A. F. Yanders

Supercritical fluid extraction and cleanup procedures for determination of xenobiotics in biological samples.

Abstract Application of supercritical carbon dioxide for rapid extraction of various xenobiotics from biological tissue and fluid samples was investigated. The results obtained indicate that good recoveries (≥ 80%) can be readily obtained for all but polar solutes (k OW ≤ 2.5)

Application of supercritical fluid extraction of biological tissue samples for the determination of polychlorinated organics

Abstract The use of supercritical carbon dioxide as an extraction medium in the determination of polychlorinated organics was investigated. The extraction procedure was found to be highly efficient and reproducible.

Studies on the transport and transformation of PCBs in plants

Abstract The uptake of polychlorinated biphenyls (PCBs) from soil by terrestrial plants was investigated. The results revealed a lack of active transport of these compounds through the plant xylem system. No measurable evidence of metabolism of PCBs in plants was observed.

Persistence of Chlorinated Dioxins and Furans in the Soil Environment

Abstract The persistence of di- to octachloro dioxins and furans has been investigated in various soil environments. Over a 15-month period, measurable degradation — i.e., that leading to loss greater than the precision level of the analytical methodology — was found to occur only in the case of di- and trichloro congeners. The degradation of tetra through octachloro congeners was minimal. In the absence of a carrier co-pollutant, the mobility rates of chlorinated dioxins and furans are not significantly affected by the presence of co-pollutants such as pentachlorophenol and creosote components which are commonly present at wood treatment sites.

On Translocation of 2,3,7,8-tetrachlorodibenzo-p-dioxin: Time Dependent Analysis at the Times Beach Experimental Site

Abstract The rate of migration and loss of 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD) in contaminated soil has been studied under natural conditions in experimental plots at the Dioxin Research Facility, Times Beach, Missouri. The TCDD concentration profiles of sample cores taken at Times Beach in 1988 are virtually the same as those in cores taken in 1984. The data confirm our earlier work with soil columns exposed to simulated environmental conditions in the laboratory, and lead us to conclude that little movement and essentially no loss of TCDD has occurred in the experimental plots in the four years since the Dioxin Research Facility was established.

A multiple sample extraction and on-line system for the analysis of chlorinated compounds

Abstract A multiple sample extraction and on-line analysis for rapid determination of polychlorinated organics in complex matrices has been developed. The system is based on the direct coupling of supercritical fluid extraction with tandem supercritical fluid chromatography and gas chromatography. The on-line system permits the simultaneous extraction and analysis with high reproducibility and accuracy, while the overall methodology is considerably faster and less laborious than the conventional liquid extraction-based analytical procedures.

Mutagenicity in the vicinity of a lead smelter

The mutagenicity of the environment in the vicinity of a lead smelter was examined for 3 years by studies of changes in the frequencies of male germinal mutations of the waxy-C system of Zea mays and somatic mutations of the stamen hair system of Tradescantia. A transect was run at 0.3, 1.7, 3.2, 7.4, and 11.4 km predominantly downwind from the smelter. The mutagenic responses vary between years, within a year, and with distance. Mutation frequencies are both directional and nondirectional with distance. Concentrations of Pb, Cd, Cu, and Zn measured in soil samples show directional changes with distance each of the 3 years, and joint monotonicity is observed in some cases between mutation frequency with distance and metal concentrations with distance. Of a total of ten experiments with both Zea mays and Tradescantia, eight show significantly higher mutation frequencies at one or more locations close to the smelter than at locations more distant or at other controls.

Role of entrainers in supercritical fluid extraction of chlorinated aromatics from soils

Abstract The application of supercritical fluid technology holds considerable potential for removing toxicants from soil. The use of carbon dioxide at temperatures and pressures above its critical point was evaluated for removal of such contaminants as chlorinated pesticides, polychlorinated biphenyls and chlorinated phenols. Experiments were carried out to optimize the extraction parameters and define the role of entrainers under varied matrix conditions.

Effects of chemical smokes on flora and fauna under field and laboratory exposures

Various types of obscurant smokes are used routinely in training by the U.S. Army. Because continued routine use of the smokes could be detrimental to the native flora and fauna at training sites, a preliminary biological and chemical field study of fogoil, hexachloroethane, and tank diesel smokes was conducted. Smoke plumes were sampled and chemically analyzed at distances of 15-150 m from the smoke source where Tradescantia clones 4430 and 03 and the native plant Ambrosia dumosa and the native rodent Dipodomys merriami were exposed for 30 min. In addition, Tradescantia clone 4430 was exposed to tank diesel in the laboratory at concentration levels equivalent to exposure at 15 and 50 m. Tradescantia clones were examined for mutagenic effects indicated by micronuclei induction in developing pollen and pink somatic mutations in stamen hairs. Photosynthetic perturbations were measured in Tradescantia and A. dumosa using variable fluorescence induction. Animals were examined for sister chromatid exchanges and chromosome aberrations. It was found that all of the smokes tested exerted varying degrees of physiological and mutagenic effects in one or more assay system at one or more exposure distance. The studies reported here indicate that exposed ecological systems, or at least components of these systems, are at a higher risk than are unexposed components (e.g., organisms) for several types of damage attributed to obscurant smoke exposure.

Studies on uptake of PCBs by Hordeum vulgare (barley) and Lycopersicon esculentum (tomato)

Abstract The uptake of polychlorinated biphenyls (PCBs) from soil by barley and tomato plants was investigated. The results indicate a lack of active transport of these compounds. However, plants readily trap airborne PCBs escaping from soil, and a good correlation between vapor pressure of PCBs and their concentration in plant tissue was observed.