Pesticide Use in Commercial Potato Production: Reflections on Research and Intervention Efforts towards Greater Ecosystems Health in Northern Ecuador

Since 1990, an interdisciplinary and interinstitutional team of scientists has led a research-intervention initiative examining pesticide impacts on agricultural production, human health, and the environment in the highly commercial potato growing province of Carchi, Ecuador. This article synthesizes the key results of that initiative, analyzes the lessons concerning the process of transdisciplinary ecosystems health research from a methodological perspective, and identifies priority future research opportunities. Research on this initiative has covered a broad range of activities with a full spectrum of rural stakeholders. These have included: health studies of the incidence of pesticide poisonings and the neurological impacts of pesticide exposure on farmers and their families; environmental and personal exposure studies; economic studies on the role of pesticides in agricultural production; sociological studies of farmers attitudes, knowledge, and practices related to pesticide use; and participatory interventions to reduce pesticide-related impacts. Research results have shown that pesticide poisoning incidence in the potato growing zones of Carchi, Ecuador match the highest reported rates in the world. A majority of farm household members suffer significant neurological impairment. Economic and participatory research has shown that there are viable alternatives to the use of Class 1 highly toxic pesticides in the zone. Nevertheless, cultural and political factors are impeding substantial changes in current practices. Future research-intervention activities include longitudinal analyses of the health, environmental, and production impacts of participatory interventions, and a scaling up of analyses to encompass other regions in the Andean mountain ecosystem with more limited indicators of key constructs.     

Human Health, Well-Being, and Global Ecological Scenarios

This article categorizes four kinds of adverse effects to human health caused by ecosystem change: direct, mediated, modulated, and systems failure. The effects are categorized on their scale, complexity, and lag-time. Some but not all of these can be classified as resulting from reduced ecosystem services. The articles also explores the impacts that different socioeconomic–ecologic scenarios are likely to have on human health and how changes to human health may, in turn, influence the unfolding of four different plausible future scenarios. We provide examples to show that our categorization is a useful taxonomy for understanding the complex relationships between ecosystems and human well-being and for predicting how future ecosystem changes may affect human health.Disclaimer: The views expressed in this article are those of the authors and do not necessarily reflect the position of the World Health Organization. This article has been subjected to EPA review and approved for publication but does not necessarily reflect EPA policy.     

Biotechnology of flavonoids and other phenylpropanoid-derived natural products. Part I: Chemical diversity, impacts on plant biology and human health

Plant natural products derived from phenylalanine and the phenylpropanoid pathway are impressive in their chemical diversity and are the result of plant evolution, which has selected for the acquisition of large repertoires of pigments, structural and defensive compounds, all derived from a phenylpropanoid backbone via the plant-specific phenylpropanoid pathway. These compounds are important in plant growth, development and responses to environmental stresses and thus can have large impacts on agricultural productivity. While plant-based medicines containing phenylpropanoid-derived active components have long been used by humans, the benefits of specific flavonoids and other phenylpropanoid-derived compounds to human health and their potential for long-term health benefits have been only recognized more recently. In this part of the review, we discuss the diversity and biosynthetic origins of phenylpropanoids and particularly of the flavonoid and stilbenoid natural products. We then review data pertaining to the modes of action and biological properties of these compounds, referring on their effects on human health and physiology and their roles as plant defense and antimicrobial compounds. This review continues in Part II discussing the use of biotechnological tools targeting the rational reconstruction of multienzyme pathways in order to modify the production of such compounds in plants and model microbial systems for the benefit of agriculture and forestry.     

GLOBALIZATION, HUMAN RIGHTS, AND THE SOCIAL DETERMINANTS OF HEALTH

Globalization, a process characterized by the growing interdependence of the world's people, impacts health systems and the social determinants of health in ways that are detrimental to health equity. In a world in which there are few countervailing normative and policy approaches to the dominant neoliberal regime underpinning globalization, the human rights paradigm constitutes a widely shared foundation for challenging globalization's effects. The substantive rights enumerated in human rights instruments include the right to the highest attainable level of physical and mental health and others that are relevant to the determinants of health. The rights stipulated in these documents impose extensive legal obligations on states that have ratified these documents and confer health entitlements on their residents. Human rights norms have also inspired civil society efforts to improve access to essential medicines and medical services, particularly for HIV/AIDS. Nevertheless, many factors reduce the potential counterweight human rights might exert, including and specifically the nature of the human rights approach, weak political commitments to promoting and protecting health rights on the part of some states and their lack of institutional and economic resources to do so. Global economic markets and the relative power of global economic institutions are also shrinking national policy space. This article reviews the potential contributions and limitations of human rights to achieving greater equity in shaping the social determinants of health.     

