Comparison of Predicted and Observed Dioxin Levels in Fish: Implications for Risk Assessment

After comparing sampled and modelled dioxin levels in the tissue of fish near pulp and paper mill discharges, the authors argue that, until an improved bioaccumulation model is incorporated into EPA\u27s Risk assessment process, determination of human health Risks associated with consuming dioxin-contaminated fish should be based on sampling

Lessons learned from the application of BEES-C: Systematic assessment of study quality of epidemiologic research on BPA, neurodevelopment, and respiratory health

AbstractEpidemiologic studies evaluating associations between biomarkers of exposure to short-lived chemicals and health endpoints in humans face special challenges. Perhaps the most critical challenges are the need to determine the type and optimal number of samples, and the proper timing of specimen collection. Further, as many short-lived chemicals are ubiquitous in the environment, utmost care is required to avoid sample contamination. A separate set of challenges is associated with appropriate interpretation and reporting of results from multiple simultaneous analyses, which are becoming increasingly feasible. The Biomonitoring, Environmental Epidemiology, and Short-Lived Chemicals (BEES-C) instrument is specifically designed to evaluate the quality of epidemiologic studies that measure biomarkers of chemicals with short physiologic half-lives. The instrument provides systematic guidance for evaluating 14 different aspects of study quality divided into three broad categories: 1) biomarker selection and measurement, 2) strategy and execution of exposure assessment, and 3) general considerations of study design and reporting. We evaluated the utility of the BEES-C instrument using epidemiologic studies of exposure to bisphenol A and its association with neurodevelopmental and respiratory health indicators. Each BEES-C element was assessed with respect to needed modifications and concordance among reviewers using professional, scientific judgment. Based on this first use of the BEES-C instrument, we found that most of its elements were effective in comparing the quality of available studies, with reviews generally concordant and justifications consistent. However, we note that certain elements would be improved with slight adjustments and that one of the elements appeared redundant and should be removed

Necessity of overvoltage protection studies for gas-insulated switchgear

Kaasueristeisten kytkinlaitosten määrä kantaverkossa lisääntyy tulevaisuudessa merkittävästi erityisesti korvausrakentamisen myötä. Kaasueristeinen kojeisto on herkkä ylijännitteille ja aiheuttaa vikaantuessaan pitkän keskeytyksen sähkönsiirtoon sekä suuret korjauskustannukset. Tämän vuoksi sen ylijännitesuojaukseen on kiinnitettävä erityistä huomiota. Suomen kantaverkkoyhtiö Fingrid Oyj on aikaisemmissa kytkinlaitoshankkeissaan tilannut kojeistovalmistajilta erillisen ylijännitesuojausselvityksen, jossa tarkastellaan tarvetta tehostaa kytkinlaitosten ylijännitesuojauksia kaasueristeisillä ylijännitesuojilla. Selvityksissä annetaan kuitenkin usein liikaa painoarvoa epätodennäköisille kytkinlaitoksen käyttötilanteille, mikä voi lopulta johtaa erittäin kalliiden kaasueristeisten ylijännitesuojien hankkimiseen ilman todellista tarvetta. Tämän diplomityön ensisijaisena tavoitteena oli selvittää, onko kaasueristeisille ylijännitesuojille tarvetta ilmaeristeisten ylijännitesuojien lisäksi kantaverkon 110 kV:n kaasueristeisten kytkinlaitosten ylijännitesuojauksessa. Toisena tavoitteena oli määritellä kytkinlaitoksen todelliset käyttötilanteet, joihin on perustelua jatkossa vaatia kojeistojen valmistajilta ylijännitesuojausselvitykset. Työssä laadittiin simulointimalli, jolla simuloitiin salamaniskun aiheuttamia ylijännitteitä eri käyttötilanteissa. Työn lopussa määritettiin suojausriskitaso, jonka perusteella tehtiin päätelmät kaasueristeisten ylijännitesuojien tarpeesta. Johtopäätöksenä voidaan todeta, ettei kaasueristeisiä ylijännitesuojia tarvita ilmaeristeisten suojien lisäksi 110~kV:n kaasueristeisten kytkinlaitosten yhteydessä. Ylijännitesuojausselvityksistä voidaan siten luopua tällä jännitetasolla. Lisäksi suositellaan, että jatkossa 220 ja 400 kV:n ylijännitesuojausselvityksissä vaaditaan selvityksen laatijaa ottamaan huomioon kytkinlaitoksen käyttötilanteiden todennäköisyydet.The number of substations with gas-insulted switchgear in the Finnish main grid will increase significantly in the future in particular due to renewal construction. Gas-insulated switchgear is sensitive to overvoltages and damages in it cause a long interruption in power transmission as well as large repair costs. Therefore, its overvoltage protection requires special attention. The Finnish transmission system operator Fingrid Oyj has ordered a separate overvoltage protection study from the switchgear manufacturers in earlier gas-insulated switchgear projects to examine the need to enhance the overvoltage protection of the switchgear with gas-insulated surge arresters. However, these studies often give too much weight to unlikely switchgear operation situations, which may eventually lead to the purchase of highly expensive gas-insulated surge arresters without actual need. The primary purpose of this thesis was to find out whether a need for overvoltage protection of 110 kV gas-insulated switchgear by gas-insulated surge arresters in addition to air-insulated surge arresters exists. Another objective was to define realistic switchgear operating situations, in which overvoltage protection studies should be required from the manufacturer in the future. A model was developed to simulate overvoltages caused by lightning surges in different operating situations. At the end of the thesis, a protection risk level was established and based on that, conclusions on the need for gas-insulated surge arresters were made. In conclusion, it is stated that no gas-insulated surge arresters are needed in addition to air-insulated surge arresters for 110~kV gas-insulated switchgear. Overvoltage protection studies can thus be given up at this voltage level. Moreover, it is recommended that taking probabilities of switching situations into account should be required from the manufacturer in the future overvoltage protection studies at voltage levels of 220 and 400 kV

