Mineralization and volatilization of polychlorinated biphenyls in sludge-amended soils
Polychlorinated biphenyls (PCBs) are toxic organics of concern limiting the reuse of sewage sludge on agricultural lands. The mineralization and volatilization of PCBs (/sup 14/C-Aroclor 1254) were monitored for 240 d in three calcareous soils, amended or unamended with sewage sludge. Two first-order rate constants were used to describe both processes and to compare treatment effects of sludge addition, PCB concentration (5, 50, 500 mg/kg), soil textural class, and length of sludge incubation with soils prior to experimentation. Total loss of PCBs ranged from 8 to 33%. Fifty and 95% disappearance times range from 2.5 to 5.9 yr and 6.1 to 26.3 yr, respectively. Treatment effects on total loss closely paralleled those of volatilization. Volatilization of organics ranged from 5 to 31%, and was the major means of loss of /sup 14/C in unamended soils and all 500 mg PCB/kg treatments. Volatilization, and thus environmental transport, was decreased by sludge addition. Exposure of the soil to sludge prior to experimentation had no effect on volatilization when compared to fresh sludge additions. Carbon-14-organic volatile loss was greater in two sandy loams than in a clay soil. Comparing PCB concentrations, volatilization was generally greatest at 50 mg/kg and least at 500 mg/kg, with comparatively smaller differences between 5 and 50 mg/kg. Degradation of /sup 14/C-Aroclor 1254 to /sup 14/CO/sub 2/ ranged from 1 to 11%. Overall, /sup 14/CO/sub 2/ evolution, and thus detoxification increased with sewage sludge addition and decreased with increasing PCB concentration. Mineralization exceeded volatilization in sludge-amended soils at 5 mg PCBs/kg.
- Research Organization:
- New Mexico State Univ., Las Cruces
- OSTI ID:
- 5967491
- Journal Information:
- J. Environ. Qual.; (United States), Journal Name: J. Environ. Qual.; (United States) Vol. 16:1; ISSN JEVQA
- Country of Publication:
- United States
- Language:
- English
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54 ENVIRONMENTAL SCIENCES
AROMATICS
CARBON 14 COMPOUNDS
CARBON COMPOUNDS
CARBON DIOXIDE
CARBON OXIDES
CHALCOGENIDES
CHLORINATED AROMATIC HYDROCARBONS
CONTAMINATION
ECOLOGICAL CONCENTRATION
ENVIRONMENTAL EFFECTS
HALOGENATED AROMATIC HYDROCARBONS
ISOTOPE APPLICATIONS
LABELLED COMPOUNDS
MINERALIZATION
ORGANIC CHLORINE COMPOUNDS
ORGANIC COMPOUNDS
ORGANIC HALOGEN COMPOUNDS
OXIDES
OXYGEN COMPOUNDS
SEWAGE
SEWAGE SLUDGE
SLUDGES
SOILS
TRACER TECHNIQUES
VOLATILITY
WASTES