Are metals accumulated in human hair affected by naturally occurring asbestos fiber contamination? A case study from a rural area of china

Our plain-English summary of Are metals accumulated in human hair affected by naturally occurring asbestos fiber contamination? A case study from a rural area of china, by B. Wei, L. Yang, J. Yu, et al (Biological Trace Element Research, 2013).

The study

• Authors: B. Wei, L. Yang, J. Yu, B. Ye, X. Jia
• Journal: Biological Trace Element Research
• Published: 2013;156(1-3):12-21
• Cited by: 10 articles, as counted by NIH iCite
• Read it: PubMed · Publisher

Abstract

Little is known about the link between metals accumulated in human and asbestos fiber contamination in the environment. Therefore, hair samples of 368 subjects (128 males and 240 females) from a rural area contaminated by crocidolite asbestos fibers were collected to investigate the distributions of 17 metals accumulated in human. The results showed that the mean concentrations of As, Al, Ba, Cd, Co, Cr, Cu, Fe, Hg, Mg, Mn, Mo, Na, Ni, Pb, Sr, and Zn in hair of the total subjects were 0.23, 23.36, 4.33, 0.11, 0.05, 0.70, 10.53, 29.74, 0.37, 241.57, 3.52, 0.08, 153.21, 0.72, 4.26, 10.96, and 113.35 mg/kg, respectively. Moreover, approximately 86.14, 52.17, 73.91, 85.05, 80.98, 74.46, and 53.80 % of the hair samples of the total subjects contained much higher concentrations of Al, Ba, Fe, Mg, Mn, Na, and Sr compared with the highest reference values, respectively. The mean concentrations of the determined metals (except for As, Co, Cr, Hg, and Mo) significantly varied among different age groups for both male and females. The results of correlation analysis and cluster analysis revealed that strong correlations were found between Al, Fe, Zn, Mg, and Na accumulated in human from the study area. These might suggest that Al, Ba, Fe, Mg, Mn, Na, and Sr were significantly derived from contamination of crocidolite asbestos fibers. Zn, Mg, and Na might also originate from diet. However, Cd, Mo, Co, As, Cr, Hg, Ni, Mn, Pb, and Ba accumulated in human seemed to be mainly derived from soil. It can be concluded that metals accumulated in human hair have a link with asbestos fiber contamination in the environment.

In plain English

This study measured 17 metals in scalp hair from 368 residents (128 men and 240 women) of several villages in Dayao, a rural area of Yunnan Province, China. The soil there contains naturally occurring crocidolite, which local people call "blue asbestos". The study measured metals in hair only. It did not measure disease. Instead of using a comparison group of its own, it compared hair levels with published reference values and with hair studies from other places. Average levels of aluminium, barium, iron, magnesium, manganese, sodium and strontium were above the highest reference values. Depending on the metal, between 52.17% and 86.14% of samples exceeded them. Average levels of arsenic, cadmium, mercury, nickel and zinc were much lower than reference values. Women had higher levels of several metals than men, and men had higher zinc. Using correlation and cluster analysis, the authors suggested that some metals might come from crocidolite in the environment and others mainly from soil or diet. The authors concluded that there is a link between metals in hair and environmental asbestos contamination.

We wrote this plain-English summary from the full article with the help of AI, and a second AI model checked each sentence against the article. It is not the authors' wording; the abstract and the article are their own account.

What the study did and found

• Design: Cross-sectional hair-sampling study of local residents, using correlation and cluster analysis. The authors call it a case study. Results were compared with published reference values and other hair studies rather than with a comparison group of their own.
• Who was studied: 368 residents (240 females, 128 males) living in several villages of Dayao, Yunnan Province, China. Age groups in the tables ran from 41–50 to over 80 years. Sampling dates were not given.
• Exposure: Environmental (non-occupational) exposure to naturally occurring crocidolite ('blue asbestos') from outcrop ore in the soil. No individual exposure measurements were reported in this study.
• Main results:
  • All 368 subjects: mean hair levels of Al (23.36 mg/kg), Ba (4.33), Fe (29.74), Mg (241.57), Mn (3.52), Na (153.21) and Sr (10.96) were higher than the highest reference values.
  • Share of all subjects' samples above the highest reference value: Al 86.14%, Ba 52.17%, Fe 73.91%, Mg 85.05%, Mn 80.98%, Na 74.46%, Sr 53.80%.
  • Mean levels of As (0.23 mg/kg), Cd (0.11), Hg (0.37), Ni (0.72) and Zn (113.35) were much lower than reference values.
  • The authors report that females had significantly higher mean Al, Ba, Cd, Co, Cu, Fe, Mg, Mn, Mo and Sr than males. Zinc was higher in males (138.88 vs 99.73 mg/kg in Table 1).
  • In females, Al, Ba, Cu, Mg, Na and Sr levels decreased with age.
  • Cluster analysis in males grouped Cd, Mo, Co, As, Cr, Hg, Ni, Mn, Pb and Ba together, with separate groups Cu–Sr–Al–Fe and Na–Zn–Mg. Females showed similar clusters.
• The authors' conclusion: The authors concluded that Al, Fe, Zn, Mg and Na in hair might derive significantly from crocidolite contamination, and that there is a link between metals in hair and environmental asbestos contamination. They considered Zn, Mg and Na might also come from diet, and Cd, Mo, Co, As, Cr, Hg, Ni, Mn, Pb and Ba mainly from soil.

Topics

The National Library of Medicine indexes this study under subjects our site covers: Crocidolite.

Medical terms in this study, explained in our Lexicon: naturally occurring asbestos (NOA), Crocidolite.

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