Characteristics of Urine Arsenic Species After Eating Organic Arsenic-Containing Seafood
Date Issued
2004
Date
2004
Author(s)
Hsu, Chia-Chin
DOI
zh-TW
Abstract
When assessing low inorganic arsenic exposure, the urinary biomarkers, including arsenite(AsIII), arsenate(AsV), methylarsonic acid(MMA) and dimethylarsinic acid(DMA), might be interfered by the metabolites of organic arsenic contained in the ingested seafood. Besides, it was reported in recent years that the intermediate metabolites of organic arsenic, i.e., MMAIII and DMAIII, were concerned of their cytotoxicity. So it is important to explore the metabolism of organic arsenic by characterizing urinary arsenic species.
Total 21 volunteers with no inorganic arsenic exposure were recruited in this study. During the experimental period of 7.5 days, participants were provided with daily meals by the study team to prevent eating any foods containing organic arsenic. From the 1st to the 3rd day, participants provided with their first morning voided urine samples for arsenic species determination in order to make sure that their urinary arsenic levels have been lowered down to the background levels. At dinner on the 4th day, participants had an aliquot of cooked oyster around 50 g. In the following 4.5 days, participants were asked to provid with both their first morning voided and the evening voided urine samples. Urinary arsenic species were determined with the high performance liquid chromatography-inductively coupled plasma-mass spectrometer (HPLC-ICP-MS), using anion-exchange column for AsIII, AsV, MMA and DMA speciation, and cation-exchange column for arsenobetaine(AsBe), arsenocholine(AsCho), trimethylarsine oxide(TMAO) and tetramethylarsonium ion(TetMA) speciation, respectively.
Detected urinary arsenic metabolites after oyster ingestion included DMA, AsBe, AsIII, MMA, TMAO, TetMA and an unknown species. This unknown species was thought dimethylarsinoylethanol, dimethylarsinoylacetate or one of arsenosugars. AsV and AsCho were rarely detected in the urine samples.
With the similar circadian daily activities, the participants’ DMA concentrations reached their maxima about 12~36 hours after oyster ingestion, and they took another 48 hours to decline and return to the respective backgrounds. Urinary DMA contents might be attributed to the original DMA in oyster and that metabolized from the AsSug contained in oyster.
Most study participants’ maximum urinary AsBe levels occurred about 36 hours after oyster ingestion. The rates of AsBe increasing and decreasing between the participants’ respective backgrounds and maximum levels were equivalent. However, urinary AsBe levels of 3 study participants did not show any significant elevation during the study period.
Urinary DMA, AsBe and the total arsenic levels were demonstrated significantly associated with the amount of ingested oyster per unit bodyweight (g/kg bodyweight). The trends of urinary DMA, AsBe and the total arsenic levels after oyster ingestion could be well predicted by using mixed model under given conditions. An increase of 17.7μg/g creatinine for DMA is expected after eating oyster at the dose of 1 g/kg bodyweight. If the participant is male, the total arsenic and AsBe may increase by 73.3 and 29.9μg/g creatinine, respectively, with oyster ingestion of 1 g/kg bodyweight.
Urinary AsIII and MMA levels were found very low but highly correlated with each other after oyster ingestion. Because AsIII consisted of 2.6% of arsenic species in the study oyster, the urinary AsIII might originally come from this part, and the urinary MMA might also resulted from this part of AsIII as metabolite.
In conclusions, 1st day after ingesting 49.9±7.4g of oyster, the urinary inorganic arsenic metabolites, including AsIII, AsV, MMA and DMA, might be significantly interfered by an increase of 35.5±9.4μg/g creatinine. The excretion rates of DMA and AsBe in urine were observed varying in the present study. So were the different individual susceptibility of the study participants for the organic arsenic metabolism.
Subjects
牡蠣代謝
液相層析串聯感應耦合電漿質譜儀
有機砷
易感受性
HPLC-ICP-MS
Susceptibility
Oyster metabolism
Organic arsenic
Type
thesis
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