Investigation and analysis of heavy metal contents from livestock feed and manure in North China.

With the popularity of understanding of pollution-free agricultural products by the public, government pays much attention to the safe application of organic fertilizer during the agricultural production process. Manure is not only the main raw material of organic fertilizer, but also one of the important factors affecting the quality of agricultural products. Due to the intensive and large-scale of livestock farming rapid development, some heavy metals such as Cu, Zn, As, Cr, Pb are widely used in feed additives. The biological potency of these trace elements is low, and with the use of animal manure into the environment, brings potential environmental risks and hazards to human health. In order to strengthen the source control of heavy metal, and further form the heavy metal resistance control system for organic fertilizer of agricultural products, in this paper, the heavy metal content in livestock and poultry feed was sampled for investigation and analysis. The results showed that the mainly exceeded elements of heavy metal in the livestock were Cu, Zn. Heavy metals Pb, Cr, As followed, and Cd, Ni, Hg were not exceeded. The exceedance of these elements in pig manure and broile manure were the most serious for all kinds of animal manure, beef cattle manure and egg chicken manure followed, and the cow dung was not exceeded. The value of the exceeded rate of Cu, Zn for pig manure and broile manure were up to 100% and 91.67%, respectively. The mainly pollutants for broile were Cr, Cu, Zn, and the value of exceeded rate were 50%, 66.67%, and 50%, respectively, but the egg chicken manure only had Cu exceeded, exceeding the rate of 11.11%. Different livestock feed exceedances of heavy metals in pig feed and beef cattle feed werethe most serious, and broile feed and cow feed followed. According to the Ministry of Agriculture's 1224 announcement for the Cu, Zn standard, Cu and Zn in pig feed exceeded the rate of 66.67% and 80.00% respectively, and broile feed Zn exceeded 62.50%; According to the feed hygiene standards for Cr, Pb, heavy metals Cr and Pb in beef cattle exceeded 83.33% and 66.67%, Cr in cow feed exceeded 60%, Pb in egg chicken feed exceeded 53.85%, and Cd in different animal feeds were not exceeded. The content of heavy metals Cd, Cr, Cu, Zn in animal manure showed a significant positive correlation with livestock feed (P<0.01), and the content of Pb in animal manure showed a significant correlation with livestock feed (P<0.05). The research helps to grasp the North China heavy metal pollution status in feed-animal manure, revealing the problem for heavy metals exceeded in manure and organic fertilizer which should be controlled from the source. This research to further reduce heavy metal pollution in the region and to ensure the quality and safety of agricultural production has an important significance. [ABSTRACT FROM AUTHOR]