Pulmonary damage due to paraquat poisoning through skin absorption

A case of recovery from acute respiratory insufficiency due to paraquat is described. A 57-year-old farmer developed breathlessness, high fever and interstitial infiltrates in the upper and middle lung fields few days after percutaneous paraquat poisoning with rapid evolution to pulmonary fibrosis. Anti-inflammatory drugs and antioxidants, were administered to the patient, though with a delay, with some improvement; the patient survived despite residual lung fibrosis. Paraquat lung, as confirmed by this paper, is not invariably fatal.

Evaluating health risks from occupational exposure to pesticides and the regulatory response

In this study, we used measurements of occupational exposures to pesticides in agriculture to evaluate health risks and analyzed how the federal regulatory program is addressing these risks. Dose estimates developed by the State of California from measured occupational exposures to 41 pesticides were compared to standard indices of acute toxicity (LD50) and chronic effects (reference dose). Lifetime cancer risks were estimated using cancer potencies. Estimated absorbed daily doses for mixers, loaders, and applicators of pesticides ranged from less than 0.0001% to 48% of the estimated human LD50 values, and doses for 10 of 40 pesticides exceeded 1% of the estimated human LD50 values. Estimated lifetime absorbed daily doses ranged from 0.1% to 114,000% of the reference doses developed by the U.S. Environmental Protection Agency, and doses for 13 of 25 pesticides were above them. Lifetime cancer risks ranged from 1 per million to 1700 per million, and estimates for 12 of 13 pesticides were above 1 per million. Similar results were obtained for field workers and flaggers. For the pesticides examined, exposures pose greater risks of chronic effects than acute effects. Exposure reduction measures, including use of closed mixing systems and personal protective equipment, significantly reduced exposures. Proposed regulations rely primarily on requirements for personal protective equipment and use restrictions to protect workers. Chronic health risks are not considered in setting these requirements. Reviews of pesticides by the federal pesticide regulatory program have had little effect on occupational risks. Policy strategies that offer immediate protection for workers and that are not dependent on extensive review of individual pesticides should be pursued.

Carbofuran toxicity

Carbofuran, an anticholinesterase carbamate, is commonly used as an insecticide, nematicide, and acaricide in agricultural practice throughout the world. Due to its widespread use in agriculture, contamination of food, water, and air has become imminent, and consequently adverse health effects are inevitable in humans, animals, wildlife, and fish. Currently, carbofuran's involvement is most frequently encountered in malicious poisoning. The literature on chemical properties, acute toxicity data, poisoning incidences, pharmacokinetics, and mechanism of toxicity of carbofuran is briefly reviewed. Much emphasis is given to the metabolism of carbofuran, and the impact of carbofuran and its two major metabolites (3-hydroxycarbofuran and 3-ketocarbofuran) on overall toxicity. Biochemical (cholinergic and noncholinergic), hematological, and immunological effects induced by carbofuran are discussed in detail. Carbofuran and/or its major metabolites can cross the placental barrier and produce serious effects on the maternal-placental-fetal unit. Carbofuran's toxicity can be potentiated by simultaneous exposure with other cholinesterase inhibitors. Literature on various biomarkers of carbofuran exposure and on induced adverse health effects is also presented. To date, a combination of atropine and memantine remains the most effective antidotal treatment against acute carbofuran toxicity.

[Milker's hand]

The predominant skin problems in cattle-breeders are toxic and allergic eczemas, with cleansers, water, rubber, disinfectants and fodder being the most frequent provoking factors. The Danish register of occupational diseases yields information based on notifications during the years 1984-1992. Detailed data especially concerning dairy farms are not obtainable, but during the whole period 101 hand-skin diseases in farmers and farming assistants were notified, 12-23 annually in recent years. This number is not alarming, but there is general agreement that underreporting is significant. The main elements of prevention are 1) reduction of harmful actions and 2) optimization of skin resistance. Among the steps that ought to be taken immediately are reduction of contact with cleansing and disinfective agents through change of working methods and behaviour. Alteration of tools, for instance substitution of rubber with less sensibilizing materials, is desirable.

Women at work: agriculture and pesticides

Numerous occupational studies of cancer risks related to agriculture, agricultural practices, and agricultural exposures have been conducted among male farmers and farmworkers. Relatively few studies of female farmers and farmworkers have been conducted. Excesses of non-Hodgkin's lymphoma, leukemia, multiple myeloma, soft tissue sarcoma, and cancers of the breast, ovary, lung, bladder, cervix, and sinonasal cavities have been observed in women in agriculture or with agricultural exposures. Agents that contribute to ill health in exposed men may also affect exposed women, sometimes in unexpected ways.

