Bouchard Michèle, Carrier Gaétan, Brunet Robert C
Département de Santé environnementale et santé au travail, Faculté de Médecine, Université de Montréal, CP 6128, Succursale Centre-ville, Montreal, QC, Canada, H3C 3J7.
Int Arch Occup Environ Health. 2008 Jan;81(3):355-70. doi: 10.1007/s00420-007-0220-1. Epub 2007 Jul 19.
This study was undertaken to estimate the absorbed doses of carbaryl and the associated health risks in a group of horticultural greenhouse workers in the Province of Quebec, Canada, using a toxicokinetic modeling approach.
A mathematical model was developed to relate the absorbed dose of carbaryl, the evolution of its body burden and that of its metabolites and the urinary excretion rate of biomarkers. The free parameters of this model were determined using published time course data in volunteers exposed to carbaryl under controlled conditions. The model was used to determine cumulative urinary amounts of 1-naphthol that would be excreted by a typical worker exposed to a pre-established no-observed-adverse-effect level (NOAEL) dose; this biomarker amount was then taken as a biological reference value below which the risks of health effects were considered negligible. As a measure of the applicability of this approach to practical situations, the model was used to estimate the dose of carbaryl absorbed by each greenhouse worker, starting from his/her cumulative urinary excretion time courses of 1-naphthol over a 24-h period following the onset of a work exposure. Their cumulative 1-naphthol levels were then compared to the biological reference value obtained from the model and the NOAEL dose.
Following the onset of a work exposure to carbaryl, a clear increase in the urinary excretion rate of 1-naphthol was observed in most workers. The reconstructed absorbed doses were found to vary between 3.3 and 143 nmol/kg of body weight (bw) depending on the working conditions. Simulations of the observed cumulative urinary excretion time course of each worker also showed that exposure appeared to occur mainly (a) through inhalation for the applicators and individuals without direct contact with treated plants and (b) through the dermal route for individuals manipulating treated plants. Although the workers under study clearly appeared to have been exposed to carbaryl in the greenhouses, 24-h cumulative 1-naphthol levels ranged from 4.8 to 65.1% of the proposed biological reference value of 32 nmol/kg bw in 24-h urine collections following the onset of a work exposure.
This suggests that the workers under study probably did not incur a serious health risk under the normal exposure conditions prevailing during the study period.
本研究采用毒物动力学建模方法，估算加拿大魁北克省一组园艺温室工人中甲萘威的吸收剂量及相关健康风险。
建立了一个数学模型，用于关联甲萘威的吸收剂量、其体内负荷及其代谢产物的变化以及生物标志物的尿排泄率。该模型的自由参数利用在受控条件下接触甲萘威的志愿者已发表的时间进程数据来确定。该模型用于确定接触预先设定的无观察到有害作用水平（NOAEL）剂量的典型工人将排泄的1-萘酚的累积尿量；然后将该生物标志物量作为生物参考值，低于该值时健康影响风险被认为可忽略不计。作为该方法在实际情况中适用性的一种衡量，该模型用于从工作暴露开始后24小时内每个温室工人的1-萘酚累积尿排泄时间进程估算其吸收的甲萘威剂量。然后将他们的累积1-萘酚水平与从模型和NOAEL剂量获得的生物参考值进行比较。
在工作接触甲萘威后，大多数工人的1-萘酚尿排泄率明显增加。根据工作条件，重建的吸收剂量在3.3至143 nmol/千克体重（bw）之间变化。对每个工人观察到的累积尿排泄时间进程的模拟还表明，暴露似乎主要通过以下方式发生：（a）对于施药者和未直接接触处理过的植物的个体，通过吸入；（b）对于操作处理过的植物的个体，通过皮肤途径。尽管所研究的工人显然在温室中接触了甲萘威，但在工作暴露开始后的24小时尿液收集样本中，24小时累积1-萘酚水平在提议的生物参考值32 nmol/kg bw的4.8%至65.1%之间。
这表明在所研究的工人在研究期间普遍存在的正常暴露条件下可能未面临严重的健康风险。
