Faecal contamination of water and sediment in the rivers of the Scheldt drainage network

Abstract

The Scheldt watershed is characterized by a high population density, intense industrial activities and intensive agriculture and breeding. A monthly monitoring (n = 16) of the abundance of two faecal indicator bacteria (FIB), Escherichia coli and intestinal enterococci (IE), showed that microbiological water quality of the main rivers of the Scheldt drainage network was poor (median values ranging between 1.4 × 10 3 and 4.0 × 10 5 E. coli (100 mL) −1 and between 3.4 × 10 2 and 7.6 × 10 4 IE (100 mL) −1 ). The Zenne River downstream from Brussels was particularly contaminated. Glucuronidase activity was measured in parallel and was demonstrated to be a valid surrogate for a rapid evaluation of E. coli concentration in the river waters. FIB were also investigated in the river sediments; their abundance was sometimes high (average values ranging between 2.1 × 10 2 and 3.3 × 10 5 E. coli g −1 and between 1.0 × 10 2 and 1.7 × 10 5 IE g −1 ) but was not sufficient to contribute significantly to the river water contamination during resuspension events, except for N. K. Ouattara · J. Passerat · P. Servais (B) Ecologie des Systèmes Aquatiques, Université Libre de Bruxelles, Campus de la Plaine, CP 221, Boulevard du Triomphe, 1050 Bruxelles, Belgium e-mail: pservais@ulb.ac.be the Scheldt and the Nethe Rivers. FIB were also quantified in representative point sources (wastewater treatment plants) and non-point sources (runoff water and soil leaching on different types of land use) of faecal contamination. The comparison of the respective contribution of point and non-point sources at the scale of the Scheldt watershed showed that point sources were largely predominant.

Real-time monitoring of beta-d-glucuronidase activity in sediment laden streams: A comparison of prototypes

“…These results are consistent with an agricultural catchment subjected to periodic manure application on the crop fields. The GLUC magnitudes are also consistent with previous published studies, ranging between GLUC levels of nearly unpolluted groundwater (Ryzinska-Paier et al, 2014) and stream water influenced by municipal sewage (Farnleitner et al, 2002;GarciaArmisen et al, 2005;George et al, 2000;Ouattara et al, 2011). The event monitoring showed that the GLUC peaks tend to be aligned with the first flush of event stream runoff.…”

Abundance and Distribution of Enteric Bacteria and Viruses in Coastal and Estuarine Sediments—a Review

“…Spatial variation within the estuary itself can also confound the issue (Quilliam et al, 2011a; Perkins et al, 2014), as can the seasonal prevalence of bacteria and viruses (Ishii et al, 2006; He and He, 2008; Siem-Jorgensen et al, 2008). Characterization of individual estuaries is underway (Stapleton et al, 2007; Ouattara et al, 2011; Huang et al, 2015) and data from these surveys are being used in models that monitor the fluxes of FIOs, with the primary aim of predicting beach closures due to poor water quality (Stapleton et al, 2007; He and He, 2008; de Brauwere et al, 2014). The sources of fecally derived bacteria and viruses in the typical mixed estuary include wastewater, agricultural runoff, persistent populations, in situ growth and infrequent deposition events such as animal feces.…”

Assessment of the characteristic of nutrients, total metals, and fecal coliform in Sibu Laut River, Sarawak, Malaysia

“…Besides, the negative loadings on FC, turbidity and TSS are not surprising. Transport of FC via resuspension of the sediments through the storm or tidal actions into the overlying water column is an important mechanism in the aquatic environment (Brauwere et al 2011;Ouattara et al 2011) as FC has longer survival in association with sediment particles (Ishii et al 2007;Lee et al 2006).…”