Highlight:
(1) Protected cultivation (PC) soil HMs over-standard rates are
prominent in China.
(2) Overall PC area is slightly contaminated, Yunnan and Henan are more
harshly affected.
(3) Cu and Zn accumulation is derived from anthropogenic agricultural
activities.
(4) Pb, Cd, and As accumulation is derived from the soil parent
material.
(5) Available Cu, Zn, As amounts showed a linear correlation with
planting years.