Ó Springer 2006
Environmental Geochemistry and Health (2006) 28:79–87 DOI: 10.1007/s10653-005-9016-y
Distribution patterns of polychlorinated biphenyls in soils collected from Zhejiang province, east China Jun Gao1,2,4, Yongming Luo2,5, Qingbo Li2, Haibo Zhang2, Longhua Wu2, Jing Song2, Wei Qian2, Peter Christie3 & Shengming Chen1 1 College of Biosystem Engineering and Food Science, Zhejiang University, Hangzhou 310029, China 2 Soil and Environment Bioremediation Research Center, State Key Laboratory of Soil and Sustainable Agriculture, Institute of Soil Science, Chinese Academy of Sciences, Nanjing 210008, China 3 Agricultural and Environmental Science Department, Queen’s University Belfast, Newforge Lane, Belfast BT9 5PX, UK 4 Agricultural and Food Engineering Department, Huaiyin Institute of Technology, HuaiÕan 223001, China 5 Author for correspondence (e-mail:
[email protected])
Key words: China, distribution patterns, PCBs, surface soils Abstract Polychlorinated biphenyls (PCBs) were determined in surface soil samples from Zhejiang Province, east China. Concentrations of total PCBs ranged widely from 7.50 to 263 ng kg)1 with a mean value of 45.4 ng kg)1 (dry matter basis). In general, concentrations in soil samples from the southern part of the test area and especially from some sites near hills tended to be higher than those from other sites. The prevailing winds may have been the main factor influencing the spatial distribution of PCBs in soils. Other factors may have included the distribution of residential areas and land use variables. In this paper we also discuss the relationships between OCPs and PCBs in soils and relationships between these and land use variables as revealed by correlation analysis. Introduction Polychlorinated biphenyls (PCBs) are widespread toxic organic pollutants which, due to their persistence and lipophility, have accumulated in the environment, especially in soils and sediments (Kubatova et al. 2001). The total background PCB burden in soils globally has been estimated to be 21,000 t and the majority of this (60%) may reside in the 30–60°N latitudinal band (Meijer et al. 2003). Soils represent one of the contamination pools from which PCBs can be transferred to air (Bidleman & Leone 2004) or water (Zhang et al. 2003). Even relatively low concentrations of PCBs in soils in the ppb range can be bioaccumulated gradually along food chains with potentially adverse effects on humans. PCBs have therefore been listed by the
United Nations Environment Program (UNEP 2001) as one of 12 classes of persistent organic pollutants (POPs) and been given high research priority. A number of studies have concentrated on PCB contamination surveys, biodegradation, transport and sorption behavior in soils and sediments (Chu et al. 1999; Wu et al. 1999; Fu et al. 2003; Marvin et al. 2004) (Table 1). In China about 10,000 t of the PCB congeners (main tri- and penta-chlorinated biphenyls) were produced during the decade from 1965 to 1974, mainly for use in the insulation of electrical equipment. Others were employed as additives to paint, with the remainder utilized in a range of products. These chemicals have polluted or are polluting various environmental components including soils (Kang et al. 2000; Bi et al. 2001).
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Table 1. Concentrations of PCBs in soils and sediments from various locations within and outside of China. Location
PCB concentration Reference (ng g)1 dry weight)
Soils Huairou (North 0.42a China, background value) WT (Zhejiang, 927.30a polluted) WT (Zhejiang, 259.36a adjacent to polluted area) FY (Zhejiang, 7.5–263.35 rural area) (45.42a) Central Germany 1–10 Southern Norway 17.5a UK 4.0a Sediments Changjiang River 3.0–9.5 (7.1) Huangpujiang 19.9a River Zhujiang River 11.54–485.45 Minjiang River 15.13–57.93
Chu et al. (1999)
Materials and methods Bi et al. (2001)
Description of study area and soil sampling Bi et al. (2001)
This study Manz et al. (2001) Lead et al. (1997) Lead et al. (1997) Wu et al. (1999) Wu et al. (1999) Kang et al. (2000) Zhang et al. (2003)
(34.49a) a
these in the surface soils (0–20 cm) under various land uses from various parts of Zhejiang province. The aim was to provide a basis for assessing soil quality in the Yangtze River Delta against a background of rapid economic development.
Denotes average values.
The Yangtze River Delta comprises the city of Shanghai and some parts of Jiangsu and Zhejiang provinces in east China. The region covers an area of about 99,530 km2, about 1.04% of the area of China, but its GDP accounts for about 16% of the national GDP and it is one of the most rapidly developing regions in China. Zhejiang province is typical of the Yangtze River Delta, with a very dense population and a large number of new industrial and commercial enterprises which contribute to regional economic development but also pose a serious threat to the environment. The quality of the environment in this region is of increasing concern. Several studies have been conducted on organochlorine contaminants in river and estuarine sediments and in indicator organisms such as birds (Ruan et al. 2003; Yang et al. 2003), and there has been one published study on organochlorine pesticides (HCB, BCH and DDX) in soils (Zhao et al. 2002). There have been few, if any, studies on PCBs in soils from this region. Such studies are required to minimize environmental degradation and develop sustainable industrial and economical development. The present study was designed to examine and evaluate levels of PCB residues and factors affecting
Sampling was conducted from 15 to 30 July, 2003. The selection of the sampling area was not based on past records of soil PCB contamination but was intended to sample surface soils in typical areas of economic development that have not been affected by serious pollution incidents. The study site comprised an area of 10 km2 in central Zhejiang province containing several small commercial plants and surrounded by hills. In addition, the area contained several villages, trunk roads and rivers (Figure 1) and was considered to be fairly representative of the Yangtze River Delta. Surface soil samples (0–20 cm) were collected with a stainless steel spatula by grid-pattern sampling. At each location five samples were collected from a 5050 m plot, one from each corner and one from the center, and thoroughly mixed to give a composite sample. The sampling positions were recorded using a global positioning system (GPS). A total of 131 soil samples were collected for analysis, representing 54 paddy soils, 23 upland soils, 31 forest soils and 23 ‘wasteland’ soils. Sample extraction and cleanup Soil samples were air dried and sieved (
