Speciation, Activity, Transformation, and Degradation of Heavy Metals and Organochlorines in Red Soils

Abstract

China launched a national soil quality and pollution survey (NSQPS) from 2006 to 2010 and released the nationwide survey of soil pollution bulletin on April 17, 2014. The survey showed that the main pollution type in China was inorganic pollution (82.2%), followed by organic pollution and combined pollution (Ministry of Environmental Protection and Ministry of Land and Resources of P. R. China 2014). The main inorganic pollutants are heavy metals, including cadmium, arsenic, copper, lead, chromium, zinc, etc. Heavy metal pollution is covert, persistent, and irreversible (Wang et al. 2001), may remain in local ecosystem for a long time, and poses a potential threat to public health (Ben Fredj et al. 2014). Organic pollutants are known to persist in the environment, bioaccumulate in biota, and pose hazard to the ecological system and human health. How to clean the heavy metals and organic pollutants from the environment in order to avoid their entrance into the food chain is important for protecting the health of animals and human beings. Therefore, understanding the status of heavy metal and organic pollutions is the basic idea for remediating the pollution from the environment. Guangdong Province, especially the Pearl River Delta (PRD), has undergone a rapid transition from a traditional agriculture-based region to an increasingly industry- and technology-based region. As a consequence, the soils in PRD have been extensively under severe environmental stresses and considered to be a perfect region for regional researching and evaluation of pollutions (Hu et al. 2013). Due to non-strictly controlled emissions from mining, smelting, and industrial activities in PRD over the past several decades, large amounts of wastewater, sludge, e-waste, and exhaust, which often contain elevated concentrations of heavy metals, have been released to the environment (Zhou et al. 2007; Zhao et al. 2012). And the agricultural boom in the recent past was accompanied with widespread applications of pesticide as DDTs and HCHs, making the PRD a region with the highest usage of pesticide in China (Hua and Shan 1996). Therefore, increasing efforts have been made to deal with environmental pollution issues in the PRD region. Our article would compile our research results, which have already been published in professional journals, to try to provide a comprehension of the heavy metal pollution in PRD and microbial remediation of organic pollutant.