Study of respiratory impairment among pesticide sprayers in Mango plantations

Decreased lung function in 7-year-old children with early-life organophosphate exposure

BACKGROUND

Organophosphate pesticides are heavily used in agriculture, and adverse associations with respiratory health in occupational settings have been reported. However, most of the evidence comes from studies where there were no biomarkers of exposure and no objective outcome measurement. Non-occupational chronic effects among residents living in agricultural communities are less well described.

OBJECTIVE

To evaluate associations between early-life organophosphate exposure and lung function of children living in an agricultural community.

METHODS

Participants were 279 children from the Center for the Health Assessment of Mothers and Children of Salinas (CHAMACOS) longitudinal birth cohort. The area under the curve for organophosphate exposure was determined by urinary diethyl and dimethyl dialkylphosphate metabolites of organophosphate pesticides, which were measured five times during childhood (6-60 months). Spirometry was performed at age 7 years. Regression models controlled for maternal smoking during pregnancy, season of birth, particulate matter concentrations with aerodynamic diameter ≤2.5 μm (PM2.5), breast feeding duration, mould and pets at home, distance of home from a highway, food insecurity, maternal education, season of spirometry, sex, height and technician.

RESULTS

Childhood diethyl, dimethyl and total dialkylphosphate concentrations were associated with significant decreases in lung function at age 7. Specifically, we found lower FEV1, (L/s) (ß=-0.16, 95% CI -0.30 to -0.02, p=0.03) and FVC (L) (ß=-0.17, 95% CI -0.34 to 0.01, p=0.06) per 10-fold increase of total dialkylphosphate levels.

CONCLUSIONS

Early-life organophosphate exposure as assessed by dialkylphosphate concentrations was adversely associated with 7-year-old children's lung function.

Association between lung function in adults and plasma DDT and DDE levels: results from the Canadian Health Measures Survey

BACKGROUND

Although DDT [1,1,1-trichloro-2,2-bis(4-chlorophenyl)ethane] has been banned in many countries since the 1970s, it may still pose a risk to human respiratory health. In agriculture, DDT exposures have been associated with asthma and chronic bronchitis. However, little is known about the effect of DDT on lung function.

METHODS

We used data on 1,696 participants 20-79 years of age from the Canadian Health Measures Survey (CHMS) and conducted multiple regression analysis to estimate associations between plasma p,p´-DDT/DDE and lung function.

RESULTS

Almost all participants (> 99.0%) had detectable concentrations of plasma p,p´-DDE, but only 10.0% had detectable p,p´-DDT. Participants with detectable p,p´-DDT had significantly lower mean FVC (difference = 311 mL; 95% CI: -492, -130; p = 0.003) and FEV1 (difference = 232 mL; 95% CI: -408, -55; p = 0.015) than those without. A 100-ng/g lipid increase in plasma p,p´-DDE was associated with an 18.8-mL decrease in mean FVC (95% CI: -29, -9) and an 11.8-mL decrease in mean FEV1 (95% CI: -21, -3). Neither exposure was associated with FEV1/FVC ratio or FEF25%-75%.

CONCLUSIONS

DDT exposures, which may have occurred decades ago, were still detectable among Canadians. Plasma DDT and DDE were negatively associated with lung function parameters. Additional research on the potential effects of DDT use on lung function is warranted.

Occupational pesticide exposures and respiratory health

Pesticides have been widely used to control pest and pest-related diseases in agriculture, fishery, forestry and the food industry. In this review, we identify a number of respiratory symptoms and diseases that have been associated with occupational pesticide exposures. Impaired lung function has also been observed among people occupationally exposed to pesticides. There was strong evidence for an association between occupational pesticide exposure and asthma, especially in agricultural occupations. In addition, we found suggestive evidence for a link between occupational pesticide exposure and chronic bronchitis or COPD. There was inconclusive evidence for the association between occupational pesticide exposure and lung cancer. Better control of pesticide uses and enforcement of safety behaviors, such as using personal protection equipment (PPE) in the workplace, are critical for reducing the risk of developing pesticide-related symptoms and diseases. Educational training programs focusing on basic safety precautions and proper uses of personal protection equipment (PPE) are possible interventions that could be used to control the respiratory diseases associated with pesticide exposure in occupational setting.

Health risks of employees working in pesticide retail shops: An exploratory study

Background:

Shop keepers dealing with pesticides are exposed to multiple pesticides that include organophosphates, organochlorines, carbamates, pyrethroids. Hence an exploratory health study was conducted on shopkeepers selling pesticides in urban areas of Lucknow and Barabanki District, Uttar Pradesh, India.

