Cancer risks in naval divers with multiple exposures to carcinogens

Area of Science:

• Environmental Health
• Occupational Medicine
• Toxicology

Background:

• The Kishon River, Israel's most polluted waterway, received substantial industrial, ship, and agricultural effluents from 1948-1995.
• Decreased fish yields and increased toxic damage to marine life indicated severe environmental contamination.

Purpose of the Study:

• To investigate cancer risks in naval commando divers with prolonged underwater exposure to Kishon River toxins.
• To establish a potential cause-effect relationship between toxic exposure and cancer development.

Main Methods:

• A cohort study of 682 naval commando divers with 16,343 person-years of follow-up (from age 18 to 2000).
• Analysis of cancer incidence (observed/expected ratio for all tumors) across five successive diving cohorts.
• Comparison of cancer risks between divers with earlier and later exposure periods (post-1960).

Main Results:

• An overall tumor incidence ratio of 2.29 (p<0.01) was observed among the divers.
• Increased cancer risks were noted in cohorts diving after 1960, especially for hematolymphopoietic, central nervous system, gastrointestinal, and skin cancers.
• Short induction periods for cancer were frequently observed, and early toxic effects in marine life correlated with later cancer risks in divers.

Conclusions:

• Prolonged exposure to multiple toxic compounds in the Kishon River is strongly linked to increased cancer risks in naval divers.
• The findings suggest direct contact and absorption of toxins led to elevated cancer rates and short induction periods.
• Environmental indicators of toxicity in the river preceded and predicted increased cancer risks for exposed personnel.