Oxidative stress potential of Lead-Zinc mining on selected plants growing in Ishiagu, Nigeria

Abstract

The study evaluated some biochemical and physiological properties of selected plants growing in the Ishiagu lead-Zinc mining area, Nigeria, in order to assess oxidative stress. Using sampling without replacement, twelve plants were randomly selected from the thirty five identified. Control samples were collected from a non-mining area about twenty five km away from the study area. Results showed that statistically significant differences were not found between sites with respect to biochemical parameters (ascorbic acid content, pH, total chlorophyll content and relative water content) at p>0.05. Physiological parameters (abaxial and adaxial stomata pore size) showed significant difference between site at p>0.05. With respect to plants, values for all parameters were statistically significant at p>0.05 except for relative water content, possibly due to stomatal occlusion from particulate contamination at the mining area. The lower mean values for pH, total chlorophyll content, and stomata pore size, and the higher mean ascorbic acid values of plants at the mining area is suggestive of oxidative stress from heavy metal accumulation. Stress is very likely to have less potential of mitigating air pollution and providing other environmental services. Such plants also suffer from compromised nutritive and phytotherapeutic values, as well as being potential sources of pollutant intoxication of man and animals through dietary origin.

 Key Words: Heavy metals, Plants, Physiochemical status, Oxidative stress, Health risks