农用化学品污染及预防建议

农用化学品是农业生产的重要组成部分,其安全问题也成为人们关注的焦点。农用化学品可分为化肥、农药、农膜3类。化肥主要用于提高土壤肥力,增加农作物产量,不合理使用则会改变土壤性质,降低土壤肥力,并且对生态环境以及人类健康造成不可忽视的危害。农药主要用于杀菌、杀虫、除草等,在促进和保障农作物健康生长中发挥重要作用,但农药的滥用造成农药事故频发,农药的毒性富集作用以及残留问题越发引起人们的关注。农膜主要用于农膜覆盖栽培技术,农膜的原料主要是聚乙烯树脂等高分子化学物质,在土壤中很难降解,造成的环境污染问题日益突出。各种农用化学品的不合理使用,可降低农产品的质量,使其在出口贸易中受到极大限制,造成巨大的经济损失。本文在肯定农用化学品在现代化农业生产中的巨大贡献的同时,深入分析了其污染状况及危害,总结了当前国际上对于化肥、农药、农膜的研究进展以及所取得的成果,最后提出了科学使用农用化学品的建议。     

Improving Environmental Performance Assessment: A Comparative Analysis of Weighting Methods Used to Evaluate Chemical Release Inventories

Managers, management scholars, regulators, nonprofit organizations, and the media are increasingly using emissions inventory data to measure organizations' environmental performance. Whereas some analysts use total mass emitted, others have applied one or more of the growing number of toxicity-weighting databases aimed at predicting the environmental and health impacts of emissions. Little research is available to guide analysts in selecting among these databases. This article compares 13 methods in terms of their sophistication, complexity, and comprehensiveness. Seven of these methods are then evaluated as to their usefulness in weighting emissions data from the U.S. Environmental Protection Agency's (U.S. EPA's) toxic release inventory, and three pair-wise comparisons are conducted. We recommend the U.S. EPA's Risk Screening Environmental Indicators for estimating impacts to human health. We recommend the Tool for the Reduction and Assessment of Chemical Impacts for estimating impacts to human health and the environment.     

Alleged misconceptions' distort perceptions of environmental cancer risks.

In a series of papers, Ames and colleagues allege that the scientific and public health communities have perpetuated a series of 'misconceptions' that resulted in inaccurate identification of chemicals that pose potential human cancer risks, and misguided cancer prevention strategies and regulatory policies. They conclude that exposures to industrial and synthetic chemicals represent negligible cancer risks and that animal studies have little or no scientific value for assessing human risks. Their conclusions are based on flawed and untested assumptions. For instance, they claim that synthetic residues on food can be ignored because 99.99% of pesticides humans eat are natural, chemicals in plants are pesticides, and their potential to cause cancer equals that of synthetic pesticides. Similarly, Ames does not offer any convincing scientific evidence to justify discrediting bioassays for identifying human carcinogens. Ironically, their arguments center on a ranking procedure that relies on the same experimental data and extrapolation methods they criticize as being unreliable for evaluating cancer risks. We address their inconsistencies and flaws, and present scientific facts and our perspectives surrounding Ames' nine alleged misconceptions. Our conclusions agree with the International Agency for Research on Cancer, the National Toxicology Program, and other respected scientific organizations: in the absence of human data, animal studies are the most definitive for assessing human cancer risks. Animal data should not be ignored, and precautions should be taken to lessen human exposures. Dismissing animal carcinogenicity findings would lead to human cancer cases as the only means of demonstrating carcinogenicity of environmental agents. This is unacceptable public health policy.     