Comparing United States and Canadian population exposures from National Biomonitoring Surveys: Bisphenol A intake as a case study

The Centers for Disease Control and Prevention provides biomonitoring data in the United States as part of the National Health and Nutrition Examination Survey (NHANES). Recently, Statistics Canada initiated a similar survey — the Canadian Health Measures Survey (CHMS). Comparison of US and Canadian biomonitoring data can generate hypotheses regarding human exposures from environmental media and consumer products. To ensure that such comparisons are scientifically meaningful, it is essential to first evaluate aspects of the surveys' methods that can impact comparability of data. We examined CHMS and NHANES methodologies, using bisphenol A (BPA) as a case study, to evaluate whether survey differences exist that would hinder our ability to compare chemical concentrations between countries. We explored methods associated with participant selection, urine sampling, and analytical methods. BPA intakes were also estimated to address body weight differences between countries. Differences in survey methods were identified but are unlikely to have substantial impacts on inter-survey comparisons of BPA intakes. BPA intakes for both countries are below health-based guidance values set by the US, Canada and the European Food Safety Authority. We recommend that before comparing biomonitoring data between surveys, a thorough review of methodologic aspects that might impact biomonitoring results be conducted

Using Systematic Reviews and Meta-Analyses to Support Regulatory Decision Making for Neurotoxicants: Lessons Learned from a Case Study of PCBs

We examined prospective cohort studies evaluating the relation between prenatal and neonatal exposure to polychlorinated biphenyls (PCBs) and neurodevelopment in children to assess the feasibility of conducting a meta-analysis to support decision making. We described studies in terms of exposure and end point categorization, statistical analysis, and reporting of results. We used this evaluation to assess the feasibility of grouping studies into reasonably uniform categories. The most consistently used tests included Brazelton's Neonatal Behavioral Assessment Scale, the neurologic optimality score in the neonatal period, the Bayley Scales of Infant Development at 5-8months of age, and the McCarthy Scales of Children's Abilities in 5-year-olds. Despite administering the same tests at similar ages, the studies were too dissimilar to allow a meaningful quantitative examination of outcomes across cohorts. These analyses indicate that our ability to conduct weight-of-evidence assessments of the epidemiologic literature on neurotoxicants may be limited, even in the presence of multiple studies, if the available study methods, data analysis, and reporting lack comparability

Workgroup Report: Biomonitoring Study Design, Interpretation, and Communication—Lessons Learned and Path Forward

Human biomonitoring investigations have provided data on a wide array of chemicals in blood and urine and in other tissues and fluids such as hair and human milk. These data have prompted questions such as a) What is the relationship between levels of environmental chemicals in humans and external exposures? b) What is the baseline or “background” level against which individual levels should be compared? and c) How can internal levels be used to draw conclusions about individual and/or population health? An interdisciplinary panel was convened for a 1-day workshop in November 2004 with the charge of focusing on three specific aspects of biomonitoring: characteristics of scientifically robust biomonitoring studies, interpretation of human biomonitoring data for potential risks to human health, and communication of results, uncertainties, and limitations of biomonitoring studies. In this report we describe the recommendations of the panel

A proposal to facilitate weight-of-evidence assessments: Harmonization of Neurodevelopmental Environmental Epidemiology Studies (HONEES)

The ability to conduct weight-of-evidence assessments to inform the assessment of potential environmental neurotoxicants is limited by lack of comparability of study methods, data analysis, and reporting. There is a need to establish consensus guidelines for conducting, analyzing, and reporting neurodevelopmental environmental epidemiologic studies, while recognizing that consistency is likewise needed for epidemiology studies examining other health outcomes. This paper proposes a set of considerations to be used by the scientific community at-large as a tool for systematically evaluating the quality of proposed and/or published studies in terms of their value for weight-of-evidence assessments. Particular emphasis is placed on evaluating the sensitivity and specificity of neurodevelopmental function tests, as these characteristics directly affect the risk of false positive and false negative decisions at the level of the individual, thus influencing the risk of incorrect conclusions at the level of study findings. The proposed considerations are the first step in what must be a larger consensus-based process and can serve to catalyze such a discussion. Achieving consensus in these types of endeavors is difficult; however, opportunities exist for further interdisciplinary discussion, collaboration, and research that will help realize this goal. Broad acceptance and application of such an approach can facilitate the expanded use of environmental epidemiology studies of potential neurodevelopmental toxicants in the protection of public health, and specifically children's health