再生水在洗车利用中的暴露剂量研究

再生水暴露剂量确定是再生水洗车利用健康风险评价的前提和制定再生水水质标准的重要依据.本文研究了手工洗车和龙门式洗车机洗车过程中再生水对典型人群的暴露剂量特征.通过现场调研,确定了洗车现场的典型暴露人群及其暴露时间分布,其中手工洗车工人的清洗耗时和擦车耗时分别平均为4.8 min和8.4 min,龙门式洗车机工人的冲洗浮土耗时、洗车机清洗耗时和擦车耗时分别平均为1.5 min、2.5 min和8.0 min.利用重量法确定了洗车现场空气中的再生水水雾浓度分布(即空气含水量增加值),结果表明手工洗车的水雾浓度为2.0 mg·L-1,洗车机过程中冲洗浮土现场和龙门式洗车机清洗现场的浓度分别为1.3 mg·L-1和3.2 mg·L-1.根据典型暴露人群的呼吸速率,得出再生水的暴露剂量.结果表明,在各种典型人群中,手工洗车清洗工的再生水日暴露剂量最大,高达15.5 mL·d-1.

Exposure dose of reclaimed water for car wash

Determination of exposure dose is the premise in pathogen risk assessment of reclaimed water for car wash and an important issue for the establishment of reclaimed water quality standard. The exposure doses of reclaimed water to typical population during manual car wash and mechanical car wash by reciprocating gantry machine were determined in this study. Firstly, the exposure time was measured. The wash time and wiping time of workers during manual car wash were 4.8 min and 8.4 min, respectively. The flushing dust time, mechanical wash time and wiping time during mechanical car wash were 1.5 min, 2.5 min and 8.0 min, respectively. Thereafter, reclaimed water fog concentration at car wash plants was measured by evaluating weight changes of water contents in air. In the manual wash plants, the water fog concentration at washing field was about 2.0 mg·L^-1. In the mechanical wash plants, the water fog concentrations at flushing dust field and reciprocating gantry machine field were 1.3 mg·L^-1 and 3.2 mg·L^-1, respectively. The exposure dose of reclaimed water to workers and car owners were determined based on the exposure time, reclaimed water fog concentration, and respiration rate. The exposure dose of reclaimed water to workers during manual car wash is the highest (15.5 mL·d^-1) among different populations.