Uptakes for each activity were summed to give the exposure metric of integrated uptake--total blood dose, for chloroform, BDCM, DBCM, THMBr, and TTHM.
Results for chloroform and BDCM uptake were similar (see Supplemental Material, Table S4).
The results of the correlation analysis indicated a weak correlation between TTHM and DBCM but no indication of correlation between TTHM and BDCM
The limits of detection (LOD) for TCM, BDCM, DBCM, and TBM were 1.
Br-THM concentration was defined as the sum of BDCM, DBCM, and TBM in blood.
Morning blood samples collected before any major water-use activity can be expected to yield baseline THM concentrations, as experimental studies have shown that preexposure breath levels of TCM were reached 4 hr after inhalation and dermal exposures during showering or bathing (Weisel and Jo 1996) and that baseline blood BDCM
levels were attained approximately 4 hr after oral administration and 6-7 hr after dermal exposure (Leavens et al.
Iszatt N, Nieuwenhuijsen MJ, Toledano MB, Nelson P, Elliott P, unpublished data) reported a statistically significant excess risk between BDCM
ingestion estimates and hypospadias (1st vs.
However, instead of the dominant bromine-containing species that were expected at the TX site, relatively low concentrations of BDCM
, DBCM, and bromoform were found, probably due to heavy rains in the area during the week preceding the subject activities in the home, which diluted the bromide concentration in the raw water.
exposure was more homogeneous, ranging from about 1.
All analyses were carried out for TTHMs, chloroform, BDCM
, and total brominated THMs (the sum of BDCM
, DBCM, and bromoform).
A recent toxicologic study hypothesized that BDCM
could disrupt the synthesis and/or secretion of placental syncytiotrophoblast-derived chorionic gonadotropin (Chen et al.
49) increased risk for stillbirths among mothers exposed to [greater than or equal to] 20 [micro]g/L BDCM