The Forest for the Trees: A Systems Approach to Human Health Research

We explore the relationship between current research directions in human health and environmental and public health policy. Specifically, we suggest there is a link between the continuing emphasis in biomedical research on individualized, therapeutic solutions to human disease and the increased reliance on individual choice in response to environmental and/or public health threats. We suggest that continued research emphasis on these traditional approaches to the exclusion of other approaches will impede the discovery of important breakthroughs in human health research necessary to understand the emerging diseases of today. We recommend redirecting research programs to interdisciplinary and population-focused research that would support a systems approach to fully identifying the environmental factors that contribute to disease burden. Such an approach would be able to address the interactions between the social, ecological, and physical aspects of our environment and explicitly include these in the evaluation and management of health risks from environmental exposures

Assessing Children’s Dietary Pesticide Exposure: Direct Measurement of Pesticide Residues in 24-Hr Duplicate Food Samples

Background: The data presented here are a response to calls for more direct measurements of pesticide residues in foods consumed by children and provide an opportunity to compare direct measures of pesticide residues in foods representing actual consumption with those reported by the U.S. Department of Agriculture Pesticide Data Program. Objective: We measured pesticide residues in 24-hr duplicate food samples collected from a group of 46 young children participating in the Children’s Pesticide Exposure Study (CPES). Methods: Parents were instructed to collect 24-hr duplicate food samples of all conventional fruits, vegetables, and fruit juices equal to the quantity consumed by their children, similarly prewashed/prepared, and from the same source or batch. Individual or composite food items were analyzed for organophosphate (OP) and pyrethroid insecticide residues. Results: We collected a total of 239 24-hr duplicate food samples collected from the 46 CPES children. We found 14% or 5% of those food samples contained at least one OP or pyrethroid insecticide, respectively. We measured a total of 11 OP insecticides, at levels ranging from 1 to 387 ng/g, and three pyrethroid insecticides, at levels ranging from 2 to 1,133 ng/g, in children’s food samples. We found that many of the food items consumed by the CPES children were also on the list of the most contaminated food commodities reported by the Environmental Working Group. Conclusions: The frequent consumption of food commodities with episodic presence of pesticide residues that are suspected to cause developmental and neurological effects in young children supports the need for further mitigation

Fish Consumption and Mercury Exposure among Louisiana Recreational Anglers

Ba c k g r o u n d: Methylmercury (MeHg) exposure assessments among average fish consumers in the United States may underestimate exposures among U.S. subpopulations with high intakes of region-ally specific fish. obj e c t i v e s: We examined relationships among fish consumption, estimated mercury (Hg) intake, and measured Hg exposure within one such potentially highlyexposed group, recreational anglers in the state of Louisiana, USA. Me t h o d s: We surveyed 534 anglers in 2006 using interviews at boat launches and fishing tourna-ments combined with an Internet-based survey method. Hair samples from 402 of these anglers were collected and analyzed for total Hg. Questionnaires provided information on species-specific fish consumption during the 3 months before the survey. re s u l t s: Anglers’ median hairHg concentration was 0.81 μg/g (n = 398; range, 0.02–10.7 μg/g);40% of participants had levels >1 μg/g, which approximately corresponds to the U.S. Environmental Protection Agency’s reference dose. Fish consumption and Hg intake were significantly positively associated with hairHg. Participants reported consuming nearly 80 different fish types, many of which are specific to the region. Unlike the general U.S. population, which acquires most of its Hg from commercial seafood sources, approximately 64% of participants’ fish meals and 74% of their estimated Hg intake came from recreationally caught seafood. co n c l u s i o n s: Study participants had relatively elevated hairHg concentrations and reported con-sumption of a wide variety of fish, particularly locally caught fish. This group represents a highlyexposed subpopulation with an exposure profile that differs from fish consumers in other regions of the United States, suggesting a need for more regionallyspecific exposure estimates and public health advisories.ISSN:1552-9924ISSN:0091-676

A Personal Perspective on the Initial Federal Health-Based Regulation to Remove Lead from Gasoline

