Biocide spray product exposure: measured gas, particle and surface concentrations compared with spray model predictions

Konferenceabstrakt til konference - 2018

Resume

Introduction Spray product emissions may be inhaled and some of the chemical ingredients may be respiratory irritants which may cause development of asthma or have other health effects. The aim of this project was to compare experimental exposure of 3 biocidal spray products (#1, #2, #3) applied in an exposure chamber with computed exposure calculations in existing models. The results were used to validate the models to contribute to a better risk assessment of spray products. Methods Three biocidal spray products with different active compounds and spray nozzles were selected. They were applied in a 20.3 m³ controlled exposure chamber in accordance with the description provided by the manufactures. Airborne organic compounds were sampled on Tenax and XAD and surface deposited by wiping with swabs. Samples were analyzed by (TD)-GC-MS/MS and LC-(QTOF)MS. Mass and number concentrations and size distributions of particles were measured on-line. Results #1 had permethrin, piperonylbutoxide, and pyrethrum extract as active compounds, which along with alkanes were found in the air after spraying. Like the particles these followed a 1st order decay, however, the removal rates were higher than the air exchange rate (AER) indicating they were associated with the depositing particles. The alkane decay followed the AER indicating they were in the gas-phase. #2 contained λ-cyhalothrin as the active compounds but it was not found in the air samples. Large particles (>0.5 μm) were found in very low concentrations (<0.1 mg/m3), while smaller particles (<0.3 μm) stayed at background levels. λ-cyhalothrin was found in wipe samples from surfaces. #3 had benzalkonium chlorides as the active compounds, which were measureable in air up to 36 min after spraying following a 1st order decay. The particle pattern was the same as for #2. The wipe samples showed that the benzalkonium chlorides were mainly on surfaces near the spray area. Preliminary results showed discrepancy between models and experiments. Conclusions The sprayed aerosols had shorter residence time in air than explained by the AER. Concentrations of the active compounds and low vapor pressure organic compounds decayed faster than explained by AER since they were associated with the aerosols, while more volatile compounds followed the AER. Aerosols of benzalkonium chlorides could be measured in the air more than ½ hour after application. The active compounds deposited mainly at the floor near the spraying position. Novel Aspect Modelling is used extensively in risk assessment; however there is a research gap on the compliance between modelling and actual exposure data using standardized conditions.

Reference

Biocide spray product exposure: measured gas, particle and surface concentrations compared with spray model predictions. 2018.

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