The problems associated with pesticide use by irrigation workers in Ghana

The use of pesticides in Ghanaian agriculture, though beneficialin reducing crop loss both before and after harvest, has beenassociated with threats to human health often due to the misapplicationof the chemicals. This study was an initial attempt to explorethe knowledge, attitudes and practices of 123 farm workers onthree irrigation project areas in the Accra Plains, Ghana, regardingthe safe handling and use of pesticides, to assess the prevalenceof symptoms associated with organophosphorus pesticides (OPs)and carbamates and to determine the prevalence of pesticide-relatedsymptoms, and blood cholinesterase. The study design was cross-sectionalin type. Methods used were interviews and observation, and biologicalmonitoring. The results revealed moderate levels of knowledgeof the routes of absorption of pesticides and of potential symptomsfollowing exposure. Knowledge of personal protective measureswas poor to moderate. High risk practices included frequenthandling of the chemicals, home storage of pesticides and shortre-entry intervals. Despite knowledge of some health risks associatedwith pesticides, the use of personal protective equipment (PPE)was minimal due primarily to financial constraints. The prevalenceof symptoms was higher and cholinesterase levels lower thanin a control group of teachers. It is suggested that there isa need for more epidemiologic studies to investigate the problemsassociated with pesticide induced ill health as well as researchinto appropriate and affordable PPE. PPE needs to be subsidized.Training of agriculture and health workers in safety precautions,recognition, and management of pesticide-related ill healthis a matter of urgency.     

Pesticide sprayers' knowledge,attitude and practice of pesticide use on agricultural farms of Ethiopia

Pesticide sprayers from five state-owned agricultural farms took part in a study that evaluated their knowledge, attitude and practice of pesticide use on farms. Demographic features of the sprayers showed that the majority of them had primary-level education. The duration of work as sprayers on the farms ranged from 1 month to approximately 10 years, with 59% of them having worked as sprayers for <5 years. Their knowledge about hazards from pesticides was indicated by the responses they gave to the standard questionnaire. Careful working was considered to be very important by 93% of them, while only 7% suggested the use of personal protective devices (PPD). On some of the farms, sprayers were provided with inappropriate/unfit and worn-out PPD; 18% of the sprayers had unfit goggles and 29% used worn-out gloves. To minimize risk from pesticide application, 63% suggested avoiding applications during windy and sunny weather, 32% suggested the provision and proper use of PPD, while only 3% of them felt medical check-ups and training were important, and 2% suggested risks from spraying were best controlled by leaving their job. The hygiene and sanitation practices of the sprayers require much improvement. An attitudinal change is needed, together with the provision of better facilities and infrastructure. We recommend that pesticide safety education be given to the sprayers. In addition, appropriate PPD should be used, with regular maintenance and timely replacement of worn-out parts.     

Effects of pesticide applications on respiratory health of Ethiopian farm workers

The effects of pesticide use on the respiratory health of agricultural farm workers were studied in 203 farm workers and 131 controls. The farm workers were sprayers, supervisors, technicians, and pest assessors. Pulmonary function was found to be remarkably poor among the non-smoker supervisors, followed by the non-smoker sprayers, as compared with that of the non-smoker controls. The means (SD) of FVC and FEV1 for supervisors and sprayers were 2.88 (0.41), 3.05(0.50) and 2.74(0.38), 2.89(0.54), respectively, p < 0.05. The non-smoker technicians had the most respiratory symptoms, with wheezing and breathlessness being the most frequent (35.7% in 14 technicians). Farm workers with various job experiences are subject to reduction of pulmonary function and frequent complaints of respiratory symptoms that could possibly lead to chronic respiratory health problems.     

Erythrocyte cholinesterase activity levels in desert farm workers

In this study we have examined 532 migrant farm workers engagedmainly in the cultivation of vegetable crops, in both greenhousesand openfarms, and an equal number of controls. Erythrocyteacetylcholinesterase activity (AChE) was measured to determinethe degree of toxicity due to exposure to organophosphate andcarbamate pesticides in the farm workers employed either asforemen (41.5%) or farmers (58.5%). The mean ages of the farmworkers and controls were 35.2±7.4 (mean±SD) yearsand 34.6±7.1 years. AChE activity of the farm workersand controls was 3.89±0.64 Ul/ml (mean±SD) and4.15±0.29 Ul/ml. The haemoglobin adjusted erythrocytecholinesterase activity (HAChE) was 29.96±4.14(mean±SD)for farm workers and 32.10±2.26 for controls. AChE activitywas very highly significantly lower for the foremen (3.76±0.69)compared to farmers (3.98±0.59) (Student's t-test=4.13,p=0.0001). HAChE was also very highly significantly lower forforemen (29.24±4.37) compared to farmers (30.46±3.88)(Student's t-test=3.64, p=0.0001). The poorly controlled useof pesticides in the farms appeared to have caused sub-clinicalintoxication in the farm workers and indicated the need fortraining and implementation of hygiene practices.     

