HEAVY METAL BIOACCUMULATION IN WETLAND ECOSYSTEMS AND ITS EFFECTS ON AVIAN REPRODUCTIVE BIOLOGY

Abstract

This study investigated the extent of heavy metal bioaccumulation in wetland ecosystems and its consequential effects on avian reproductive biology. Comprehensive environmental sampling across multiple wetland sites revealed elevated concentrations of mercury (Hg), lead (Pb), cadmium (Cd), and arsenic (As) in both sediments and water, with spatial variability linked to proximity to industrial discharge and agricultural runoff. Temporal analysis indicated heightened metal levels during the wet season, likely due to enhanced runoff dynamics. Bioaccumulation assessments identified Typha latifolia and Phragmites australis as key phytoremediators due to their high uptake of chromium, arsenic, and mercury, while benthic macroinvertebrates demonstrated significant metal burdens, facilitating trophic transfer to higher-order consumers. Avian blood, feathers and eggs contained heavy metals over the thresholds considered hazardous to animals. These levels were also related to lower numbers of eggs laid, fewer eggs that hatched and a lower chance of birds surviving until they fledged. Examination of the liver and kidneys of birds affected by chronic metal exposure showed damage to cells and signs of oxidative stress. Statistical models revealed strong links between high metal levels in the environment and reproductive difficulties found in people. The results underline how heavy metal pollution endangers birdlife and weakens wetland habitats, so experts need to introduce strategies such as controlling sources of pollution and planting pollution-reducing plants. This research gives important understanding of how biodiversity can be protected in contaminated aquatic environments and supports the creation of policies to do so.