Distribution Characteristics of Organochlorine Pesticides in Soil and Groundwater of Different Irrigation Areas in Southeast Suburb of Beijing

Abstract

Wastewater has been widely used in agriculture irrigation for nearly a century in the world, due to the scarcity and quality declination of water resources. The wastewater irrigation technologies in USA, Japan, Israel and some developed countries are more mature than other developing countries (Angelakis A N et al., 1999; U Pinto et al., 2010; US EPA, 2004). Although wastewater irrigation can supply a lot of nutrients to crop, such as Nitrogen and Phosphor sources, it can cause soil pollution, like heavy metals, organic pollution and so on. Therefore, reclaimed water, instead of wastewater, as agriculture irrigation water resources became more popular now, because not only can reclaimed water relieve the tensions of agriculture water resource, but also relieve the pressure of wastewater on environment (T.Asano et al., 1996; D.Levine et al., 2004; I.K.Kalavirouziotis et al., 2008; V.Reboll et al., 2000). However, the nature of reclaimed water is still a poor-quality water, the amounts of contaminants in reclaimed water are changed with treatment, still a lot of pollutants can not be effectively removed. Some matters in reclaimed water may benefit crops, such as N, P, K, some else may be harmful to the surrounding environment, crop, operator and consumer of agriculture products, like heavy metals, salts, and various carcinogenic, teratogenic, or mutagenic organic compounds, the long-term irrigation will bring harmful to soil and groundwater, causing a new source pollution (Francisco P et al., 2009; Friedler E et al., 2004; Gross A et al., 2007). As a large agricultural country, the agricultural irrigation water consumption accounts for more than 70% of the total water consumption in China. Due to water shortage, wastewater irrigated area expanded rapidly from 1970s to the 1990s. By 1998, wastewater irrigated area has reached 361.8 × 104 hm2, which accounting for 7.3% of the total irrigated area. The city of Beijing in China began to use wastewater irrigation since the early 50s of the 20th century, so far, the wastewater irrigation area in Beijing are nearly 80,000 hm2 and the yearly wastewater irrigation is about 220 million m3 which accounting for 20% of the city’s wastewater emissions, 87% of the wastewater irrigation area are mainly in Tongzhou District, Daxing District and Chaoyang District (Zhang H Y et al., 2006; Hua X M et al., 1996). The quality and fertility of domestic sewage are better and beneficial to rice, but the industrial effluents are not as well, it contains some heavy metal salts, such as lead, chromium, arsenic, mercury, and some harmful ingredients, take chlorine, sulfur, phenol,