Pesticide exposure Health effects

OFFICE OF PESTICIDE PROGRAMS (1998). Guidance for Submission of Probabilistic Exposure Assessments to the Office of Pesticides Programs Health Effects Division. US Environmental Protection Agency. 

Hazard identification, step one, means identification of new chemicals or other factors that may cause harmful health effects. Previously, novel hazards were usually observed in case studies or after accidents or other excessive exposures, usually in occupational environments. Today, thorough toxicity studies are required on all pesticides, food additives, and drugs. New chemicals also have to be studied for their potential toxic effects. Thus, earlier hazards were in most cases identified after they had caused harmful effects in humans. Today, most chemical products have been evaluated for their toxicity with experimental animals. Therefore, hazard identification has become a preventive procedure based on safety studies conducted before a chemical compound or product reaches the market, and before individuals are exposed to it. ... 

For methyl parathion, most of the information on health effects in humans is derived from cases of acute exposure to relatively high concentrations of the pesticide. Such reports have not addressed the issue of the potential endocrine-disrupting capacity of methyl parathion in humans. An added complication in determining whether methyl parathion has endocrine-disrupting capabilities in humans is the fact that humans are seldom exposed to a single pesticide. 

Figure 3-5 graphically depicts the information that currently exists on the health effects of methyl parathion in humans and animals by various routes of exposure. The available literature reviewed concerning the health effects of methyl parathion in humans described case reports of longer-term studies of pesticide workers and case reports of accidental or intentional ingestion of methyl parathion. The occupational exposure is believed to be via the dermal and inhalation routes. The information on human exposure is limited in that the possibility of concurrent exposure to other pesticides or other toxic substances cannot be quantified. 

Azaroff LS, Neas LM. 1999. Acute health effects associated with nonoccupational pesticide exposure in mral El Salvador. Environ Res A80 158-164. 

Children s Susceptibility. The information on health effects of endosulfan in humans is derived mainly from cases of accidental or intentional exposure of adults to high amounts of the pesticide, and the main adverse effect is neurotoxicity. No reports of adverse effects in endosulfan-exposed children were found, but it is reasonable to assume that children will exhibit similar signs and symptoms to those in adults under similar exposure conditions. Some studies in animals have provided evidence that young animals respond to endosulfan differently than adult animals (Kiran and Varma 1988 Lakshmana and Raju 1994 Sinha et al. 1995,1997 Zaidi et al. 1985), but there is no conclusive evidence to suggest that young animals are more susceptible than older ones. Further studies that evaluate a number of different end points in young as well as older organisms would provide valuable information. 

No significant harmful health effects to humans, animals, or plants are expected from exposure to this pathogen. Some strains have been used as pesticides to control crop damaging insects. ... 

Environmentally Induced Illnesses Ethics, Risk Assessment and Human Rights. Thomas Kerns, Jefferson, NC McFarland, [in press]. Addresses the ethics of managing environmental health and ubiquitous toxicants (such as solvents, pesticides and artificial fragrances). The work includes recent medical literature on chronic health effects from exposure to toxicants and the social costs of these disorders relevant historic and human rights documents recommendations for public policy and legislation and primary obstacles faced by public health advocates. 

Humans can be exposed to POPs through diet, occupational exposures (for example, farmworkers may be exposed to POPs through pesticides), industrial accidents and the environment (including indoor exposure). Exposure to POPs, either acute or chronic, can be associated with a wide range of adverse health effects, including illness and death (L. Ritter et al., 1995). Laboratory animal studies and wildlife studies have associated POPs with endocrine disruption, reproductive and immune dysfunction, neurobehavioral disorders and cancer. More recently, some POPs have also been connected to reduced immunity in infants and children and a concomitant increase in infections. Other studies have linked POPS concentrations in humans with developmental abnormalities, neurobehavioral impairment and cancer and tumor induction or promotion.4... 

There are few studies that specifically describe the effects of heptachlor or heptachlor epoxide in humans following exposure via the oral, inhalation, or dermal routes. There are data on the health effects of chlordane from occupational studies of pesticide applicators and manufacturers, and from studies of people who consumed food contaminated with chlordane and heptachlor. Chlordane is a pesticide that is structurally similar to heptachlor, and technical-grade preparations may contain... 

In order to assess the potential extent of human exposures and health effects, members of dairy farm families who consumed raw dairy products known to be contaminated with heptachlor epoxide were studied (Stehr-Green et al. 1986). These individuals and an unexposed urban reference population were compared with regard to serum pesticide levels and liver toxicity. The farm family members had significantly higher mean serum levels of heptachlor epoxide (0.81 0.94 ppb), oxychlordane (0.70 0.75 ppb), and transnonachlor (0.79 0.60 ppb) than the unexposed population. This study is limited because exposure level, duration, and frequency of exposure are not known. There was no increase in prevalence of abnormal liver function tests in the dairy farm families... 

Most of the data located concerning the health effects of heptachlor and heptachlor epoxide in humans come from case reports and occupational epidemiology studies of workers engaged either in the manufacture or application of pesticides. There is some information on people who have consumed heptachlor-contaminated food or dairy products, but no adverse health effects have been related to these exposures. The occupational studies involve exposures that are predominantly inhalation with contributions from dermal exposure, whereas all the animal studies were conducted using oral or intraperitoneal exposures. The occupational and case reports provide no quantitation of dose or duration of exposure, which makes it impossible to determine with any precision the effect levels for humans. There are no data that indicate that heptachlor or heptachlor epoxide are carcinogenic to humans. However, human studies are limited by the long latency period of carcinogenesis and by ascertainment and follow-up biases. 

The Natural Resources Defense Council (NRDC) report Intolerable Risk Pesticides in Our Children s Food focused on the increased risk of the adverse effects of pesticides on children. This was in part because of the smaller size of the child relative to the adult and because of different food consumption practices. Relative to their size, children eat, drink, and breathe more than adults in part because they are growing. The use and regulation of pesticides illustrate the complexities of risk analysis and risk management and the difficulties in determining an acceptable level of exposure with acceptable risks. In the United States approximately 1 billion pounds of pesticides (with about 600 different active ingredients) are used annually in the agricultural sector, and worldwide approximately 4 billion pounds are used. There are a range of human health and environmental health effects associated with the use of pesticides. 

It is considered desirable to keep workplace exposure to pesticides as low as practical regardless of the current knowledge of their acute and chronic toxicity. All too often pesticides which were considered to be of negligible toxicity are later found to have a potential for causing adverse health effects following a sufficient period of exposure to an adequate dose. DBCP and nitrophen are good examples of this type of problem. We also gather and analyze detailed information on more than 2,000 illness reports per year from physicians who describe possible occupational exposures to specific pesticides. We also obtain or make detailed workplace measurements of the levels of pesticides to which workers may be exposed. 

The attention of those concerned with occupational exposure to pesticides has turned from immediate acute effects to chronic effects. The California regulations lists chronic health effects as a criteria for special reentry studies. The EPA, in their first public draft of reentry guidelines, also lists chronic effects as a criteria to be utilized in setting reentry intervals. One problem with this is determining what constitutes a chronic health effect and what information should be used It is clear that animal studies which unequivocably demonstrate onco-... 

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