Toxicity reference value

The biomagnification LOE involves determining concentrations of contaminants such as DDT, PCBs, dioxins, TBT, and methyl mercury in benthic invertebrates or fish. This LOE only applies to those few organic contaminants that actually biomagnify. Concentrations are compared to reference areas or literature-based toxicity reference values (TRVs) and assessed via food chain bioaccumulation models (Grapentine et ah, 2002). 

Maintenance of bottom fish and marine mollusk communities. Bioaccumulation in the marine food chain will not result in unacceptable tissue COPC concentrations. Measure COPC concentrations in tissue samples and compare to literature-based toxicity reference values. 

TBT concentration < ambient water quality criterion (0.001 jig/L) E TBT concentration > ambient water quality criterion (0.001 jig/L) TBT concentration > toxicity reference value (1 jig/L)... 

These criteria are selected by the Office of the Army Surgeon General as the most appropriate oral toxicity reference values for use in environmental risk assessments, and represent the Army s position (Opresko etal, 2001). The RfDg values have been input to USEPA risk models along with accepted chronic vapor exposure limits (as cited in Watson and Dolislager, 2007) to generate agent-specific... 

The risk quotient (RQ) for each combination of contaminant and receptor (plant or animal) of concern is calculated by dividing the estimated environmental concentration (EEC) by the toxicity reference value (TRY) ... 

Dyer SD, White-Hull CE, Shephard BK. 2000. Assessments of chemical mixtures via toxicity reference values overpredict hazard to Ohio fish communities. Environ Sci Technol 34 2518-2524. 

ENSR International Inc. and Parametrix, Derivation of Toxicity Reference Values for the Acute and Chronic Toxicity of Hexahydro-l,35-trinitro-l,3,5-triazine (RDX) to Marine Aquatic Organisms, Final Report, U.S. Army Public Works, ENSR Project No. 09000-279-400, Redmond, WA, USA, 2005. 

Terrestrial wildlife movements are such that site-specific tools are more efficiently used to refine exposure estimate. In this case, site-specific exposure estimates are used and compared with safe thresholds for toxicity, termed toxicity reference values (TRVs). Toxicity reference values for wildlife have been developed for energetic compounds. This chapter presents a brief overview of the processes used to establish these tools for ERA for explosives and related soil contaminants that are frequently of potential ecological concern at the affected military sites. This chapter also provides recommendations for use of these values in the ERA process. Investigations addressing the importance and extent of habitat disturbance as a component of the ERA process on explosives-contaminated ranges are reviewed in Chapter 11. General bioaccumulation principles and applications of the bioaccumulation factor and bioconcentration factor (BAF and BCF, respectively) concepts that are often employed in the ERA process to determine bioaccumulation potential of MC for terrestrial receptors are reviewed in Chapter 10. 

ERA process are also being applied in the ongoing Operational Range Assessment Program carried out by the DoD in order to assess risks of MC migration beyond installation boundaries. Eco-SSLs have been developed by the USEPA to facilitate initial screening of contaminated soils at Superfund sites. Future Eco-SSL development will include additional selected MC. Other ERA tools include the derivation of toxicity reference values (TRVs) for wildlife and empirically derived bioaccumulation models. 

United States Army Center for Health Promotion and Preventive Medicine (USACHPPM), Standard Practice for Wildlife Toxicity Reference Values, Technical Guide 254, U.S. Army Center for Health Promotion and Preventive Medicine, Aberdeen Proving Ground, MD, USA, 2000. 

Mineau, P., Baril, A., CoiIin.s. B. T.. Duffe, J., Joerman. G., and Luttik, R. (2001). Pe.sticide acute toxicity reference values for birds. Jfer. Environ. Contam. Toxicol. 170, 13-74. 

Kannan, K., Blankenship, A.L., Jones, P.D., and Giesy, J.P. (2000) Toxicity reference values for the toxic effects of polychlorinated biphenyls to aquatic mammals. Human Ecol. Risk Assess., 6,181—201. 

