Suelos

land degradation & development
Land Degrad. Develop. (2011)
Published online in Wiley Online Library (wileyonlinelibrary.com) DOI: 10.1002/ldr.1077

CHEMICAL AND MICROBIAL PROPERTIES IN CONTAMINATED SOILS
AROUND A MAGNESITE MINE IN NORTHEAST CHINA
D. YANG1,2, D.-H. ZENG1*, J. ZHANG3, L.-J. LI1,2 AND R. MAO1,2
1

Institute of Applied Ecology, Chinese Academy of Sciences, Shenyang 110016,China
2
Graduate University of Chinese Academy of Sciences, Beijing 100049, China
3
USDA Forest Service, Pacific Southwest Research Station, 3644 Avtech Parkway, Redding, CA 96002, USA
Received 24 July 2009; Revised 3 November 2010; Accepted 3 November 2010

ABSTRACT
We measured soil chemical and microbial properties at a depth of 0–20 cm among mine tailings, abandoned mined land,contaminated
cropland, and uncontaminated cropland around a magnesite mine near Haicheng City, Liaoning Province, China. The objective was to clarify
the impact of Mg on the soils. We found that soluble Mg2þ concentration and pH were significantly higher in contaminated soils (266–
345 mg kgÀ1 and 9Á9–10Á3, respectively) than in uncontaminated soils (140 mg kgÀ1 and 7Á1, respectively). Soil nutrients(total N, total P,
mineral N, available P and soluble Ca) and microbial biomass C and N decreased as pH and soluble Mg2þ concentration increased. In addition,
an increase of microbial metabolic quotient and a decrease of N mineralization rate were found in contaminated soils. Soluble Mg2þ/Ca2þ
ratios in contaminated soils were 3Á5–8Á9-times higher than in uncontaminated soils. Our results indicatethat soil contamination in such
magnesite mine regions is characterized by high pH, Mg2þ concentration and soluble Mg2þ/Ca2þ ratio, and low microbial activity and N and
P availability. Future soil amelioration in the magnesite regions should consider applying acid ameliorants to neutralize high pH and applying
calcareous ameliorants to increase Ca2þ concentration. Copyright # 2011 John Wiley &Sons, Ltd.
key words: magnesium dust; soil contamination; soil microbial activity; soil microbial biomass; Northeast PR China; soil chemistry

INTRODUCTION
Mining is one of the most land-degrading industries. Mining
operations not only destroy original soils and vegetation
cover but often leave some waste materials that contaminate
air, water, and soils (Singh, 2005). Magnesite mining is agood example; the dusts from the mining and magnesite
calcination have been reported to severely damage native
vegetation and soils (Bradshaw, 1997; Machin and Navas,
2000). The current remediation actions are insufficient to
prevent the spreading of dust with high concentrations of
magnesium (mainly MgO and MgCO3) to surrounding
forestlands and crop fields, so soil pollution and vegetationdestruction are widespread in the regions. Machin and Navas
(2000) found a significant pH increase in soils polluted by
magnesite dusts in the Pamplona Valley in Spain. Kautz
et al. (2001) reported that soil microbial biomass and
activities decreased around a magnesite factory in the Slovak
Republic compared with soils far from the factory. Joshi
(1997) also found that the magnesite miningreduced soil
organic matter and nitrogen content. Moreover, studies
from a pot experiment showed that the high ratio of soluble
* Correspondence to: D.-H. Zeng, Institute of Applied Ecology, Chinese
Academy of Sciences, 72 Wenhua Rd, Shenyang 110016, China.
E-mail: zengdh@iae.ac.cn

Copyright # 2011 John Wiley & Sons, Ltd.

Mg2þ/Ca2þ caused by Mg-contaminants affects absorption
of Ca2þduring plant growth, and is an important factor
limiting plant colonization and survival (Li et al., 1990; Li
and Yu, 1997). The causticity of the magnesium oxides in the
mining dust burns leaves and broad-leaved species are especially
vulnerable (Machin and Navas, 2000). Raman et al. (1993)
reported that vegetation in a magnesite mining region of the
Eastern Ghats, southern India, consisted...