TABLE 2.

Occurrence of Cryptosporidium PCR-positive samples by site

SiteLog turbidity (mean ± SD)Log E. coli count (mean ± SD)aCryptosporidium PCR positiveC. andersoni PCR positiveWildlife genotype PCR positive
RateIntensity (mean ± SD)bRateIntensity (mean ± SD)bRateIntensity (mean ± SD)b
Base flow
    Corbalis WTP0.86 ± 0.30NDc5/133.80 ± 1.305/133.00 ± 1.412/130.80 ± 1.30
    Potomac WFP0.76 ± 0.521.42 ± 0.925/133.40 ± 1.825/133.00 ± 2.002/130.40 ± 0.55
    Monocacy River0.54 ± 0.491.92 ± 0.707/134.43 ± 1.137/134.29 ± 1.111/130.44 ± 0.38
    North Fork Shenandoah River0.33 ± 0.25ND7/133.71 ± 1.386/133.14 ± 1.952/130.57 ± 1.13
    Great Seneca Creek0.60 ± 0.391.86 ± 0.463/122.00 ± 1.000/1203/122.00 ± 1.00
Storm flow
    Corbalis WTP1.28 ± 0.75ND4/65.00 ± 0.004/65.00 ± 0.000/60
    Potomac WFP1.59 ± 0.73ND5/73.80 ± 1.104/72.80 ± 2.282/71.10 ± 1.41
    Monocacy River1.21 ± 0.48ND6/65.00 ± 0.006/65.00 ± 0.000/60
    North Fork Shenandoah River1.05 ± 0.07ND3/44.67 ± 0.583/44.33 ± 1.151/40.33 ± 0.58
    Great Seneca Creek1.71 ± 0.46ND5/52.00 ± 0.711/50.20 ± 0.454/51.80 ± 1.10
  • a Number of colonies per 100 ml of sample.

  • b Number of PCR-positive replicates/5 PCR replicates for all positive samples.

  • c ND, not done.