A cross-sectional study about mental health of farm-workers from Serra Gaucha (Brazil)]

OBJECTIVE: In view of the shortage of population-based rural studies, this research project evaluated the associations between the characteristics of rural work and the occurrence of minor psychiatric disorders (MPD). METHODS: A cross sectional study was carried out on the 1,282 farm workers of 446 farms. Information about the farms (land extension, agricultural activities, technology and pesticide use) was collected. Demographic and socioeconomic data, characteristics of the work process and mental health indicators were obtained from the workers. RESULTS: MPD were found in 37.5% of the farm workers. The risk was higher on farms with a land extension of from 26 to 50 hectares, and lower where there was an increased level of job technology and schooling. The prevalence of MPD was higher among bean producers and lower among apple producers. Despite the impossibility of defining the direction of the causal link, pesticide poisoning was strongly associated with MPD. CONCLUSION: The results call attention to the dimension of the problem and to the importance of adopting new policies for the protection of farm workers' mental health.     

Sense of smell in workers exposed to agricultural odours

AIM: To investigate the effect of occupational exposure to agricultural odours on sense of smell. METHODS: Olfaction was investigated in 60 employees of dairy and pig-breeding farms and compared to 60 non-farm controls living in the same rural area. Both groups were matched for age, sex and smoking habits. All participants underwent standardized, validated tests for olfactory function and were tested before and after the first day of a working cycle. In addition, farm subjects were also tested in the evening of Day 5 of this period. RESULTS: There was no difference in overall olfactory function between the two groups. Olfactory function was not related to duration of exposure to the odorous environment. CONCLUSION: These results suggest that occupational exposure to strong agricultural odours has no major impact on the sense of smell.     

A survey of semen indices in insecticide sprayers

This study aims at clarifying the semen indices of insecticide sprayers who are exposed mainly to organophosphorus and pyrethroid insecticides. Eighteen male sprayers out of 54 working for 9 companies in central Japan and 18 age-matched students or medical doctors as unexposed controls participated in detailed reproductive check-ups conducted in summer and the following winter. The sprayers were exposed to insecticides more in summer, the busiest season, than winter, the off-season (p<0.05). Erythrocyte true cholinesterase activities in the sprayers were lower than in the controls in summer (p<0.05), and decreased in significant association with the increase in exposure frequency. Testicular volumes in the sprayers tended to be smaller than in the controls (p=0.06). The serum testosterone concentration in winter in the sprayers was higher than in the controls (p<0.05), though luteinizing hormone and follicle stimulating hormone concentrations were not significantly different. The sperm counts and vitality were comparable between the groups, but detailed sperm motility analysis in summer revealed that the percentages of slow progressive and nonprogressive motile sperm were twice as high in the sprayers (p<0.05), and that of rapid progressive sperm tended to be lower (p=0.06). Such differences were not observed in winter. Differential sperm morphology counts showed that interaction of group and abstinence effects were significant in sperm with normal morphology and with head deformity only in the summer check-up. Despite possible inherent differences between the groups, the above season-dependent differences suggested that the observed lower semen quality in the sprayers was associated with pesticide spraying work.     

Organophosphate pesticide exposure in a group of Washington State orchard applicators.

As part of a study to investigate the potential for organophosphates to cause chronic neurologic sequelae, we assessed the pesticide exposure experience of a group of Washington State apple orchard applicators. Seasonal monitoring of cholinesterase activity for 48 regular organophosphate applicators and a control group of 40 slaughterhouse workers was performed. A subset of the pesticide applicators participated in an in-depth exposure assessment. This involved observation of spraying activities during 1 spray day, as well as cholinesterase monitoring and dermal exposure assessment using a fluorescent tracer in the pesticide formulation. Comparison of seasonal red blood cell cholinesterase change in pesticide workers according to exposure level, characterized by frequency of pesticide spraying and protective equipment use, showed lower cholinesterase levels among higher exposed groups compared to lesser exposed groups. In-depth exposure assessment revealed exposure primarily on the head and hand regions. Subclinical changes (less than 15% inhibition) in red cell cholinesterase correlated well with dermal exposure calculations. This study suggests that cholinesterase monitoring may be a useful biological marker for even subclinical organophosphate pesticide effects.     

