FECAL‐INDICATOR BACTERIA IN STREAMS ALONG A GRADIENT OF RESIDENTIAL DEVELOPMENT¹

Abstract

Fecal‐indicator bacteria were sampled at 14 stream sites in Anchorage, Alaska, USA, as part of a study to determine the effects of urbanization on water quality. Population density in the subbasins sampled ranged from zero to 1,750 persons per square kilometer. Higher concentrations of fecal‐coliform, E. coli, and enterococci bacteria were measured at the most urbanized sites. Although fecal‐indicator bacteria concentrations were higher in summer than in winter, seasonal differences in bacteria concentrations generally were not significant. Areas served by sewer systems had significantly higher fecal‐indicator bacteria concentrations than did areas served by septic systems. The areas served by sewer systems also had storm drains that discharged directly to the streams, whereas storm sewers were not present in the areas served by septic systems. Fecal‐indicator bacteria concentrations were highly variable over a two‐day period of stable streamflow, which may have implications for testing of compliance to water‐quality standards.

Urban Influences on Stream Chemistry and Biology in the Big Brushy Creek Watershed, South Carolina

“…In urban areas, the combination of extensive impervious surface cover and high density of storm drains promote the rapid flushing of bacteria from lawns, roads, and other surfaces into streams (Frenzel & Couvillion, 2002;Mallin et al, 2000). However, we have documented high concentrations of E. coli and total coliforms under baseflow, rather than storm flow, conditions.…”

“…Similar results have been found by studies in other regions. For example, Frenzel and Couvillion (2002) found that concentrations of E. coli, fecal coliforms, and enterococci were higher in stream sub-basins with higher human population densities in and near Anchorage, Alaska. Similarly, Mallin, Williams, Esham, and Lowe (2000) found that fecal coliform abundance correlated positively with human population density, percentage of developed land, and percentage of impervious surface in five tidal creek basins in North Carolina.…”

“…Increased nutrient loading to streams could stimulate algal (and therefore secondary) productivity, although this response depends in part on other factors such as shading by riparian vegetation, turbidity, stability of streambed sediments, and pollutant levels (Paul & Meyer, 2001). Finally, bacterial abundances, especially of coliform bacteria, can be high in urban streams, possibly due to leaking or overflowing sanitary sewers (Duda, Lenat, & Penrose, 1982), runoff from impervious surfaces and lawns (Young & Thackston, 1999), or discharges from storm sewer drains (Frenzel & Couvillion, 2002). Although often peaking during storm events, bacterial abundances also may be high under baseflow conditions (Duda et al, 1982;Young & Thackston, 1999).…”

Spatial water quality assessment of Langat River Basin (Malaysia) using environmetric techniques

“…The positive correlation of NO − 3 and agricultural land in the HPS region (located downstream) is consistent with many others studies (Hill 1978;Neill 1989;Johnson and Gage 1997;Tufford et al 1998). There are also weak positive and negative loadings on T, and E. coli temperature is most possibly related to seasonal effects, while E. coli is strongly related to municipal sewage and wastewater treatment plants (Frenzel and Couvillion 2002) are due to agricultural runoff such as livestock waste and fertilizers (Buck et al 2003), industrial effluents, municipal sewage, and existing sewage treatment plants because PO 3− 4 is an important component of detergents (Vega et al 1998). VF6 explains 4.9% of the total variance and has strong positive loading on coliform, while VF7 explained 5.8% of the total variance with strong loading on COD.…”

Local calibration of coliforms parameters of water quality problem at Igapó I Lake, Londrina, Paraná, Brazil

“…Fecal coliforms bacteria are found in the intestinal tract of humans and other hot-blooded animals. Although fecal coliform bacteria are not necessarily dangerous to men, their high concentrations in water bodies indicate hazards for the human health 1 . Thus, the monitoring of such concentrations consists of a method to identify contamination magnitude, and a very well calibrated mathematical model may be used to describe such pollution.…”