Donald P. Morgan

Morbidity and mortality in workers occupationally exposed to pesticides.

Utilizing cause-of-death information and responses to questionnaires addressed to survivors, mortalities and health impairments in a cohort of workers occupationally exposed to pesticides were compared to occurrences in workers not pesticide exposed, over the period 1971–1977. Seventy-two percent of 2,620 pesticide-exposed workers, and 75 percent of 1,049 “controls”, recruited in 1971–73, were accounted for either by returned questionnaire or mortality. Disease incidence rates were studied in relation to broadly defined occupational subclasses, and to serum concentrations of organochlorine pesticides (OC1) measured at the time of recruitment.Death by accidental trauma was unusually frequent among pesticide applicators. Mortalities from cancer and arteriosclerosis were not detectably different from those observed in the controls. Among survivors, dermatitis and skin cancer were unusually common in structural pest-control operators. Internal cancer was no more frequent in the intensively pesticide-exposed workers than in the controls, but it appeared to occur at an unusually high rate in workers characterized as “possibly pesticide-exposed”.There were apparent associations between high serum pesticide OCl levels measured in 1971–73 and the subsequent appearance of hypertension, arteriosclerotic cardiovascular disease, and possibly diabetes. This could imply a causal role of any of the pesticidal and other environmental stresses to which these workers were exposed.The limitations of this type of followup study are discussed.

Urinary excretion of paranitrophenol and alkyl phosphates following ingestion of methyl or ethyl parathion by human subjects.

Nitrophenolic and alkyl phosphate metabolites of methyl and ethyl parathion appear in the urine of human subjects soon after doses of 1 to 4 mg have been ingested. Particular alkyl phosphates can serve as specific indices of absorption of the respective parathions. Paranitrophenol and diethyl thiophosphate are rapidly eliminated in the urine, while excretions of dimethyl phosphate, and particularly diethyl phosphate, are more protracted. Cumulative excretions of paranitrophenol and alkyl phosphates exhibit sufficient dose-dependence at convenient intervals following parathion ingestion to encourage use of metabolite measurements in estimating occupational absorption of the parathion insecticides.

Blood organochlorine pesticide concentrations, clinical hematology and biochemistry in workers occupationally exposed to pesticides

Organochlorine pesticide concentrations in blood and various clinical test variables were measured in 2,620 pesticide-exposed subjects and in 1,049 persons not occupationally exposed to pesticides. Differences in the pesticide contents of blood were identified in relation to geography, age, and occupational exposure. Analysis of hematologic and biochemical variables in terms of broad occupational categories revealed only very limited differences, but relationships of certain biochemical tests to serum organochlorine pesticide contents suggested subtle effects of these pesticides on liver function.

Urinary 1-Naphthol as a Biological Indicator of Naphthalene Exposure

Abstract Doses of naphthalene ranging from 1 μg to 1.0 g were administered to swine housed in metabolism cages. The major urinary metabolite, conjugated 1-naphthol, was hydrolyzed, and the free 1-naphthol was reacted with pentafluorobenzyl bromide to generate an ether derivative which was separated by packed-column gas chromatography and detected by electron capture as pentafluoro-benzyl-1-naphthyl ether. Most 1-naphthol excretion occurred during the first 24-hour period following dosing. Metabolic 1-naphthol could be detected after administration of as little as 100 μg naphthalene. This suggests the use of 1-naphthol as a biological indicator of the magnitude of occupational exposure to naphthalene. Keimig, S. D.; Morgan, D. P.: Urinary 1-naphthol as a biological indicator of naphthalene exposure.

A pesticide (dieldrin)-induced immunohemolytic anemia

The unusual presentation of a factory worker with severe hemolytic anemia which remitted following splenectomy prompted a search for an environmental cause for red cell injury. The investigation showed the presence of an immunoglobulin in the patients serum and on the red cells and small amounts of complement on red cells. The patients serum caused agglutination of a normal persons red cells only when dieldrin-coated, a reaction blocked by first reacting the serum with dieldrin. The spleen of the patient had a greater than normal concentration of dieldrin, the source of dieldrin being dietary. It is concluded that dieldrin became immunogenic and provoked a chemical immunohemolytic anemia. The spleen played a major role in destruction of red cells injured by the immunopathic process and in accumulation of the antigenic substance dieldrin.

A fatal diazinon poisoning

A case of fatal suicidal ingestion of diazinon insecticide is presented. Diazinon concentrations in post-mortem body fluids and tissues were determined using electron capture and flame ionization gas-liquid chromatography. The highest concentrations of diazinon were found in blood, stomach contents, bile and adipose tissue.

Minimizing occupational exposure to pesticides: Acute and chronic effects of pesticides on human health

As is true of toxic substances in general, pesticides pose several different kinds of threats to health. Defined broadly as “adverse effects,” they are commonly considered either acute effects, developing promptly and resolving rapidly, or chronic effects, which may appear after a delay, but then persist for weeks to years.

Worker reentry safety. IX. Techniques of determining safe reentry intervals for organophosphate-treated cotton fields

Several circumstances have revealed a need for better appraisal of the hazard incurred by workers who reenter cotton fields recently treated with pesticides: (1) the increased use of parathions and other organophosphate insecticides on cotton as substitutes for DDT, (2) the rapid expansion of cotton pest-management programs involving large numbers of cotton checkers, and (3) a lack of human exposure information for establishing reentry intervals. A “reentry interval” is the waiting period required to protect field workers from possible poisoning when they enter pesticide-treated fields. Reentry information on treated fields is needed essentially for workers who are intimately associated with the foliage of maturing cotton for extended periods, e.g., cotton insect field checkers (cotton scouts), hoe crews, and scientists. Irrigators and tractor drivers are the only other personnel entering fields and they do not normally contact cotton foliage. Cotton scouts, by reason of their direct contact with cotton foliage, in field after field, for up to 10 hr of intermittent exposure/day and approaching 40 hr/week, become the principal concern in establishing safe reentry intervals for cotton.