The Women's Health Initiative. What is on trial: nutrition and chronic disease? Or misinterpreted science, media havoc and the sound of silence from peers?

The first results of the Women's Health Initiative dietary intervention trial were published in the USA in February. This is a colossal intervention designed to see if diets lower in fat and higher in fruits, vegetables and grains than is usual in high-income countries reduce the incidence of breast cancer, colorectal cancer, heart disease and other chronic diseases, in women aged 50-79 years. As interpreted by US government media releases, the results were unimpressive. As interpreted by a global media blitz, the results indicate that food and nutrition has little or nothing to do with health and disease. But the trial was in key respects not reaching its aims, was methodologically controversial, and in any case has not produced the reported null results. What should the public health nutrition profession do about such messes?     

Food-based dietary guidelines and implementation: lessons from four countries--Chile, Germany, New Zealand and South Africa

OBJECTIVE: Food-based dietary guidelines (FBDGs) are globally promoted as an important part of national food and nutrition policies. They are presented within policy as key features of the strategy to educate the public and guide policy-makers and other stakeholders about a healthy diet. This paper examines the implementation of FBDGs in four countries: Chile, Germany, New Zealand and South Africa - diverse countries chosen to explore the realities of the FBDG within policy on public health nutrition. DESIGN: A literature review was carried out, followed by interviews with representatives from the governmental, academic and private sector in all four countries. RESULTS: In all four countries the FBDG is mainly implemented via written/electronic information provided to the public through the health and/or education sector. Data about the impact of FBDGs on policy and consumers' food choice or dietary habits are incomplete; nutrition surveys do not enable assessment of how effective FBDGs are as a factor in dietary or behavioural change. Despite limitations, FBDGs are seen as being valuable by key stakeholders. CONCLUSION: FBDGs are being implemented and there is experience which should be built upon. The policy focus needs to move beyond merely disseminating FBDGs. They should be part of a wider public health nutrition strategy involving multiple sectors and policy levels. Improvements in the implementation of FBDGs are crucial given the present epidemic of chronic, non-communicable diseases.     

A review of the epidemiological evidence for the 'antioxidant hypothesis'

OBJECTIVE: The British Nutrition Foundation was recently commissioned by the Food Standards Agency to conduct a review of the government's research programme on Antioxidants in Food. Part of this work involved an independent review of the scientific literature on the role of antioxidants in chronic disease prevention, which is presented in this paper. BACKGROUND: There is consistent evidence that diets rich in fruit and vegetables and other plant foods are associated with moderately lower overall mortality rates and lower death rates from cardiovascular disease and some types of cancer. The 'antioxidant hypothesis' proposes that vitamin C, vitamin E, carotenoids and other antioxidant nutrients afford protection against chronic diseases by decreasing oxidative damage. RESULTS: Although scientific rationale and observational studies have been convincing, randomised primary and secondary intervention trials have failed to show any consistent benefit from the use of antioxidant supplements on cardiovascular disease or cancer risk, with some trials even suggesting possible harm in certain subgroups. These trials have usually involved the administration of single antioxidant nutrients given at relatively high doses. The results of trials investigating the effect of a balanced combination of antioxidants at levels achievable by diet are awaited. CONCLUSION: The suggestion that antioxidant supplements can prevent chronic diseases has not been proved or consistently supported by the findings of published intervention trials. Further evidence regarding the efficacy, safety and appropriate dosage of antioxidants in relation to chronic disease is needed. The most prudent public health advice remains to increase the consumption of plant foods, as such dietary patterns are associated with reduced risk of chronic disease.     

Competencies for effective public health nutrition practice: a developing consensus

OBJECTIVES: To assess the level of consensus amongst an international panel of public health nutrition leaders regarding the essential competencies required for effective public health nutrition practice. DESIGN: A modified Delphi study involving three rounds of questionnaires. SUBJECTS: A panel of 20 public health nutrition experts from seven countries in the European Union, the USA and Australia. RESULTS: Expert panellists completed three rounds of the study relating to competencies. A literature review conducted as a prelude to the expert panel survey identified common competency units from the fields of public health, health promotion, nutrition and dietetics, and health education. These were categorised into seven competency areas including analytical, socio-cultural and political, public health service, communication, management and leadership, nutrition science and professional competency categories. There was strong initial agreement (> or = 90% of panellists at Round 1) that developing internationally recognised competencies for public health nutrition specialists was a priority. Twenty-six of an initial listing of 52 competency units were rated as essential competencies by > or = 80% of the panellists after Round 1. Iteration rounds resulted in the addition of five extra competency units suggested by panellists after Round 1 and an increase by 13 in the number of competencies rated as essential to consensus levels. From a total of 57 competency units rated after the final survey round, 41 competency units were rated as essential competencies by > or = 80% of the panellists (consensus), with 21 of these unanimously rated as essential competencies. CONCLUSIONS: There is strong international agreement amongst public health nutrition leaders in Europe, the USA and Australia about a range of competencies required for effective public health nutrition practice. Essential competency units identified can be used to develop and review competency standards for public health nutrition.     

