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Contaminant levels and endocrine disruptive effects in Clarias gariepinus exposed to simulated leachate from a solid waste dumpsite in Calabar, Nigeria.
Aquatic Toxicology ( IF 4.1 ) Pub Date : 2019-11-28 , DOI: 10.1016/j.aquatox.2019.105375
Oju R Ibor 1 , Andem B Andem 2 , George Eni 2 , Gabriel A Arong 2 , Aina O Adeougn 3 , Augustine Arukwe 4
Affiliation  

Solid waste dumpsites (SWDs) and landfills are significant sources of emerging contaminants to terrestrial and aquatic ecosystems. We have studied the endocrine disruptive effects of simulated leachate from a solid waste dumpsite in Calabar, Nigeria. Juvenile C. gariepinus were exposed to simulated leachate, diluted to 0:0 (control), 1:10, 1:50, 1:100 for 3, 7 and 14 days. In addition, 17β-estradiol (E2: 100 μg/L)-exposed positive control group was included. Hepatic transcripts for the genes encoding vitellogenin (vtg), estrogen receptor-α (er-α), and aromatase (cyp19a1) were analyzed by real-time PCR. Protein expression for Vtg and Cyp19 were measured by immunoblotting and plasma steroid hormones (testosterone: T and E2) were measured using enzyme immunoassay (EIA). Soil samples from the dumpsite were analyzed for selected group of contaminants showing that DEHP was the only detected phthalate ester (PE) at 1300 ± 400 ng/g. Further, perfluoroalkyl substances (PFASs) such as PFBS, PFOS, PFHxA, PFOA, PFNA, PFDA, PFUnDA and PFDoDA were detected in the soil samples from the dumpsite. We observed significant and apparent concentration-dependent increases in mRNA (vtg, er-α, and cyp19a1) and their corresponding functional protein products, after exposure to the simulated leachates. Further, the simulated leachate produced concentration-specific changes in plasma E2 and T levels. In general, the estrogenic endocrine and reproductive alterations in the exposed fish may directly be attributed to the PFASs and DEHP detected at the dumpsites. However, in addition to PFASs and DEHP, there could be other estrogenic contaminants in the leachate. Given the rapid utilization, for residential purposes, and increases in human settlement in areas around the Lemna SWDs, this study provides a direct cause-and-effect evidence of the potential contaminants at the dumpsite with significant environmental and human health consequences.

中文翻译:

暴露于来自尼日利亚Calabar的固​​体垃圾场的模拟渗滤液中的Clarias gariepinus中的污染物水平和内分泌干扰作用。

固体废物堆放场(SWD)和垃圾填埋场是陆生和水生生态系统中新出现污染物的重要来源。我们已经研究了尼日利亚卡拉巴尔的一个固体垃圾场中模拟渗滤液的内分泌干扰作用。将幼年的加拿大油茶(C. gariepinus)暴露于模拟渗滤液中,分别稀释至0:0(对照),1:10、1:50、1:100 3、7和14天。另外,包括暴露于17β-雌二醇(E2:100μg/ L)的阳性对照组。通过实时PCR分析了编码卵黄蛋白原(vtg),雌激素受体-α(er-α)和芳香化酶(cyp19a1)的基因的肝转录本。Vtg和Cyp19的蛋白质表达通过免疫印迹法测定,血浆类固醇激素(睾丸激素:T和E2)通过酶免疫法(EIA)进行测定。分析了垃圾场的土壤样品中的选定污染物组,表明DEHP是唯一检测到的1300±400 ng / g邻苯二甲酸酯(PE)。此外,在垃圾场的土壤样品中检测到了全氟烷基物质(PFAS),例如PFBS,PFOS,PFHxA,PFOA,PFNA,PFDA,PFUnDA和PFDoDA。我们观察到暴露于模拟浸出液后,mRNA(vtg,er-α和cyp19a1)及其相应功能蛋白产物的浓度明显增加,并且明显依赖浓度。此外,模拟的渗滤液在血浆E2和T水平上产生了浓度特定的变化。通常,裸露鱼类的雌激素内分泌和生殖变化可能直接归因于在垃圾场检测到的PFAS和DEHP。但是,除了PFAS和DEHP,渗滤液中可能还存在其他雌激素污染物。鉴于出于居民目的的快速利用,以及Lemna社署附近地区人类住区的增加,这项研究提供了直接的因果关系证据,表明垃圾场的潜在污染物具有严重的环境和人类健康后果。
更新日期:2019-11-29
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