Appendix 2 Open Literature Review Summaries for Malathion
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For the plasma sex steroid determinations, the males in the dimethoate treatment group showed high levels of T and E2 compared to the control (data not provided). Lower plasma levels of T and E2 were observed for males in the malathion treatment group. For females, lower plasma levels of T and E2 were observed in the dimethoate and malathion treatment groups. For the histological examination of testes, the dimethoate treatment group exhibited necrosis and degeneration of seminiferous tubules with complete absence of the line germ cells, and pyknosis of spermatocytes nucleus. For the malathion treatment group, the male histological observations included degenerative changes in seminiferous tubules and pyknosis of spermatocytes nucleus. For the histological examination of ovaries, observations in both the dimethoate and malathion treatment groups included multiple atretic oocytes with oocyte necrosis embedded in ovarian interstitial tissues and decrease of vitellogenic oocytes. Conclusions: The study authors concluded that dimethoate at 1.6 mg/kg and malathion at 0.17 mg/kg caused reproductive and endocrine function effects in O. niloticus after 120 days exposure in fish food. The observed effects on fecundity and sperm quality are possibly caused by the low estradiol and testosterone levels detected, and the degenerative changes in gonads which lead to decreased GSI. The study was conducted at Benha University in Egypt. The Good Laboratory Practices status of this research is unknown. Given that the purity of the test compounds were not reported, this study was not included in the EDSP WoE analysis. For use in other risk assessments, the study may be used qualitatively. The following study limitations are: Only one replicate was used, and so it appears the endpoints are based on psuedoreplication (fish all from same test vessel). Only one treatment group was used per chemical, therefore an understanding of dose-response was not possible. The purity of the test compounds was not reported. Test compounds were dissolved in cod liver oil, and it is unknown if there were potential contaminants in this carrier. No individual quantitative data were provided for the reproductive, sperm quality, or GSI and K parameters (means presented). No quantitative data were provided for the plasma sex steroid (T and E2) determinations. [Additional comment: given that the purity and impurity profile are not know, this study is valid for arrays (qualitative) for the pilot endangered species assessment for malathion – Amy Blankinship, December 7, 2016.] Directory: pesticides -> nas -> final final -> Appendix 1-10: Summary of Diazinon Monitoring Data nas -> Description of revision final -> Appendix 2 Chlorpyrifos Species Sensitivity Distribution Analysis for Fish Download 6.04 Mb. Share with your friends:
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