Veterinary growth promoters in cattle feedlot runoff: estrogenic activity and potential effects on the rat male reproductive system.

The contribution of veterinary growth promoters (VGP) to the environmental burden of endocrine-disrupting chemicals (EDCs) is largely unknown. At cattle feedlots, the excrement of cattle may contain VGPs, which can contaminate aquatic systems and pose reproductive health risks. The study identifies VGPs used at cattle feedlots in South Africa and confirms associated estrogenic activity in feedlot runoff water. Using a rat model, we investigate the potential reproductive health effects and thyroid function of an environmentally relevant mixture of VGPs. Collected water samples had low levels of selected VGPs, and estrogenic activity was detected in the T47D-KBluc bioassay. Rats exposed to VGP had significant adverse effects on male reproductive health, including shortened anogenital distance, lowered sperm counts, disorganized seminiferous tubules, and thyroid parameters. In conclusion, VGP can contribute to complex environmental EDC mixtures and may adversely affect the reproductive and thyroid health of both humans and wildlife. The varied topography of individual cattle feedlots will govern the rate and extent of effluent runoff, thus continuous monitoring of VGPs in aquatic systems surrounding cattle feedlots is necessary.

Estrogenic activity, chemical levels and health risk assessment of municipal distribution point water from Pretoria and Cape Town, South Africa.

Endocrine disrupting chemicals (EDCs) are ubiquitous in the environment and have been detected in drinking water from various countries. Although various water treatment processes can remove EDCs, chemicals can also migrate from pipes that transport water and contaminate drinking water. This study investigated the estrogenic activity in drinking water from various distribution points in Pretoria (City of Tshwane) (n = 40) and Cape Town (n = 40), South Africa, using the recombinant yeast estrogen screen (YES) and the T47D-KBluc reporter gene assay. The samples were collected seasonally over four sampling periods. The samples were also analysed for bisphenol A (BPA), nonylphenol (NP), di(2-ethylhexyl) adipate (DEHA), dibutyl phthalate (DBP), di(2-ethylhexyl) phthalate (DEHP), diisononylphthalate (DINP), 17ß-estradiol (E2), estrone (E1) and ethynylestradiol (EE2) using ultra-performance liquid chromatography-tandem mass spectrophotometry (UPLC-MS/MS). This was followed by a scenario based health risk assessment to assess the carcinogenic and toxic human health risks associated with the consumption of distribution point water. None of the water extracts from the distribution points were above the detection limit in the YES bioassay, but the EEq values ranged from 0.002 to 0.114 ng/L using the T47D-KBluc bioassay. BPA, DEHA, DBP, DEHP, DINP E1, E2, and EE2 were detected in distribution point water samples. NP was below the detection limit for all the samples. The estrogenic activity and levels of target chemicals were comparable to the levels found in other countries. Overall the health risk assessment revealed acceptable health and carcinogenic risks associated with the consumption of distribution point water.

Pesticide residues and estrogenic activity in fruit and vegetables sampled from major fresh produce markets in South Africa.

Food is likely to be one of the major pathways through which people are exposed to endocrine-disrupting chemicals. With the exception of residual effects, there are concerns that a number of naturally occurring and synthetic chemicals exert adverse effects upon endocrine systems in wildlife and humans. The current study reports selected pesticide concentrations and the total estrogenic activity of fruit and vegetables using the recombinant yeast oestrogen screen (YES) and T47D-KBluc reporter gene assays. A total of 53 food samples (27 fruit and 26 vegetables) from Johannesburg and Tshwane fresh produce markets (in South Africa) were analysed. Of these, 17 contained one to three different pesticide residues with concentrations ranging between 0.01 and 0.68 mg kg(-1), whereas in the rest of the samples no residues were detected. All pesticides detected except in one sample were below the maximum residue level (MRL), but others were unauthorised for use in specified fruit and vegetables. Estrogenic activity was detected in 26.4% (14 samples) of the samples tested, and the estradiol equivalents ranged from 0.007 to 2 pg g(-1). Although the estrogenic activity was low, it may contribute to adverse health effects. Continuous monitoring for pesticides in fruit and vegetables is important in view of the unauthorised pesticides detected in produce from South Africa and the endocrine-disrupting chemical activity found.