基于农产品质量安全的土壤资源管理与可持续利用

目前我国土壤和农作物中有毒物质的残留问题日趋突出。有机氯农药虽已禁用近20年,但通过某些食物链富集仍可对人体健康产生威胁。此外,残留农药的种类和数量逐年增加,其中有机磷农药问题尤为突出。重金属残留超标主要集中在大中城市郊区、污灌区和矿区农产品,尤其是城郊蔬菜中重金属污染问题比较突出。硝酸盐积累主要在农业集约化地区,尤其是塑料大棚等保护地问题比较普遍。农产品中的有机氯残留、重金属残留以及硝酸盐积累均与土壤污染有密切的关系,土壤是影响农产品质量安全的源头因素。因此,为了保证农产品质量安全,应尽快开展全国土壤环境质量调查与评价,建立长期性的土壤环境质量监测网络,并加强土壤中环境激素类的研究和监测,修订土壤环境质量与农产品质量标准,建立基于污染物生物有效性的环境质量标准体系与评价方法。同时制订土壤质量修复和保护规划,并完善有关立法,实现土地资源由数量管理向数量与质量管理并重的战略转变。

SUSTAINABLE MANAGEMENT OF SOIL RESOURCES FOR FOOD SAFETY

The problem of toxic residues in soils and agricultural products has become more and more prominent recent years in China. Although the use of organochlorines has been banned for nearly 20 years, their residues can still be detected in many kinds of food and produce potential adverse effects on human health through the food chains. Furthermore, residue of pesticides in agricultural products has been increasing in both kind and level, especially the organophosphates. Pollution of heavy metals occur largely in suburbs of large and medium-sized cities, lands irrigated with sewage and minings, resulting in residues in agricultural produce, particularly in vegetables grown there. Nitrates accumulate mainly in intensively cultivated soils, principally in the protected vegetable lands. Soil contamination is one of the major factors controlling food safety, because residues of organochlorines, heavy metals and nitrates in agricultural produce are closely related to soil pollution. To produce safe agricultural products, a countrywide project of surveying and assessing soil environmental quality should be launched, long-term monitoring systems on soil pollution established and plans for soil remediation and protection made. Moreover, standards and methods for evaluation of soil environmental quality and food safety should be developed based on bioavailability of the pollutants, including the environmental hormones. Finally, some laws and regulations should be issued, to realize a strategic change in management of land resources from quantity-based one to one based on both quality and quantity.