Plasma Cholinesterase Levels and Health Symptoms in Peruvian Farm Workers Exposed to Organophosphate Pesticides

The purpose of this study was to examine plasma cholinesterase (PChE) changes and the adverse health effects associated with chronic low-dose exposure to organophosphates (OPs) in a Peruvian agricultural population. A cross-sectional study with a clinical interview and blood tests was performed among 213 farm workers from two subtropical valleys in Peru. The control group consisted of 78 nonexposed workers from the same areas. PChE levels from the two exposed subgroups (pesticide applicators and other agricultural jobs) were significantly lower than those of controls (1554 ± 315 U/l, 1532 ± 340 U/l, and 1787 ± 275 U/l, respectively). Fifteen percent of the exposed population reported a past poisoning by pesticides, all of them needing medical evaluation and treatment. They had significantly lower PChE levels as compared to those without this antecedent. Approximately 61% of the exposed workers reported pesticide-related symptoms, but no significant difference was found in their PChE as compared to workers without symptoms. On the other hand, the use of personal protective equipment (PPE) was significantly associated with higher PChE levels and with a lower risk of reporting pesticide-related symptoms, which supports the benefit from using appropriate protective measures. In conclusion, data indicate that farm workers exposed to OPs in developing countries need to be monitored by means of PChE and an examination of their clinical status, which would allow identification of farm workers most at risk from pesticide toxicity. The use of correct PPE is highly recommended.     

Absenteeism and mortality of workers exposed to electromagnetic fields in the French Electricity Company

The objective of this study was to describe the health status of electricity workers exposed to electromagnetic fields during their job. Two groups of exposed workers were studied from 1978 to 1993: the live line workers (n = 121) and the substation workers (n = 232.7) of the French Electricity Company (EDF). A control group was randomly selected from all the company non-management male employees; one control for each exposed subject was matched for the first year of employment. Absenteeism indices and mortality rates were computed and compared in the exposed and control groups. The absence rates were 1.98% in the substation workers and 2.5% in the control group (p < 0.001) and 2.7% in the live-line workers and 2.8% in the control group (NS). No effect of the length of exposure was found. However the medical causes of sickness absence were different: exposed employees had less psychiatric and respiratory diseases but more accidents at work than their control group. Relative risks of accidents at work were 1.2 95% confidence interval (CI) = 1.08-1.33[ for substation workers and 3.22 (CI = 1.78-5.88) for live line workers. EDF electromagnetic field exposed workers seemed not to be affected by any specific health problems except for an excess of accidents at work.     

Pesticide Exposure and Cholinesterase Levels in Migrant Farm Workers in Thailand

Objectives: In this study, we examined the effects of pesticides in migrant farm workers from Cambodia after workplace exposure on fruit plantations in eastern Thailand. Methods: We studied 891 migrant farm workers employed on pineapple, durian, and rambutan plantations in Thailand. Data were collected via a detailed questionnaire survey and measurements of serum cholinesterase level (SChE). Results: The majority of subjects was male (57.7%), with an average age of 30.3 years. Most subjects (76.8%) were moderately aware of good industrial hygiene practices. SChE level was divided into four groups based on the results. Only 4.4% had normal levels of cholinesterase activity, 20.5% had slightly reduced levels, 58.5% had markedly reduced levels and were “at risk,” and 16.6% who had highest levels of cholinesterase inhibition were deemed to be in an “unsafe” range. SChE was classified into two groups, SChE value of 87.5 was “normal” and <87.5 units/mL “abnormal.” For the multiple logistic regression analysis of the abnormal SChE levels, the variables entered in the model included gender, period of insecticide use, the total area of plantation, frequency of spraying, period of daily insecticide spraying, and insecticide spraying method. The results indicated that the aOR (adjust odds ratio) for male migrant farm workers (95% confidence interval [CI]) was 1.58 (1.14, 2.17). The OR for farm migrant workers who worked on larger plantations of more than 39.5 acres (95% CI) was 2.69 (1.51, 4.82). Finally, the OR for the migrant farm workers who used a backpack sprayer (95% CI) was 2.07 (1.28, 3.34). Conclusions: These results suggest that health screening should be provided to migrant farm workers, especially those who spray pesticides on plantations of >39 acres, use a backpack sprayer, or have a low level of compliance with accepted industrial hygiene practices. These three classes of workers are at increased risk of chemical exposures and developing acute or chronic illness from pesticide exposures.     

