TABLE 3.
Soil samples used in this study
| Site | Description | Mean ± SD
|
||
|---|---|---|---|---|
| TPHa (mg kg−1) | DNAb (μg) | DNA recoveryc (%) | ||
| SC | Fuel oil contaminated soil obtained from an oil storage tank yard in Shizuoka | 15,000 ± 3,500 | 4.9 ± 0.8 | 24 ± 3.2 |
| SN | Uncontaminated soil obtained from a site proximate to the SC soil sampling site | BDLd | 4.1 ± 0.2 | 31 ± 5.7 |
| TH | Coal and oil sludge dumping site in Aichi | 2,900 ± 700 | 2.0 ± 0.3 | 19 ± 4.0 |
| SS | Heavy fuel oil-contaminated soil obtained from an oil storage tank yard in Fukuoka | 44,000 ± 5,200 | 0.9 ± 0.1 | 18 ± 5.2 |
| KM | Uncontaminated garden soil in Kamaishi | BDLd | 8.0 ± 1.8 | 34 ± 3.8 |
a
TPH, total petroleum hydrocarbon (lower detection limit, 50 mg kg−1) determined by the infrared method by using an OCMA-350 TPH analyzer (Horiba) after extraction with solvent CFC-316 (Horiba) (n = 3).
b
That is, the amount of DNA extracted from 0.5 g (wet weight) of soil as quantified by comparing the band intensity with the intensity of bands of the molecular size markers (n = 3).
c
As estimated by the recovery of the phc gene (37) introduced into soil prior to DNA extraction (n = 3).
d
BDL, below detection limit.