Knowledge, attitudes and practices (KAP) among agricultural extension workers concerning the reduction of the adverse impact of pesticides in agricultural areas in Tanzania.

BACKGROUND: Extension workers are educated locally to enable them to train farmers in using improved local farming methods and imported technology, such as pesticides, to increase crop production. However, the extension workers are not adequately trained in health aspects of pesticides and hence are unable to provide adequate services to farmers with regard to safe use of pesticides. OBJECTIVE: The present study assessed the knowledge, attitudes and practices of agricultural extension workers with respect to health effects of pesticides in order to develop strategies for the control of pesticide exposure and prevention of pesticide poisoning in Tanzania. METHODS: A survey of Tanzanian agricultural extensionists was undertaken in 1991-1994 using a standardized questionnaire in face-to-face interviews. Extensionists who were district agricultural officers, assistant agricultural officers, agricultural assistants, and field assistants, working in the coffee and cotton growing areas (N = 61) within a radius of 15 km of farm, estate or village under farm worker study (reported elsewhere) were included in the survey. RESULTS: The majority of extensionists knew that pesticides could enter the human body but only a quarter perceived pesticides as a major problem in the community they served. The majority showed awareness of potential health hazards of the different pesticides used in their service areas, but they did not recognize what pesticides were responsible for poisoning. A high proportion was familiar with first aid procedures in case of pesticide poisoning; however, many procedures described were not appropriate for pesticide poisoning. CONCLUSIONS: The survey indicated that training of agricultural workers in health aspects of pesticide exposure is an important task for adequate provision of service to farmers with regard to safe use of pesticides in Tanzania. Nevertheless, the appropriate role of extensionists in reducing the health impact of pesticides would be to advocate pesticides of low toxicity or non-chemical pest control.

Acute health effects of organophosphorus pesticides on Tanzanian small-scale coffee growers.

Acute health effects of organophosphorus (OP) pesticides on coffee farmworkers in 1991-1992 in Tanzania are reported to provide a basis for concern over farmworkers being overexposed during application. Workers exposed to OP pesticides (N=133) were drawn from a population of about 240,000 coffee farmers. They were interviewed on symptoms and personal protection, and their erythrocyte acetylcholinesterase (AChE) activity was determined during both spraying and nonspraying period. AChE activities during spraying and nonspraying period were comparable (mean 32.0, SD 7.8 vs. 33.0, SD 8.7 U/g HgB, P=0.26). The prevalence of cough, headache, abdominal pain, excessive sweating, nausea, excessive salivation, diarrhea, and vomiting did not differ significantly between spraying and nonspraying periods. There was no suggestion of decreased AChE in exposed subjects who complained of OP-related symptoms compared to symptomless exposed subjects. Use of gloves, long boots, head cover, face cover, and coverall was not significantly associated with AChE activity. No marked AChE depression was found during spraying season, which may explain the lack of association between symptoms and AChE. The fact that only moderately toxic OP pesticides were used may indicate that toxicity was not sufficiently high to cause depression. Experience, however, suggests that occupational poisoning remains a potential serious danger in coffee cultivation in Tanzania.

Paraquat in developing countries.

The herbicide paraquat is considered safe by industry and the bulk of regulators worldwide. However, determinants of exposure from 30 years ago persist in developing countries. Little is known about systemic absorption from occupational exposures. The relationships between exposure determinants, levels of external exposure, biomarkers of exposure, and outcomes are not clear. High rates of severe acute poisonings have been documented. In addition, topical injuries occur in as many as 50% of exposed workers. Non-worker populations are also at risk, particularly children. Long-term and delayed health effects include Parkinson's disease, lung effects, and skin cancer. Regulatory agencies have not fully recognized either the inherent toxicity of paraquat or the particular risks derived from exposures in developing countries. Independent risk assessment in the developing-country context and application of the precautionary principle are necessary to prevent adverse effects of dangerous pesticides in susceptible populations.

Pesticide-handling practices in agriculture in Tanzania: observational data from 27 coffee and cotton farms.

