Problem section: Effluents from the surrounding industries such as tannery and textile are used by vegetable farmers for the irrigation of their crops. These effluents may contain some toxic metals which bioaccumulate along the food chain. Moreover the uptake of such toxic metals by crops is governed by their availability and concentration in the soil. Therefore such crops may accumulate heavy metals in excessive amount in their various parts. This may ultimately, adversely affect humans and other species that depend on such crops for food, hence the need to evaluate the pollutant levels in vegetables samples in these areas. Approach: Six vegetable samples of various organs were freshly harvested from ten farms within the vicinity of Challawa industrial areas. The concentration of heavy metals which include, Cu, Zn, Co, Mn, Mg, Fe, Cr, Cd As, Ni and Pb, were determined using Perkin-Elmer analyst 300 Atomic Absorption Spectroscopy (AAS). Levels of some anions (nitrate, nitrite, sulphate and phosphate were determined using Hach direct reading 2000 Spectrophotometer. Results: The results obtained from this analysis revealed that Cr and Fe shows the highest concentrations, while As shows the lowest levels in the whole vegetable organs studied. The concentrations of the anions ranged between 40.00-1300.00 µg g −1 nitrite, 65-1500 µg g −1 nitrate, 122.00-765.00µg g −1 and12.00-60.00 µg g −1. The leaves contained much higher concentrations of heavy metals and anions than roots and stems. Conclusions: The concentrations of the above parameters were higher than the FAO, WHO/EU and FAO/WHO allowed limit. The high values might be attributed to the used of untreated effluents from textile and tanneries industries by farmers for the irrigation of these vegetables. Thus, the high values of these trace metals and anions in the vegetable samples could put the consumers of these vegetables at health risk. Further works should be carried out in the soil samples were the vegetables are grown.

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Effluent samples from tanneries and textile industries from Kano industrial area of Challawa, Bompai and Sharada industrial area were collected on quarterly basis from June to September, 2007 (Rainy season), November, 2007-February, 2008 (Harmattan season) and March-May, 2008 (Dry season) to reflect the seasonal factors. Effluents from ten industries were sampled and determined for physicochemical parameters. The physicochemical pollutants indicators determined include; Biological oxygen demand (BOD) and Chemical oxygen demand (COD) which all depend on the concentration of dissolved oxygen (DO) in effluent samples. Anions and trace elements were also determined. The above parameters were determined using standard procedures. From the results of the study, the concentrations of BOD, COD, DO, nitrate, nitrite, sulphate, phosphate, chloride and heavy metals were higher than the limits set by WHO for the discharged of tanneries and textile effluents into river. Result of analysis of variance (ANOVA) showed that variations between some industries were statistically significant (p≤0.05), but there were no marked seasonal variation in all the industries studied. Based on the high levels of the above parameters, it can be suggested that regular monitory of pollutants in the tannery and textile effluent are necessary to ensure proper discharge of these effluents into receiving river.

Leachates from selected dumpsites and control site in Lokoja municipal were analyzed for trace metal concentrations. These parameters were compared with control samples and established international standards (FEPA) and (WHO). Dumpsite leachates contained very high concentrations of iron (73.60±0.58)mg/L, manganese (16.53±0.309)mg/L, copper 1.00±0.02mg/L, zinc 2.41±0.042mg/L, and lead 1.55±0.097mg/L. All the parameters except nickel and cadmium were above the control and exceed FEPA and WHO guidelines. The study revealed that the dumpsite is a major polluting source in the surrounding environment. This underlines the need for appropriate government agency of Kogi State, Nigeria to initiate active remediation process such as phytoremediation in combination with physiochemical methods to recover the dumpsite from contaminants and reduce the level of pollution in the surrounding environment.

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