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The phytotoxicity and degradation of diesel hydrocarbons in soil
Author(s) -
Siddiqui Samina,
Adams W. A.,
Schollion John
Publication year - 2001
Publication title -
journal of plant nutrition and soil science
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.644
H-Index - 87
eISSN - 1522-2624
pISSN - 1436-8730
DOI - 10.1002/1522-2624(200112)164:6<631::aid-jpln631>3.0.co;2-e
Subject(s) - population , respiration , diesel fuel , soil respiration , chemistry , soil water , hydrocarbon , soil contamination , germination , phytotoxicity , environmental chemistry , horticulture , botany , agronomy , zoology , biology , ecology , demography , organic chemistry , sociology
Hydrocarbon contamination in soils may be toxic to plants and soil microorganisms and act as a source of groundwater contamination. The objective of the study was to evaluate the fate of adding diesel in soil with no previous history of hydrocarbon contamination. Particular aspects examined were soil respiration, changes in microbial population, breakdown of diesel hydrocarbon and phytotoxicity to germination of ryegrass. Soil respiration was measured as evolved CO 2 . Bacterial population was determined as Colony Forming Units (CFUs) in dilution plates, and fungal activity was measured as hyphal length. The fate of individual hydrocarbons was determined by GC‐MS after extraction with dichloromethane. When 0.64 % (w/w) of diesel was added to soil, the respiration response showed a lag phase of 2 days and maximum respiration occurred at day 7. The lag phase was 5 days and maximum respiration occurred at day 11 in soil after adding 1.6 %, 4.0 %, and 13.6 % of diesel (w/w). After the peak, respiration decreased up to 20 days, in each of the four levels of diesel addition to the soil. Thereafter, respiration becomes more or less constant but substantially greater than the control. Diesel addition up to 4.0 % (w/w) increased the bacterial population to 10 fold but fungal hyphal length did not increase. However, bacterial population did not increase after adding 13.6 % (w/w) of diesel and fungal hyphal length was significantly less than the control and other three levels of diesel. Removal of inhibition to germination of perennial ryegrass was linked to the decomposition of n ‐C 10 and n ‐C 11 hydrocarbons and took from 11 to 30 days depending on the levels of diesel added to the soil. Contamination with 13.6 % (w/w) of diesel inhibited the germination of perennial ryegrass until 24 weeks of incubation.