Antimicrobial silver: uses, toxicity and potential for resistance

This review gives a comprehensive overview of the widespread use and toxicity of silver compounds in many biological applications. Moreover, the bacterial silver resistance mechanisms and their spread in the environment are discussed. This study shows that it is important to understand in detail how silver and silver nanoparticles exert their toxicity and to understand how bacteria acquire silver resistance. Silver ions have shown to possess strong antimicrobial properties but cause no immediate and serious risk for human health, which led to an extensive use of silver-based products in many applications. However, the risk of silver nanoparticles is not yet clarified and their widespread use could increase silver release in the environment, which can have negative impacts on ecosystems. Moreover, it is shown that silver resistance determinants are widely spread among environmental and clinically relevant bacteria. These resistance determinants are often located on mobile genetic elements, facilitating their spread. Therefore, detailed knowledge of the silver toxicity and resistance mechanisms can improve its applications and lead to a better understanding of the impact on human health and ecosystems.     

Non-target impacts of forest defoliator management options: Decision for no spraying may have worse impacts on non-target Lepidoptera than Bacillus thuringiensis insecticides

Management programs for major forest defoliators such as gypsy moths or forest tent caterpillars, and crop pests such as the European corn borer have shifted from broad-spectrum insecticides to more environmentally benign microbial pesticides such as Bacillus thuringiensis (foliage sprays and transgenic toxin expression in plant tissues). Phytochemically resistant host plants and natural enemies have been used as alternative pest management strategies (including generalist tachinid flies such as Compsilura, viruses, microsporidians, and fungi), but all of these have some non-target impacts, as described from literature review. A sequence of lab and field studies were conducted to determine non-target impacts on native Lepidoptera in North America. The conclusions reached are that a decision not to spray Bt pesticides (i.e. to allow defoliation and natural pest outbreaks to run their course) could be as bad or worse for non-target Lepidoptera as the microbial insecticides would be. The important concept that must be maintained is that all pest management programs have some risk of negative non-target impacts, but it is the magnitude and relative importance that will remain the most critical issue for environmental impacts and pest management.     

Measuring environmental value for Natural Lawn and Garden Care practices

Background, Aims and Scope   Measuring Environmental Value for Natural Lawn and Garden Care Practices provides a life cycle assessment and impacts valuation methodology to quantify environmental (public health and ecological) and water conservation benefits from natural lawn and garden care practices in Seattle. Seattle Public Utilities (SPU) initiated this study as part of a triple-bottom-line analysis of its Natural Lawn and Garden Care program. Methods  The study uses life cycle assessment (LCA) methods, including the Carnegie-Mellon Economic Input-Output Life Cycle Assessment (EIOLCA) tool publicly available on the Internet, to inventory pollutant generation from a synthetic nutrients and pesticide approach to lawn and garden care compared against a natural/organic care approach. The study applies US Environmental Protection Agency’s TRACI (Tool for the Reduction and Assessment of Chemical and other environmental Impacts) climate change, acidification, eutrophication, and human health-criteria air pollutant stressor factors, along with the Lawrence Berkeley National Laboratory’s CalTOX risk assessment model’s human and ecosystem toxicity potentials to roll up the numerous pollutant quantities into six environmental impact categories (global warming potential, human respiratory disease potential, human toxicity potential, ecological toxicity potential, acidification potential and eutrophication potential). The study develops cost valuation estimates for each impact category to produce a dollar estimate of the environmental cost of the two archetypical lawn and garden care methods. Results  Lawns and gardens account for 25% of Seattle’s land area, so lawn and garden care methods potentially have substantial impacts on the city’s land-and water-based ecosystems. LCA methods provide an informative methodology for comparing environmental impacts from lawn and garden care practices. These methods reveal the importance of more natural lawn and garden care practices. They also show that resource extraction and manufacturing impacts of pesticides and synthetic fertilizers dominate their on site use impacts in the case of global warming, but that the reverse holds for human and ecological toxicity, and eutrophication. In addition, releases of particulates, SO_x and NO_x associated with gasoline-powered lawn mowing are nearly an order of magnitude larger than releases of these pollutants as a result of the production of pesticides and fertilizers. Discussion  The study proceeds by using available data and research to build a desktop model that characterizes and contrasts two archetypical lawn and garden care practices: (1) Petroleum-based fertilizers and pesticides, a gasoline-powered lawn mower, and substantial irrigation to maintain a traditional weed-free, always-green lawn and garden, versus (2) A backyard compost system to provide lawn and garden nutrients, supplemented moderately by purchased non-synthetic soil amendments, an electricity-powered mower, no pesticides, and drought tolerant lawn and garden species having little need for irrigation. Conclusions  The study concludes that each household converting from synthetic to natural practices produces nearly $75 in annual ongoing public health, ecological, water conservation and hazardous waste management benefits — between $16 and $21 of environmental benefits from reduced use of synthetic fertilizers and pesticides, $8 of environmental benefits for switching from gas to electricity for lawn mowing, $42 in cost savings due to reduced irrigation, and $5 or $6 from lower hazardous waste management costs. There also is a potential one time avoidance of $31 in construction costs resulting from reduced need for storm water detention and diversion capacity. Recommendations and Perspectives  This study’s estimates of environmental value would benefit from comprehensive information on direct exposure to active ingredients in insecticides during their application. Estimates of impacts are based only on volatilization and runoff of active ingredients after application. Furthermore, the study would benefit from estimates of carbon sequestration in soils promoted by natural lawn and garden care techniques, and on the upstream pollutant releases from production of synthetic versus organic fertilizers. All three of these data gaps suggest that the estimated $75 per single family residence for environmental value is probably a lower bound on benefits from natural lawn and garden care versus more traditional pesticide-and-synthetic-fertilizer-based approaches. ESS-Submission Editor: Mary Ann Curran (curran.maryann@epa.gov)     

