Mortality of nitrate fertiliser workers

Area of Science:

• Occupational Health
• Epidemiology
• Toxicology

Background:

• Nitrate exposure in fertilizer production is a potential occupational hazard.
• Concerns exist regarding nitrates' role in endogenous carcinogen formation.
• Previous studies suggested a link between nitrates and increased cancer risk, particularly gastric cancer.

Purpose of the Study:

• To investigate mortality patterns in workers exposed to nitrates.
• To test the hypothesis that high nitrate exposure increases cancer risk.
• To assess the relationship between occupational nitrate exposure and cancer mortality.

Main Methods:

• An epidemiological cohort study of 1327 male fertilizer production workers (1946-1981).
• Follow-up until March 1981, comparing observed deaths to regional rates.
• Analysis included a subgroup with heavy nitrate exposure (>10 mg/m³).
• Saliva nitrate levels confirmed exposure in a subset of workers.

Main Results:

• No significant excess mortality from all causes or specific cancers in the overall cohort.
• No significant excess mortality observed in the heavily exposed subgroup.
• A small excess of lung cancer was noted in heavily exposed men (>10 years) over 20 years post-exposure.
• Elevated salivary nitrate levels confirmed significant occupational exposure.

Conclusions:

• The study does not support the hypothesis that environmental nitrate exposure leads to significant in vivo carcinogen formation.
• Occupational nitrate exposure in fertilizer production does not appear to substantially increase overall cancer risk.
• A potential, though small, lung cancer risk may exist for workers with prolonged, heavy nitrate exposure.