Inferring past pesticide exposures: a matrix of individual active ingredients in home and garden pesticides used in past decades.
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BACKGROUND: In retrospective studies of the health effects of home and garden pesticides, self-reported information typically forms the basis for exposure assessment. Study participants generally find it easier to remember the types of pests treated than the specific pesticides used. However, if the goal of the study is to assess disease risk from specific chemicals, the investigator must be able to link the pest type treated with specific chemicals or products. OBJECTIVES: Our goal was to develop a "pesticide-exposure matrix" that would list active ingredients on the market for treating different types of pests in past years, and provide an estimate of the probability that each active ingredient was used. METHODS: We used several different methods for deriving the active ingredient lists and estimating the probabilities. These methods are described in this article, along with a sample calculation and data sources for each. RESULTS: The pesticide-exposure matrix lists active ingredients and their probabilities of use for 96 distinct scenarios defined by year (1976, 1980, 1990, 2000), applicator type (consumer, professional), and pest type (12 categories). Calculations and data sources for all 96 scenarios are provided online. CONCLUSIONS: Although we are confident that the active ingredient lists are reasonably accurate for most scenarios, we acknowledge possible sources of error in the probability estimates. Despite these limitations, the pesticide-exposure matrix should provide valuable information to researchers interested in the chronic health effects of residential pesticide exposure. (+info)
Integrated pest management: the push-pull approach for controlling insect pests and weeds of cereals, and its potential for other agricultural systems including animal husbandry.
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This paper describes the 'push-pull' or 'stimulo-deterrent diversionary' strategy in relation to current and potential examples from our own experiences. The push-pull effect is established by exploiting semiochemicals to repel insect pests from the crop ('push') and to attract them into trap crops ('pull'). The systems exemplified here have been developed for subsistence farming in Africa and delivery of the semiochemicals is entirely by companion cropping, i.e. intercropping for the push and trap cropping for the pull. The main target was a series of lepidopterous pests attacking maize and other cereals. Although the area given to the cereal crop itself is reduced under the push-pull system, higher yields are produced per unit area. An important spin-off from the project is that the companion crops are valuable forage for farm animals. Leguminous intercrops also provide advantages with regard to plant nutrition and some of the trap crops help with water retention and in reducing land erosion. A major benefit is that certain intercrop plants provide dramatic control of the African witchweed (striga). Animal husbandry forms an essential part of intensive subsistence agriculture in Africa and developments using analogous push-pull control strategies for insect pests of cattle are exemplified. (+info)
Agricultural biosecurity.
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The prevention and control of new pest and disease introductions is an agricultural challenge which is attracting growing public interest. This interest is in part driven by an impression that the threat is increasing, but there has been little analysis of the changing rates of biosecurity threat, and existing evidence is equivocal. Traditional biosecurity systems for animals and plants differ substantially but are beginning to converge. Bio-economic modelling of risk will be a valuable tool in guiding the allocation of limited resources for biosecurity. The future of prevention and management systems will be strongly influenced by new technology and the growing role of the private sector. Overall, today's biosecurity systems are challenged by changing national priorities regarding trade, by new concerns about environmental effects of biological invasions and by the question 'who pays?'. Tomorrow's systems may need to be quite different to be effective. We suggest three changes: an integration of plant and animal biosecurity around a common, proactive, risk-based approach; a greater focus on international cooperation to deal with threats at source; and a commitment to refocus biosecurity on building resilience to invasion into agroecosystems rather than building walls around them. (+info)
Opportunities and challenges of sustainable agricultural development in China.
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This paper introduces the concepts and aims of sustainable agriculture in China. Sustainable agricultural development comprises sustainability of agricultural production, sustainability of the rural economy, ecological and environmental sustainability within agricultural systems and sustainability of rural society. China's prime aim is to ensure current and future food security. Based on projections of China's population, its economy, societal factors and agricultural resources and inputs between 2000 and 2050, total grain supply and demand has been predicted and the state of food security analysed. Total and per capita demand for grain will increase continuously. Total demand will reach 648 Mt in 2020 and 700 Mt in 2050, while total grain yield of cultivated land will reach 470 Mt in 2010, 585 Mt in 2030 and 656 Mt in 2050. The per capita grain production will be around 360kg in the period 2000-2030 and reach 470kg in 2050. When productivities of cultivated land and other agricultural resources are all taken into consideration, China's food self-sufficiency ratio will increase from 94.4% in 2000 to 101.3% in 2030, suggesting that China will meet its future demand for food and need for food security. Despite this positive assessment, the country's sustainable agricultural development has encountered many obstacles. These include: agricultural water-use shortage; cultivated land loss; inappropriate usage of fertilizers and pesticides, and environmental degradation. (+info)
Reducing vector-borne disease by empowering farmers in integrated vector management.