Tea or coffee? A case study on evidence for dietary advice

The present paper explores the level of evidence required to justify giving dietary advice to the public. There are important practical differences between the development of public health nutrition guidelines and guidelines for clinical practice. While the gold standard for evidence for clinical practice guidelines is a meta-analysis of a number of randomised controlled trials, this is often unrealistic and sometimes unethical for the evaluation of public health nutrition interventions. Hence, epidemiological studies make up the bulk of evidence for nutrition guidelines. Tea and coffee are an interesting case study in relation to this issue. They are two of the most commonly consumed beverages worldwide, yet there is little dietary advice on their use. The evidence for a relationship between coffee or tea consumption and several diseases is discussed. The available studies, predominantly epidemiological, together with animal and in vitro studies, indicate that coffee and tea are both safe beverages. However, tea is the healthier option because it has a possible role in the prevention of several cancers and CVD. While the evidence for such relationships is not strong, the public will continue to drink both tea and coffee, and will continue to ask nutritionists to make recommendations. It is therefore argued that advice should be given on the best available data, as waiting for complete data to become available could have severe consequences for public health.     

Why the Bush administration and the global sugar industry are determined to demolish the 2004 WHO global strategy on diet, physical activity and health

OBJECTIVE: To indicate why the world's most powerful nation state and one powerful sector of the food and drink production and manufacturing industry are determined to demolish the 2004 WHO (World Health Organization) global strategy on diet, physical activity and health, and to disassociate it from the 2003 WHO/FAO (Food and Agriculture Organization) expert report on diet, nutrition and the prevention of chronic diseases, which with its background papers is the immediate scientific basis for the strategy. To encourage representatives of nation states at the 2004 WHO World Health Assembly to support the strategy together with the report, so that the strategy is explicit and quantified, and responds to the need expressed by member states at the 2002 World Health Assembly. This is for an effective global strategy to prevent and control chronic diseases whose prevalence is increased by nutrient-poor food low in vegetables and fruits and high in energy-dense fatty, sugary and/or salty foods and drinks and also by physical inactivity. Of these diseases, obesity, diabetes, cardiovascular diseases and cancers of several sites are now the chief causes of morbidity and mortality in most countries in the world. METHOD: A summary of the global strategy and its roots in scientific knowledge accumulated over the last half-century. Reasons why the global strategy and the expert report are opposed by the current US government and the world sugar industry, with some reference to modern historical context. A summary of the trajectory of the global strategy since its first draft made in early 2003, and a further summary of its weaknesses, strengths and potential. CONCLUSION: The 2004 WHO global strategy and the 2003 WHO/FAO expert report are perceived by the current US administration as an impediment to US trade and international policy, within a general context of current US government hostility to the UN (United Nations) system as a brake on the exercise of its power as the world's dominant nation. Policy-makers throughout the world should be aware of the contexts of current pressures put on them by powerful nation states and sectors of industry whose ideologies and commercial interests are challenged by international initiatives designed to improve public health and to leave a better legacy for future generations.     

Review of chromatographic methods for chloramphenicol residues in milk, eggs, and tissues from food-producing animals

Although chloramphenicol is not approved for use in food-producing animals in the United States, this broad spectrum antibiotic has been widely used to treat diseases in such animals including the lactating dairy cow. Extremely low ophthalmologic doses of chloramphenicol are known to cause aplastic anemia in humans. The residues in meat, milk, and eggs intended for human consumption cause particular public health concern because the bone marrow aplasia is not dose dependent. Furthermore, chloramphenicol, a known inhibitor of protein synthesis, also retards erythropoiesis, a condition that is dose dependent and may cause allergic hypersensitivity reactions. This paper is a review of sensitive methods that use gas, liquid, thin layer, and simple column chromatography as both determinative and cleanup steps for detecting and quantitating chloramphenicol in edible animal tissues, milk, and eggs.     

