BIOACCUMULATION PATTERNS OF LEAD AND CADMIUM IN WILD DUCKS: IMPLICATIONS FOR AVIAN HEALTH AND ECOSYSTEM MONITORING

Abstract

Heavy metals are the hazardous elements which pose serious threats to human health if surpassed normal amounts. Heavy metals with the density greater than 5.0 g/cm³ are ingested by humans through the consumption of meat and other dairy products. A few major heavy metals include lead, cobalt, cadmium, copper, arsenic, zinc and mercury. They are specifically harmful to bird population like wild ducks which are frequently exposed to these heavy metals. We will review the effect of lead and cadmium in liver and kidneys of wild ducks. Wild ducks act as the bio indicators of environmental pollution in a particular area especially wetland ecosystems.as liver and kidney are the most effected tissues by heavy metals because of their physiological functions like detoxification and in few studies metal processing. These two organs serve as the site of accumulation for these metals. The toxic metals can find their way into numerous food sources via several routes, such as farming methods, agricultural soils, irrigation water, air, animal feed, and packaging materials. The prolonged exposure to these metals may have toxicological effects on reproduction and survival of the wild ducks. These metals may cause oxidative stress or histopathological alterations in the affected individuals. The factors that affect the accumulation of these metals includes specie-specific characteristics, age, sex, food habits and the level of environmental pollution. Lead (Pb) and cadmium (Cd) are persistent environmental toxicant that pose serious risk to aquatic ecosystem and avian biodiversity. Wild ducks are continuously exposed to these metals through polluted water, sediments, aquatic vegetation, invertebrates, and fish, making them effective biological indicators of wetland contamination. This Study reviews existing research on the sources, environmental pathways, toxicokinetics, and tissue-specific accumulation of lead and cadmium the heavy metals in wild ducks population. Particular attention is given to the liver and kidneys as major target organs because of their critical roles in detoxification, filtration, and metal storage. Prolonged exposure leads to oxidative stress, tissue damage, immune suppression, and long-term physiological dysfunction. The review also identifies specie -related difference in accumulation pattern influenced by feeding, ecology, habitat use, age, sex, and tropic position within aquatic food webs. Evidence further confirms that bioaccumulation and biomagnification processes intensify metal concentrations across trophic levels, increasing ecological and biological risks. In addition to physiological toxicity, exposure to lead and cadmium is associated with reproductive impairment, neurological disruption, and behavioural abnormalities in birds. Overall, the findings establish wild ducks as reliable sentinel species for monitoring environmental pollution and ecosystem health. Continuous biomonitoring programs, stronger pollution control measures, and habitat -based conservation strategies are essential for minimizing heavy metal exposure and protecting avian biodiversity and aquatic ecosystem stability. This review also takes a dig at the eco toxicological effects of Pb and Cd in the wild ducks, emphasizing their implication as sentinel species for wetland pollution monitoring. Future research guidelines and moderation procedures are also considered, underlining the compulsion of more rigorous environmental laws and continuous biomonitoring initiatives. The goal of this thorough review is to upkeep conservation efforts and advance knowledge of heavy metal toxicity in avian fauna.