The effects of combined sewer overflow events on riverine sources of drinking water.

This study was set out to investigate the impacts of Combined Sewer Overflows (CSOs) on the microbiological water quality of a river used as a source of drinking water treatment plants. Escherichia coli concentrations were monitored at various stations of a river segment located in the Greater Montreal Area including two Drinking Water Intakes (DWIs) in different weather conditions (dry weather and wet weather (precipitation and snowmelt period)). Long-term monitoring data (2002-2011) at DWIs revealed good microbiological water quality with E.

Temporal analysis of E. coli, TSS and wastewater micropollutant loads from combined sewer overflows: implications for management.

A combined sewer overflow (CSO) outfall was monitored to assess the impact of temporal mass loads on the appropriateness of treatment options. Instantaneous loads (mass per s) varied by approximately three orders of magnitude during events (n = 9 in spring, summer and the fall) with no significant seasonal variations. The median fraction of total loads discharged with the first 25% of the total volume ranged from 28% (theophylline) to 40% (Total Suspended Solids (TSS)) and loads remained high for the duration of the events.

Source tracking of leaky sewers: a novel approach combining fecal indicators in water and sediments.

In highly urbanized areas, surface water and groundwater are particularly vulnerable to sewer exfiltration. In this study, as an alternative to Microbial Source Tracking (MST) methods, we propose a new method combining microbial and chemical fecal indicators (Escherichia coli (E. coli)) and wastewater micropollutants (WWMPs) analysis both in water and sediment samples and under different meteorological conditions.

Temporal variability of combined sewer overflow contaminants: evaluation of wastewater micropollutants as tracers of fecal contamination.

A monitoring program was initiated for two sewage outfalls (OA and OB) with different land uses (mainly residential versus institutional) over the course of a year. Eleven CSO events resulting from fall and summer precipitations and a mixture of snowmelt and precipitation in late winter and early spring were monitored. Median concentrations measured in CSOs were 1.

Evaluating pharmaceuticals and caffeine as indicators of fecal contamination in drinking water sources of the Greater Montreal region.

We surveyed four different river systems in the Greater Montreal region, upstream and downstream of entry points of contamination, from April 2007 to January 2009. The studied compounds belong to three different groups: PPCPs (caffeine, carbamazepine, naproxen, gemfibrozil, and trimethoprim), hormones (progesterone, estrone, and estradiol), and triazine herbicides and their metabolites (atrazine, deethylatrazine, deisopropylatrazine, simazine, and cyanazine). In the system A, B, and C having low flow rate and high TOC, we observed the highest detection frequencies and mass flows of PPCPs compared to the other compounds, reflecting discharge of urban contaminations through WWTPs and CSOs.

Fecal coliforms, caffeine and carbamazepine in stormwater collection systems in a large urban area.

Water samples from streams, brooks and storm sewer outfall pipes that collect storm waters across the Island of Montréal were analyzed for caffeine, carbamazepine and fecal coliforms. All samples contained various concentrations of these tracers, indicating a widespread sanitary contamination in urban environments. Fecal coliforms and caffeine levels ranged over several orders of magnitude with a modest correlation between caffeine and fecal coliforms (R(2) value of 0.

Time-dependent integrity during storage of natural surface water samples for the trace analysis of pharmaceutical products, feminizing hormones and pesticides.

Monitoring and analysis of trace contaminants such as pharmaceuticals and pesticides require the preservation of the samples before they can be quantified using the appropriate analytical methods. Our objective is to determine the sample shelf life to insure proper quantification of ultratrace contaminants. To this end, we tested the stability of a variety of pharmaceutical products including caffeine, natural steroids, and selected pesticides under refrigerated storage conditions.

On-line solid phase extraction and liquid chromatography/tandem mass spectrometry to quantify pharmaceuticals, pesticides and some metabolites in wastewaters, drinking, and surface waters.

A simple on-line method was developed for the analysis of pharmaceuticals, pesticides and some metabolites in drinking, surface and wastewater samples. The technique is based on the use of on-line solid-phase extraction combined with liquid chromatography electrospray tandem mass spectrometry with positive electrospray ionization (LC-ESI(PI)-MS/MS). The injection of only 1 mL of filtered water sample is used with a total analysis time of 20 min, including the period required to flush the SPE cartridge with organic solvent and reconditioning the LC column.