农药残留急性膳食风险评估研究进展

Review on Pesticide Residues Acute Dietary Risk Assessment

农药残留急性膳食风险评估直到最近才引起大家的关注。目前,JMPR研究国际范围农药急性膳食风险评估;美国、英国、荷兰、澳大利亚和新西兰也开始进行国家农药急性膳食风险评估。农药残留急性膳食风险是急性或短期接触毒性与农药残留急性膳食摄入量的函数。急性膳食风险评估包括设定急性毒性参考剂量、急性膳食摄入量评定和急性膳食风险描述。急性毒性参考剂量是根据现有的认知水平,在24h或少于24h的期间,人体摄入的食品或水中某物质对消费者不产生可察觉的健康危险的量,单位为毫克/公斤体重(mg/kgbw)。急性膳食接触量评估常用的方法有:定点或确定性方法和概率模型法。在确定性方法中选取食物的大部分人群消耗量和高残留量来计算膳食摄入量,为了解决混合样品中食品个体之间的残留差异,在计算中引入了变异因子。概率模型法是将食品中农药残留分布曲线与膳食摄入食品分布曲线进行整合得到农药膳食摄入量的分布曲线。目前最常用的是蒙特卡洛分析法。使用该方法需要收集个体在每天或每顿饭的食品膳食消耗数据和田间残留试验、市场残留检测数据以及关于加工、削皮、清洗、烹饪等行为对农药残留影响的研究数据。我国应该尽快建立健全膳食结构和农产品性状数据库,建立健全市场中农产品的农药残留数据库,并在高毒和中等毒性农药登记前,进行急性膳食风险评估,提高农药膳食摄入的安全性。首先应采用JMPR的确定性方法,然后再开发适合我国使用的概率模型法。

Pesticide residues acute dietary risk assessment has attracted Chinese attention only recently. So far, JMPR （Joint FAO/WHO Meeting on Pesticide Residues） is working on international acute dietary risk assessment while USA, UK, Netherlands, Australia and New Zealand are likewisely working on their own national acute dietary risk assessments. Acute dietary risk is a function of acute or short-term toxicity and acute dietary intake. Pesticide acute dietary risk assessment is comprised of （1） acute reference dose （aRfD） setting; （2） acute dietary exposure assessment; and （3） acute risk characterization, aRfD is an estimate of the amount of a substance in food or drinking water, expressed on a milligram per kilogram body weight basis, which can be ingested in a period of 24 hours or less, without appreciable health risk to the consumer on the basis of all the known facts at the time of the evaluation. Acute dietary exposure can be calculated by a point or deterministic method as well as by a probabilistic modeling method. In the deterministic method the intake is estimated with the assumption of large portion consumption of a ＇high residue＇ food. In addition, the method also includes a variability factor to allow for the elevated residue in some single unit which may not be seen in composite samples. In the probabilistic method the distribution of dietary consumption and the distribution of possible residues are combined in repeated probabilistic calculations to yield a distribution of possible residue intakes. A common approach to do probabilistic modeling is the Monte Carlo analysis. This requires （1） comprehensive food consumption data by individuals, by time of day, and by eating occasion; and （2） comprehensive residue data such as the supervised trials median residues （STMR）, anticipated residues, food residue monitoring data such as market basket study, and food processing data, such as peeling, washing, cooking, and food processing. China should conduct acute dietary risk assessment, before the high or moderately toxic pesticides are to be registered for use. This would involve the establishment of comprehensive food consumption database, food commodity properties database, and market residue monitoring database. At first, China should adopt the JMPR deterministic method of acute dietary risk assessment. Then China can move forward to develop the probabilistic modeling method of acute dietary risk assessment for future use.