Hazardous metals in animal manure and their changes from 1990 to 2010 in China

Abstract

Contents and changes of some hazardous elements in 388 animal feed and manure samples collected in 2009–2010 from 194 animal farms in 10 provinces of China were determined. The concentrations of Cu, Zn, Cr, and Pb in animal manures were in the ranges of 10–1800, 50–6300, 0.1–340, and 1.0–310 mg kg−1, with median concentrations of 200, 500, 15, and 11 mg kg−1, respectively. As, Cd, and Hg were in ranges from undetectable to 280, undetectable to 10, and 0.01–2.5 mg kg−1, respectively. The concentrations of Cu, Zn, and As were highest in the manure from pig, followed by the manure from poultry and dairy cows. From 1990 to 2010, Cu, Zn, As, Cd, and Cr contents in manure increased strongly, especially in pig and poultry manure. Most of the increases occurred before 2003 and then stabilized or decreased which reflects the extensive use of feed additives before 2003 and the gradual stabilization since then.