Heavy metals contamination of soil and fodder: a possible risk to livestock

Heavy metals are significant ecological pollutant, principally in areas with sky-scraping anthropogenic stress. Their existence in the environment, soil and water, still in traces can cause severe tribulations to all organisms; heavy metal bioaccumulation in the food chain particularly can be extremely hazardous to animal and human health. Heavy metals generally come into the body by breathing and eating, ingestion being the most important route of contact to these elements in animals. The current study was conducted to examine lead (Pb), cadmium (Cd) and chromium (Cr) in the soil and fodders. Representative samples of soil were collected during two different seasons from two different sites, known as feeding sites for ruminants and analysed for heavy metals after wet digestion, using Atomic Absorption Spectrophotometer. The results showed that location and season had a significant effect (P>0.001) on soil and heavy metal concentrations. Soil and forage Pb, Cd, and Cr concentrations were higher in summer than in winter. From the results of the current study, it was determined that all the metals in soil were lower than deadly levels, posing no probable threat to both plant and animal life. There is an incessant need for monitoring the bioavailability of these heavy metals to grazing livestock, principally in summer season when these metals were found in relatively elevated concentrations, so that their possible toxic consequence to the grazing livestock can not be permitted. Agronomic practices, such as, manure and water managements as well as crop alternation system, can affect bioavailability and crop accretion of heavy metals, thus influencing the thresholds for assessing nutritional toxicity of heavy metals in the foodstuff. This study would be important for livestock owners and scientists working in extension services in Pakistan and other countries with same ecological condition. (author)