Exposure analysis occurrence data

Exposure data and other information on an agent under consideration are also reviewed. In the sections on chemical and physical properties, on analysis, on production and use and on occurrence, published and unpublished sources of information may be considered. 

Recently, some models have been derived to analyze the occurrence of interactive joint action in binary single-species toxicity experiments (Jonker 2003). Such detailed analysis models are well equipped to serve as null models for a precision analysis of experimental data, next to the generalized use of concentration addition and response addition as alternative null models. However, in our opinion these models are not applicable to quantitatively predict the combined toxicity of mixtures with a complexity that is prevalent in a contaminated environment, because the parameters of such models are typically not known. Recently a hazard index (Hertzberg and Teus-chler 2002) was developed for human risk assessment for exposure to multiple chemicals. Based on a weight-of-evidence approach, this index can be equipped with an option to adjust the index value for possible interactions between toxicants. It seems plausible that a comparable kind of technique could be applied in ecotoxicological risk assessments of mixtures for single species. However, at present, the widespread application of this approach is prevented by lack of available information. 

Tools should be developed to support the identification of mixture exposure situations that may cause unexpectedly high risks compared to the standard null models of concentration addition and response addition, for example, based on an analysis of food consumption and behavioral patterns, and the occurrence of common mixture combinations that cause synergistic effects. Criteria should be developed for the inclusion of interaction data in mixture assessments. 

When evaluating data from the Harvey (1952) study, Johns (1952) reported on the occurrence of miosis in exposed individuals. Regression analysis of 150 observations, including 55 controls, indicated that the concentration at which a 50% decrease in pupil diameter would be attained was approximately 4.1 mg-min/m, with 90% confidence limits of about 2.7 and 5.7 mg-min/m. Johns (1952) defined mild miosis as a decrease of 1 to 2 mm in pupil diameter, which usually disappeared within 24 h. While mild miosis as defined above was observed in some subjects at the lowest Ct tested (Ct = 1.0 mg-min/m ), other subjects exhibited mean maximal pupil decreases of < 1 mm, indicating attainment of a response threshold at this level of exposure. Untreated controls exhibited a pupil diameter decrease of >0.33 mm Johns (1952) attributed this difference to observer bias and pointed out that there was still a relative difference between the control group and the exposed groups. 

AFL occurrence and concentration data, submitted from 22 European Union (EU) Member States for the European Food Safety Authority (EFSA) risk assessment requested by the European Commission (EC) in 2006, were available for this evaluation. Australia, Brazil, the Islamic Republic of Iran, Japan, Turkey, United Arab Emirates and the United States of America (USA) also submitted data on AFL contamination. In total, the Committee had access to over 100 000 data points for its analyses. Other data on contamination by these toxins have been taken from published literature, but they were not used to calculate dietary exposure because the disaggregated data were not available. Rather, they were used to reinforce the analysis made in the document. 

The SNL Compliance Metrics Department tabulates a set of Performance Indicators (Pis) for SNL/NM facilities and issues a quarterly report to track trends and provide data for analysis on these Pis. The Pis with particular applicability to HCF operations include personnel radiation exposures, low-level radioactive waste generation, reportable releases to the environment, DOE reportable occurrences, and Price Anderson Amendments Act violations. 

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