TABLE 2.
Recovery of viable E. coli O157:H7 strain B6914 from leachate and soil during a preliminary experiment in which there was 8 h of rainfall at a rate of 1.65 cm h−1a
| Expt | Soil | Treatment
|
B6914 concn (log CFU g−1) | Vol (ml) | Wt (g) | Total amt (log CFU) | |
|---|---|---|---|---|---|---|---|
| Length of rainfall (h) | Soil depth (cm) | ||||||
| Recovery from hourly leachate samples | Sandy loamb | 1 | 3.682 (0.0000)c | 45 | 5.335 | ||
| 2 | 4.454 (0.0635) | 111 | 6.450 | ||||
| 3 | 5.456 (0.0513) | 100 | 7.456 | ||||
| 4 | 5.385 (0.0251) | 86 | 7.319 | ||||
| 5 | 5.454 (0.0251) | 72 | 7.312 | ||||
| 6 | 5.382 (0.0475) | 74 | 7.251 | ||||
| 7 | 5.334 (0.0000) | 86 | 7.269 | ||||
| 8 | 5.443 (0.0090) | 66 | 7.263 | ||||
| Drain overnight | 5.526 (0.0373) | 800 | 8.429 | ||||
| Silty clay loamd | 1 | 2.716 (0.3010) | 41 | 4.329 | |||
| 2 | 5.529 (0.0042) | 160 | 7.733 | ||||
| 3 | 5.793 (0.0023) | 120 | 7.872 | ||||
| 4 | 5.625 (0.0390) | 106 | 7.650 | ||||
| 5 | 5.672 (0.0236) | 112 | 7.721 | ||||
| 6 | 5.533 (0.0021) | 126 | 7.633 | ||||
| 7 | 5.641 (0.0057) | 146 | 7.805 | ||||
| 8 | 5.401 (0.0085) | 152 | 7.583 | ||||
| Drain overnight | 5.444 (0.0283) | 400 | 8.046 | ||||
| Recovery from different soil depths after overnight drainage | Sandy loame | 0 (manure) | 5.686 (0.0170) | 40 | 7.319 | ||
| 2 | 5.403 (0.0282) | 261 | 7.830 | ||||
| 4 | 5.148 (0.0229) | 293 | 7.690 | ||||
| 6 | 4.940 (0.1374) | 371 | 7.522 | ||||
| 8 | 4.773 (0.0121) | 332 | 7.330 | ||||
| 10 | 4.751 (0.0095) | 353 | 7.310 | ||||
| Silty clay loamf | 0 (manure) | 5.396 (0.1039) | 43 | 6.998 | |||
| 2 | 5.430 (0.0226) | 267 | 7.846 | ||||
| 4 | 5.024 (0.0152) | 348 | 7.491 | ||||
| 6 | 4.841 (0.0387) | 382 | 7.410 | ||||
| 8 | 4.320 (0.0000) | 360 | 6.841 | ||||
| 10 | 4.469 (0.0668) | 362 | 7.017 | ||||
The concentration of strain B6914 in the inoculum was 7.600 log CFU g−1. For the sandy loam soil the amount of B6914 recovered from the leachate and soil over a 24-h period was 15.37 times the amount inoculated, and for the silty clay loam soil the amount of B6914 recovered from the leachate and soil over a 24-h period was 16.01 times the amount inoculated.
The total amount of B6914 recovered from sandy loam soil in this experiment (concentration multiplied by volume of leachate) was 8.60 log CFU, and the ratio of the amount recovered to the amount inoculated was 10.00.
The values in parentheses are standard errors, which were calculated from the values for replicate plates prepared by using single soil cores.
The total amount of B6914 recovered from silty clay loam soil in this experiment (concentration multiplied by volume of leachate) was 8.68 log CFU, and the ratio of the amount recovered to the amount inoculated was 12.02.
The total amount of B6914 recovered from sandy loam soil in this experiment (concentration multiplied by soil weight) was 8.33 log CFU, and the ratio of the amount recovered to the amount inoculated was 5.37.
The total amount of B6914 recovered from silty clay loam soil in this experiment (concentration multiplied by soil weight) was 8.19 log CFU, and the ratio of the amount recovered to the amount inoculated was 3.89.