Objective: This article describes the personal experience and perspective of the authors, who had primary responsibility for drafting the initial health-based regulation limiting lead content of gasoline during the early 1970s while employed by the U.S. Environmental Protection Agency (EPA). Data s o u r c e: Information used by the U.S. EPA in developing the initial health-based regulation limiting lead content of gasoline in December 1973 and studies documenting the impact of that and subsequent actions. Data extraction: Among the lessons learned from this experience is the importance of having input from independent scientists to the regulatory decision-making process. This also demonstrates the critical role of independent peer-reviewed research, such as that supported by the National Institutes of Health, as well as research conducted by scientists from the Centers for Disease Control and Prevention, in delineating the consequences of lead exposure in the population. Data synthesis: Removal of lead from gasoline in the United States has been described as one of the great public health achievements of the 20th century, but it almost did not happen. The experience of the authors in developing this regulation may be helpful to others involved in developing health-based regulatory policy in the future. Co n c l u s i o n: The initial U.S. EPA health-based regulation to remove lead from gasoline is clearly an example where science successfully affected public policy. The leadership of the U.S. EPA at that time deserves much credit for establishing an atmosphere in which this was possible

Effects of Dietary Distillers Dried Grains with Solubles and Soybean Meal on Extruded Pellet Characteristics and Growth Responses of Juvenile Yellow Perch

A 126-d feeding trial was performed to investigate graded combinations of distillers dried grains with solubles (DDGS) and soybean meal (SBM) in diets formulated for yellow perch Perca flavescens. Six experimental diets contained DDGS and SBM at 0 and 31.5% (dry matter basis), respectively (0/31.5 diet), 10 and 26% (10/26), 20 and 20.5% (20/20.5), 30 and 15% (30/15), 40 and 9.5% (40/9.5), and 50 and 4% (50/4) to obtain similar levels of crude protein (mean ± SE = 30.1 ± 0.2%), crude lipid (16.7 ± 0.7%), and digestible energy (13.5 ± 0.2 kJ/g). Fourteen fish (initial individual weight = 19.1 ± 0.5 g) were randomly selected and stocked into each of twenty-four 110-L tanks (4 replicate tanks/diet). Common biological and mechanical filter systems were used to recirculate the water and maintain similar water quality. Fish that received the 40/9.5 diet exhibited the highest apparent absolute weight gain and percent weight gain, while fish that were fed the 10/26, 20/20.5, 30/15, and 40/9.5 diets exhibited similar absolute weight gain. Fish that were given the 20/20.5, 30/15, and 40/9.5 diets also exhibited similar percent weight gain. Fulton’s condition factor and apparent protein digestibility were significantly lower and higher, respectively, for fish that received the 50/4 diet than for all other treatment groups. Crude protein and crude lipid levels in muscle samples did not significantly differ among treatment groups. Results indicated that yellow perch can utilize DDGS plus SBM at a combined inclusion level of up to 49.5% without negative effects on growth. The mechanical strength and color of the extruded pellets were related to the level of DDGS plus SBM in the feed blends. Hepatosomatic indices were correlated with pellet color, while protein digestibility decreased with increasing pellet strength

Targeting Conservation Investments in Heterogeneous Landscapes: A distance function approach and application to watershed management

To achieve a given level of an environmental amenity at least cost, decision-makers must integrate information about spatially variable biophysical and economic conditions. Although the biophysical attributes that contribute to supplying an environmental amenity are often known, the way in which these attributes interact to produce the amenity is often unknown. Given the difficulty in converting multiple attributes into a unidimensional physical measure of an environmental amenity (e.g., habitat quality), analyses in the academic literature tend to use a single biophysical attribute as a proxy for the environmental amenity (e.g., species richness). A narrow focus on a single attribute, however, fails to consider the full range of biophysical attributes that are critical to the supply of an environmental amenity. Drawing on the production efficiency literature, we introduce an alternative conservation targeting approach that relies on distance functions to cost-efficiently allocate conservation funds across a spatially heterogeneous landscape. An approach based on distance functions has the advantage of not requiring a parametric specification of the amenity function (or cost function), but rather only requiring that the decision-maker identify important biophysical and economic attributes. We apply the distance-function approach empirically to an increasingly common, but little studied, conservation initiative: conservation contracting for water quality objectives. The contract portfolios derived from the distance-function application have many desirable properties, including intuitive appeal, robust performance across plausible parametric amenity measures, and the generation of ranking measures that can be easily used by field practitioners in complex decision-making environments that cannot be completely modeled. Working Paper # 2002-01