High Dose Extrapolation in Climate Change Projections of Heat-Related Mortality

One challenge for statisticians and epidemiologists in projecting the future health risks of climate change is how to estimate exposure-response relationships when temperatures are higher than at present. Low dose extrapolation has been an area of rich study, resulting in well-defined methods and best practices. A primary difference between high dose and low dose extrapolation of exposure-response relationships is that low dose extrapolation is bounded at no exposure and no (or a baseline) response. With climate change altering weather variables and their variability beyond historical values, the highest future exposures in a region are projected to be higher than current experience. Modelers of the health risks of high temperatures are making assumptions about human responses associated with exposures outside the range of their data; these assumptions significantly affect the magnitude of projected future risks. Further, projections are affected by adaptation assumptions; we explore no adaptation (extrapolated response); individual (physiological) adaptation; and community adaptation. We present an example suggesting that linear models can make poor predictions of observations when no adaptation is assumed. Assumptions of the effects of weather above what has been observed needs to be more transparent in future studies. Statistical simulation studies could guide public health researchers in identifying best practices and reducing bias in projecting risks associated with extreme temperatures. Epidemiological studies should evaluate the extent and time required for adaptation, as well as the benefits of public health interventions.     

利用土壤改良剂固定污染土壤中铅、镉的研究进展

Since the inception of industrial revolution, metal refining plants using pyrometallurgical processes have generated the prodigious emissions of lead (Pb) and cadmium (Cd). As the core target of such pollutants, a large number of soils are nowadays contaminated over widespread areas, posing a great threat to public health worldwide. Unlike organic pollutants, Pb and Cd do not undergo chemical or microbial breakdown and stay likely in site for longer duration after their release. Immobilization is an in-situ remediation technique that uses cost-effective soil amendments to reduce Pb and Cd availability in the contaminated soils. The Pb and Cd contamination in the soil environment is reviewed with focus on source enrichment, speciation and associated health risks, and immobilization options using various soil amendments. Commonly applied and emerging cost-effective soil amendments for Pb and Cd immobilization include phosphate compounds, liming, animal manure, biosolids, metal oxides, and biochar. These immobilizing agents could reduce the transfer of metal pollutants or residues to food web (plant uptake and leaching to subsurface water) and their long-term sustainability in heavy metal fixation needs further assessment.     

Solid Wastes In Urban And Rural Areas Of Ibadan,Nigeria: Composition,Treatment And Public Health Concerns

The composition of solid waste produced at various locations in Nigeria differs considerably because the amounts generated and the constituents thereof are determined by social customs and living standards. Nigeria has undergone extensive industrial development which has often changed the composition of domestic solid waste as well as agricultural wastes. The disposal and utilization of these mixed wastes has presented new risks and problems for our society and environment. Though most solid waste in Nigeria contains little human and animal material, pathogenic organisms affecting both continue to be present. Potential risks to human health and the environment that can arise from domestic solid waste disposal and utilization in Nigeria include pollution of water and air, accidents, contact contamination and breeding sites for flies and rodents. There also are long-term problems in relation to the human food chain.     

The role of foreign direct investment in the nutrition transition

OBJECTIVE: To examine the role of foreign direct investment (FDI) in the nutrition transition, focusing on highly processed foods. DESIGN: Data on FDI were identified from reports/databases and then compiled and analysed. A review of published literature on FDI into the food sector was conducted. SETTING: The nutrition transition is a public health concern owing to its connection with the rising burden of obesity and diet-related chronic diseases in developing countries. Global health leaders are calling for action to address the threat. Highly processed foods often have considerable fat, sugar and salt content, and warrant closer examination. RESULTS: FDI into food processing, service and retail has risen rapidly since the 1980s, mainly from transnational food companies (TFCs) in developed countries. As FDI has risen, so has the proportion invested in highly processed foods for sale in the host market. FDI has proved more effective than trade in generating sales of highly processed foods, and enables TFCs to cut costs, gain market power and obtain efficiencies in distribution and marketing. The amount of FDI targeted at developing countries is increasing; while a disproportionate share enters the larger developing economies, foreign affiliates of TFCs are among the largest companies in low- and low- to middle-income countries. The effect of FDI is to make more highly processed foods available to more people. FDI has made it possible to lower prices, open up new purchasing channels, optimise the effectiveness of marketing and advertising, and increase sales. CONCLUSION: FDI has been a key mechanism in shaping the global market for highly processed foods. Notwithstanding the role of demand-side factors, it has played a role in the nutrition transition by enabling and promoting the consumption of these foods in developing countries. Empirical data on consumption patterns of highly processed foods in developing countries are critically needed, but since FDI is a long-term investment vehicle, it is reasonable to assume that availability and consumption of highly processed foods will continue to increase. FDI can, however, bring considerable benefits as well as risks. Through its position 'upstream', FDI would therefore be an appropriate entry-point to implement a range of public health policies to 'redirect' the nutrition transition.     