Comparison of Concentrations of Selected Metals and Organics in Fish Tissue and Sediment in the Grand River,Ohio, and the Southern Lake Erie Drainage Basin

The purpose of this paper is to develop a database of fish tissue and sediment concentrations of selected chemicals in the southern Lake Erie drainage basin, to compare contaminant concentrations in fish tissue and sediment collected from the Grand River, Ohio, in the vicinity of a former soda ash and chromate plant with that for other waterbodies in the drainage basin, and to evaluate the potential human health risks posed by these chemicals, with special focus on chromium. The results of this study indicate that chemical concentrations in fish tissue and sediment from the Grand River are generally lower than that of other waterbodies in the southern Lake Erie drainage basin. Although arsenic and beryllium concentrations in Grand River sediment are above their respective human health-based concentrations, these concentrations are comparable with local and regional background and are not expected to pose a significant incremental risk to human health. In addition, sediment concentrations do not exceed ecological screening criteria. Although PCB and several pesticides were found to have concentrations in fish tissue from the Grand River in excess of human health based concentrations, these concentrations are among the lowest found in waterbodies in the southern Lake Erie drainage basin.     

Lactate Engages Receptor Tyrosine Kinases Axl,Tie2, and Vascular Endothelial Growth Factor Receptor 2 to Activate Phosphoinositide 3-Kinase/Akt and Promote Angiogenesis

Although a high level of lactate is quintessential to both tumors and wound healing, the manner by which lactate impacts endothelial cells to promote angiogenesis and thereby create or restore vascular perfusion to growing tissues has not been fully elucidated. Here we report that lactate activated the PI3K/Akt pathway in primary human endothelial cells. Furthermore, activating this signaling pathway was required for lactate-stimulated organization of endothelial cells into tubes and for sprouting of vessels from mouse aortic explants. Lactate engaged the PI3K/Akt pathway via ligand-mediated activation of the three receptor tyrosine kinases Axl, Tie2, and VEGF receptor 2. Neutralizing the ligands for these receptor tyrosine kinases, pharmacologically inhibiting their kinase activity or suppressing their expression largely eliminated the ability of cells and explants to respond to lactate. Elucidating the mechanism by which lactate communicates with endothelial cells presents a previously unappreciated opportunity to improve our understanding of the angiogenic program and to govern it.     