The practices of pesticide handling in agriculture were surveyed in 1991-1993 in Tanzania, to identify hazardous practices and farms where they occurred. The study involved 23 coffee farms with 246 persons exposed to hazardous practices, and four cotton farms with 45 exposed. An observation form addressed locations of important places with respect to pesticide spraying, storage, disposal, and equipment; personal protection; and hygiene. More pesticide formulations were used for coffee compared with cotton and by individual rather than cooperative farms. Coffee farms more often had unlabeled pesticide containers and missing mixing instructions, while cotton pesticides were stored in bedrooms, near food, and near open fires, and pesticide leftovers were often present. Hazardous practices were more pronounced at individual than cooperative farms, with significant differences in pesticide storage areas, as well as unlabeled and non-original containers. The study demonstrated the need to train farmers in pesticide safety, strengthen advisory and regulatory services, and extend protection to farm workers' families.

Hazardous pesticides in Central America.

Pesticides are an extensively documented occupational and environmental hazard in Central America. Yet, severe problems persist. Toxic pesticide use in the Region increased during 1985-1999. High exposure levels and ineffectiveness of personal protective equipment evidence the difficulties for risk reduction. Acute poisonings remain a severe problem. Delayed and/or long-lasting health effects include dermatoses, cancer, and genotoxic, neurotoxic, and respiratory effects. The use of hazardous pesticides persists through deficiencies in government-driven assessment and risk management; excessive focus on regional harmonization; short-term economic interests; strong links between industry and governments; aggressive marketing; weak trade unions; and failure of universities to reach decision makers. Regulation based on local data is lacking. An agreement of the Ministries of Health for restricting the most toxic pesticides in Central America has potential for progress. The most effective way to reduce risk is to greatly reduce pesticide use. Actions needed include development of multidisciplinary strategies for local studies on health and environmental impact of pesticides; development of sustainable nonchemical agricultural technologies; evaluation of interventions; extending and sharing of expertise within the Region; strengthening of unions and communities; and redefining the role of industry toward development of safer products, with responsible marketing and reliable information.

Assessment of the ability of health care providers to treat and prevent adverse health effects of pesticides in agricultural areas of Tanzania.

A survey of Tanzanian health care providers in agricultural areas was undertaken in 1991-1994 to assess their knowledge of toxic effects of pesticides, experiences and practices, as well as of their needs for appropriate information in order to develop effective strategies for reducing pesticide poisoning. Face-to-face interviews were conducted with 104 physicians, clinical officers and nurses at health care facilities in the coffee and cotton growing areas. Eighty percent of respondents reported to have seen one and nine of them two to four cases of pesticide poisoning in the preceding three months. A significantly higher annual number of poisonings were observed in coffee than in cotton area (GM 0.5 vs 0.1). Also the number of cases registered in hospitals was considerably higher than that in the out-patient health care (GM 1.7 vs 0.2). Pesticide poisoning was regarded as a major problem in the community by 63% of health care providers, including 77% of hospital staff. One third of health care providers thought that a certain percent of pesticide poisoning cases remain unrecognized, and that this percentage is higher in cotton than in coffee growing areas. The respiratory tract was the major route for pesticide to enter the human body; this was followed by gastrointestinal tract, skin, and eyes. Only one percent of the respondents could identify the groups of pesticides (organophosphate vs organochlorine) mostly used in the study areas. The survey indicated that training of hospital staff in toxicity of pesticide exposure is an important task and a prerequisite for efficient recognition, diagnosis and treatment of pesticide poisoning cases in Tanzania.

Occupational exposures and pancreatic cancer: a meta-analysis.

OBJECTIVES: Consolidation of epidemiological data on pancreatic cancer and worksite exposures. METHODS: Publications during 1969-98 were surveyed. Studies without verified exposures were excluded. Meta-analyses were conducted on data from 92 studies covering 161 populations, with results for 23 agents or groups of agents. With a standard format, five epidemiologists extracted risk estimates and variables of the structure and quality of each study. The extracted data were centrally checked. Random meta-models were applied. RESULTS: Based on 20 populations, exposure to chlorinated hydrocarbon (CHC) solvents and related compounds was associated with a meta-risk ratio (MRR) of 1.4 (95% confidence interval (95% CI) 1.0 to 1.8). Nickel and nickel compounds were considered in four populations (1.9; 1.2 to 3.2). Excesses were found also for chromium and chromium compounds (1.4; 0.9 to 2.3), polycyclic aromatic hydrocarbons (PAHs) (1.5; 0.9 to 2.5), organochlorine insecticides (1.5; 0.6 to 3.7), silica dust (1.4; 0.9 to 2.0), and aliphatic and alicyclic hydrocarbon solvents (1.3; 0.8 to 2.8). Evidence on pancreatic carcinogenicity was weak or non-positive for the following agents: acrylonitrile (1.1; 0.0 to 6.2); arsenic (1.0; 0.6 to 1.5); asbestos (1.1; 0.9 to 1.5); diesel engine exhaust (1.0; 0.9 to 1.3); electromagnetic fields (1.1; 0.8 to 1.4); formaldehyde (0. 8; 0.5 to 1.0); flour dust (1.1; 0.3 to 3.2); cadmium and cadmium compounds (0.7; 0.4 to 1.4); gasoline (1.0; 0.8 to 1.2); herbicides (1.0; 0.8 to 1.3); iron and iron compounds (1.3; 0.7 to 2.5); lead and lead compounds (1.1; 0.8 to 1.5); man-made vitreous fibres (1.0; 0.6 to 1.6); oil mist (0.9; 0.8 to 1.0); and wood dust (1.1; 0.9 to 2.5). The occupational aetiological fraction of pancreatic cancer was estimated at 12%. In a subpopulation exposed to CHC solvents and related compounds, it was 29%; to chromium and chromium compounds, 23%; to nickel and nickel compounds, 47%; to insecticides, 33%; and to PAHs, 33%. CONCLUSION: Occupational exposures may increase risk of pancreatic cancer. High quality studies are called for on interactions between occupational, environmental, and lifestyle factors as well as interactions between genes and the environment.

