Reviews of Radiological Environmental Programs (1988 - 1991)
In 1989, Greg Dempsey of the EPA conducted a 3-day review of the radiological environmental program at SSFL. Mr. Dempsey's review report was critical of certain aspects of the program and is provided below. In addition Mr. Dempsey reported on a variety of on-site and off-site sample results in the second report below.
Subsequently, Rocketdyne commissioned two additional independent reviews. These reviews provided a more balanced assessment and took issue with some of the criticisms of the Dempsey report. Neverthelesss they also made some recommendations for improvements. These two reports are provided below.
In 1991, Rocketdyne documented these reviews and described (1) corrective actions that addressed areas of improvement, and (2) provided rebuttal to invalid criticisms. This report is provided below.
Several of the more widely publicised criticisms are addressed below.
- Soil is sampled for gross alpha and gross beta radioactivity - While Rocketdyne maintained that gross alpha and gross beta was a valid screening technique for determining whether environmental contamination existed in soil, the company nevertheless committed to conduct isotope-specific analysis for all future soil samples. No gross alpha or gross beta analysis of soil samples has been conducted at SSFL since 1989. It is interesting to point out that the EPA themselved conducted gross alpha and gross beta analysis of soil samples in Bell Canyon in 1998. It is further interesting to note that the EPA relies on gross alpha and gross beta analysis for its principal drinking water screening analyses, presumably trusted these techniques to adequately protect the nations drinking water supply.
- Vegetation is washed to "remove contamination" - The objective of vegetation analysis is to determine if any potential sub-surface soil contamination is taken up by the root structure. The objective is not to measure potential airborne fallout ... surface soil sampling was performed to measure potential airborne fallout. Attempting to measure potential airborne fallout from that quantity deposited on the surfaces of leaves would be an extremely unreliably method, given the propensity for such contamination to be either washed off by rainfall or blown off by wind. Therefore washing was very appropriate given the objective. With few exceptions, Rocketdyne ceased widescale vegetation sampling in 1989.
- Soil and vegetation samples are heated to high temperature to "volatalize the contaminants" - Rocketdyne was following established laboratory protocols. Heating of soil and vegetation samples is required since "activity per dry weight" is the conventional way of reporting sample results. This ensures a consistent measurement baseline that would be impossible with soil and vegetation samples of varying moisture content. Literature and subsequent experimentation demonstrated that volatalization of cesium compounds only occurs at more than twice the temperature to which soil samples were heated. Nevertheless Rocketdyne has not heated soil samples since 1989, and sends most samples to off-site state certified laboratories.