Biological monitoring urinary metabolites

Urinary levels of di(2-ethylhexyl) phthalate, its metabolites and total phthalates have been shown in a few studies to be higher in di(2-ethylhexyl) phthalate-exposed workers than in non-exposed workers and in post-shift samples than in pre-shift samples. No standard method has been proposed for biological monitoring of exposure to di(2-ethylhexyl) phthalate (Liss et al, 1985 Nielsen et al, 1985 Dirven et al, 1993a). 

The major urinary metabolite of di(2-ethylhexyl) adipate, 2-ethylhexanoic acid, has been shown to be an appropriate marker for biological monitoring of dietary di(2-ethylhexyl) adipate intake (Loftus etal., 1993, 1994). A limited population study in the United Kingdom was undertaken to estimate the daily intake of di(2-ethylhexyl) adipate following intake of a mean dose of 5.4 mg di(2-ethylhexyl) adipate presented with food. The study involved the determination of the urinary metabolite, 2-ethyl-hexanoic acid (24-h mine sample) in 112 individuals from five geographical locations. A skewed distribution with a median value for the daily intake of 2.7 mg was determined (Loftus et al., 1994). This value is about one third of the indirectly estimated maximum intake of 8. 2 mg per day. The probability of a daily intake in excess of 8.2 mg in the limited population (112 individuals) was calculated to be 3% (Loftus etal, 1994). 

Clonfero E, Jongeneelen FJ, Zordan M, et al. 1990. Biological monitoring of human exposure to coal tar. Urinary mutagenicity assays and analytical determination of polycyclic aromatic hydrocarbon metabolites in urine. In Vainio H, Sorsa M, McMichael AJ, eds. Complex mixtures and cancer risk. International Agency for Research on Cancer. Lyon, France lARC Sci. Publ. No. 104, 215-222. 

Cocker J, Boobis AR, Wilson HK, et al. 1990. Evidence that a beta-n-glucuronide of 4,4 -methylene-bis(2-chloroaniline) (MBOCA) is a major urinary metabolite in man Implications for biological monitoring. Br J Ind Med 47(3)154-161. 

The actual biological monitoring of workers to detect evidence of exposure such as a drop in blood cholinesterase levels or the presence of a urinary metabolite is superior to the indirect techniques employed in this study. Realizing the difficulties in accurately determining the dermal exposures of mixers, loaders, and applicators to pesticides, the employment of simpler monitoring techniques than the ones performed by CDFA in this report might... 

An epimer of testosterone, epitestosterone (17a-hydro-xylated testosterone), is produced by the testes and excreted as such in the urine in amounts approximately equal to that of testosterone(T epiT 1 1). Epitestosterone is biologically inactive, but it is not a metabolite, and is believed to be produced only by the gonads thus, it is used as a gonadal steroid marker. In women, the ratio of T to epiT is also normally 1 1. Urinary T epiT is useful in monitoring abuse of anabolic steroids by athletes because the ratio increases when any exogenous testosterone derivative is used. 

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