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.

Occurrence and seasonal variation of organochlorine pesticides in selected vegetable farmlands in Lagos State, Nigeria.

Pest infestation in crop production have increased farmers' interest in pesticides use with short and long term consequences. This study investigated the occurrence and seasonal variations of organochlorine pesticide residues in vegetable farms in selected areas of Lagos State. Non carcinogenic and carcinogenic risk assessment was also evaluated. Soil samples were collected during the wet and dry seasons at soil depth of 0-30 cm. Gas chromatography coupled with an Agilent mass spectrometer was used to analyse organochlorine residues (alpha-lindane,lindane, delta.-lindane, aldrin, heptachlor epoxide, alpha.-endosulfan, p,p'-dichlorodiphenyldichloroethylene (p,p'-DDE), endrin, endosulfan, m,p'-dichlorodiphenyldichloroethane (m,p'-DDD), endosulfan sulfate, o,p'-dichlorodiphenyltrichloroethane (o,p'-DDT) and endrin ketone) in soil. Heptachlor epoxide showed maximum concentration of 43.03 mg/kg in Station 19 in Western zone during the dry season while m,p'-DDD and endosulfan had minimum value of 0.004 mg/kg in Station 2 and Station 5 respectively during the wet season in the Far eastern zone. The concentrations of organochlorine residues were intermediate in the Eastern zone in both seasons. There was significant (p < 0.05) increase in dry season concentrations when compared to wet season. The risk assessment indicated Hazard Quotient (HQ) > 1 for non-cancer risk and cancer risk > 10-6. Thus a need for stringent monitoring programs for pesticides.

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.