Materials and Methods:

Detailed information regarding socio-economic status, family history, personal habits and work practices were recorded for 20 subjects and controls by the investigator on a pre-tested questionnaire. Clinical examination including neurological studies of the shopkeepers and control subjects was done.

Results:

The study revealed significant slowing of motor nerve conduction velocity and low peak expiratory flow rate among shopkeepers as compared to control subjects. Prevalence of significantly higher gastro-intestinal problems was also observed among exposed subjects. Neurological, ocular, cardiovascular and musculo-skeletal symptoms were also found to be higher among shopkeepers. This was not statistically significant. Significantly higher relative risk for sickness related to systems viz., cardio-vasular, genito-urinary, respiratory, nervous and dermal was observed among exposed subjects compared to controls.

Conclusions:

These findings provide a prima facie evidence of clinical manifestations because of multiple exposures to pesticides and poor safety culture at work place.

Multipesticide residue assessment of agricultural soil and water in major farming areas in Benguet, Philippines

This study investigated the concentration and presence of pesticide residues in water and soil in Benguet, which is a vegetable producing region in the Philippines. Seventy-eight samples and 49 water samples were taken from different farms covering three municipalities in the province of Benguet and were analyzed using gas chromatography. Meteorological conditions of temperature and humidity were also taken. Thirty-four of the soil samples were found to be positive for pesticide residues. The most significant pesticide type with the highest concentration was technical endosulfan, with a mean concentration of 0.025 mg/kg, followed by endosulfan sulfate (0.015 mg/kg), chlorpyrifos (0.01 mg/kg), profenofos (0.003 mg/kg), chlorothanil, cypermethrin, and cylohathrin (all at 0.002 mg/kg). One water sample was found to be positive for pesticide residue of chlorpyrifos in municipality 2 at a concentration of 0.07 mg/L. The data also showed that endosulfan, which is restricted in the Philippines and banned in other countries, was found to be the most prevalent pesticide used (17.7%) and the second highest in concentration (0.015 mg/kg) in soil samples. The study also showed a relationship between temperature and pesticide concentration in soil. In conclusion, pesticide residues were found in soil and water samples in the farming areas of Benguet.

Adverse health effects of pesticides in agrarian populations of developing countries

Developing countries use only 20% of the world's agrochemicals, yet they suffer 99% of deaths from pesticide poisoning. Pesticide poisoning is a significant problem in developing countries primarily because of unsafe pesticide application and handling practices. Safety is further exacerbated by the illiteracy and poverty that prevails in most farming communities of developing countries. Pesticides classified as being extremely or highly hazardous by FAO and WHO, including those banned by other countries, continue to be used in developing countries. Many farmers in developing countries continue to be exposed to pesticides from either storing them in or near their residences, or from inadequate or unsafe application or handling practices. Farming populations exposed to pesticides suffer from several health problems, primarily neurological abnormalities, respiratory ailments, and reproductive, endocrinological, and dermal problems. In developing countries, the scientific literature (including the Indian Institute of Toxicology Research, India) have taken the initiative to monitor health problems resulting from pesticide exposure in agrarian communities. The welfare fund for agricultural laborers could institute a special program for pesticide applicators in developing countries. The primary need, currently, in such countries is creation and implementation of sound national policies to effectively articulate appropriate guidelines for managing farm pest control activities. Such policies should be aimed at both limiting pesticide exposure and usage, but doing so without damaging the yields of food production. If such steps are taken, it is fully expected that the incidence of adverse health consequences for agrarian populations from pesticide toxicity will decrease, and the health of farmers improve.

Biomonitoring of organochlorines, glutathione, lipid peroxidation and cholinesterase activity among pesticide sprayers in mango orchards

BACKGROUND

Pesticide sprayers in mango orchards of Malihabad, Lucknow (India) are generally exposed to organophosphate (OP) and pyrethroid pesticides. We determined the pesticide exposure levels along with their biochemical and clinical effects in 31 sprayers, compared with 18 controls.

METHODS

Assay of acetyl and butyrylcholinesterases (AChE, BChE respectively) as an indirect measurement of OP exposure and levels of malondialdehyde (MDA) and glutathione (GSH) were estimated in blood samples to determine their impact on redox potential. Organochlorines were estimated by GLC-ECD.

RESULTS

Significantly inhibited AChE, BChE activities and higher MDA level were found among sprayers compared to controls (p<0.05). Mean of total organochlorines were surprisingly higher (97.65+/-13.38 ppb) in sprayers than in those of controls (20.42+/-3.56 ppb) (p<0.05). Respiratory morbidity (32.4%), ocular problems (8.8%), gastrointestinal (17.6%) and skin problems (23.5%) were found in sprayers. There was significant correlation between AChE and GSH (r=0.29, p<0.05) and AChE with MDA (r=-0.34, p<0.05).