Collaboration between developing and developed countries and between developing countries in occupational health research and surveillance.

Collaborative occupational health and safety studies between counterparts in developing and developed countries and between developing countries have demonstrated their potential for improving occupational health and safety. Such collaboration in occupational health and safety is encouraged in the development of infrastructure in research empowerment and capacity building. This action includes the setting of priorities, the identification and documentation of problems, sponsorship, data bases and surveillance systems, technical support, methodology, publishing, research and training programs, controlled intervention, information exchange, and networking. Examples of priorities in occupational health and safety in the developing world include the informal sector (informally hired and independent workers), temporary work, pesticides, accidents, dusts, carcinogens, solvents, ergonomics, women and child labor, human immunodeficiency virus/acquired immunodeficiencey syndrome (HIV/AIDS), and transfer of hazardous materials and technologies. The sustainability of occupational health and safety structures and functions in the developing countries is a primary concern. Socioethical principles emphasize local, national, mutual and global gains. Examples of collaboration are given. Pervasive problems and strategies toward their solution are highlighted.

Epidemiology of occupational and environmental risk factors related to ovarian cancer.

This paper reviews articles published during 1970-1997 from 48 epidemiologic studies on occupational and environmental risk factors of ovarian cancer. Current evidence is characterized by poorly focused data for occupational and environmental agents, vulnerability to biases, and an almost complete lack of quantitative exposure-response data. The moderate amount of data on nurses, teachers, professionals, dry cleaning employees, women in agriculture, the pharmaceutical industry, pharmacists, waitresses, and cooks show very little, if any, evidence of excess risk. Hairdressers, beauticians, and women employed in the printing industry may be at increased risk, but the data are insufficient for strong conclusions. Some case-referent studies suggest a modest-to-moderate excess in association with genital talc application. Few high-quality studies have been carried out, and no chemical agents have been studied extensively, with the exception of exposure to talc. Ovarian cancer may have occupational and environmental etiologies intertwined with cultural, behavioral, and life-style factors and genetic susceptibility, but current knowledge is insufficient to quantify occupational and environmental etiologies reliably. Well-designed analytic epidemiologic studies with sufficient power are needed.

Environmental risk factors of breast cancer.

Breast cancer is women's most ubiquitous cancer. The role of dietary factors is controversial, but there is limited evidence for such occupational risk factors as employment in the pharmaceutical industry and as a beautician. Ionizing radiation probably increases the risk. Exposure to chlorinated hydrocarbon pesticides, chlorinated solvents, and polychlorinated biphenyls may be risk factors, although the evidence is insufficient. Data on low-frequency electromagnetic fields are inconclusive. Tobacco smoking may be a risk factor, but the effect may depend on N-acetyltransferase 2 genetic polymorphisms. There are yet unidentified determinants, probably environmental, that may act via estrogenic activity or through other mechanisms. The etiology may vary according to the joint estrogen and progesterone receptor status of the tumor. P53 mutation frequency varies considerably in breast cancer populations, which may reflect variation in exogenous exposures. Epidemiology research on breast cancer needs to consider subtypes of the disease, lifetime exposure assessment, host susceptibility, and adjustment for reproductive and menstrual history.

