Sawmill Activities Near the Lagos Lagoon, Nigeria: Polycyclic Aromatic Hydrocarbons and Embryotoxic Evaluations of Sediment Extracts Using Clarias gariepinus.

The physicochemical parameters and 16 priority PAHs in surface water, porewater and sediment at a sawmill wastes-impacted and High-Rise study sites on the Lagos lagoon in Nigeria were assessed. Further, the embryotoxic effects of sediment organic and porewater extracts from the study sites were evaluated in Clarias gariepinus (African sharptooth catfish) embryos for 26 h. High molecular weight PAHs dominated the PAHs profile especially in the sediment. Source apportionment of the PAHs in the three environmental matrices revealed mainly pyrogenic sources. Developmental abnormalities and decreased hatching success were observed in C. gariepinus embryos exposed to extracts from the Okobaba site compared to High-Rise study site. The results demonstrate the potential though non-significant ecological risk of sawmill activities near the lagoon on water quality and fisheries. Further studies are recommended to provide holistic evidence-based information to promote sustainable fisheries in the lagoon in support of the UN SDGs 13 (climate action) and 14 (life below water).

Children's exposure to hazardous brominated flame retardants in plastic toys.

We report concentrations of brominated flame retardants (BFRs) in 23 plastic samples from 20 new and second-hand children's toys sourced from the UK that had been previously shown to be Br-positive by XRF. The results reinforce existing evidence that the recycling of BFR-treated electronic plastics has led to the unintentional BFR contamination of articles not required to be flame-retarded. The principal BFRs detected were PBDEs (and in particular BDE-209), HBCDD and TBBP-A. PBDEs were detected in all samples with a maximum concentration of BDE-209 of 2500 mg/kg, and while TBBP-A was detected in 11 samples with a maximum concentration of 3100 mg/kg. HBCDD was detected in 14 cases and was present in four toys at concentrations (139-840 mg/kg) that would currently prevent their sale on the EU market. While estimated exposures to PBDEs via accidental ingestion of toy plastic fell well below USEPA reference doses, a child weighing 8.67 kg and ingesting 8 mg/day of a toy (the default assumption of the European Commission's Toy Safety Directive for scraped-off toy material) contaminated at our arithmetic mean concentration would be exposed to 0.2 ng/kg bw/day BDE-99. This compares closely to a health-based limit value (HBLV) proposed in The Netherlands of 0.23-0.30 ng/kg bw/day BDE-99. Of greater concern, the same child playing with a toy contaminated at the maximum concentration in this study would be exposed to 1.4 ng/kg bw/day BDE-99, thereby exceeding the HBLV. This paper is the first to consider BFR exposure via incidental ingestion of plastic from both contemporary and historical toys, revealing it to be considerable and for some children their most significant pathway of exposure.

Human Health Risk of Organochlorine Pesticides in Foods Grown in Nigeria.

BACKGROUND: Production of foods safe for consumption is an important issue worldwide. Organochlorine pesticides (OCP) are often used to preserve crops. Their use can have serious impacts on human health. OBJECTIVES: This research aims at assessing OCP residues in food samples from markets in Lagos in southwestern Nigeria and their risk to human health. METHODS: Sixteen food samples were collected from Lagos, Nigeria and analyzed for organochlorine pesticide residues. Extraction was performed using an ultrasonicator, and analysis was carried out using a gas chromatograph-electron capture detector. Risk assessment was carried out by determining the hazard quotient. RESULTS: Results of the OCP residues found in the foods were generally low, with dichlorodiphenyldichloroethylene (p,p'-DDE) having the highest residue concentration. The concentration of p,p'-DDE was as high as 110 ng/g in pulses and 123 ng/g in Cameroon and chili peppers. The risk index was <1 in most cases, with the exception of dichlorodiphenyldichloroethane (p,p'-DDD) in fruits for children. DISCUSSION: The results were generally lower than what has been documented in other parts of the world and suggest that consumption of the foods investigated in the present study in Nigeria may be considered safe for the 13 OCPs investigated. CONCLUSIONS: There is a need for continuous monitoring of these OCPs and investigation of carbamate and phosphate pesticide residues since they are more widely used in farming practices in Nigeria.