[Hygienic evaluation of working conditions and indicators of health status of workers in poultry farms]

The main unfavourable factor of poultry farms environment is contact of workers with chemical disinfectants. Changes in morphofunctional, cytochemical, immunological parameters and higher level of morbidity were revealed in poultry farms. Hygienic prophylactic recommendations were made.

Neurotoxins: a neuroscience nursing challenge

Societal awareness of toxins in general has been heightened in the past few decades with the increased focus on environmental concerns. The medical profession has been aware of the effects of some toxins such as lead and mercury for centuries, while other toxins have more recently been identified. Neuroscience nurses are challenged to be aware of the neurological effects of lesser known toxins, such as ciguatera and methyl bromide, and to meet the complex needs of patients who are suffering from the effects of toxic levels of these substances.

Time to pregnancy and occupational exposure to pesticides in fruit growers in The Netherlands

OBJECTIVES

Although pesticides are regularly used in agriculture, relatively little is known about possible adverse health effects, especially reproductive effects, due to occupational exposure. This explorative study investigates the relation between exposure of the fruit grower to pesticides and fecundability (probability of pregnancy) in a population of fruit growers.

METHODS

The analysis is based on self reported data and includes 91 pregnancies during 1978-1990 of 43 couples. Cox' proportional hazards model was used to analyse time to pregnancy after correction for gravidity and consultation with a physician for fertility problems.

RESULTS AND CONCLUSIONS

Application of pesticides solely by the owner was associated with a long time to pregnancy, resulting in a fecundability ratio of 0.46 (95% confidence interval (95% CI) 0.28-0.77). Similarly a low spraying velocity (< or = 1.5 hectares/h) resulted in a fecundability ratio of 0.47 (95% CI 0.29-0.76) and is associated with the use of older spraying techniques and tractors without a cabin. These factors were assumed to cause high exposure, which was confirmed by exposure measurements in the field. The effect of high exposure was mainly apparent if the couple had intended to become pregnant in the period from March-November (fecundability ratio 0.42, 95% CI 0.20-0.92). This is the period in which pesticides are applied. Out of the spraying season the effect of a high exposure was absent (fecundability ratio 0.82, 95% CI 0.33-2.02). In the high exposure group 28% of the pregnancies had been preceded by consulting a physician because of fertility problems, compared with 8% in the low exposure group. These findings indicate that an adverse effect of exposure to pesticides on fecundability is likely.

Effect of occupational exposure to aldrin on urinary D-glucaric acid, plasma dieldrin, and lymphocyte sister chromatid exchange

The effects of exposure to the chlorinated cyclodiene termiticide aldrin was evaluated in pest control workers potentially exposed to this material. Sister chromatid exchange (SCE) frequencies were not elevated in workers handling aldrin. This is consistent with the fact that chlorinated cyclodienes are not genotoxic. Plasma dieldrin concentrations (up to 250 ng/ml) confirmed exposure in workers actively performing termiticide treatments and in maintenance and store workers, when compared with unexposed control workers (median concentration, 4.8 ng/ml). Urinary D-glucaric acid (DGA), an index of hepatic enzyme activity, was elevated in pesticide-exposed groups but urinary DGA was poorly correlated with plasma dieldrin level. This indicates that concurrent exposures of these groups to other pesticides may have influenced mixed-function oxidase metabolic activity.

A remarkable case of hyperventilation

We have seen a case of hyperventilation which appeared to have been caused by contact with an insecticide. Pathophysiology, epidemiology and treatment are discussed. Familiarity with the clinical symptoms greatly facilitate diagnosis, especially in emergency situations.

Survey of health and use characterization of pesticide appliers in Minnesota

We surveyed 1,000 randomly selected state-licensed pesticide appliers to improve our understanding of pesticide use and its potential health effects. Participants were stratified by pesticide class (herbicides, insecticides, fungicides, fumigants) to determine potential differences in health characteristics among different pesticide groups. A subset of 60 applicators, divided by pesticide class used, were studied for exposure-related cholinesterase (ChE) depression. ChE depression in excess of 20% was most frequent in fumigant applicators who did enclosed-space application, in addition to other pesticide application procedures (p < .05). Survey data demonstrated that the prevalence of all common chronic diseases considered together was significantly increased (p = .015) in fumigant appliers, compared with all other pesticide use groups. The frequency of chronic lung disease was also significantly increased in the fumigant applier group (p = .027). Curiously, two cases of a rare hematopoietic neoplasm--hairy cell leukemia--were identified in our study group (annual incidence 0.67/100,000 in Minnesota). Whether there is an association between this unique tumor and agricultural work is uncertain, and further study is needed in this regard.