Neuropsychological Effects of Long-Term Low-Level Organophosphate Exposure in Orchard Sprayers in England

The health effects from prolonged low-level organophosphate exposure are unknown. We hypothesized that exposed individuals would show neuropsychological decrements when compared with unexposed individuals, and that cumulative organophosphate exposure would be correlated with neuropsychological performance. We used a quasiexperimental cross-sectional design to compare neuropsychological test scores among three groups: orchard sprayers exposed to organophosphates, and construction worker and pig farm workers who were not exposed. Relative to construction workers, orchard sprayers were significantly slower on negative statements of the syntactic reasoning test. However, we found no relationship between cumulative exposure and test response. The slower response of the orchard sprayers was apparently exposure-related, but we could not identify an underlying neurotoxic mechanism. Therefore, we are unable to conclude whether this is a specific cognitive effect, or a decrement arising on the most sensitive test employed.     

The recovery of plasma cholinesterase and erythrocyte acetylcholinesterase activity in workers after over-exposure to dichlorvos

Plasma cholinesterase and erythrocyte acetylcholinesterase activities have a long history of use in monitoring both workers at risk of organophosphorus pesticide (OP) exposure and in investigating accidental exposures to OPs. On account of wide inter-individual variation, the establishment of unexposed, baseline enzyme activities is necessary for accurate interpretation. This paper describes the rate of recovery of the two enzymes' activity after substantial over-exposure of eight subjects to the OP dichlorvos. Plasma cholinesterase activity, immediately after exposure, was substantially more inhibited than erythrocyte acetylcholinesterase activity. The plasma enzyme activity showed an exponential pattern of recovery with a half-life of around 12 days, so recovery was essentially complete after about 50 days. This reported half-life of recovery is consistent with the reported de novo synthesis rate of plasma cholinesterase. The mean recovery of erythrocyte acetylcholinesterase activity appeared linear over time, attaining unexposed activity after about 82 days, which is somewhat shorter than the life-span of erythrocytes. These indicate the sort of time period, after an OP incident, before a valid unexposed level can be established in an individual; and substantiate the guidance given in the Health & Safety Executive's document MS17 on a minimum period of 60 days without exposure in order to establish pre-exposure baseline levels.     

Neuropsychological effects of long-term low-level organophosphate exposure in orchard sprayers in England

The health effects from prolonged low-level organophosphate exposure are unknown. We hypothesized that exposed individuals would show neuropsychological decrements when compared with unexposed individuals, and that cumulative organophosphate exposure would be correlated with neuropsychological performance. We used a quasiexperimental cross-sectional design to compare neuropsychological test scores among three groups: orchard sprayers exposed to organophosphates, and construction worker and pig farm workers who were not exposed. Relative to construction workers, orchard sprayers were significantly slower on negative statements of the syntactic reasoning test. However, we found no relationship between cumulative exposure and test response. The slower response of the orchard sprayers was apparently exposure-related, but we could not identify an underlying neurotoxic mechanism. Therefore, we are unable to conclude whether this is a specific cognitive effect, or a decrement arising on the most sensitive test employed.     

农药对喷洒员健康影响的研究

[目的]探讨农药使用所致农药中毒的相关因素及对喷洒员健康的影响。[方法]对浙江省嘉兴县、安吉县的4个村100名农药喷洒员为喷洒组 ,分初中以下和以上两种受教育程度 ;门诊查体健康者100名为对照组。对喷洒组调查内容 ,包括喷洒员的教育水平、农药中毒史、中毒发生在全年中的时间、造成农药中毒的农药种类、喷洒时采取的防护措施与农药用量的掌握、每户农药用量与医疗花费、内科体检及空腹抽取静脉血作生化及常规检查。[结果]生产性农药中毒在中国农村存在普遍性 ;农药中毒在初中以下者比初中以上者有更高的发生率 ,在中、重度中毒中尤为显著 (P<0.05,P<0.01) ;造成农药中毒的主要品种是有机磷类 (76.5 % ) ;中毒发生时间集中在6、9、10月份 (90 % ) ;防护措施差和超量使用农药 ;每户的农药使用量与医疗花费有密切的关联 ;血生化及血常规各参数异常人数明显高于对照组 (P<0.01)。[结论]农药的使用严重影响喷洒员的健康 ,应采取相应的预防措施降低农药中毒发生率     

Neurological symptoms among Sri Lankan farmers occupationally exposed to acetylcholinesterase-inhibiting insecticides

BACKGROUND: In many agricultural districts in Sri Lanka, pesticide poisoning is a leading cause of death. This study aims to evaluate the impact of pesticide use on Sri Lankan farmers' health. METHODS: A total of 260 subjects were surveyed in both a low and a high exposure period. Acetylcholinesterase activity was measured and data on symptoms were collected with questionnaires. RESULTS: Twenty-four percent of surveyed farmers had suffered at least once from acute pesticide poisoning. Farmers showed significantly more inhibition of cholinesterase activity than controls. Acute symptoms indicative for exposure to cholinesterase-inhibiting pesticides were associated with farming and a higher degree of cholinesterase suppression (more than 13% inhibition). Integrated Pest Management (IPM) training seemed to result in less insecticide use, and less cholinesterase inhibition. CONCLUSIONS: Our results suggest that occupational acetylcholinesterase-inhibiting insecticide exposures have a negative impact on Sri Lankan farmers' health. Overall reduction in pesticide use seems the best option to protect farmers from the adverse effects of pesticides.     

