To clarify the dissolution patterns of pathogenic microorganisms in rainwater runoff, a laboratory-simulated rainfall experiment was conducted to flush soil treated with earthworm castings. Propidium monoazide(PMA)combined with quantitative PCR(qPCR)was used to investigate changes in the abundance of viable fecal indicator bacteria(FIB). The results exhibited that after rainfall, the concentrations of electrical conductivity, ammonia, nitrate, and total phosphorus(TP)in the mixed soil matrix decreased by 51.34%, 45.20%, 99.09%, and 26.22%, respectively. In runoff water, the concentrations of ammonia, total phosphorus, and chemical oxygen demand(COD)exhibited a trend of initially rising and then falling, with peak values occurring within the first 15minutes. The qPCR quantification results for four fecal indicator bacteria—total coliforms(TC), fecal coliforms(FC), Escherichia coli(EC), and Enterococcus spp(ES)—also displayed a similar trend of increasing and then decreasing. A significant positive correlation was found between the PMA-qPCR results and the culture method(Spearman r=0.723, P<0.001). The fecal coliform counts in all runoff samples exceeded the limits specified in the "Surface Water Quality Standard"(40000CFU/L). The study indicates that viable pathogenic microorganisms can be washed into water bodies through rainfall and are widely dispersed during initial runoff, increasing the risk of their environmental transmission.
| 科 Family | 属数 Number of genus | 种数 Number of species | 占总种数比例 Percentage of total species (%) | 属 Genus | 种数 Number of species | 占总种数比例 Percentage of total species (%) |
|---|---|---|---|---|---|---|
| 鹅膏菌科Amanitaceae | 2 | 11 | 5.26 | 鹅膏菌属 Amanita | 10 | 4.78 |
| 小菇科 Mycenaceae | 2 | 12 | 5.74 | 丝盖伞属 Inocybe | 5 | 2.39 |
| 多孔菌科 Polyporaceae | 8 | 14 | 6.70 | 蜡蘑属 Laccaria | 5 | 2.39 |
| 红菇科 Russulaceae | 3 | 23 | 11.00 | 小皮伞属 Marasmius | 6 | 2.87 |
| 小菇属 Mycena | 11 | 5.26 | ||||
| 光柄菇属 Pluteus | 5 | 2.39 | ||||
| 红菇属 Russula | 17 | 8.13 | ||||
| 栓菌属 Trametes | 5 | 2.39 |