Intrusion of Chlorinated Hydrocarbons and their Degradation Products from Contaminated Soil: Measurement of Indoor Air Quality and Biomonitoring by Analysis of End- Exhaled Air

摘要

A historic contamination of chlorinated hydrocarbons from a former dry cleaning shop caused a soil contamination. These chemicals and their degradation products intruded into a book shop. Indoor air was characterized and the uptake by shop personnel was studied by biomonitoring. The aim of this study was to determine indoor air quality and uptake of soil contaminants and their degradation products. Samples of indoor air were collected over one week in the warm and cold season. Indoor air was sampled using canisters. End-exhaled air was collected from a male and female employee before the shop opened and after closure time. Chlorinated hydrocarbons were analysed with TD-GC-MS. Tetrachloroethylene (PER), trichloroethylene (TRI) and their degradation products 1,1-dichloroethylene (1,1-DCE), 1,2-trans-dichloroethylene (1,2-tDCE), 1,2-cis-dichloroethylene (1,2-cDCE) and methylene chloride (MC) were detected in ambient air. The carcinogen vinyl chloride was not detected. PER was the prime contaminant with week average air levels (±sd) of 805.21598.6 in June 2016 and 1031±499.3 ug/m3 in December 2017. Levels of MC, 1,2-tDCE, 1,2-cDCE and TRI were detected at concentrations below 2.3 ug/m3. When the barometric pressure was <1000 mbar all substances of interest were detected in end-exhaled air but not anymore at >1000 mbar. For PER the mean concentrations in end-exhaled air on each of the five workdays (±sd) increased from 26.0±3.6 and 22.218.0 ng/L in the morning to 52.6115.5 and 63.6112.7 ng/L in the evening, for the male shop owner (p<0.05) and female cashier (p<0.01), respectively. For MC and 1,1-DCE this pattern was not observed. Accumulation over the workweek was observed for MC but not for 1,1-DCDE and PER. Intrusion of soil contamination resulted in enhanced indoor air concentrations of chlorinated hydrocarbons above current indoor air standards. For PER in end-exhaled air an increase over the workday was consistent but accumulation over the week was not observed.