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6311681 
Journal Article 
Contaminant levels and endocrine disruptive effects in Clarias gariepinus exposed to simulated leachate from a solid waste dumpsite in Calabar, Nigeria 
Ibor, OR; Andem, AB; Eni, G; Arong, GA; Adeougn, AO; Arukwe, A 
2020 
Yes 
Aquatic Toxicology
ISSN: 0166-445X
EISSN: 1879-1514 
Elsevier 
219 
Elsevier 
105375 
English 
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. 
Dumpsites; DEHP; PFASs; Endocrine disruption; Clarias gariepinus 
• PFBS
     LitSearch: May 2019 - May 2020
          WoS
          PubMed
• PFDA
     Literature Search Update 5/2020
          PubMed
• PFHxA
     LitSearch: May 2019 - May 2020
          PubMed
          WoS
• PFNA
     LitSearch: May 2019 - May 2020
          PubMed
          WoS
• PFOA (335-67-1) and PFOS (1763-23-1)
     LitSearch: Feb 2019 - May 2020
          WoS
     Literature Search Update (Apr 2019 - Sep 2020)
          PubMed
          WOS