Gender and occupational health and safety requirements among Saskatchewan farm adolescents

Children on farms perform hazardous work that exposes them to risks for injury. Hazards include operation of heavy machinery, working with limited supervision, working at heights, and performing work prohibited by law in other industries. Incidence rates and patterns of injury are known to differ between boys and girls on farms. Farm adherence to occupational health and safety practices, and whether such practices vary by gender, has received limited study in this occupational setting. The objective of this study was to evaluate associations between gender and work practices, and required occupational health and safety practices, within a sample of adolescent children age 12 to 18 years living on Saskatchewan farms. A cross-sectional study was performed. Measures were obtained by self-report. We compared requirements for boys and girls on the following: (1) use of personal protective equipment (PPE), (2) conduct of specific hazardous jobs, (3) training and supervision for equipment work, and (4) training and supervision for large animal work. A total of 434 children were identified, and 297 (68%) met the eligibility criteria. Of these, 170 were boys (57%) with a mean age of 14.5 years (SD 1.9). Occupational health and safety requirements varied by gender; girls were less likely to be required to use PPE (adjusted OR 2.39; 95% CI: 1.16, 4.94). There was no evidence of an association between gender and the conduct of hazardous work. Gender patterns in required training and supervision for work suggested disadvantages for girls, but were not significant. Adolescent girls and boys both performed hazardous jobs on the farm. Girls were as likely to conduct hazardous jobs but not to be required to use PPE. This gender disparity may indicate a need for a public health approach that recognizes gender as a determinant of work assignment and of health and safety practices on farms.     

Carcass Composting for Management of Farm Mortalities: A Review

For the last two decades, carcass disposal by burial is being replaced with alternatives such as composting. Improper animal mortality disposal may generate various environmental and health hazards such as odor nuisance (resulting from the anaerobic breakdown of proteins) that can reduce the quality of life and decrease property values. Pathogens, which may still be present in the decomposed material, are capable of spreading diseases in soil, plants, animals and humans. The potential leaching of harmful nitrogen and sulfur compounds from animal mortalities to ground water is another concern. To control these side effects, compost facility operators need to know and understand the science and guidelines of carcass composting. While basic principles of carcass composting are similar to those for composting of organic materials, its management issues, including appropriate composting methods for large or small scale carcass composting, quantities and types of carbon sources, composting time, odor and leachate control, and equipment requirements differ from composting of organics. The purpose of this study is to review the previous works related to carcass composting and provide information on recent advances in small and large-scale carcass composting enabling higher decomposition rates, minimum usage of carbon source materials, easier and shorter management control strategies and reduced land requirement while producing a useful end product and avoiding negative impact on public safety and environmental parameters.     

Utilization of municipal organic wastes in agriculture: where do we stand,where will we go?

Generation of organic waste is increasing worldwide and strategies for its environmentally sound use must be developed and optimized. Regulations in European countries and the USA differ largely with respect to requirements of organic waste quality and the quantities of pollutants which can be added to the soil. Research has shown beneficial effects regarding the improvement of soil fertility. Enrichment of total metals in soil was attributed to long‐term sludge application but the effect on bioavailability of metals must be further clarified. A number of organic pollutants, such as hydrophobic persistent organic contaminants and surfactants, are known to accumulate in organic wastes. However, the former interact strongly with organic matter in the sludge‐soil‐plant system and systemic plant uptake is generally assumed to be minimal. Surfactants may cause adverse environmental impacts when they enter sewage systems in high loads and accumulate in sludge. Surfactants and some of their metabolites are not readily biodegraded in non‐aerated environments. Due to their toxicity and estrogenic activity, of nonylphenol for example, more research is needed to optimize analytical techniques and to trace their behavior in soil. Some options to cope with the risks of huge amounts of organic waste and also some benefits are presented: (1) further limitation of standards for pollutants and reduced application rates; (2) improved treatment of sewage sludge to reduce the total and bioavailable portions of both heavy metals and organic pollutants; (3) adaptation of waste application rates to soil properties such as sorption capacity for pollutants; (4) harmonization of analytical protocols for organic contaminants, i.e. surfactants and metabolites, enabling a more thorough monitoring of the wastes which are to be applied onto soils.     

