Degradation of carbon disulphide (CS₂) in soils and groundwater from a CS_{2 -}contaminated site

This study is the first investigation of biodegradation of carbon disulphide (CS2) in soil that provides estimates of degradation rates and identifies intermediate degradation products and carbon isotope signatures of degradation. Microcosm studies were undertaken under anaerobic conditions using soil and groundwater recovered from CS2-contaminated sites. Proposed degradation mechanisms were validated using equilibrium speciation modelling of concentrations and carbon isotope ratios. A first-order degradation rate constant of 1. 25 × 10-2 h-1 was obtained for biological degradation with soil. Carbonyl sulphide (COS) and hydrogen sulphide (H2S) were found to be intermediates of degradation, but did not accumulate in vials. A 13C/12C enrichment factor of -7. 5 ± 0. 8 ‰ was obtained for degradation within microcosms with both soil and groundwater whereas a 13C/12C enrichment factor of -23. 0 ± 2. 1 ‰ was obtained for degradation with site groundwater alone. It can be concluded that biological degradation of both CS2-contaminated soil and groundwater is likely to occur in the field suggesting that natural attenuation may be an appropriate remedial tool at some sites. The presence of biodegradation by-products including COS and H2S indicates that biodegradation of CS2 is occurring and stable carbon isotopes are a promising tool to quantify CS2 degradation

BURNING OF OILED LOUISIANA COASTAL MARSH: FIELD EVALUATION

ABSTRACT Burning was evaluated as a method of remediating oiled Louisiana Spartina alterniflora salt marsh. A short-term reduction in plant biomass was observed; however, 1 year after burning, plant biomass was the same as in control plots. A comparison of the normal alkane profile in the soil residue following oiling to preburn oil showed a loss of more volatile hydrocarbons. Similar patterns were observed for aromatic hydrocarbons. More than half the aromatic hydrocarbons detected in the plume were derived from unburned hydrocarbons. Carbonyl sulfide and carbon disulfide were the main sulfur gases found in the smoke plume.</jats:p