October 1942: a strange epidemic paralysis in Saval, Verona, Italy. Revision and diagnosis 50 years later of tri-ortho-cresyl phosphate poisoning

In the autumn of 1942 a strange epidemic paralysis started in Saval, at that time a country area but now part of the city of Verona. The epidemic went on for several months and affected 41 people, all working as owners or labourers on the same farm. Some of the farm animals (chickens, horses, cattle, pigs) also became ill. About 20 patients were admitted to the nearby city hospital. The outbreak was diagnosed as polyneuritis with a probable viral cause. Fifty years later, seven people with sequelae of the disease were examined. The most severe cases present a spastic paraplegia and lower leg muscle atrophy without sensory impairment, resembling an amyotrophic lateral sclerosis "frozen" for 50 years. The clinical syndrome can now be attributed confidently to organophosphate induced delayed polyneuropathy. All the epidemiological data obtained from the survivors were evaluated and a careful review of the literature was made. Contamination of the ground from a rubbish dump near the farmyard would explain the epidemiology of the Saval outbreak.

Mortality study on a cohort of Italian licensed pesticide users

This study describes the mortality experience in a cohort of 23,401 farmers, residing in southern Piedmont, Italy, and licensed to use pesticides. From 1970 to 1986 the cohort included 340,794 person-years and 2683 deaths were observed. A strong attenuation of the death risk was found due to the healthy worker effect (seen as an active role in the application for the license by the members of the cohort) and due to the limited comparability of the cohort with respect to the reference population. The standardized mortality ratios (SMRs) were remarkably < 100 for all causes (SMR = 59; 95% confidence interval = 57-61) and for all tumors (SMR = 60; 95% CI 55-64), but they increased with the increasing duration of the follow-up. A risk increase was observed with respect to melanomas and eye tumors in the entire cohort and lymphoma and tumors of the connective tissue in the subcohort of subjects living in villages with mainly arable land.

Pesticide poisoning among farmers in a health area in Sri Lanka

OBJECTIVES

1. To determine the incidence and the prevalence of pesticide poisoning in Kelaniya Medical Officer of Health (MOH) area. 2. To establish causes of pesticide poisoning in the community.

DESIGN

Questionnaire survey based on 10% cluster sample of agricultural workers.

SETTING

Kelaniya MOH area situated 10 km north-east of Colombo, during April 1986 to May 1987.

FUNDING

Natural Resources Energy and Science Authority of Sri Lanka.

RESULTS

The percentage of pesticide users ever poisoned in the past was 21.7% and during the year before the study was 7.5%.

CONCLUSION

Lack of knowledge on pesticides and inability to afford protective clothing are the major factors contributing to pesticide poisoning.

Chronic health effects among sheep and humans surviving an aldicarb poisoning incident

Aldicarb is a granular carbamate insecticide, acaricide and nematocide applied to soil. In 1989, a large scale aldicarb poisoning of grazing sheep occurred in south central Washington State. Among 1600 animals in 3 different groups, 288 of 318 sheep in 1 group died within a very short time. An investigation by the Washington State Department of Agriculture concluded that aldicarb poisoning was the cause of the acute sheep deaths. Within 3 w of the incident, all the 30 sheep which survived the initial exposure from the 1 group had died or were near death and euthanized. Among the approximately 1300 sheep nearby but not affected by the acute incident, low fertility and poor health were apparent over the next 3 y. These sheep also suffered more deaths than expected, and lambs born to the sheep had a higher frequency of limb and gastrointestinal malformations than usual. All of the 6 men present in the field the day of the acute sheep deaths complained of acute symptoms. Three men were hospitalized the night of the sheep deaths and 2 were seen by a physician the next day. All men were healthy prior to the sheep deaths. Within a few days 4 of the 6 men developed a productive cough and 1 reported right-sided abdominal pain. Three years after the incident 5 of the men were still seeking medical attention or reporting symptoms they felt associated with the acute exposure. The chronic health effects in the sheep and men are not expected following exposure to aldicarb. No explanation exists for the chronic health effects, nor have such effects been previously reported in aldicarb poisonings.