<Emphasis Type="Italic">Withania somnifera</Emphasis> Dunal-mediated dissipation of lindane from simulated soil: implications for rhizoremediation of contaminated soil

Background, aim, and scope  

Lindane is an organochlorine chemical that has been used both as an agricultural insecticide and as a treatment for head lice and scabies. It is a neurotoxin that interferes with GABA neurotransmitter function. In humans, lindane primarily affects the nervous system, liver, and kidneys and may be a carcinogen and/or endocrine disruptor. Currently, India is the largest consumer and producer of lindane in the world. Due to its continuous use and indiscriminate industrial production, lindane-contaminated soils are widespread in the country. Apart from India, historical lindane production sites were found in Austria, France, Spain, Bulgaria and in China, Turkey, and the former USSR. Before 1984, lindane was also manufactured in the German Democratic Republic, Poland, Yugoslavia, Romania, and Hungary; since then, all production has been stopped in Germany, Japan, The Netherlands, the UK, and the USA. Because of its worldwide use for more than 50 years, lindane-contaminated soils can be found in most countries of the world. Although many countries have restricted or eliminated its usage, obsolete stock piles continue to pose a threat to various ecosystems and human health. Physical, chemical, and biological methods can all be used for the remediation of contaminated sites, but phytoremediation is now recognized as a cost-effective method for the decontamination of soil sites. The present study examines the potential of Withania somnifera Dunal (previously shown to accumulate lindane from contaminated industrial area; Abhilash et al., Chemosphere 72:79–86, 2008) to take up lindane (γ-HCH) and the subsequent plant-mediated dissipation of lindane from an artificially contaminated soil.     

Hunger and health among undocumented Mexican migrants in a US urban area

OBJECTIVES: To measure the occurrence and correlates of hunger and to evaluate the association between hunger and three health indicators among undocumented Mexican immigrants. DESIGN: Non-probability cross-sectional sample. SETTING: Neighbourhoods within New York City. SUBJECTS: Four hundred and thirty-one undocumented Mexican immigrants living in the USA. RESULTS: Hunger was indicated by approximately 28% of respondents. In a multivariate model, working as a day labourer was associated with hunger (odds ratio (OR) 3.33, 95% confidence interval (CI) 1.83-6.06) while receiving public assistance protected against hunger (OR 0.23, 95% CI 0.06-0.88). In multivariate models, respondents who reported experiencing hunger also reported poorer overall health (OR 1.69, 95% CI 0.95-3.02) and more days of poor mental (P = 0.045) and physical health (P < 0.0001). Greater amount of time lived in the USA was also associated with worse overall health (P = 0.054) and more days of poor mental and physical health (P < 0.01). CONCLUSIONS: The present study shows that food insecurity and hunger may be problems among undocumented migrants living in the USA. Uncertain and unpredictable work schedules and limited access to public assistance may contribute to high levels of hunger, which in turn may also negatively affect mental and physical health. Increasing amount of time lived in the USA is also associated with poorer health indicators. Programmes that provide undocumented migrants with emergency access to resources may reduce food insecurity and lead to improved health outcomes among this vulnerable population.     

Se和Cd在土壤-植物系统中的迁移与食品安全

本文就Se和Cd在土壤-植物系统中的迁移及其与食品安全及人体健康之间的潜在关系进行了综合评述。Cd和Se在植物中积累并迁移到植物的可食或收获部分,取决于土壤条件、气候因子、农艺管理措施等。Cd是对食物链造成污染的重要元素,其在土壤中的富集通常是由工农业生产或城市人为污染造成的,减少Cd对土壤的污染及Cd污染土壤的生物修复已成为土壤学、环境科学及生态学研究的热点。Se是一种对动植物有益的元素,在土壤中含量过低会引发人体疾病,但Se含量过高也会导致污染并引发人体疾病;土壤中的高浓度Se通常来自于含Se量高的母岩以及燃煤的灰尘污染;基于食品安全的需要,中国在重视Se素营养补给的同时,要防止富Se地区及人为因素造成的Se污染。     

