HAZARDOUS SUBSTANCES

Measurement of Hazardous Substances in occupational Hygiene

Measurement of Hazardous Substances in occupational Hygiene

1: Asbestos Fibre (Industrial Manufacturing Industry):

Risks of carcinogenic and non-carcinogenic effects from asbestos continue owing to the persistence of the fibres in building materials and other products. For this reason, epidemiological and mechanistic research on the toxic effects of asbestos and mineral fibres is still needed. The present molecular epidemiological study was conducted in a former asbestos cement plant in Slovakia.

Altogether 82 subjects were investigated, 61 exposed subjects (24 smokers and 37 non-smokers), and 21 factory controls (8 smokers and 13 non-smokers). Workers were exposed to asbestos for between 5 and 40 years. Though the exposure to asbestos during past 40 years was relatively high, at the time of sampling the concentrations of asbestos in the production hall exceeded the Slovak occupational limit (0.001 fibre/cm3) by a factor of only 3-5.

The office area levels were below this limit. Biomarkers of exposure, effect and individual susceptibility were measured, including DNA damage (strand breaks [SBs], base oxidation and alkylation, using the comet assay); cytogenetic parameters; and individual DNA repair capacity (incision at 8-oxoguanine measured using a modified comet assay). Oxidised pyrimidines were significantly higher in exposed men compared with non-exposed (P = 0.04).

There was also a positive association between SBs (P = 0.04) and age, and alkylation damage to DNA (P = 0.04) and age. Moreover, oxidised pyrimidines (P = 0.01) and alkylated bases (P = 0.001) strongly correlated with years of occupational exposure. Micronucleus frequency did not differ between exposed and control subjects. Repair capacity overall did not show any effect of exposure, though female controls had higher incision rates than did female exposed subjects. However, exposed asbestos workers had significantly higher numbers of chromosomal aberrations (P = 0.01) compared with control group. This finding is consistent with the known association of chromosome aberrations with cancer-risk.

DNA damage measured in lymphocytes is generally assumed to be a marker of whole-body exposure to DNA-damaging agents. Our results show that DNA damage (especially oxidised pyrimidines) reflects exposure to asbestos. The correlation of DNA damage (oxidised pyrimidines and alkylated bases) with duration of exposure to asbestos implies either an accumulation of unrepaired damage or an effect of persistent inflammation, caused by the asbestos fibres still present in the body.

Chromosome aberrations were elevated in the asbestos-exposed workers, and especially in those who smoked. This finding is consistent with the known association of chromosome aberrations with cancer risk.

2: Air pollutants fall into four main categories: criteria air contaminants, persistent organic pollutants, heavy metals and toxics. Individual pollutants differ from one another in their chemical composition, reactions with other chemicals, sources, persistence, ability to travel through the atmosphere, and impacts.

There are two main types of airborne hazards: Outdoor Air pollution and Indoor air pollution. The Primary air pollutants are CO, CO2, SO2, NO, NO2 whereas the secondary air pollutants are HNO2, SO3, HNO3, H2SO4, H2O2. There is great impact of outdoor air pollution on ...