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Biological Monitoring of Metal Exposure
Published in Stephen K. Hall, Joana Chakraborty, Randall J. Ruch, Chemical Exposure and Toxic Responses, 2020
In industry, workers are usually exposed to inorganic arsenic compounds. Whatever the arsenic compound to which the workers are exposed, the absorbed arsenic is rapidly eliminated in the urine either in the unchanged form or in the methylated forms of monomethylarsonic acid and cacodylic acid (dimethylarsonic acid). The biological monitoring of workers should be carried out by measuring the total amount of arsenic present in urine collected at the end of the shift or at the beginning of the next shift. As some marine organisms may contain very high concentrations of organoarsenicals of negligible toxicity that are also rapidly excreted in urine, workers should be instructed to refrain from eating seafood for 2 or 3 days before urine collection. As in urine, the arsenic concentration in blood reflects mainly recent exposure. Arsenic in hair is an indicator of the amount of inorganic arsenic absorbed during the growth period of the hair.
Biological Monitoring of Occupational Neurotoxicants
Published in Lucio G. Costa, Luigi Manzo, Occupatinal Neurotoxicology, 2020
Specific determination of inorganic arsenic (Asi), monomethylarsonic acid (MMA) and cacodylic acid (DMA) in urine is the method of choice to assess exposure to inorganic arsenic compounds. The sum of these three metabolites reflects the amount of inorganic arsenic recently absorbed. However, since seafood might still influence the excretion rate of DMA, the workers should preferably refrain from eating seafood during 48 hours prior to urine collection.15 In persons nonoccupationally exposed to inorganic arsenic and who have not recently eaten seafood, the sum of Asi, MMA and DMA generally is less than 10 pg/g creatinine. Values around 50 pg/1 or even higher have been reported in Japan.98,115 It has been estimated that in the absence of seafood consumption a time-weighted-average exposure to 10 and 50 pg/m3 inorganic arsenic leads to mean urinary excretions of the sum of As metabolites (Asi, MMA, DMA) in postshift urine sample of 30 and 50 pg/g creatinine, respectively.68
Toxicology
Published in W. David Yates, Safety Professional’s Reference and Study Guide, 2020
Chronic exposure to arsenic in the occupational setting, skin lesions, and peripheral neuropathy are the most common adverse effects. Patchy hyperpigmentation is the classic skin lesion of chronic arsenic exposure. Other adverse effects include anemia, leukopenia, thrombocytopenia, eosinophilia, and liver injury. Arsenic exposure occurs when workers sand or burn this wood. Arsenic is used as an alloy in lead-acid batteries. Inorganic arsenic is no longer used in agriculture in the United States. Organic arsenic pesticides (cacodylic acid, disodium methyl arsenate, and monosodium methyl arsenate) are used on cotton.7 The high-risk occupations at greatest risk of arsenic poisoning include the following: Applying arsenic preservatives to wood,Manufacturing of pesticides containing arsenic,Sawing or sanding arsenic-treated wood,Smelting or casting lead,Smelting or refining of zinc or copper.
Arsenic in edible macroalgae: an integrated approach
Published in Journal of Toxicology and Environmental Health, Part B, 2020
Julieta R. Camurati, Vanesa N. Salomone
Methylated As compounds formation is derived from i-As and this process could be related to a possible detoxification mechanism since, apparently, methylation promotes metal excretion (Bozack, Saxena, and Gamble 2018; Tseng 2009). However, there is sufficient evidence of cancer induced by DMA in experimental animals, and because MMA is extensively metabolized to DMA, both compounds are classified as “possibly carcinogenic to humans” (Group 2B) (International Agency for research on Cancer (IARC) 2009). Some investigators associated this with acute toxicity attributed to DMA or methylarsenic species (Kenyon and Hughes 2001). Studies on DMAV, commonly known as cacodylic acid used as a foliar herbicide for nonselective control of grasses and weeds, suggested that in high doses it might be carcinogenic (Arnold et al. 2006). Petrick et al. (2001) demonstrated that monomethylarsonous acid (MMAIII) is more toxic than As(III), both in vivo and in vitro assays. These results call into question the hypothesis that methylation of i-As is a detoxification process. Styblo et al. (2000) also reported that methylation of i-As failed to provide reliable protection for cells under conditions of acute exposure and may in fact generate potentially toxic metabolites that may significantly contribute to the adverse effects associated with exposure to i-As.
Magnetic hetero-structures as prospective sorbents to aid arsenic elimination from life water streams
Published in Water Science, 2018
Anuradha Jabasingh S., Ravi T., Abubeker Yimam
Several research findings reported the mechanism behind the removal of heavy metals by the magnetic sorbents. Such mechanisms, for removal of arsenic from the solution phase to the sorbents, as reported by various researchers are discussed in detail, in this section. In order to understand the mechanism of the adsorption of metal ions by nanoparticles, a number of methods have been investigated, including as infrared (IR) spectroscopy (Abollino et al., 2003; Lefèvre et al., 2008), X-ray diffraction (XRD) (Lo-Irene and Chen, 2005), X-ray photoelectron spectroscopy (XPS) (Lee and Anderson, 2005) and extended X-ray absorption fine structure (EXAFS) spectroscopy (Singh et al., 2011). The basis of discussion includes, ion exchange (Lo-Irene and Chen, 2005), physical adsorption (Lee and Anderson, 2005), surface complexation (Shen et al., 2009), electrostatic interaction (Liu et al., 2008) and hard/soft acid-base interaction (Pearson, 1963). Though arsenic removal by adsorption mechanism is relatively intricate, potential removal mechanisms can be assumed based on the batch experiments and adsorbent characteristics. The mechanisms and relative rates by which arsenic is removed from solution and incorporated into the sorbents has been the core area of interest. The kinetically stable bonds created with the sulfur and carbon inorganic compounds are the primary reasons for arsenic toxicity (Webb, 1966). The most important aspect is that the compounds which are formed are thermodynamically unstable but persistent. Many thousands of these arsenic compounds include, phenylarsenic acid [C6Hs AsO(OH)2], phenyl- and diphenyl-diarseno-compounds, Cacodylic acid [(CHa) EAsOOH], methane arsonic acid [CH3AsO(OH)2], lewisite [CHaCH=CHAsC12]. Most of these compounds are rapidly hydrolyzed, degraded or oxidized, nevertheless some persist in water. For example, Trimethylarsine, (CH3)3As, which is formed by microorganisms from inorganic arsenic compounds (Bird et al., 1948).