Contribution of combined sewer overflows to trace contaminant loads in urban streams

A Methodology to Model Environmental Preferences of EPT Taxa in the Machangara River Basin (Ecuador)

“…The sensitivity score ranges from one (for very tolerant taxa) to 10 (for the most sensitive families). The BMWP-Col, which is measured from one to 120, gives a five water quality classification in function of the sum of sensitive scores obtained in each location: bad (≤15), deficient (16)(17)(18)(19)(20)(21)(22)(23)(24)(25)(26)(27)(28)(29)(30)(31)(32)(33)(34)(35), moderate , good (61-99), very good (100-120) [33,35].…”

“…This is mainly due to some sewage networks and industrial pollution points that are discharging in certain locations along the river and its tributaries that are affecting the water quality of these streams [19,24]. Moreover, discharges from combined sewer overflows (CSOs) events, when wet-weather flows exceed the sewage treatment plant capacity, as well as the surface water outfalls (SWO), cause the degradation of physicochemical and biological quality [8,[25][26][27]. Similarly, pollution from agricultural and livestock runoffs transport polluted water into the rivers [28].…”

Enterococci levels in the Bronx River during dry and wet weather conditions

“…Table 4 shows that there was a negative correlation found between conductivity and enterococci concentration (Adjusted r 2 = 0.21, p<0.01). Passerat et al (2010) and Weyrauch et al (2010) notes that the conductivity of river water decreases because of the dilution with storm water during rain events. This weak correlation suggests that the CSO is only one of the sources of increased Enterococci concentration in the river during wet weather conditions.…”

“…(US EPA, 2004) Some of the impacts of CSO in surface water bodies include decrease of dissolved oxygen concentration due to biodegradation of the increased amount of organic matter, increased levels of metallic and organic pollutants, and high concentration of fecal microorganisms. (Even et al, 2007;Weyrauch et al, 2010;Gasperi et al, 2008) The amount of fecal microorganisms in surface waters is a public health concern because of the possible presence of human pathogens. This is especially a problem for waters that are designated for recreational uses.…”

Evaluating the effectiveness and hydrological performance of green infrastructure stormwater control measures.

“…14 A study by Weyrauch et al (2010) examined the contribution of combined sewer overflows (CSO) to loads and concentrations of trace contaminants in receiving surface water. The results of the study indicate that CSO may be a significant source of sewagebased trace substances and can lead to potentially problematic acute concentrations in receiving waters during storm events (Weyrauch et al 2010).…”