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Posts Tagged ‘DOD’

Reducing Errors through Multi-Increment Sampling

Wednesday, August 18th, 2010

By Gregory Salata, Ph.D.

Multi-Increment Sampling

The objective of environmental sampling is to quantify contamination at a given location. In situations where sample collection may result in discrete samples of a heterogeneous nature, results may be biased based on the particle size of each sub-aliquot collected at the site. One option to help reduce the errors associated with non-uniform sample composition is to use multi-increment sampling (MIS) to create a representative, homogeneous aliquot for analysis of analytes.


Highly Anticipated Perchlorate Report Released

Friday, February 4th, 2005

Highly Anticipated Perchlorate Report ReleasedOn Tuesday, January 11, 2005 the Committee to Access the Health Implications of Perchlorate Ingestion, convened by the National Research Council at the request of the EPA, DOD, NASA, and the DOE, released their report on the adverse health effects of perchlorate ingestion from clinical, toxicological and public health perspectives. The report also evaluated relevant scientific literature and key findings of the EPA’s 2002 draft risk assessment document on perchlorate. The full report can be found online here.

The committee noted that a no observed-effect level (NOEL) or lowest observed-adverse-effect level (LOAEL) identified from a critical study, is used as the basis for establishing a reference dose for daily oral exposures. The committee decided to use a NOEL rather than a LOAEL as the basis for perchlorate risk assessment. They based their reference daily dose on the identified critical study done by Greer, et al (2002)1 in which healthy men and women were given doses of perchlorate of 0.007 to 0.5 mg/Kg body weight per day for 14 days. In this study, the NOEL was found to be 0.007 mg/Kg/day. Using this amount and applying an uncertainty factor of 10 to protect the most sensitive population (identifi ed as pregnant women who may have hypothyroidism or iodide deficiency), the committee recommended a reference daily dose of perchlorate of 0.0007 mg/Kg of body weight per day from all sources. The EPA’s draft reference daily dose from the 2002 risk assessment was 0.00003 mg/Kg per day. The committee also noted that additional studies are needed, especially long-term, chronic exposure as well as clinical, mechanistic and epidemiological studies.