Pancreas cancer, tobacco smoking and consumption of alcoholic beverages: a case-control study.

A population-based case-control study investigated pancreas cancer in relation to consumption of alcoholic beverages, tobacco smoking and pancreatitis, utilizing historical proxy data for 662 decedent Finnish pancreas cancer cases and 1770 cancer controls. Tobacco smoking increased the risk, with an attributable case fraction of 0.27. The data are consistent with a joint effect of early and late stage carcinogens in tobacco smoke. Consumption of distilled beverages did not increase risk, but heavy drinking of wine or beer did. History of pancreatitis was a strong risk factor.

Cancer risk for European asphalt workers.

OBJECTIVES: The feasibility of a European epidemiologic study of cancer risk among asphalt workers was examined in Western Europe. The study was motivated by occupational and public health concern about possible health risk from exposure to bitumen fumes. METHODS: Information on the accessibility and quality of epidemiologic resources, retrospective worker records, mortality and cancer incidence records, and exposures was requested from research institutes and road paving and asphalt mixing companies in 15 European countries. RESULTS: Research institutes and asphalt companies in 12 countries responded. It was found that at least 44 companies in seven countries can be included in a retrospective mortality study of a minimum of 32,000 employees with 356,000 person-years (over 100 lung cancers). Coal tar will be an important confounder for these data. The power of a cohort study of workers who have never worked with tar-containing materials remains insufficient. Even in an ambispective study extending to the year 2005, the expected lung cancer deaths in a tar-free cohort would be only four. CONCLUSIONS: The results suggest that a case-referent study of lung cancer, nested in an international cohort of asphalt workers, represents the design of choice, conditionally on the possibility of assessing relevant individual life-time exposures. A cross-sectional determination of relevant biomarkers of exposure such as adducts in lymphocytes or the presence of metabolites of polycyclic aromatic compounds in urine in a group of workers exposed to bitumen fumes will provide further relevant information.

Chemical exposures and respiratory cancer among Finnish woodworkers.

A case-control study of respiratory cancer, nested within a cohort of male woodworkers, was updated in Finland. The update extended the initial follow up of 3805 workers from 19 plants to 7307 workers from 35 plants. Each case of respiratory cancer (n = 136) diagnosed between 1957 and 1982 within the cohort was matched by year of birth with three controls (n = 408) from the cohort. Chemical exposures were assessed for the cases and the controls by a plant and period specific job exposure matrix. An excess of respiratory cancer was associated with phenol. Concomitant exposures to several other agents occurred as well, however, and no exposure-response relation for phenol was seen. An excess risk and an increasing exposure-response relation were found for engine exhaust from petrol and diesel driven factory trucks. The excess risk associated with pesticides was lower than in our previous study, an indication of qualitative and quantitative differences in exposure between the initial and augmented cohorts. Slightly increased risks were found for terpenes and mould spores, which may be due to chance although the contribution of occupational exposure cannot be ruled out. Exposure to wood dust, mainly from pine, spruce and birch, at a level of about 1 mg/m3, was not associated with lung cancer, upper respiratory cancer, or adenocarcinoma of the lung.

Respiratory cancers and chemical exposures in the wood industry: a nested case-control study.

A cohort of 3805 men who had worked for at least one year in the particleboard, plywood, sawmill, or formaldehyde glue industries between 1944 and 1965 was followed up until 1981. From within the cohort the 57 patients with verified "respiratory" cancer (ICD 7 codes: 160-162.1, 141, 143-8) were defined as "cases," and 171 men without respiratory cancer from within the cohort were matched on birth year and used as controls. The comparison of exposures was carried out according to work histories and job exposure matrices for each plant. The odds ratio for exposure to wood dust was 1.03 (32 exposed cases) without provision for any latent period, and 0.97 (27 exposed cases) when provision for a minimum latent period of ten years was applied. The odds ratios were 1.60 and 1.68, respectively, when smoking was controlled by stratification. These results did not differ significantly from unity. The estimated average level of exposure to wood dust among the exposed was 1-2 mg/m3 and the mean duration of exposure about ten years. Significantly (one sided test, 5% level) raised odds ratios were observed for exposure to pesticides and phenol. No single pesticide could be identified as "causative" because of frequent multiple exposures. The raised odds ratios for phenol were partly explained by smoking and exposure to pesticides which confounded the observed associations for phenol exposure. Exposure to terpenes and other heating products of coniferous woods was significantly associated with a risk of respiratory cancer when the duration of exposure exceeded five years.