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PROBLEM: Irrigated agriculture exposes rural people to health risks associated with vector-borne diseases and pesticides used in agriculture and for public health protection. Most developing countries lack collaboration between the agricultural and health sectors to jointly address these problems. APPROACH: We present an evaluation of a project that uses the "farmer field school" method to teach farmers how to manage vector-borne diseases and how to improve rice yields. Teaching farmers about these two concepts together is known as "integrated pest and vector management". LOCAL SETTING: An intersectoral project targeting rice irrigation systems in Sri Lanka. RELEVANT CHANGES: Project partners developed a new curriculum for the field school that included a component on vector-borne diseases. Rice farmers in intervention villages who graduated from the field school took vector-control actions as well as improving environmental sanitation and their personal protection measures against disease transmission. They also reduced their use of agricultural pesticides, especially insecticides. LESSONS LEARNED: The intervention motivated and enabled rural people to take part in vector-management activities and to reduce several environmental health risks. There is scope for expanding the curriculum to include information on the harmful effects of pesticides on human health and to address other public health concerns. Benefits of this approach for community-based health programmes have not yet been optimally assessed. Also, the institutional basis of the integrated management approach needs to be broadened so that people from a wider range of organizations take part. A monitoring and evaluation system needs to be established to measure the performance of integrated management initiatives. (+info)
Sustainable agriculture and plant diseases: an epidemiological perspective.
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The potential for modern biology to identify new sources for genetical, chemical and biological control of plant disease is remarkably high. Successful implementation of these methods within globally and locally changing agricultural environments demands new approaches to durable control. This, in turn, requires fusion of population genetics and epidemiology at a range of scales from the field to the landscape and even to continental deployment of control measures. It also requires an understanding of economic and social constraints that influence the deployment of control. Here I propose an epidemiological framework to model invasion, persistence and variability of epidemics that encompasses a wide range of scales and topologies through which disease spreads. By considering how to map control methods onto epidemiological parameters and variables, some new approaches towards optimizing the efficiency of control at the landscape scale are introduced. Epidemiological strategies to minimize the risks of failure of chemical and genetical control are presented and some consequences of heterogeneous selection pressures in time and space on the persistence and evolutionary changes of the pathogen population are discussed. Finally, some approaches towards embedding epidemiological models for the deployment of control in an economically plausible framework are presented. (+info)
Biological monitoring of pyrethroid exposure of pest control workers in Japan.
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Synthetic pyrethroids such as cypermethrin, deltamethrin and permethrin, which are usually used in pest control operations, are metabolized to 3-phenoxybenzoic acid (3-PBA) and excreted in urine. Though 3-PBA can be used to assess exposure to pyrethroids, there are few reports describing urinary 3-PBA levels in Japan. This study aimed to investigate the seasonal variation of the exposure levels of pyrethroids and the concentration of urinary 3-PBA among pest control operators (PCOs) in Japan. The study subjects were 78 and 66 PCOs who underwent a health examination in December 2004 and in August 2005, respectively. 3-PBA was determined using gas chromatography-mass spectrometry. The geometric mean concentration of urinary 3-PBA in winter (3.9 microg/g creatinine) was significantly lower than in summer (12.2 microg/g creatinine) (p<0.05). Geometric mean concentrations of urinary 3-PBA in the spraying workers and the not-spraying workers within 2 d before the survey were 5.4 microg/g creatinine and 0.9 microg/g creatinine for winter with a significant difference between the groups (p<0.05), and 12.3 microg/g creatinine and 8.7 microg/g creatinine for summer (p>0.05), respectively. A significant association of 3-PBA levels and pyrethroid spraying was thus observed only in winter. In conclusion, the results of the present study show that the exposure level of pyrethroids among PCOs in Japan assessed by monitoring urinary 3-PBA was higher than that reported in the UK but comparable to that in Germany. Further research should be accumulated to establish an occupational reference value in Japan. (+info)
Guidelines for environmental health management in children's homes in sub-Sahara Africa.
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The field of environmental health focuses on the relationships between human health and well being and the influence of the physical, social and societal environments. Our understanding of the environment-health interface has progressed because of two relatively recent insights: First, the recognition that the unprecedented environmental changes of the last half-century are affecting global population health. Secondly, the recognition that children have greater vulnerability to environmental hazards and are inadequately protected by current regulatory standards. Efforts to redress this situation have shaped the current thrust in environmental health research toward preventing further harm to children's health. The disproportionate vulnerability of children to environmental hazards can be explained by several reasons. Children are not "little adults." It is known that children have greater risk of exposure and greater risk of harm compared to adults for many reasons that are unique to each developmental stage. Their behaviour and activity patterns bring them into greater contact with toxins. Children have important biological differences. Immature developing organs and tissues are more vulnerable to harm from toxic exposures. Immature metabolic and physiological systems less effectively protect the child from toxic exposure and effects. In addition, children have additional pathways of exposure that are not applicable to adults, e.g., in utero, via breast milk and via products such as toys, clothing, etc. Children also have a longer "shelf life." They have much more of their life ahead of them during which time they will be exposed and may develop health problems as a result. Finally, children are more often involuntarily exposed and unable to avoid exposures of their own accord [1]. Due to the AIDS catastrophe in Sub- Saharan Africa, the numbers of children in difficult circumstances have increased. To mitigate the effects of the catastrophe, charitable organizations have sprung up to establish homes for such children, especially those orphaned by AIDS or those infected with HIV. It is important to ensure that environmental health hazards and risks are minimized in these children's homes. By use of a conceptual synthesis approach, the authors attempt to generate guidelines from literature for environmental health management in children's homes in sub-Saharan Africa. (+info)