Spatial trend and pollution assessment of total mercury and methylmercury pollution in the Pearl River Delta soil, South China

• Published in: Chemosphere (Oxford) 2012-07, Vol.88 (5), p.612-619
• Main Authors: Chen, Laiguo, Xu, Zhencheng, Ding, Xiaoyong, Zhang, Weidong, Huang, Yumei, Fan, Ruifang, Sun, Jiaren, Liu, Ming, Qian, Donglin, Feng, Yongbin
• Format: Article
• Language: English
• Subjects: Applied sciences; Assessments; China; Deltas; Earth sciences; Earth, ocean, space; Engineering and environment geology. Geothermics; Exact sciences and technology; Hydrogen-Ion Concentration; Land use; Mercury; Mercury - analysis; Methylmercury; Methylmercury Compounds - analysis; Pollution; Pollution abatement; Pollution sources. Measurement results; Pollution, environment geology; Rivers; Rivers - chemistry; Soil; Soil (material); Soil - chemistry; Soil and sediments pollution; The Pearl River Delta; Time Factors; Water Pollution - statistics & numerical data
• ISSN: 0045-6535; 1879-1298
• DOI: 10.1016/j.chemosphere.2012.03.041

► Distribution of THg and MeHg in the PRD area was featured by analyzing large number of soil samples. ► Two expanding high THg pollution zones were observed in the PRD area. ► Pollution status and risk assessment using two methods may be more persuasive. Total mercury (THg) and methylmercury (MeHg) were measured in large number of soil samples collected from areas with different types of land use, different depth in the Pearl River Delta (PRD) of South China. THg and MeHg concentrations ranged from 16.7 to 3320ngg−1 and 0.01 to 1.34ngg−1, respectively. THg levels are highest in the top 0–20cm soil layer, and decrease from the surface to bottom layer soil. Spatial variation was observed with different types of land use. Urban parks had the highest concentrations and the other areas tended to decrease in the order of residential areas, industrial areas, vegetable fields, cereal fields, and woodlands. Temporal variation was also noted, and two relatively high THg contamination zones located in the northwestern part of the PRD have significantly expanded over the last two decades. Both THg and MeHg concentrations were correlated significantly with soil organic matter (OM), but not with soil pH. THg pollution status was evaluated using two assessment methods.