John J. Beauchamp

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A frequent assumption in environmental risk assessment is that the underlying distribution of an analyte concentration is lognormal. However, the distribution of a random variable whose log has a t-distribution has infinite mean. Because of the proximity of the standard normal and t-distribution, this suggests that a distribution such as the gamma or(More)
Many potentially hazardous organic compounds associated with synthetic-fuel production possess physicochemical properties that suggest a high potential for bioconcentration in aquatic organisms. Some of these compounds have been found to be metabolized by fish and other aquatic organisms. In this study, the bioconcentration of four polycyclic bases, or(More)
Microbial abundance, activity, and community-level physiological profiles (CLPP) were examined at centimeter and meter scales in the subsurface environment at a site near Oyster, VA. At the centimeter scale, variations in aerobic culturable heterotrophs (ACH) and glucose mineralization rates (GMR) were highest in the water table zone, indicating that water(More)
After lentectomy of the adult newt eye, non-dividing iris epithelial cells re-enter the cell cycle. Some of the iris epithelial cells become completely depigmented while they are in the cell cycle, and then differentiate into lens cells. The remaining iris epithelial cells become partially depigmented in the induced cell cycle, but resynthesize melanosomes(More)
ACKNOWLEDGMENTS The authors would like to thank Ron Mellot and Rob Pastorok of PTI Environmental Services for their assistance in providing unpublished validation data. In addition, this report has benefitted from the review and comments of Sylvia Talmage and Chris Welsh. v PREFACE While considerable data are available concerning chemical concentrations in(More)
Lithium (Li) is the lightest metal and occurs primarily in stable minerals and salts. Concentrations of Li in surface water are typically <0.04 mg l(-1) but can be elevated in contaminated streams. Because of the general lack of information concerning the toxicity of Li to common toxicity test organisms, we evaluated the toxicity of Li to Pimephales(More)