Open AccessImpact of electrical cable insulating oil on the mineralisation of [1‐ 14 C]glucose in soil
Author(s) -
Reid Brian J.,
Lee Philip H.,
Macleod Christopher J.A.,
Morriss Alistair W.J.,
Patel Dax,
Semple Kirk T.
Publication year - 2000
Publication title -
fems microbiology letters
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.899
H-Index - 151
eISSN - 1574-6968
pISSN - 0378-1097
DOI - 10.1111/j.1574-6968.2000.tb08923.x
Subject(s) - mineralization (soil science) , zoology , mineral oil , soil respiration , soil water , chemistry , environmental science , soil science , biology , organic chemistry
Subsurface high voltage electric cables are commonly insulated using dodecylbenzene in combination with mineral oil. This work assessed the impact of increasing concentrations of cable insulating oil (0–10% dry weight) on soil microbial respiration as determined by mineralisation of [1‐ 14 C]glucose (11 μg C g −1 soil). Acute impact was assessed from 0 days to 21 days, and chronic impact was assessed after 300 days. This study found that cable insulating oil increased respiratory activity of soil microflora. The extent of impact was found to depend on both oil concentration and the length of oil–soil contact time. Following acute exposure (21‐days oil–soil contact time), it was found that oil concentrations up to 1% promoted a significant ( P <0.05 ) increase in the extent of [1‐ 14 C]glucose mineralisation to 14 CO 2 relative to the control. In contrast, higher concentrations of cable insulating oil (5% and 10%) promoted no significant ( P >0.05 ) increase in the extent of [1‐ 14 C]glucose mineralisation to 14 CO 2 relative to the control. Following chronic exposure (300‐days oil–soil contact time), the extent of mineralisation was greater at all oil concentrations applied relative to the control. For oil concentrations up to and including 1%, there was a decrease in the extent of elevation in mineralisation relative to the values after 21‐days exposure. At higher oil concentrations, namely 5% and 10%, the extent of elevation in mineralisation was comparable with that after 21‐days oil–soil contact time. We suggest that the increase in mineralisation of glucose indicates that cable insulating oil is a readily available carbon source to the carbon‐limited soil microflora.