To date, limited information exists on the distribution of endocrine disrupting compounds in groundwater resources from African rural settlements. In view of this knowledge gap, the present study investigated the concentrations and potential health risks of phenolic endocrine disrupting chemicals (EDCs) in underground water samples obtained from eight rural settlements in Nigeria, West Africa. The water samples were obtained from domestic drinkable communal wells at Anambra (Mgbaukwu and Umudioka), Lagos (Bariga, Itire and Mushin), and Delta (Agbarho, Ikweghwu and Orhokpokpor) states representing the South-East, South-West and South-South Nigeria respectively. Samples were analyzed for 10 selected chlorinated, nitrogen-containing and alkyl phenolic compounds using gas chromatography coupled with flame ionization detector technique. At all understudied sites, selected phenolic compounds with the exception of 2-chlorophenol which was below detectable limits at 4 sites (Agbarho, Mgbaukwu, Umudioka site 1 and Mushin) were detected. The concentrations of the phenolic compounds in the samples from the different sites ranged between below detectable limits to 0.0904 ppm. Nonylphenol, 2,4-dinitrophenol and 2,4,6-trichlorophenol were predominant at EDCs in most sites when compared with the other phenolic contaminants. The calculated chronic daily intake (CDI) results for the exposed populations at the communities implies that the level of occurrence and daily intake of 2-nitrophenol, 2,4-dimethylphenol, 4-nitrophenol, 2-chlorophenol and bisphenol A were still below their respective oral reference doses. Nonylphenol and 2,4,6-trichlorophenol (risk quotient, RQ > 1) were identified as the major EDC contributors to potential health risk for exposed populations at the communities.

The occurrence and ecological risk associated with nine pharmaceuticals; Ciprofloxacin, Metronidazole, Amoxycillin, Trimethoprim, Tetracycline, Sulfamethoxazole, Ibuprofen, Diclofenac and Paracetamol were investigated in water and sediments of Usuma Dam, Abuja, Nigeria. The samples were extracted with solid phase extraction and analysed with high performance liquid chromatography coupled with UV/VIS detector (HPLC-UV/VIS). Metronidazole with a concentration range of 191.11-572.73 ng/L and Trimethoprim with a concentration range of 0.27-0.42 µg/g d.w. were the predominant antibiotics in the water and sediments respectively. Ibuprofen was the only analgesics detected in the samples. The ecological risk assessed with the worst observed data for each pharmaceutical in the samples showed that Amoxycillin and Ibuprofen pose a high toxic risk to aquatic life in the dam while Trimethoprim and Ciprofloxacin could result in medium ecological risk. The results of this study draw attention to the occurrence and ecological risks of pharmaceuticals to aquatic life.

Microplastics (MPs) are currently global environmental pollutants, and their associated health risks cannot be ignored. However, research on MP toxicity in mammals is limited. We investigated the effects of polystyrene microplastic (PS-MP) particles on the lipid profile and oxidative stress markers of Wistar rats. Two forms of PS-MP-pristine polystyrene and Styrofoam microplastics-particles of diameter <5 mm were used in this study. Each form was separately incorporated into rat feed in varying proportions of 1, 5 and 10%. A total of seventy rats (thirty-five male and thirty-five female rats) were used for this study and were separately distributed into seven groups of five rats each. The rats were then randomly assigned to a control group which received normal rat feed and water and six (6) test groups which were fed varying percentages (1, 5 and 10) of polystyrene microplastics diet for a period of 90 days. The rats were sacrificed under mild diethyl ether anesthesia 12 hr after cessation of treatment and blood was collected for lipid profile and oxidative stress analyses. Results obtained showed that oral exposure to microplastics caused decreased high density lipoprotein cholesterol (HDL-C) and increased low density lipoprotein cholesterol (LDL-C) in the rats. In contrast, there were no significant changes in oxidative stress parameters in the rats following microplastics exposure. Atherogenic indices in the PS-MP exposed rats differed according to gender. These results indicated that PS-MP dietary exposure may lead to dyslipidemia and male rats had higher cardiovascular risk.

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The concentration of selected endocrine disrupting chemicals in tissues of Chrysichthys nigrodigitatus (catfish) and Liza falcipinnis (mullet) obtained from Choba river in Rivers State, Nigeria was analyzed to determine their levels and possible hazard for human consumption. Pesticides and polychlorinated biphenyls were assessed using gas chromatography coupled with electron capture detector. Heavy metals analysis was carried out using atomic absorption spectrophotometer. The concentration of pesticides ranged from 0.0013±0.0002 to 0.0130±0.0002 µg/l and 0.0077±0.0000 to 0.0390±0.0001µg/g in water and sediments, respectively. Similarly, pesticides concentration ranged from 0.0001±0.0000 to 0.0171±0.0002µg/g and 0.0002±0.0001 to 0.0385±0.0002µg/g respectively. The concentration of PCBs in analyzed fish ranged from 0.2439±0.0001 to 0.2683±0.0003µg/g in the muscle and liver, respectively. Heavy metal concentration ranged from 0.004±0.001 to 0.460±0.002µg/g for cadmium and mercury, respectively. Risk hazard estimates of dichlorodiphenyltrichloroethanes, Chlordanes, hexachlorobenzene, and heavy metals (Cd, Cr) in the studied fishes showed no potential adverse effect to human consumption at the observed concentrations. Mercury was high in all fish analyzed with a quotient value greater than unity indicating potential mercury poisoning. The cancer risk was also evaluated according to USEPA, (2005) and was within acceptable risk range of 10-4. Thus exposed populations are not at cancer risk through consumption of fish.