Antibiotic Resistance Genes in the Human-Impacted Environment: A One Health Perspective

Antibiotic resistance and its environmental component are gaining more attention as part of combating the growing healthcare crisis. The One Health framework, promulgated by many global health agencies, recognizes that antimicrobial resistance is a truly inter-domain problem in which human health, animal agriculture, and the environment are the core and interrelated components. This prospectus presents the status and issues relevant to the environmental component of antibiotic resistance, namely, the needs for advancing surveillance methodology:the environmental reservoirs and sources of resistance, namely, urban wastewater treatment plants, aquaculture production systems, soil receiving manure and biosolid, and the atmosphere which includes longer range dispersal. Recently, much work has been done describing antibiotic resistance genes in various environments; now quantitative, mechanistic, and hypothesis-driven studies are needed to identify practices that reduce real risks and maintain the effectiveness of our current antibiotics as long as possible. Advanced deployable detection methods for antibiotic resistance in diverse environmental samples are needed in order to provide the surveillance information to identify risks and define barriers that can reduce risks. Also needed are practices that reduce antibiotic use and thereby reduce selection for resistance, as well as practices that limit the dispersal of or destroy antibiotic-resistant bacteria or their resistance genes that are feasible for these varied environmental domains.     

Use of national food balance data to estimate the adequacy of zinc in national food supplies: methodology and regional estimates

OBJECTIVES: Adequate zinc nutriture is critically important for human health, but the development of programmes to control zinc deficiency is limited by the lack of reliable information on population zinc status. The present analyses were conducted to: (1) estimate the absorbable zinc content of national food supplies; (2) compare this information with theoretical population requirements for zinc; and (3) use these results to predict national risks of inadequate zinc intake. SETTING AND DESIGN: National food balance data were obtained for 176 countries from the Food and Agriculture Organization of the United Nations. The amount of absorbable zinc in these foods was estimated from food composition data, and zinc absorption was predicted using a model developed by the International Zinc Nutrition Consultative Group (IZiNCG). Demographic data were obtained from United Nations estimates, and age- and sex-specific physiological requirements for absorbable zinc were estimated using IZiNCG recommendations. RESULTS AND CONCLUSIONS: The mean per capita absorbable zinc content of national food supplies ranged from 2.98-3.01 mg day(-1) in Western Europe and USA & Canada to 2.09 mg day(-1) in Southeast Asia. The estimated percentage of individuals at risk of inadequate zinc intake ranged from 9.3-9.5% in the regions of North Africa & Eastern Mediterranean and USA & Canada to 33.1% in Southeast Asia. Overall, approximately 20.5% of the world's population is estimated to be at risk of inadequate zinc intake. Data on the absorbable zinc content of national food supplies can be used to determine whether further assessments of population zinc status and development of intervention programmes are warranted.     

Prioritization of ground water contaminants and sources

The objective of this research was to identify chemical, physical, bacteriological, and viral contaminants, and their sources, which present the greatest health threat in public ground water supplies in the USA; and to classify (prioritize) such contaminants and relative to their health concerns. The developed contaminant prioritization methodology was based on frequency of occurrence and adverse health effects. Adverse health effects were based on carcinogenic potency, toxicity, hazardous chemical priorities and drinking water standards. Application of the methodology for wellhead protection areas, (WHPAs) revealed that approximately 200 different contaminants have been detected in the nation's public ground water supplies. The seven chemical constituents with the highest priority were arsenic, chromium, cadmium, carbon tetrachloride, chloroform, 1, 1-dichloroethylene, and ethylene dibromide. Other contaminants of concern were trichloroethylene, nitrates, barium, 1,1,1-trichloroethane, benzene, tetrachloroethylene, selenium, lead, toluene, mercury, gross alpha radiation, methylene chloride, coliform bacteria, metolachlor, metribuzin, 1, 1, 2, 2-tetrachloroethane, dibromochloroethane, simazine, radium-266, and toxaphene. The contaminant source prioritization methodology was also based on frequency of occurrence. Over 30 categories of sources were evaluated, with the eight with highest priority including agricultural activities, hazardous waste sites, landfills, industrial operations, septic tank systems, oil and gas field activities, urban land use, and underground storage tanks.