Increased occurrence of heavy metals, antibiotics and resistance genes in surface soil after long-term application of manure.

The purpose of this study was to investigate the impact of long-term application of pig manure on the accumulation of heavy metals, antibiotics and ARGs in surface soil sampled from the Jiaxing long-term field experimental site with three manure treatments, N-PM (0 kg/ha/y, dw), L-PM (7720 kg/ha/y, dw), and H-PM (11,580 kg/ha/y, dw), in 2013 and 2014. The results showed that most serious metal pollution of Zn and Cu was recorded in all manured samples in both years, and their contents exceeded the soil quality standards. Among the three tetracyclines, chlortetracycline was the predominant antibiotic detected with a range of 3.