Levels of exposure and biological monitoring of pyrethroids in spraymen.

Abstract

To assess the exposure response relation of pyrethroids in spraymen, 50 adult male cotton growers were selected and divided into three groups, one group to spray pyrethroids for one day, two groups to spray for three days. Deltamethrin, fenvalerate, and a deltamethrin methamidophos mixture were sprayed by appropriate subgroups for five hours a day. Exposure levels were evaluated by measuring the air concentration, dermal exposure concentration, and urinary content of pyrethroids by gas chromatography. Air concentrations of deltamethrin at the breathing zone were 0.01-0.89 microgram/m3 in the deltamethrin exposed group. For fenvalerate, air concentrations were 0.06-1.98 micrograms/m3. Dermal exposure, particularly on the legs, feet, and hands was appreciable and indicated that this was the main route of absorption. In those spraying for one day, urinary deltamethrin was not detectable by 12 hours after the beginning of exposure whereas fenvalerate was still detectable up to 24 hours after first exposure. Both pyrethroids could be detected two days after the end of three day spraying. Health effects were investigated by interview and physical examination. Twenty nine spraymen complained of abnormal facial sensations that developed mostly two to three hours from the start of pyrethroid spraying and that disappeared by 24 hours after exposure ceased. Some had dizziness, headache, and nausea, but no subject was diagnosed as having acute pyrethroid poisoning. The symptoms showed no significant correlation with urinary pyrethroid excretion. Blood cholinesterase activity of spraymen using the pyrethroid methamidophos mixture did not change.

Differential Behavioral Responses of <I>Anopheles gambiae</I> (Diptera: Culicidae) Modulate Mortality Caused by Pyrethroid-Treated Bednets

“…No signs of acute deltamethrin poisoning were observed during physical examination (He et al, 1988(He et al, , 1989. No exposure-related differences were detected in haematological parameters or in heart, lung, liver, kidney or nervous system functions, and the electrophysiological assessment of peripheral nerve function did not reveal any abnormality (He et al, 1988;Chen et al, 1991;Zhang et al, 1991). No correlation was observed between urine pyrethroid metabolite excretion and severity of symptoms ).…”

“…Itching, pricking sensations, numbness, burning of the skin and the eyes or tingling of the skin are the symptoms most commonly reported after contact with pyrethroids (Le Quesne et al, 1980;Tucker & Flannigan, 1983;Kolmodin-Hedman, 1982;He et al, 1988;Chen et al, 1991;Zhang et al, 1991). Symptoms usually start 1-6 hours after exposure (KolmodinHedman, 1982;He et al, 1989;Zhang et al, 1991) and last not more than 24 hours, but in some cases they may last up to 3 days (for example after local application of large doses of active ingredients -13.8 mg/cm 2 skin) (Aldridge, 1990).…”

“…From comparative toxicity studies it has been concluded that absorption from the respiratory tract is effective. While for the general population the main route of exposure to agricultural pesticides is through residues in food, studies carried out on workers suggest that, similarly to any other pesticide, dermal exposure is the most significant route of absorption for agricultural applicators and sprayers (Zhonghua et al, 1991;Zhang et al, 1991). The exposure scenario for pesticides used for public health purposes is quite variable, from exposure to larvicides in drinking-water, to dermal and inhalation exposure from bednets, or from space spraying and vapour of household insecticides (e.g.…”

“…Symptoms usually start 1-6 hours after exposure (KolmodinHedman, 1982;He et al, 1989;Zhang et al, 1991) and last not more than 24 hours, but in some cases they may last up to 3 days (for example after local application of large doses of active ingredients -13.8 mg/cm 2 skin) (Aldridge, 1990).…”

Biological Monitoring of Exposure: Trends and Key Developments

“…In the case of pesticides for which occupational exposure, mainly in agriculture, fluctuates in time and the skin is a significant route of absorption 99) , biological monitoring constitutes an important tool for obtaining information on exposure and possible early health effects.…”