Pesticides in the Cagayan valley (Philippines): usage, drift patterns and the exposure of farmers differing in income and market access

Over the past ten years, the amount and number of different types of pesticides have increased significantly, which led to a growing concern about the possible adverse effects on human health and the environment. This is particularly true for countries where regulations are not strictly implemented and farmers' knowledge of safe handling is often inadequate. This paper discusses the results of a series of spray experiments to determine drift patterns along field boundaries and the exposure of farmers during their usual spraying exercises. Moreover, farmers' pesticide usage and methods of application will be described, and the effects of income and market accessibility on pesticide use patterns will be investigated. It is based on a study conducted in four villages located at increasing distance from the national highway leading to regional markets and connecting the Cagayan Valley in Northeast Luzon with Manila. The 20 pesticides encountered in this study cover 18 different active ingredients, 9 of which are classified by the WHO as 'highly hazardous' or 'moderately hazardous'. The EPA has classified at least 6 of the encountered pesticide formulations as Restricted Use Pesticides. Nevertheless, all pesticides are freely sold in stores or on markets and applied by farmers without personal protection in an unsafe manner. The farmers living nearest to the highway have the highest income and largest farms. Yet they are most at risk, having easiest access to pesticides and spraying the largest quantities of pesticides per hectare, compared to the farmers living at greater distance from the highway. It is recommended to review the list of pesticides approved for use in the Philippines and discern between Restricted and General Use Pesticides. Several recommendations for improving the implementation of pesticide policies and the IPM program are given.     

Evaluation of a leadership program for First Nations,Métis,and Inuit Youth: Stories of positive youth development and community engagement

First Nations, Métis, and Inuit (FNMI) youth experience many health disparities in comparison with their mainstream Canadian peers. Researchers have recommended that interventions developed to enhance health and well-being for FNMI youth apply a strengths-based approach that acknowledges contextual challenges. This article uses a qualitative approach to examine the perceived impacts of a program designed to enhance positive development and leadership in FNMI youth. Semistructured interviews were conducted with front-line staff and participants. A thematic data analysis resulted in three major themes that describe the perceived program effects at the participant, staff, and community levels. Findings are discussed in relation to current research and theory, and recommendations are provided for programming and future research. Leadership programming for FNMI youth may be an effective way to promote development across many levels of stakeholders.     

Biochemical effects of chlorpyrifos and deltamethrin on altered antioxidative defense mechanisms and lipid peroxidation in rat liver

Pesticides such as organophosphorus and organochlorine compounds commonly used in agriculture for achieving better quality products are toxic substances and lead to generation of reactive oxygen species (ROS) which have harmful effects on human health. While pyrethroid pesticides are used in preference to organophosphates and organochlorines due to their high effectiveness, low toxicity to non-target organisms and easy biodegradability, they may also produce oxidative stress. Thus, we investigated the effects of chlorpyrifos (CP, an organophosphate) and deltamethrin (DM, a pyrethroid pesticide) treatments at low and high doses on lipid peroxidation (LPO) and antioxidant enzyme activities such as SOD, GSH-Px and CAT in rat liver following 16 weeks exposure. Antioxidative defence mechanisms and lipid peroxidation in rat liver tissues display different responses depending on different pesticide treatments and doses. Biochemical analysis showed that administrations of the chlorpyrifos and deltamethrin cause liver damage. In the present study, we observed that lipid peroxidation levels are higher at high doses than at low doses, but DM caused more pronounced increase than CP. Experimentally, we have also observed that oxidant-antioxidant balance is more affected by deltamethrin treatment than by chlorpyrifos.     

Health risks of consuming apples with carbendazim,imidacloprid, and thiophanate-methyl in the Chinese population: Risk assessment based on a nonparametric probabilistic evaluation model

The pesticides carbendazim (CA), imidacloprid (IM), and thiophanate-methyl (TH) are used extensively in apple production. However, the presence of pesticide residues in apples has been associated with a wide range of human health hazards. To assess whether apples are safe to consume, evaluating their potential health risk is of great significance. We tested apples from two dominant apple-producing areas for the presence of pesticide residues and constructed a statistical model to evaluate their health risks. Of the three commonly used pesticides, thirty-two samples (11.3% of all tested samples) were residue-free and 231 (81.9%) contained CA residues, which was the most frequently detectable pesticide, followed by TH (52.1%) and IM (39.0%). All of the samples were below the maximum residue limits. The probabilistic assessment results indicated that the pesticide intake risks for kids (aged 2–6 years) and children (aged 7–13 years) were significantly higher than those of other groups, so that they were the vital monitoring objects. Our findings indicate that consumption of apples with these three pesticides does not pose a health threat for the population. Nevertheless, we recommend an investigation into continuous monitoring and stricter regulations on fruits' quality and safety throughout China.     

