Water-Air Volatilization Factors to Determine Volatile Organic Compound (VOC) Reference Levels in Water

Toxics

Vicenç Martí²  Joan De Pablo²  Irene Jubany¹  Miquel Rovira¹ 

[1] Fundació CTM Centre Tecnològic, Environmental Technology Area, Plaça de la Ciència, 2, Manresa E-08243, Spain; E-Mails:;Universitat Politècnica de Catalunya, Department of Chemical Engineering, ETSEIB, Av. Diagonal, 647, Barcelona E-08028, Spain; E-Mail:

关键词: environmental contaminants;    volatile organic compounds;    water-air modeling;    human health risk assessment;    exposure models;    volatilization factors;   

DOI  :  10.3390/toxics2020276

来源: mdpi

【 摘 要 】

The goal of this work is the modeling and calculation of volatilization factors (VFs) from water to air for volatile organic compounds (VOCs) in order to perform human health risk-based reference levels (RLs) for the safe use of water. The VF models have been developed starting from the overall mass-transfer coefficients (K_overall) concept from air to water for two interaction geometries (flat surface and spherical droplets) in indoor and outdoor scenarios. For a case study with five groups of risk scenarios and thirty VOCs, theoretical VFs have been calculated by using the developed models. Results showed that K_overall values for flat and spherical surface geometries were close to the mass transfer coefficient for water (K_L) when Henry’s law constant (K_H) was high. In the case of spherical drop geometry, the fraction of volatilization (f_V) was asymptotical when increasing K_H with f_V values also limited due to K_overall. VFs for flat surfaces were calculated from the emission flux of VOCs, and results showed values close to 1000K_H for the most conservative indoor scenarios and almost constant values for outdoor scenarios. VFs for spherical geometry in indoor scenarios followed also constant VFs and were far from 1000K_H. The highest calculated VF values corresponded to the E2A, E2B, E3A and E5A scenarios and were compared with experimental and real results in order to check the goodness of flat and sphere geometry models. Results showed an overestimation of calculated values for the E2A and E2B scenarios and an underestimation for the E3A and E5A scenarios. In both cases, most of the calculated VFs were from 0.1- to 10-times higher than experimental/real values.

【 授权许可】

CC BY   
© 2014 by the authors; licensee MDPI, Basel, Switzerland.