This study assessed the concentration of pesticides residue in an agriculturally endemic basin in southeastern Nigeria, where pesticide is freely used without any form of regulations. Analysis of water and fish from the streams and tributaries in the basin reveal a very high level of pollution from organochloride pesticides and atrazine which occur above international drinking water standards and at health hazard levels where ecosystem and human health can be compromised. Some of these chemicals have been outrightly banned or their use restricted by international conventions, yet they are freely used in the study area. There is therefore a need for Nigeria to adhere to the provisions of the Stockholm Convention and the earlier Rotterdam Convention which list more chemicals for various forms of restriction to protect man and the environment.

Background: Today, pollution is a serious issue that threatens the health of billions of people, weakens the economic security of nations, and is to blame for a significant portion of the world's burden of disease, disability, lost productivity, medical expenses, and costs associated with ecosystem damage and premature death. However, despite their enormous size, these expenses are often hidden and frequently go unnoticed as a result of pollution. This has the effect of preventing the entire costs of pollution from being understood, often going uncounted, and being used to counteract economic arguments which are biased towards pollution control. Objectives: This study investigated air quality in the Mgbede Oil Fields of South-south Nigeria. Methods: Air quality sampling points were selected purposefully to meet the objectives of the study. Portable Real-Time Monitoring Technique was used was used for measurement. Results: From the analysis of air samples, cadmium (0.005-0.008 µg/m3) and lead (0.012ug/m3) were detected within the vicinity of the gas flare. Nickel was in the range <0.002 to 0.014 µg/m3 with highest concentrations in the gas flare area. Total suspended particles were within acceptable limits (120 ug/m3) in all locations with PM10 component above standards in the vicinity of the gas flare (20.6-22.6 ug/m3). Zinc was in the range <0.002 to 0.014 ug/m3 with maximum concentrations around the gas flare site. Although these concentrations are well within the acceptable daily exposure range but could be associated with exacerbations in risks of paediatric asthma. NOx ranged between 0.038-0.058 ug/m3 in the study area and falls above standards (0.04 ug/m3) in over 80% of sampled locations. Highest concentrations (0.058 ug/m3) were found around the flare area. SO2 was only detected at concentrations above acceptable limits within the gas flare site at Ebocha. Conclusion: The study therefore concluded that air quality in the area is not only negatively influenced by continuous gas flaring but occur at levels above acceptable international standards where environmental health could be adversely affected. Relocation of all homesteads within 1km radius of the gas flare with adequate compensation for inhabitants with improvement in healthcare delivery; and the establishment of a special health insurance trust fund for long-term exposure to pollutants from oil producing activities are among recommendations. Additionally, since this public health issue necessitates environmental health policies to reduce air pollution, efforts to battle the massive air pollution issues in the Niger Delta and its environmental quality must be combined by worldwide mitigation.

This study assessed the nutrient and heavy metal concentrations in sediments and macrophytes of the Oroma wetland, University of Port Harcourt, Nigeria. A map representation of the wetland was assigned North-South (N-S) grid lines and six numbers were randomly selected to represent the six sampling points -SS1, SS2, SS3, SS4, SS5 and SS6. Sediment and three macrophytes (Alchornea cordifolia, Sacciolepis africana, and Harungana madagascariensis) that were present in each grid were collected and analyzed. Results showed that the wetland sediment was polluted with cadmium (4.80-54.10 mg/kg) and lead (98.60-175.30 mg/kg) whereas, only the sediment obtained from SS1 was polluted with nickel (75.9 mg/kg). In the sediment, cadmium posed a very high ecological risk; lead posed a considerable ecological risk whereas, the other heavy metals analyzed in this study posed low ecological risks. SS5 and SS6 had very high ecological risks whereas, the other sampling sites had moderate ecological risks. Cadmium, cobalt, copper, iron, zinc and arsenic were in same cluster in sediment based on cluster analysis while, chromium and nickel were assigned a separate cluster. The macrophytes collected from each site bioaccumulated the heavy metals from the sediment albeit at varying levels. Major sources of the nutrient and heavy metal burden in Oroma wetland were identified as runoffs and effluents from the adjoining University, residential areas, farmlands, car wash centers, generator houses, slaughter houses, metal dump sites, automobile maintenance shops, and vehicle exhaust. This study has highlighted the pollution status of the Oroma wetland sediment, the heavy metal burden of its macrophytes and the ecological risks posed by these heavy metals which have serious public health and ecological consequences.

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