Biotechnology of flavonoids and other phenylpropanoid-derived natural products. Part II: Reconstruction of multienzyme pathways in plants and microbes

Plant natural products derived from phenylalanine and the phenylpropanoid pathways are impressive in their chemical diversity and are the result of plant evolution, which has selected for the acquisition of large repertoires of pigments, structural and defensive compounds, all derived from a phenylpropanoid backbone via the plant-specific phenylpropanoid pathway. These compounds are important in plant growth, development and responses to environmental stresses and thus can have large impacts on agricultural productivity. While plant-based medicines containing phenylpropanoid-derived active components have long been used by humans, the benefits of specific flavonoids and other phenylpropanoid-derived compounds to human health and their potential for long-term health benefits have only been recognized more recently. In this part of the review, we discuss in detail the recent strategies and achievements used in the reconstruction of multienzyme pathways in plants and microbes in an effort to be able to attain higher amounts of the desired flavonoids and stilbenoids exploiting their beneficial properties as analyzed extensively in Part I of this review.     

Assessing Health Risks from Pesticides in Recycled Water: A Case Study of Augmentation of Drinking Water Supplies in Perth,Western Australia

A characterization of pesticides in secondary treated effluent (STE) and a screening health risk assessment were conducted to evaluate potential health impacts of recycled water for potable reuse. Samples of STE were examined pre- and post-reverse osmosis (RO) treatment in two plants. Risk quotients (RQ) were estimated by expressing the maximum and median concentration as a function of the health value. Of 128 pesticides analyzed, 11 were detected in STE. Trifluralin was detected in 86.5% of the STE samples followed by metolachlor (67.6%), 2,4-D (50%), and propiconazole (42.5%). Metolachlor was the only pesticide detected post-RO in one sample (0.08 μg/L, limit of reporting = 0.05 μg/L). RQ(max) were all below health values in the STE with the exception of thiophanate methyl (RQ max = 2.4). RO was able to reduce the concentration of all pesticides below LOR. Median removal efficiency for RO ranged from 67.1% (atrazine) to 98.8% (2,4-D). The results indicate that, despite the detection of pesticides in STE, the impact on indirect potable reuse is negligible due to the low concentrations in STE and their subsequent removal during RO treatment. Implementation of risk management strategies to optimize safety and recommendations for a monitoring program are also discussed.     

Issues Related to Chemical Analysis,Data Reporting,and Use: Implications for Human Health Risk Assessment of PCBs and PBDEs in Fish Tissue

Recent reports in the scientific literature and the media, related to elevated levels of polychlorinated biphenyls (PCBs) and polybrominated diethyl ethers (PBDEs) in farmed and wild salmon have had significant impacts on public opinion and consumer behavior, influencing the sales of farmed salmon in North America and Europe. The assessment of contaminants in fatty fish, an important source of omega-3 fatty acids, is therefore an exercise in balancing risks and benefits. Human health risk assessors and risk managers will benefit from an understanding of the level of uncertainty that is integrated into all aspects of evaluating risk in this context. Significant variability exists in the way in which analyses are conducted, how data are reported, and how they are used in risk assessments. We conducted an analytical review of PCB and PBDE data in farmed and wild salmon, and identified critical issues having implications on human health risk assessment from fish consumption. These issues include: analytical methodologies used, quantification issues, reporting of QA/QC information, tissue sampling, nature of tissue analyzed, and laboratory competence. This article reviews and outlines these issues, discusses their implications for human health risk assessment, and recommends the consistent application of analytical fish tissue data in human health risk assessment.