Aldrin and dieldrin: a reevaluation of the cancer and noncancer dose-response assessments.

The dose-response analyses of cancer and noncancer health effects of aldrin and dieldrin were evaluated using current methodology, including benchmark dose analysis and the current U.S. Environmental Protection Agency (U.S. EPA) guidance on body weight scaling and uncertainty factors. A literature review was performed to determine the most appropriate adverse effect endpoints. Using current methodology and information, the estimated reference dose values were 0.0001 and 0.00008 mg/kg-day for aldrin and dieldrin, respectively. The estimated cancer slope factors for aldrin and dieldrin were 3.4 and 7.0 (mg/kg-day)(-1), respectively (i.e., about 5- and 2.3-fold lower risk than the 1987 U.S. EPA assessments). Because aldrin and dieldrin are no longer used as pesticides in the United States, they are presumed to be a low priority for additional review by the U.S. EPA. However, because they are persistent and still detected in environmental samples, quantitative risk assessments based on the best available methods are required. Recent epidemiologic studies do not demonstrate a causal association between aldrin and dieldrin and human cancer risk. The proposed reevaluations suggest that these two compounds pose a lower human health risk than currently reported by the U.S. EPA.

Setting the research agenda on the health effects of chemicals.

In 2011, World Health Organization (WHO) scientists reported that a significant percentage of global deaths and disability-adjusted life years (DALYs) in 2004 could be attributed to chemicals. The 2011 review focused only on certain chemicals, however, and concluded that the global burden of disease was underestimated because of serious data gaps. While various chemical assessment documents have identified research needs for individual chemicals, a systematic review of such documents to identify research themes that could be applied to the multitude of chemicals for which there is little information has not been done. Even for chemicals for which there are considerable data, the information is not sufficient to make an estimate of the chemical's contribution to the burden of disease. The WHO Environmental Health Criteria (EHC) documents and Concise International Chemical Assessment Documents (CICADs) identify research needs or data gaps in our knowledge of chemicals. We identified several common themes in these documents and in documents prepared by WHO on 10 chemicals of major public health concern. These themes include biomarkers, longitudinal epidemiological studies, mechanisms of disease, reproductive and developmental effects and exposure assessment. Specific examples of data gaps culled from more than 300 WHO documents provide researchers with specific topics for further research.

Analyses of radiation and mesothelioma in the US Transuranium and Uranium Registries.

OBJECTIVES: We examined the relationship between radiation and excess deaths from mesothelioma among deceased nuclear workers who were part of the US Transuranium and Uranium Registries. METHODS: We performed univariate analysis with SAS Version 9.1 software. We conducted proportionate mortality ratio (PMR) and proportionate cancer mortality ratio (PCMR) analyses using the National Institute for Occupational Safety and Health Life Table Analysis System with the referent group being all deaths in the United States. RESULTS: We found a PMR of 62.40 (P < .05) and a PCMR of 46.92 (P < .05) for mesothelioma. PMRs for the 4 cumulative external radiation dose quartiles were 61.83, 57.43, 74.46, and 83.31. PCMRs were 36.16, 47.07, 51.35, and 67.73. The PMR and PCMR for trachea, bronchus, and lung cancer were not significantly elevated. CONCLUSIONS: The relationship between cumulative external radiation dose and the PMR and PCMR for mesothelioma suggests that external radiation at nuclear facilities is associated with an increased risk of mesothelioma. The lack of a significantly elevated PMR and PCMR for trachea, bronchus, and lung cancer suggests that asbestos did not confound this relationship.

A multi-year field olfactometry study near a concentrated animal feeding operation.

This study developed and tested a protocol for monitoring odors near a Concentrated Animal Feeding Operation (CAFO). The Nasal Ranger, a portable field olfactometry instrument, was used by a panel of trained individuals to conduct the monitoring near a swine CAFO. Monitors were selected based on olfactory sensitivity, scheduling availability, and lack of association with the CAFO or residential neighbors of the CAFO. Monitors were trained to use the Nasal Ranger, collect and record weather data, and characterize any odors detected. Data were collected over a 3-year period (2007-2009) for approximately 9 months each year. The data recorded included odor intensity, a description of the odor, date and time of the reading, and weather conditions. Of more than 50,000 readings, forty-one (0.1%) odor readings had a dilution to threshold ratio (D/T) of +/- 7:1 and were attributed to hog manure. The frequency of odor readings attributed to hog manure with D/T +/-7:1 was found to negatively correlate with log wind speed and positively correlate with wind from the direction of the farm. Other meteorological variables (temperature, precipitation, cloud cover) and time of day did not influence the frequency.