Measurement of Heavy Metals in Occupational Health Samples

Measurement Heavy metals in occupational health samples

Introduction

Metals, particularly heavy metals such as lead, mercury, cadmium, and arsenic, pose a significant potential threat to human health, both occupationally and environmentally. Unfortunately, these non-essential elements are highly toxic even at very low doses, non-degradable, and have extremely long biological half-lives. Consequently, exposure to these heavy metals can be potentially harmful. Some metals have even been identified as human carcinogens, including arsenic, chromium, and nickel. Additionally, welding and cutting processes generate gases and particles that form complex mixtures of metal oxides. Fumes are vaporized metals that react with air and transform into inhalable particles, which, with prolonged exposure, may lead to lung cancer.

Given these considerations and the importance of the issue, it is essential to ensure accuracy in determining pollutant levels in order to make informed judgments based on reliable data.

Exposure limits

The American Conference of Governmental Industrial Hygienists (ACGIH) has established Threshold Limit Values (TLVs) for heavy metals. Due to the extensive data, these values are fully presented in Table 2 of NIOSH Methods 7300 and 7301.

Sampling and analysis

Given the sensitivity of these compounds, various sampling and analysis methods have been introduced. It is essential to carefully review the preliminary information on these compounds before sampling and, based on this assessment, select the appropriate sampling and analysis method. The table below examines the different sampling and analysis methods for these compounds

A key consideration in metal analysis is the selection of the instrumental method, which significantly helps optimize costs and allows for broader metal monitoring. For instance, if only a single metal or fume needs to be measured, atomic absorption (AA) is recommended. However, if more than three to four metals are to be analyzed, ICP (Inductively Coupled Plasma) should be used, as it can read all metals simultaneously in under two minutes. Therefore, as previously recommended, the availability of sampling filters, the cost-effectiveness of the filter and analysis method, and the ability to measure the collected sample are the most critical factors in selecting a metal analysis method.