TABLE 5.
E. coli concentrations, fecal concentrations, and percentages of bovine-associated and human-associated fecal concentrations in watersheds with different land use patterns
| Land use type | Site name (flow) | E. coli concna (CFU/100 ml) | Real-time PCR assay result (mg/liter) for:
|
% Spiked plasmid recoveryb | % Recoveryc that was
|
|||
|---|---|---|---|---|---|---|---|---|
| AllBac | BoBac | HuBac | Attributable to bovines | Attributable to humans | ||||
| Pasture/rural housing | NS-1 (low flow) | 267 | 17.4 ± 8.5 | 2.3 ± 1.5 | 0.8 ± 0.7 | 77 ± 18 | 13 | 4 |
| NS-1 (high flow) | 17,800 | 100 ± 7.6 | 15.4 ± 8.9 | 19 ± 8.7 | 97 ± 1 | 15 | 19 | |
| NS-3 (low flow) | 60 | 5.6 ± 3.7 | 2.3 ± 3.1 | 1.2 ± 0.5 | 67 ± 19 | 41 | 21 | |
| NS-3 (high flow) | 39,600 | 452 ± 68 | 144 ± 33 | 37 ± 7.2 | 91 ± 4 | 32 | 8 | |
| Urban | U2 (low flow) | 1,967 | 70.9 ± 21 | 2.1 ± 1.5 | 14 ± 4.0 | 85 ± 42 | 3 | 21 |
| Resort/forest | R07 (low flow) | 600 | 17.7 ± 6.3 | NDd | 0.6 ± 0.3 | 63 ± 41 | ND | 3 |
| R20 (low flow) | 3,160 | 231 ± 1.7 | 1.2 ± 1.8 | 243 ± 62 | 113 ± 35 | 0.5 | 105 | |
a
Single-sample E. coli concentration.
b
Percent recovery = (sample spiked with 2.5 × 105 copies − measured copies in unspiked sample)/(2.5 × 105) × 100. The percent recovery was determined for each assay and then averaged.
c
Percent total = [concentration (mg/liter) of BoBac or HuBac/concentration (mg/liter) of AllBac] × 100.
d
ND, not detected in this sample.