The role of biodegradation in limiting the accumulation of petroleum hydrocarbons in raingarden soils

The role of biodegradation in limiting the accumulation of petroleum hydrocarbons in raingarden soils

2012

Previous studies have indicated that raingardens are effective at removing petroleum hydrocarbons from stormwater. There are concerns, however, that petroleum hydrocarbons could accumulate in raingarden soil, potentially resulting in liability for the site owner. In this work, 75 soil samples were collected from 58 raingardens and 4 upland (i.e., control) sites in the Minneapolis, Minnesota area, representing a range of raingarden ages and catchment land uses. Total petroleum hydrocarbon (TPH) concentrations in the samples were quantified, as were 16S rRNA genes for Bacteria and two functional genes that encode for enzymes used in the degradation of petroleum hydrocarbons. TPH levels in all of the raingarden soil samples were low (<3 ?g/kg) and not significantly different from one another. The TPH concentration in raingarden soil samples was, however, significantly greater (p ? 0.002) than TPH levels in upland sites. In addition, the number of copies of Bacteria 16S rRNA genes and functional genes were greater in the raingardens planted with deeply-rooted natives and cultivars than in raingardens containing simply turf grass or mulch (p < 0.036), suggesting that planted raingardens may be better able to assimilate TPH inputs. The ability of microorganisms present in the soil samples to degrade a representative petroleum hydrocarbon (naphthalene) was also investigated in batch experiments. A sub-set of the field sites was selected for re-sampling, and all soil samples tested (n = 8) were able to mineralize naphthalene. In these experiments the initial mineralization rate correlated with the number of copies of Bacteria 16S rRNA genes present.

LeFevre, Gregory H.
Hozalski, Raymond M.

Also noted Lefevre, G. H.. Environmental Engineering Program, Dept. of Civil Engineering, U of M
Also noted Hozalski, R. M.. Environmental Engineering Program, Dept. of Civil Engineering, U of M

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Urban & Industrial Stormwater

raingarden
raingardens
rain garden
rain-garden
rain gardens
rain-gardens
raingardening
rain gardening
rain-gardening
biodegradable
biodegrades
biodegrade
biodegrading
Petroleum
stormwater
storm-water
storm water
Infiltration
infiltrate
infiltrates
infiltrating
urban & industrial stormwater
urban and industrial stormwater
urban and industrial storm water
urban and industrial storm-water
urban & industrial storm water
urban & industrial storm-water
storm water managment
stormwater management

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