CONCLUSION

Results indicated the significantly enhanced lipid peroxidation in sprayers correlated with cholinesterases inhibition. A small sample size limits the significance of this study. However, it paves the way for a larger Indian study with extended practical significance.

Possible mechanism of pesticide toxicity-related oxidative stress leading to airway narrowing

The study was conducted to assess the magnitude of oxidative stress and lung function abnormalities in 34 male pesticide sprayers on exposure to pesticides in mango plantations. Biochemical studies on blood antioxidant enzymes revealed an unchanged glutathione level and increased level of malondialdehyde (P < 0.001), which indicates that pesticide sprayers may have suffered from oxidative stress. Decreased acetyl-cholinesterase levels (P < 0.001) in sprayers compared to the controls suggest inhibition of cholinesterase activity. The present study shows that pesticide toxicity might lead to oxidative stress and airway narrowing resulting in decreased peak expiratory flow rate.

Acetylcholinesterase Inhibition as an Indicator of Organophosphate and Carbamate Poisoning in Kenyan Agricultural Workers

Acetylcholinesterase inhibition was determined for 666 Kenyan agricultural workers; 390 (58.6%) mainly pesticide applicators exposed to organophosphate and carbamate pesticides and 276 (41.4%) unexposed controls from four rural agricultural areas during 1993 and 1994. Baseline levels were depressed in the exposed group (6.1 +/- 0.84; 4.09 +/- 0.84) but not in the unexposed group (5.83 +/- 0.91; 5.60 +/- 0.87). Acetylcholinesterase inhibition was found in all exposed individuals and led, on average, to a decrease of baseline acetylcholinesterase levels of 33% (+/-12%). The control groups had a nonsignificant decrease of only 4% (+/- 8%). The exposed subjects in Naivasha (flower growers) had the largest inhibition (36%), followed by Homabay (cotton growers) (35%) and Wundanyi (vegetable growers) (33%). Those in Migori (tobacco growers) had, by far, the least inhibition of acetylcholinesterase activity (26%), indicating inherent factors that led to less inhibition. Acetylcholinesterase activity levels of 115 exposed individuals (29.6%) and no controls were depressed to values below 60% of baseline levels. The dramatic inhibition observed could lead to chronic clinical and subclinical intoxication. These findings show that acetylcholinesterase inhibition can be used as an indicator of organophosphate and carbamate poisoning in occupationally exposed agricultural workers. There is, therefore, an urgent need for primary prevention programs to monitor and address occupational exposures to these hazardous substances in agriculture in Kenya and other developing countries, as well as to use integrated pest management strategies in crop protection.

Agricultural pesticide use in developing countries: health effects and research needs

Large worker populations in the Third World are exposed to increasing amounts of pesticides, including pesticides severely restricted and banned in industrialized countries. Studies on knowledge, attitudes, and practices indicate that unsafe use of pesticides is the rule in Third World countries. Surveys of acute poisonings show high rates in these countries, despite underregistration. The scarce studies on chronic health outcomes demonstrate neurotoxic, reproductive, and dermatologic effects. Exposure assessment consists mainly of cholinesterase testing, and few studies have quantified dermal and respiratory exposure. The few intervention studies demonstrate the need for evaluation of the impact of preventive measures and policies. There is no evidence that widespread "safe-use" programs have greatly affected exposure and morbidity. It was concluded that research should focus on simple methods for surveillance of exposure and on surveillance of acute illness and its causes in order to develop and evaluate rapid local interventions. Studies on chronic effects should be carried out in selected countries, aiming at long-term and broader interventions. Policies that promote the use of pesticides should be critically evaluated. North-South and South-South research collaborations must be encouraged to address this global health problem.

Human health effects of agrichemical use

The use of pesticides and nitrogen fertilizers in agriculture has grown dramatically over the past 30 years. Currently, approximately 600 active pesticide ingredients are used, but adequate toxicologic data are available for only approximately 100 of these. Environmental exposure of humans to agrichemicals is common and results in both acute and chronic health effects, including acute and chronic neurotoxicity (insecticides, fungicides, fumigants), lung damage (paraquat), chemical burns (anhydrous ammonia), and infant methemoglobinemia (nitrate in groundwater). A variety of cancers also have been linked to exposure to various pesticides, particularly hematopoietic cancers. Immunologic abnormalities and adverse reproductive and developmental effects due to pesticides also have been reported. The health effects associated with pesticides do not appear to be restricted to only a few chemical classes. Therefore, enhanced efforts are needed to control or eliminate human exposures wherever possible. Research also is needed to better characterize and quantitate the adverse effects of agrichemicals on human health.