Fate and Toxicity Effects of Phthalic Acid Easters in Farmland Soil

Phthalates or phthalic acid esters (PAEs), a class of endocrine-disrupting chemicals, widely used as additives in the manufacture of various plastic, rubber, and resin. With the increasing usage and substantial production of these products, PAEs have become the most residual and concerned organic pollutants in Chinese agricultural soil, posing potential threats to agro-ecological environment and human health. According to current references, this study summarized the research progress on the sorption, biodegradation, migration and volatilization of PAEs in agricultural soil based on the systematic summary of the main source and distribution of PAEs in agricultural soil, and the toxic effects of PAEs on soil organisms (including microorganisms, animals and crops) and human body were also respectively reviewed. The agricultural film covering and its residues were disclosed as the main causes of PAEs pollution in Chinese agricultural soil. About 58.5% of PAEs were distributed in 0-20 cm depth of agricultural soil surface, and there were significant spatial variations among different regions. The PAEs with high octanol-water partition coefficient (lg K_ow) and fat solubility were mostly adsorbed on the topsoil, while the PAEs with low lg K_ow and high water solubility had high migration potential. Soil organic matter was the main factor to hamper the downward migration of PAEs. Microbial degradation was the main way to remove PAEs from agricultural soil, which was affected by the chemical structure and the characteristics of soil. Short-term exposure to high concentrations of PAEs would produce different degrees of physiological, biochemical and even genotoxic effects on soil organisms, and eventually endangered human (especially children) health through dietary intake. At present, the researches on PAEs in agricultural soil are still focused on the investigation of soil pollution distribution patterns and occurrence characteristics. Studies about the migration and transformation process and combined toxic effects of several PAEs in natural soil, as well as the environmental behavior and toxicity of their metabolites, is the research trends in the future, so as to provide theoretical basis for the formulation of control standards and ecological risk assessment of PAEs in agricultural soils.