Accumulation, risk assessment and source apportionment of heavy
metals in protected cultivation soil, China
Weihong Lu a, b, 1, Juan Liu a, b,
1, Naiming Zhang b, c, *, Kangwei Haob, c, Hong Yu b, c, Jiaqi Lib,c, Chang Yu b, c, Kelin Hud
a College of Plant Protection,
Yunnan
Agricultural University, Kunming 650201, China
b Yunnan Province Soil Fertilization and Pollution
Remediation Engineering Laboratory, Kunming 650201, China
c College of Resource and Environment, Yunnan
Agricultural University, Kunming 650201, China
d College of Soil and Water Sciences, China
Agricultural University, Beijing, 100193, China
1 Weihong Lu and Juan Liu as Co-first author
* Corresponding author: Naiming Zhang
Correspondence address: College of Resource and Environment Science,
Yunnan Agricultural University, Kunming 650201, China
Tel: +86-871-65229840
E-mail: soilenvironment@163.com
Abstract: The problem of soil heavy metals (HMs) accumulation
from protected cultivation (PC) needs an urgent solution. 132 soil
samples from typically high-density PC areas were analyzed for
accumulation, risk, and sources of 8 HMs in 16 cities of 8 provinces,
China. The soil HMs accumulation characteristics were prominent; Cu, Zn,
Pb, Cd, As over-standard (GB 15618-2016) rates reached 15.2, 4.5, 3.0,
27.3, and 2.3%, respectively. The single-factor pollution index
indicates that Cd reached slightly contaminated levels in the whole
area, while Cu was at a slightly contaminated level only in Yunnan
Province. The Nemeiro comprehensive pollution index and the
comprehensive quality index suggested that HMs accumulation were at the
slightly contaminated levels, with Yunnan province being the most
affected and Henan followed. Cu and Zn accumulations are mainly related
to frequent input of organic fertilizer, especially livestock manure’s
direct return to the field. Therefore, Cu and Zn showed a strong
correlation (P<0.01) with soil organic material (SOM), and their
available amounts linearly correlated with the extension of planting
years in PC. On the contrary, Pb and Cd amounts are only related
(P<0.01) to soil texture, and their main sources are related to the
parent material of soil formation. Moreover, their available amounts did
not correlate with the planting years. Our results suggest that
long-term and unreasonable PC may lead to soil HMs accumulation.
Therefore, appropriate agricultural materials, planting systems, and
fertilization methods must be used to effectively avoid the risk of
excessive HMs accumulation in the PC soils.
Key words: Protected cultivation soil; Heavy metals;
Accumulation characteristics; Risk assessment; Planting years