Researchers at the Department of Public Health, Okayama University Graduate School of Medicine, Dentistry and Pharmaceutical Sciences may have the answer. Wang et al examined the use of Unmetabolized VOCs in Urine as Biomarkers of Low Level Exposure in Indoor Environments.
Twenty-four subjects were examined from 13 residences in Japan. Air samples were collected from both the living room and bedroom at the height of the subjects breathing zone. The concentrations of volatile organic compounds (VOCs) were higher in the bedroom than the living room.
Urine samples were collected before bed and upon awakening. Twenty one of the twenty four had no work related exposure to VOCs and showed significant correlations between the urinary and air concentrations of toluene (.54), o-xylene (.61), total xylene (.56), and p-dichlorbenzne (.84). Only the air VOCs in the bedroom influenced morning urinary VOC concentrations and the researchers concluded that the unmetabolized VOCs toluene, o-xylene, total xylene, and p-dichlorobenzene in urine can provide a reliable biological indicator for air VOC exposures in non-occupational environments.
This is crucial, as exposures to high concentrations of VOCs can lead to respiratory problems, eye irritation, and throat irritation. Though urinary concentration has been used in the past to ascertain occupational exposure, few studies have done the same with indoor air in non-occupational environments. One limitation to doing so is that some urinary biomarkers are also the metabolites food items, making the urine concentration invalid for low air concentrations as the food origin would be higher.
Of interest is the finding that gender was a confounder for urinary toluene levels due to the higher percentage of fat women carry. Fat tissue stores solvents during exposure, delaying urinary excretion in women. It is therefore conceivable that this additional body burden women carry may explain the higher prevalence of women who develop environmental illnesses, such as sick building syndrome and multiple chemical sensitivities.
Wang BL, Takigawa T, Takeuchi A, Yamasaki Y, Kataoka H, Wang DH, Ogino K. Unmetabolized VOCs in Urine as Biomarkers of Low Level Exposure in Indoor Environments. J Occup Health. 2007 Mar;49(2):104-10.
About the Author
Lourdes Salvador is a writer and social advocate based in Hawaii. She is a passionate advocate for the homeless, having worked with her local governor to open new shelters and provide services to the homeless in a new approach to end homelessness. That passion soon turned to advocacy and activism for victims of multiple chemical sensitivity. Since 2006, she has been the president of MCS America and a featured monthly writer for MCS America News. She co-founded MCS Awareness in 2005. She also serves as Partner, Environmental Education Week and Partner, Collaborative on Health and the Environment (CHE). For more information about Lourdes and her advocacy work, please visit: www.mcs-america.org, www.thetruthaboutmcs.blogspot.com, and www.cafepress.com/mcsamerica.
Copyrighted © 2007 Lourdes Salvador