sci Total Environ. 2020 Oct 10;738:140346. doi: 10.1016/j.scitotenv.2020.140346. Epub 2020 Jun 19.
The present study was conducted during a time of drought to assess the concentration of herbicides and their potential for accumulation in marine biota found in the near shore marine environment of an urban setting (Camps Bay, Cape Town, South Africa). The purpose was to establish whether raw sewage containing selected persistent chemicals that are released through a local marine outfall would be sufficiently diluted by the ocean to prevent impact on the near-shore marine environment of the suburb Camps Bay. Samples of seawater, sediment, seaweed, and selected marine organisms present in the near shore environment, such as limpets (Cymbula granatina), mussels (Mytilus galloprovincialis), and sea urchins (Parechinus angulosus), were analysed for five indicator herbicides, namely atrazine, alachlor, simazine, metolachlor, and butachlor, with gas chromatography coupled with a mass spectrometer. The concentration of the compounds detected ranged from below the limit of detection (<LOD) to 4.2 ng/L in seawater, <LOD to 45.3 ng/g dry weight (dw) in sediments, <LOD to 157.8 ng/g dw in marine organisms, and between 12.3 and 87.0 ng/g dw in seaweed. Results of ecological risk assessment for acute and chronic risk, calculated following the US Environmental Protection Agency method, showed a possible threat to the near shore environment from sewage released by the marine outfall, as the herbicide contamination in the biota posed a low to high ecotoxicological risk for marine organisms. The hazard quotients and carcinogenic risk caused by herbicide pollution in Camps Bay seawater were above the acceptable level indicating that these chemicals pose adverse health effects, should an average sized human (70 kg) consume any of the marine species analysed herein on a daily basis (daily consumption of 54 g), over a lifetime period (life expectancy of 70 years). The study also indicated the extensive use of these herbicides for cosmetic and ornamental purposes in gardening, or for weed control in an urban setting, thus, it is apparent that consumers and municipalities need to be educated about their inadvertent use and safe disposal of these compounds. The use of these herbicides to control weeds within the area and discharge of sewage to Camps Bay must be checked through adequate control of the trade, handling of herbicides, and enforcement of appropriate sanctions and development of suitable regulations.
本研究在干旱时期进行，以评估城市环境近岸海洋环境中发现的海洋生物体内除草剂的浓度及其潜在积累情况（南非开普敦坎普斯湾）。目的是确定含有通过当地海洋排污口释放的选定持久性化学物质的未经处理污水是否会被海洋充分稀释，从而防止对坎普斯湾郊区近岸海洋环境造成影响。对近岸环境中的海水、沉积物、海藻以及某些海洋生物（如鳞笠螺（Cymbula granatina）、贻贝（Mytilus galloprovincialis）和海胆（Parechinus angulosus））进行了 5 种指示性除草剂（莠去津、甲草胺、西玛津、异丙甲草胺和丁草胺）的分析，采用气相色谱-质谱联用技术。检测到的化合物浓度范围从海水中低于检测限（<LOD）至 4.2 ng/L，沉积物中<LOD 至 45.3 ng/g 干重（dw），海洋生物中<LOD 至 157.8 ng/g dw，海藻中为 12.3 至 87.0 ng/g dw。根据美国环境保护署方法计算的急性和慢性风险生态风险评估结果表明，海洋排污口排放的污水可能对近岸环境构成威胁，因为生物群中除草剂污染对海洋生物构成了低至高的生态毒理学风险。坎普斯湾海水中除草剂污染造成的危害系数和致癌风险均高于可接受水平，这表明如果一个平均体重为 70 公斤的人每天食用此处分析的任何一种海洋物种（每天食用 54 克），那么这些化学物质会对健康造成不利影响，在一生中（预期寿命为 70 年）。该研究还表明，这些除草剂广泛用于园艺中的美容和观赏目的，或用于城市环境中的杂草控制，因此，显然需要对消费者和市政当局进行教育，使其了解这些化合物的无意使用和安全处置方法。必须通过对贸易的充分控制、对除草剂的处理、执行适当的制裁和制定适当的法规，来检查该地区杂草控制和向坎普斯湾排放污水使用这些除草剂的情况。
