James C. McFarlane

Adsorption and desorption of benzene in two soils and montmorillonite clay.

Research report: The adsorption, desorption, and possible degradation of benzene in two silty clay loam soils and montmorillonite clay saturated with either aluminum or calcium ions were studied. With benzene concentrations in water of 10, 100, and 1000 ppb, it was found that sorption was minimal for the soils and the calcium-saturated clay. Benzene sorption on the aluminum-saturated clay was seven times greater than on the soils and three times greater than on the calcium-laden clay. Once sorbed, benzene tends to resist desorption. The most likely route of benzene loss from soils appears to be volatilization. (6 graphs, 11 references, 4 tables)

Influence of root exposure concentration on the fate of nitrobenzene in soybean

Abstract The influence of exposure concentration on the physical and chemical fate of nitrobenzene was studied by providing 0.02, 0.2, 2.0 and 100 μg/ml to roots of intact soybean plants. The results of this study illustrate how plants may govern the physical and chemical fate of environmental pollutants, and emphasize the importance of plants as a vector for foodchain contamination even when biomagnification does not occur.

Metabolism of 2-chlorobiphenyl by suspension cultures of Paul's Scarlet rose

Several studies have shown that plant-soil systems were capable of degrading chlorinated biphenyls, with the resulting accumulation of breakdown products in both the plants and the soil. However, since these studies were performed under field conditions, it is not certain what portion of the degradation was due to plant metabolism and what portion to that of soil microbes which have been demonstrated in pure culture to degrade chlorinated biphenyls. This question is addressed in the present research by determining the metabolism of (/sup 14/C)-labeled 2-chlorobiphenyl provided aseptically to axenic cultures of Pauls Scarlet rose.

PHYTOTOX: a database dealing with the effect of organic chemicals on terrestrial vascular plants

Description de PHYTOTOX, banque de donnees relative aux effets des composes organiques sur les plantes et leurs ecosystemes. PHYTOTOX comporte deux fichiers: un fichier bibliographique des articles publies sur cette question et un fichier des informations primaires extraites de la litterature

Sorption of carbon tetrachloride, ethylene dibromide, and trichloroethylene on soil and clay

The sorption of carbon tetrachloride, ethylene dibromide, and trichloroethylene in two silty clay loam soils and aluminium (Al3+) or calcium (Ca2+) saturated montmorillonite clay was studied. When the adsorbents were exposed to environmental levels of these chemicals (10 to 1000 ppb in water) the amounts of each of the chemicals sorbed were 6% or less of that available except for a 17% sorption of trichloroethylene by Al-saturated clay. In the case of the Ca-saturated clay, there was no apparent sorption of carbon tetrachloride or trichloroethylene. When soil sorption was normalized based on the soil organic carbon content (Koc) a correlation was found between the Koc, water solubility, and octanol/water partitioning coefficients of the chemicals. However, carbon tetrachloride did not behave according to with the predicted relationships.

Atmospheric benzene depletion by soil microorganisms

Gaseous benzene was rapidly depleted in exposure chambers containing viable soils and plants. When separate components of the system were analyzed, no benzene was detected in soils, plants, or water. Soil microorganisms were shown to be responsible for metabolizing benzene, yielding CO2 as the main product. The rates were sufficiently rapid to suggest that this reaction forms a major pathway for the elimination of benzene from the environment.

Uptake of bromacil by isolated barley roots.

A study of bromacil uptake by excised barley (Hordeum vulgare) roots was used to evaluate this procedure as a tool to learn the uptake characteristics of toxic organic chemicals. Bromacil uptake was shown to be a passive process with an uptake rate (at 0.8 mg l-1) of 0.64 μg bromacil g-1 fresh root hr-1. A Q10 for the process was determined to be 1.5 and living roots were required for bromacil uptake. This procedure was judged to be a quick and inexpensive method to screen plant uptake of toxic chemicals.

Elemental tritium analysis by bio-oxidation.

A procedure for the quantitative analysis of elemental tritium is presented. This method includes the biological oxidation of elemental hydrogen by ubiquitous soil microorganisms and distillation of the water and liquid scintillation analysis of the tritium activity. This analytical procedure is useful primarily in experimental work where verification of the concentration of an HT source or dose is needed. Universal availability of the needed equipment is a major advantage.