A biological indicator of inorganic arsenic exposure using the sum of urinary inorganic arsenic and monomethylarsonic acid concentrations

Abstract

Objectives: The sum of urinary inorganic arsenic (iAs), monomethylarsonic acid (MMA), and dimethylarsinic acid (DMA) concentrations is used for the biological monitoring of occupational iAs exposure. Although DMA is a major metabolite of iAs, it is an inadequate index because high DMA levels are present in urine after seafood consumption. We estimated the urinary iAs+MMA concentration corresponding to iAs exposure. Methods: We used data from two arsenic speciation analyses of urine samples from 330 Bangladeshi with oral iAs exposure and 172 Japanese workers without occupational iAs exposure using high-performance liquid chromatography with inductively coupled plasma mass spectrometry. Results: iAs, MMA, and DMA, but not arsenobetaine (AsBe), were detected in the urine of the Bangladeshi subjects. The correlation between iAs+MMA+DMA and iAs+MMA was obtained as log (iAs+MMA) = 1.038 log (iAs+MMA+DMA) -0.658. Using the regression formula, the iAs+MMA value was calculated as 2.15 and 7.5 μg As/l, corresponding to 3 and 10 μg As/m3 of exposures, respectively. In the urine of the Japanese workers, arsenic was mostly excreted as AsBe. We used the 95th percentile of iAs+MMA (12.6 μg As/l) as the background value. The sum of the calculated and background values can be used as a biological indicator of iAs exposure. Conclusion: We propose 14.8 and 20.1 μg As/l of urinary iAs+MMA as the biological indicators of 3 and 10 μg As/m3 iAs exposure, respectively.

Variable Power Functional Dilution Adjustment of Spot Urine

“…37,44,[56][57][58][59]64 It was therefore proposed to use the sum of urinary iAs + MMA or even iAs in blood as more adequate parameters for chronic iAs exposure instead of 'Total uAs'. 29,65 In clinical settings, TWuAs is usually measured as a first-line test, while speciation analysis is reserved for high TWuAs samples. In the present retrospective study, TWuAs was chosen as a paradigmatic marker because of its abundant presence in human urine, providing for a sufficiently high number of samples featuring a broad enough concentration range to establish adequate numerical non-linear adjustment functions.…”

“…37,44,56-59,64 It was therefore proposed to use the sum of urinary iAs + MMA or even iAs in blood as more adequate parameters for chronic iAs exposure instead of ‘Total uAs’. 29,65…”

Environmental Contamination of Arsenic and its Toxicological Impact in Cardiovascular Tissues of Patients with Coronary Heart Disease

“…The mechanism across mammalian animals including man metabolises and detoxify inorganic As is methylation to methylarsonate and dimethylarsinate (20). Before this methylation arsenate must be reduced to arsenite; the binding of arsenite to tissue proteins would be an additional or perhaps the first step in the detoxification of inorganic As prior to methylation (21).…”

“…However after an acute lethal dose (8.0 g of As 2 O 3 ), the highest levels were observed decreasing order in liver, kidney and other organs (muscle, lungs, brain). The inorganic trivalent species was predominant (>80%) and the metabolites MMA and DMA represented 10 and 5% respectively except in lipid rich organs that concentrations of these species are higher (20). In animals arsenate has been shown to incorporate in the skeleton due to its similarity with phosphate anions.…”