Seasonal Occurrences and Risk Assessment of Phthalate Esters in Sediment, Water and Biota of Two Sub-Saharan Rivers.

The global environmental occurrence of phthalates is inevitable due to their substantial annual production and consumption rate of approximately 5 million tonnes. This study aimed to evaluate the seasonal occurrence of selected phthalate esters congeners in sediment, water, and biota in two freshwater bodies (River Owena and River Ogbese) in Nigeria, and to calculate their ecological risks they pose to aquatic organisms. Dibutyl-phthalate (DBP), di-2-ethylhexyl phthalate (DEHP), and dimethyl-phthalate had an all-year presence in various environmental matrices. DBP was the most prevalent phthalate congener in all environmental matrices with a considerable potential to bioaccumulate in fish tissues. The estimated risk quotient calculated revealed that DBP and DEHP showed a high risk to algae, invertebrates, and fish populations in both freshwater bodies. It is recommended that more comprehensive monitoring campaigns in freshwater bodies be implemented, especially in areas with high anthropogenic activities, to prevent deterioration of aquatic life.

Chronic levels of ibuprofen induces haematoxic and histopathology damage in the gills, liver, and kidney of the African sharptooth catfish (Clarias gariepinus).

Numerous active pharmaceutical ingredients (APIs) have been detected in various environmental matrices. Thus, their potential to elicit their toxic effect on non-target organisms is a growing concern, especially in the aquatic environment. This study aimed to investigate the potential toxicity of ibuprofen (IBU) at environmentally relevant concentration on the haematology and histology of the gill, liver, and kidney over 30 days. The 96-h acute toxicity data showed that IBU was moderately toxic to C. gariepinus with an LC50 value of 3.78 mg/L. After 15 and 30 days of exposure, there was a significant alteration in haematological indices in the treated fishes when compared to the control group. Throughout the experimental duration, the level of the mean corpuscular volume (MCV) and mean corpuscular haemoglobin (MCH) were consistently lower significantly, in contrast to the control group. IBU induced histopathological deformities in the gills, liver, and kidney of the exposed fishes, with alterations such as showing severe secondary lamella necrosis (SLN), epithelial lifting (EL), mild deformity of the secondary lamella (DSL), mild secondary lamella necrosis (MLN), and mild vascular congestion in the liver and kidney, respectively. This study has demonstrated that IBU at environmentally relevant concentrations can significantly impact the haematology, gills, liver, and kidney of C. gariepinus. This study's results can provide baseline info for regulatory agencies to set safe limits for NSAIDs as a safeguard for the aquatic environment.

Occurrence of chemical pollutants in major e-waste sites in West Africa and usefulness of cytotoxicity and induction of ethoxyresorufin-O-deethylase (EROD) in determining the effects of some detected brominated flame retardants and e-waste soil-derived extracts.

We investigated the occurrence of chemical pollutants in major e-waste sites in West Africa and usefulness of cytotoxicity and induction of ethoxyresorufin-O-deethylase (EROD) in determining the effects of some detected brominated flame retardants (BFRs) and e-waste soil-derived extracts. Analysis of the e-waste site samples using AAS and GC-MS techniques revealed the presence of a range of toxic metals as well as persistent and toxic organic pollutants, respectively, in the vicinity of the e-waste sites. As expected, the occurrence (%) of all the detected chemical pollutants in experimental soils significantly (P < 0.05) differs from occurrence (%) in control soil. The calculated LC50 values on RBL-2H3 cells of the detected tetrabromobisphenol A (TBBPA) and hexabromocyclododecane (HBCD) were 3.75 µM and 4.2 µM, respectively. Tribromophenol (TBP), dibromobiphenyl (DBB), and decabromodiphenyl ether (DBDE) were remarkably less toxic on RBL-2H3 cells compared with TBBPA and HBCD as they did not reduce RBL-2H3 cell viability below 50% in the tested concentration range (0-20 µM). The study revealed that TBBPA and HBCD could induce significant RBL-2H3 cell death through caspase-dependent apoptosis. The study further shows that the cytotoxicity of some of these BFRs could increase synergistically when in mixtures and potentially activate inflammation through the stimulation of mast cell degranulation. The e-waste soil-derived extracts induced a concentration-dependent increase in EROD activity in the exposed RTG-W1 cells. Ultimately, nonpolar extracts had higher EROD-inducing potency compared with polar extracts and hence suggesting the presence in higher amounts of AhR agonists in nonpolar e-waste soil-derived extracts than polar extracts. Overall, there is urgent need for actions in order to improve the environmental quality of the e-waste sites.