Nails, arsenic levels

Analysis of hair, fingernails, and toenails can serve as evidence of arsenic ingestion. Such analyses are complicated by the possible presence of arsenic contamination, particularly in a work environment in which the air and surroundings may be contaminated with arsenic. Levels of arsenic may be correlated with the growth of nails and hair so that careful analysis of segments of these materials can indicate time frames of exposure. 

Essentially, all organ systems must be evaluated. Thus laboratory tests, should include complete blood count, liver and renal functional tests, and blood, nail and urine arsenic levels. Other biomarkers of arsenic exposure include nonerythrocyte porphyrin enzyme activities and urine transforming growth factor TNF-a, accompanied by induction of heme oxygenase, mitogen-activated protein kinases, the ubiquitin-dependent proteolytic pathway, and protein kinase C in various tissues. These tests are still being investigated in laboratories and their clinical usefulness remains to be proven (Chapell et al, 2001). 

A Olguin, P Jauge, M Cebrian, A Albores. Arsenic levels in blood, urine, hair, and nails from a chronically exposed human population. Proc West Pharmacol Soc 26 175-177, 1983. 

Arsenic with three or five valences contained in foods can be easily absorbed by the gastroenteric tube. Then it can be easily transported into all tissues and organs. It is mainly accumulated on the skin, hair, nails, and to a certain degree on the bones and the muscles. The total arsenic level in the human organism has been estimated to be 14-20 mg. ... 

Animal tissues usually contain low levels (<0.3 mg As/kg fresh weight) of arsenic. After the administration of arsenicals, these levels are elevated, especially in liver, kidney, spleen, and lung and several weeks later, arsenic is translocated to ectodermal tissues (hair, nails) because of the high concentration of sulfur-containing proteins in these tissues. 

The diagnosis of chronic arsenic poisoning involves integration of the clinical findings with confirmation of exposure. Urinary levels of total arsenic, usually less than 50 g/24 h, may return to normal within days to weeks after exposure ceases. Because it may contain large amounts of nontoxic organoarsenic, all seafood should be avoided for at least 3 days prior to submission of a urine sample for diagnostic purposes. The arsenic content of hair and nails (normally less than 1 ppm) may sometimes reveal past elevated exposure, but results should be interpreted cautiously in view of the potential for external contamination. 

Nakaaki Kand Fukabori S (1990) Determination of tdlurium, selenium, antimony, arsenic, lead, cadmium and chromium levels in nails. J Lab Sd 65 353-360. 

Normal levels of arsenic in hair, nails, organs and bone were taken from several basic studies (e.g. Smith, 1964 Liebscher and Smith 1968 Hopps, 1977 Lindh et al., 1980 Brune et al., 1980 Aalbers et al. 1987, Sabbioni et al., 1992). The studies for kidney, liver. 

Creatine SH groups of the skin retain up to 30% of the absorbed arsenic. Parts of this are later located in hair and nails. Periods of higher arsenic intake cause higher concentrations of arsenic in limited areas of the hair. Controls in the hair of infants during the first year of infancy demonstrated that the levels of arsenic in hair depend first on the arsenic content of food [56]. Four weeks after ingestion As is localized mainly as As(V) in bone substituting for phosphate [9,12,19]. 

Blood levels decrease within a few hours. They do not lend themselves to the detection of chronic exposure [29,58,73]. But during spraying season the blood levels of workers who applied arsenic herbicides were significantly elevated [60]. Increased serum contents of 78-180 p.g/liter of Indian opium eaters are exotic [88]. More information is available from hair. Children living near a coal power plant showed a mean level of 3260 (ig As/kg in comparison to unexposed children with 152 p.g/kg [15]. Similar results were evoked by smelter emission high exposure led to 182600 p,g As/kg low exposure to 8900 p-g/kg [78], 5500 p.g/kg [18] or 2600 p.g/kg [13]. Significantly lower are the concentrations caused by arsenic in well water (450-1240 p.g/kg) [31,80,89]. Nails also contain remarkably high contents of arsenic compared with normal levels 21100-72800 p,g As/kg in smelter workers [78] and 4550 p.g/kg in persons exposed to arsenic well water [31],... 

A level II study gathers data that are not available in public records. The kinds of data depend on whether the study design is case control or cohort. A level II case-control study typically investigates pathways of exposure for the at-risk population. An investigation of exposure includes interviews with individuals in the at-risk population about their length of residence in the presumed impact area, dietary habits, workplace conditions, and places where children play. It may also include qualitative or semiquantitative modeling of the environmental fate and transport of chemicals of concern (Chapter 2). Samples of body fluids and tissues such as blood, urine, hair, or nails may be analyzed for evidence of exposure to bioaccumulative chemicals such as arsenic, mercury, or PCBs. An effort is made to identify and exclude possible confounding factors. Erin Brockovich and A Civil Action are examples of level II case-control studies. 

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