Zhang Xiaofei, Driver Jeffrey H, Li Yanhong, Ross John H, Krieger Robert I
Personal Chemical Exposure Program, Environmental Toxicology Graduate Program, and infoscientific.com, Inc, Manassas, Virginia 20111, USA.
J Agric Food Chem. 2008 Nov 26;56(22):10638-45. doi: 10.1021/jf8018084.
Trace residues of organophosphorus (OP) pesticides are associated with fruits and vegetables that have been sprayed with those OP pesticides to guard against insect pests. Human dietary exposure to these OP pesticides is commonly estimated by measuring the amount of OP metabolites in urine, assuming a stoichiometric relationship between a metabolite and its parent insecticide. Dialkylphosphates (DAPs) are the OP metabolites that are most often used as markers in such biomonitoring studies. However, abiotic hydrolysis, photolysis, and plant metabolism can convert OP chemicals (OP residues) to DAP residues on or in the fruits and vegetables. To evaluate the extent of these conversions, OPs and DAPs were measured in 153 produce samples. These samples from 2 lots were known to contain OP insecticide residues based on routine monitoring by California producers and shippers. A total of 12 OPs were quantified, including mevinphos, naled, acephate, methamidophos, oxidemeton-methyl, azinphos-methyl, dimethoate, malathion, methidathion, phosmet, chlorpyrifos, and diazinon. All OP insecticide residues were below their respective residue tolerances in 2002-2004. A total of 91 of 153 samples (60%) contained more DAP residues than parent OPs. The mean mole fractions [DAPs/(DAPs + OPs)] for the first and second lots of produce were 0.62 and 0.50, respectively, and the corresponding geometric means were 0.55 and 0.34. The corresponding mean mole ratios (DAPs/OP) were 7.1 and 3.4, with geometric means of 2.1 and 0.9. Any preformed DAPs ingested in the diet that are excreted in urine may inflate the estimated absorbed OP insecticide doses in occupational and environmental studies. In subsequent prospective studies, time-dependent production of dimethylphosphate (DMP) and dimethylthiophosphate (DMTP) in strawberries and leaves following malathion sprays occurred concomitant with the disappearance of the parent insecticide and its oxon. DAPs are more persistent in plants and produce at routinely measured levels than their parent OP insecticides.
有机磷（OP）农药的痕量残留与那些为防治虫害而喷洒了此类OP农药的水果和蔬菜有关。通常通过测量尿液中OP代谢物的量来估算人类通过饮食接触这些OP农药的情况，这是假定代谢物与其母体杀虫剂之间存在化学计量关系。二烷基磷酸酯（DAPs）是此类生物监测研究中最常被用作标志物的OP代谢物。然而，非生物水解、光解和植物代谢可将OP化学品（OP残留）转化为水果和蔬菜上或内部的DAP残留。为评估这些转化的程度，对153份农产品样本中的OP和DAP进行了测量。根据加利福尼亚州生产商和运输商的常规监测，已知来自2批的这些样本含有OP杀虫剂残留。共对12种OP进行了定量，包括速灭磷、二溴磷、乙酰甲胺磷、甲胺磷、氧化乐果、甲基谷硫磷、乐果、马拉硫磷、杀扑磷、亚胺硫磷、毒死蜱和二嗪农。在2002 - 2004年期间，所有OP杀虫剂残留均低于各自的残留限量。153份样本中有91份（60%）的DAP残留量高于母体OP。第一批和第二批农产品的平均摩尔分数[DAPs/(DAPs + OPs)]分别为0.62和0.50，相应的几何平均值分别为0.55和0.34。相应的平均摩尔比（DAPs/OP）分别为7.1和3.4，几何平均值分别为2.1和0.9。饮食中摄入的、经尿液排出的任何预先形成的DAPs可能会在职业和环境研究中夸大估计的吸收OP杀虫剂剂量。在随后的前瞻性研究中，马拉硫磷喷洒后草莓和叶片中磷酸二甲酯（DMP）和二甲基硫代磷酸酯（DMTP）随时间的生成与母体杀虫剂及其氧类似物的消失同时发生。与它们的母体OP杀虫剂相比，DAPs在植物和农产品中的残留更持久，处于常规测量水平。
