Burial leakage: A human accustomed groundwater contaminant sources and health hazards study near cemeteries in Benin City, Nigeria.

This study was carried out to assess the levels of physico-chemical parameters that could be impacted by burial leakage and associated human health risks in Benin City, Nigeria. A total of thirty groundwater samples were collected from two cemeteries and analysed for pH, alkalinity, chloride, sulphate, nitrate, phosphate, ammonia- N, calcium, sodium, potassium, BOD5, COD, Mn, Cd, Cu, Ni, Pb, Zn and Fe. The concentrations of the parameters were compared to national and international standards. The results revealed that the groundwater is highly acidic in nature. Principal component analysis (PCA) revealed that except for alkalinity, all other parameters characterised contributed significantly to various principal components (PC) with eigenvalues ≥ 1. Moreover, the significance of the PC depicted decomposition of the body corpse and associated burial materials. Water quality index (WQI), heavy metal evaluation index (HEI) and Nemerov pollution index (NI) indicated that groundwater from the study area is of poor quality, and highly contaminated by heavy metals. We determined the Chronic health risk through exposure by calculating the hazard quotient (HQ) and hazard index (HI), for both children and adults. For the oral exposure, approximately 33% of samples suggest the high category of chronic risk for children while the medium category was indicated for adults. We found that oral exposure showed relatively higher risk than dermal exposure, and chronic risk for children and adults ranged from low to negligible. However, the carcinogenic risk of Ni and Pb via oral exposure route suggests, very high risk for Ni and medium risk for Pb. In consideration that long term exposure to low concentrations of some heavy metals (including Pb, Cd, and Ni) could result in different manifestations of cancer, we recommend that residents of these areas should find an alternative source of water for drinking and other domestic uses.

Ingestion and Dermal Cancer Risk via Exposure to Polycyclic Aromatic Hydrocarbon-Contaminated Soils in an Oil-Producing Community, Niger Delta, Nigeria.

There is an intrinsic link between polycyclic aromatic hydrocarbons (PAHs) accumulated in soils and increased health risk to humans after exposure to contaminated soil via ingestion, inhalation of particulates carrying PAHs, and direct contact with polluted soils. However, the assessment of PAH contamination in most developing countries fails to consider health risk assessment. Therefore, a comprehensive study was conducted to determine the concentration, source, toxicity, and human health risks of 16 PAHs in an urban area in Warri, Delta State, in the Niger Delta region of Nigeria. The results showed varying contamination levels for PAH in soil samples from all sampling points, with benzo[a]anthracene (BaP; at 338.81 µg/kg) being the most abundant at all 9 sampling stations. The highest total concentration of PAH was observed at station 5 (1230.98 µg/kg), which was closest to a flow station. Further comparison with PAH contamination standards showed that soils from stations 1 and 2 were weakly contaminated (<600 µg/kg), and soil samples from stations 3, 4, 6, 7, and 9 were moderately contaminated (<1000 µg/kg). Soil samples from stations 5 and 8 were observed to be heavily contaminated (>1000 µg/kg). The BaP estimates for soil samples obtained for stations 3 to 9 were higher than the BaP soil screening value (15 µg/kg), indicating a carcinogenic potential of soil samples. The results also showed that the incremental lifetime cancer risk estimates for PAH in the soil for adults and children were above the recommended threshold (10-4 ) for ingestion and dermal contact, implying that exposure to contaminated soil could lead to cancers in adults and children. Currently, there are no regional or national standards for PAHs in soil that would indicate an increased likelihood for human exposure and subsequent health issues. Environ Toxicol Chem 2021;40:261-271. © 2020 SETAC.

Interactions of trace metals with bacteria and fungi in selected agricultural soils of Egbema Kingdom, Warri North, Delta state, Nigeria.

This study was aimed at investigating the relationship of trace metals with prevalence of bacteria and fungi in polluted farmland of Egbema Kingdom, Delta state. This may contribute to the knowledge on the influence of the microorganism to the arability of agricultural soil from an ecotoxicological viewpoint. Soil samples were analyzed for physico-chemical parameters and trace metals using atomic absorption spectrophotometer (Buck Scientific, 210VGP). The samples were also screened for fungi and bacteria isolates. Trace metals (Fe, Zn, Cd, Ni and Cu) determined in the agricultural soils of Egbema kingdom were below WHO limits. The fungi species with the highest number of occurrence was Aspergillus niger, while the species with the lowest occurrence were Fusarium oxsporium, Penicillium dirty white, and Penicillium sp. The order of abundance of fungi across the stations was Station 2> Station 4> Station 3> Station 1> Station 7> Station 5> Station 6> Station 9> Station 8. The bacteria species with the highest number of occurrence was Proteus sp I, while the species with the lowest occurrence was Alcaligenes sp. which occurred only once at Station 5. The order of abundance of bacteria in the soil samples across the stations was Station 4> Station 3> Stations 5 and 9> Station 2> Station 8> Station 7> Station 6. All trace metals in the agricultural soils of Egbema kingdom were below WHO limits. Fe, Zn, Cd and Ni showed no relationship with the microbial contents of the soil. Various strains of fungi and bacteria (gram positive and gram negative) were observed in the soil samples. An antagonistic relationship was observed between bacteria and fungi. Significant positive correlation occurred between the concentration of copper and bacteria counts indicating that the concentration of copper in the soil might have enhanced the abundance of bacteria in the soil, vice versa. The bacteria might be a promising tool in regulation of soil copper concentration.