Sanchez-Bayo F (2006) Comparative acute toxicity of organic pollutants and reference values for crustaceans. I. Branchiopoda, Copepoda and Ostracoda. Environ Pollut 139 (3) 385 120... 

Acute toxicity refers to effects that occur within a brief time after a short-term exposure, such as a simple oral administration. The generally low acute oral toxicity of colorants is well-established [78-81]. This is normally expressed in terms of the LD50 value, a... 

Threshold limit value (TLV) American Conference of Governmental Industrial Hygienists No official standing widely used by industry Toxicity reference dose (RfD) Environmental Protection Agency Official regulatory... 

The US-EPA has concluded that in many cases, concerns regarding pre- and postnatal toxicity can be addressed by calculating an RfD by using pre- or postnatal developmental endpoints and applying the UFs (interspecies (Section 5.3), intraspecies (Section 5.4), LOAEL-to-NOAEL (Section 5.7), subchronic-to-chronic (Section 5.6), and database-deficiency (Section 5.9)) to account for deficiencies in the toxicity data when there are gaps considered essential for setting a reference value, including lack of data on children (US-EPA 2002). 

The overlap of areas covered by the FQPA factor and those addressed by the traditional UFs was recognized, and it was concluded that the current UFs, if appropriately applied using the approaches recommended in the review (i.e., US-EPA 2002), will be adequate in most cases to cover concerns and uncertainties regarding the potential for pre- and postnatal toxicity and the completeness of the toxicology database. In other words, an additional UF is not needed in the RfC/RfD methodology because the currently available factors are considered sufficient to account for uncertainties in the database from which the reference values are derived (and it does not exclude the possibility that these UFs may be decreased or increased from the default value of 10). 

Default Reference Values for Body Weights in Oral and Inhalation Toxicity Studies... 

The bacterial Microtox tests and the other in vitro bioassays clearly indicated differences in sediment toxicity between locations (Table 7). In the Microtox SP assay inhibitory effects were found in sediment extracts from the Port of Amsterdam transect (i.e. TU values greater than 20 at sites 7 and 11). The highest response in the Mutatox assay was found at Oranjesluis (site 11) in the Port of Amsterdam. The reference values from the Mutatox assay at this site were below... 

Considerations for the acceptability of the are similar to those for the uncertainty factor used to calculate the RfD, RfC or other reference values from the NOAEL or BMD. The has been calculated from reproductive toxicity data for several chemicals. Examples include dinoseb (US EPA, 1986), lithium (Moore, 1995) and boric acid and borax (Moore, 1997). In the case of dinoseb, the MOEs were very low, in some cases less than one, indicating toxicity in the animal studies at levels to which people are exposed. This information on dinoseb led to an emergency suspension of use of this pesticide in the USA in 1986 and ultimately led to its removal from the market (Kimmel Kimmel, 1994,1996). 

The biomonitoring data presented in each of the national exposure reports include descriptive statistics on the distribution of blood or urine concentrations of each chemical, including geometric means and percentiles with confidence intervals (CDC 2003). Each report also includes brief toxicity profiles and information relating the findings to biological exposure indices and European reference values or ranges, if available. Additionally, the raw data from the reports are publicly available and serve as a valuable resource. 

Toxic unit summation Point extimates on Toxicological reference values for... 

The issues of method validation and assessment of measurement uncertainty in the determination of potentially toxic trace elements in rice are of permanent interest for the scientific community. In this context, the sources of uncertainty associated with the determination of Cd, Cu, Pb, and Zn have been recently estimated in rice through an interlaboratory comparison [30]. Four Brazilian laboratories participated in the proficiency test. The analytical technique used were FAAS, ET-AAS, and ICP-AES. The rice samples were supplied by the Institute for Reference Materials and Measurements (IRMM), Joint Research Center of the European Commission, within the scope of the interlaboratory comparison International Measurement Evaluation Programme (IMEP) 19 Trace Elements in Rice (see also Chapter 7 in this book). Three out of the four laboratories reported values close to the reference values. It was emphasized that, in order to establish a reliable uncertainty budget, all significant sources of uncertainty should be identified. 

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