Using probabilistic modeling to evaluate human exposure to organotin in drinking water transported by polyvinyl chloride pipe.
The leaching of organotin (OT) heat stabilizers from polyvinyl chloride (PVC) pipes used in residential drinking water systems may affect the quality of drinking water. These OTs, principally mono- and di-substituted species of butyltins and methyltins, are a potential health concern because they belong to a broad class of compounds that may be immune, nervous, and reproductive system toxicants. In this article, we develop probability distributions of U.S. population exposures to mixtures of OTs encountered in drinking water transported by PVC pipes. We employed a family of mathematical models to estimate OT leaching rates from PVC pipe as a function of both surface area and time. We then integrated the distribution of estimated leaching rates into an exposure model that estimated the probability distribution of OT concentrations in tap waters and the resulting potential human OT exposures via tap water consumption. Our study results suggest that human OT exposures through tap water consumption are likely to be considerably lower than the World Health Organization (WHO) "safe" long-term concentration in drinking water (150 microg/L) for dibutyltin (DBT)--the most toxic of the OT considered in this article. The 90th percentile average daily dose (ADD) estimate of 0.034 +/- 2.92 x 10(-4)microg/kg day is approximately 120 times lower than the WHO-based ADD for DBT (4.2 microg/kg day).
Fristachi
Anthony
A
Battelle, Statistics and Information Analysis, Columbus, OH, USA. antaknee@gmail.com
Xu
Ying
Y
Rice
Glenn
G
Impellitteri
Christopher A
CA
Carlson-Lynch
Heather
H
Little
John C
JC
D000293:Adolescent; D000328:Adult; D000368:Aged; D002648:Child; D002675:Child, Preschool; D004781:Environmental Exposure; D006801:Humans; D007223:Infant; D007231:Infant, Newborn; D008875:Middle Aged; D009947:Organotin Compounds / Q000633:toxicity*; D011143:Polyvinyl Chloride / Q000737:chemistry*; D011336:Probability; D014874:Water Pollutants, Chemical / Q000633:toxicity*; D018508:Water Purification; D014881:Water Supply
D009947:Organotin Compounds; D014874:Water Pollutants, Chemical; C056189:di-n-butyltin; D011143:Polyvinyl Chloride