MORTALITY IN A COHORT OF ORCHARD WORKERS EXPOSED TO LEAD ARSENATE PESTICIDE SPRAY

During the period from 1890 to 1940, lead arsenate was the major pesti cide used in apple orchards to control the coddling moth. In the Wenat chee area of Washington State, lead arsenate spray was used for longer periods and in larger quantities than in other areas of the United St ates. In 1938, a cohort of 1 231 people who lived in this area was sel ected for a study to determine the effects of exposure to lead arsenat e spray and residue. This same cohort was re-examined to determine whe ther there was excess mortality that could be attributed to the lead a rsenate exposure. Three levels of exposure (i.e., orchardist, intermed iate, consumer) were defined, based upon the use of lead arsenate pest icide spray before and during the 1938 apple growing season. Age-adjus ted hazard ratios for all causes of mortality were elevated for both m ale orchardists and male intermediates. The only significantly increas ed age-adjusted hazard ratio (1.94) was heart disease in male intermed iates. No significantly elevated age-adjusted hazard ratios were obser ved for women in any exposure group. The lack of evidence that support ed an increase in mortality from respiratory cancer in this cohort may have resulted from the lower cumulative concentration of arsenic expo sure, the type of arsenical compound, and the small number of study su bjects.