Cardiovascular effects of occupational exposure to carbon disulphide

The objective of this study was to investigate the effect of occupational exposure to carbon disulphide (CS2) on the total cholesterol, blood pressure and prevalence of coronary heart disease (CHD). A cross-sectional study involving 252 viscose rayon workers and 252 age and sex matched controls was carried out. Depending on the job and specific work place, the CS2 concentrations were between 10 and 64 mg/m3. A cumulative exposure index (CS2 index) was calculated for each worker by multiplying the number of years he had held a particular job with the CS2 concentrations in that job. CHD prevalence among the exposed was higher than among the controls; the difference reaching significance only for highly exposed workers. Cholesterol levels were significantly higher in both highly and moderately exposed groups. In conclusion, the results demonstrated that occupational exposure to CS2 increases total cholesterol and the risk for CHD. While the risk for CHD is increased in workers exposed to high CS2 concentration for many years (CS2 index > or = 300), even the relatively modest exposure (CS2 < 300) may increase the serum cholesterol.     

Self reported symptoms and inhibition of acetylcholinesterase activity among Kenyan agricultural workers

OBJECTIVES—This study was part of the East African pesticides project. The general objective was to assess health hazards posed by handling, storage, and use of pesticides, on agricultural estates and small farms with a view to developing strategies for prevention and control of pesticide poisoning. The aim of this paper is to describe the prevalence of symptoms in this population, to relate levels of inhibition to reported symptoms and evaluate at which levels of inhibition symptoms become increased.
METHODS—Complete data were available for 256 exposed subjects and 152 controls from four regions in Kenya. A structured questionnaire on symptoms experienced at the time of interview was given to all subjects and controls. Information was also obtained on sex, age, main occupation, and level of education. Symptoms reported during the high exposure period, were initially clustered in broader symptom categories from reference literature on health effects of pesticides that inhibit cholinesterase (organophosphate and carbamate). Prevalence ratios were estimated for symptoms with changes in cholinesterase activity in serum.
RESULTS—Symptom prevalence in exposed subjects was higher during the high exposure period than the low exposure period, although these differences were not significant. Interestingly, a clear and significant change in symptoms prevalence was found in the controls with a higher prevalence in the low exposure period. Analysis of the relation between cholinesterase inhibition and symptoms showed that prevalence ratios were significantly >1 for respiratory, eye, and central nervous system symptoms for workers with >30% inhibition. Similar results were found for analyses with the actual level of acetylcholinesterase activity.
CONCLUSION—The results suggest the presence of a relation between exposure and acetylcholinesterase inhibition, acetylcholinesterase activity, and respiratory, eye, and central nervous system symptoms. Increased symptom prevalence was found at acetylcholinesterase activities generally considered to be non-adverse.


Keywords: cholinesterase inhibition; symptoms; health effects; Kenya; agricultural workers     

Occupational exposure and health problems in small-scale industry workers in Dar es Salaam, Tanzania: a situation analysis

BACKGROUND: Workers in informal small-scale industries (SSI) in developing countries involved in welding, spray painting, woodwork and metalwork are exposed to various hazards with consequent risk to health. Aim To assess occupational exposure and health problems in SSI in Dar es Salaam, Tanzania. METHODS: Focused group discussions (FGD) were conducted among SSI workers. Participants were assessed for exposure to occupational and environmental hazards, the use of protective equipment and health complaints by interview. The findings were discussed with participants and potential interventions identified. RESULTS: Three hundred and ten workers were interviewed (response rate 98%). There was a high level (>90%) of self-reported exposure to either dust, fumes, noise or sunlight in certain occupational groups. There was low reported use of personal protective equipment. There was a high level of self-reported occupational health problems, particularly amongst welders and metalworkers. Workers reported their needs as permanent workplaces, information on work related hazards, water and sanitation, and legislation for SSI. CONCLUSIONS: In SSI in Tanzania, our study suggests that workers have high levels of exposure to multiple health hazards and that use of protective equipment is poor. This group of workers warrants improved occupational health and safety provision.