Title: Epidemiologic study of physiological effects in usual and volunteer citrus workers from organophosphate pesticide residues at reentry Kraus JF, Mull R, Kurtz P, Winterlin W, Franti CE, Borhani N, Kilgore W Ref: J Toxicol Environ Health, 8:169, 1981 : PubMed
Biological parameters associated with organophosphate (OP) pesticide exposure were evaluated in a study of citrus harvesters. Changes in these parameters related to environmental residues of cholinesterase (ChE) inhibiting pesticides were studied. Further, it was determined whether usual and volunteer workers differed in their biochemical parameters after exposure to pesticide residues during field operations. Urine metabolite findings for usual farm workers showed that some exposure to OP pesticides had occurred. Too few workers were available during the reentry stage of the field study to evaluate the effect of this exposure on blood ChE. Baseline (nonexposure) acetylcholinesterase (AChE) and plasma cholinesterase (PChE) activities were significantly higher in usual (Mexican American) workers than in volunteer workers (student volunteers). Student volunteers in the test citrus grove showed statistically significant declines in PChE during the exposure period, yet changes in AChE activity, urine metabolites, and residue levels were very small. The implications of these findings are discussed in light of current reentry standards as well as future epidemiologic studies on reentry research.
Blood acetylcholinesterase (ACHE) and pseudocholinesterase (PCHE) activity and urinary dialkyl phosphate (DAP) excretion were measured in a group of 15 male agriculture field workers during a five-day thinning operation in a Northern California peach orchard. Eight men were randomly assigned to work in a Guthion-treated plot, and seven men to work in an adjoining plot free from organophosphate residues. Foliage samples were taken to measure dislodgeable and total Guthion residues. The daily mean percent change in the ACHE and in the PCHE activity was less than -10.0 percent of baseline values for each group of men. Mean ACHE activity of workers in the Guthion treated plot was different from that of workers in the control plot on the fifth exposure day. The mean PCHE activity of workers in the Guthion treated plot was not different from that of workers in the control plot. Daily group-mean urinary metabolite excretion levels for workers exposed to Guthion residues were highly correlated with their daily group-mean percent change in ACHE activity. No urinary metabolites were detected in workers in the control plot. Decay in Guthion residues was markedly slower in this trial than in a comparable study conducted one year previously, emphasizing the difficulty in setting re-entry intervals based on time elapsed from pesticide application. Suggestions were made to extend the time interval of future studies on the human health effects of organophosphate residue exposure, and to further refine urinary metabolite surveillance methods toward the goal of establishing a threshold level of metabolites which would correspond to meaningful exposure to these pesticides residues.
Title: Dislodgable residues of dialifor and phosalone and their oxygen analogs following a reported worker-injury incident in the San Joaquin Valley, California Winterlin W, Kilgore W, Mourer C, Mull R, Walker G, Knaak J, Maddy K Ref: Bulletin of Environmental Contamination & Toxicology, 20:255, 1978 : PubMed
