Environmental predictors of Escherichia coli concentration at marine beaches in Vancouver, Canada: a Bayesian mixed-effects modelling analysis.

Understanding historical environmental determinants associated with the risk of elevated marine water contamination could enhance monitoring marine beaches in a Canadian setting, which can also inform predictive marine water quality models and ongoing climate change preparedness efforts. This study aimed to assess the combination of environmental factors that best predicts Escherichia coli (E. coli) concentration at public beaches in Metro Vancouver, British Columbia, by combining the region's microbial water quality data and publicly available environmental data from 2013 to 2021. We developed a Bayesian log-normal mixed-effects regression model to evaluate predictors of geometric E. coli concentrations at 15 beaches in the Metro Vancouver Region. We identified that higher levels of geometric mean E. coli levels were predicted by higher previous sample day E. coli concentrations, higher rainfall in the preceding 48 h, and higher 24-h average air temperature at the median or higher levels of the 24-h mean ultraviolet (UV) index. In contrast, higher levels of mean salinity were predicted to result in lower levels of E. coli. Finally, we determined that the average effects of the predictors varied highly by beach. Our findings could form the basis for building real-time predictive marine water quality models to enable more timely beach management decision-making.

Characterization and Interpolation of Sediment Polychlorinated Biphenyls and Polybrominated Diphenyl Ethers in Resident Killer Whale Habitat along the Coast of British Columbia, Canada.

The northeastern Pacific northern and southern resident killer whale (Orcinus orca) populations are listed as threatened and endangered in Canada, respectively, with persistent, bioaccumulative contaminants, such as polychlorinated biphenyls (PCBs) and polybrominated diphenyl ethers (PBDEs), posing threats to their recovery. Concentrations of PCBs and PBDEs in subtidal surface sediments collected from 97 sites along the British Columbia (BC) coast were used to identify their distribution and profiles, and to assess killer whale habitat quality. Victoria Harbour (VH3(site ID: 1) ) sediments exhibited the highest PCB and PBDE concentrations. For PCBs, PCB-138 was found at the highest concentration, followed by PCB-153, PCB-110, PCB-149, PCB-101, and PCB-118. For PBDEs, individual congeners were ranked as follows: BDE-209 > BDE-207 > BDE-206 > BDE-208 > BDE-47 > BDE-99. Principal component analyses (PCA) illustrated the variations in contaminant profiles, with PC1 for PCBs and PBDEs correlated with the octanol-water partition coefficient (log KOW , p < 0.003). Based on the PCA, sediment particle size, total organic carbon (TOC), and water depth at collection were other factors associated with the distribution of PBDEs, while PCB profiles were associated with TOC. Total PCB and PBDE concentrations at 100% and 34% of the sites, respectively, exceeded the recently adopted British Columbia's Ministry of Environment and Climate Change Strategy Working Sediment Quality Guidelines (PCBs 3.7 pg/g dry wt and PBDEs 1000 pg/g dry wt), considered protective of killer whales. Our findings suggest that the legacy of banned PCBs and PBDEs has the potential to constrain the recovery of killer whales as a result of their mobilization from sediments and consequent uptake by marine food webs. Environ Toxicol Chem 2022;41:2139-2151. © 2022 SETAC.

Retention of microplastics in a major secondary wastewater treatment plant in Vancouver, Canada.

Municipal wastewater treatment plants (WWTPs) are conduits through which microplastics (MPs) are released into aquatic environments. However, the technical challenges in working with wastewater sample matrices have precluded reliable particle count budget calculations. We applied newly-adapted methods for MP collection and analysis to a study of a major WWTP serving a population of 1.3 million people near Vancouver, Canada. Suspected MP particles, including fibres, were counted and categorized using light microscopy in influent, primary effluent, secondary effluent, primary sludge and secondary sludge. Fourier Transform Infrared Spectroscopy (FT-IR) confirmed that just 32.4% of the suspected MPs were plastic polymers. Using FT-IR corrected data, we estimate that 1.76 ±â€¯0.31 trillion MPs enter the WWTP annually, with 1.28 ±â€¯0.54 trillion MPs settling into primary sludge, 0.36 ±â€¯0.22 into secondary sludge, and 0.03 ±â€¯0.01 trillion MPs released into the receiving environment. This corresponds to a retention of microplastics of up to 99% in the WWTP.

Immunological responses, histopathological finding and disease resistance of blue mussel (Mytilus edulis) exposed to treated and untreated municipal wastewater.

This study provides new information on the response of the immune system of Mytilus edulis exposed to untreated and treated sewage, linking immune response to ecologically relevant endpoints, such as disease resistance. Our goal was to assess the potential effects of sewage on the immune system (phagocytic activity and production of cytotoxic metabolites, disease resistance) and gills (light microscope) of mussels through a bioassay and field study in an estuarine receiving environment (RE). A semi-static experiment was developed in a wastewater treatment plant in New Glasgow, NS Canada. Mussels were exposed for 21 days to 12.5%, 25%, 50% and 100% of untreated sewage influent and artificial seawater control. Sampling occurred after 7, 14 and 21 days of exposure. In the field study, eight sites were selected in East River and Pictou Harbour, NS, positioned upstream and downstream of sewage effluents outfalls. Caged mussels were exposed to the RE for 90 days (May-July 2005). Mussels were challenged to test their efficiency at eliminating the bacteria, Listonella anguillarium in the bioassay and field studies. The bioassay results showed that higher concentrations of untreated sewage could modulate the immune system of mussels through increased of phagocytic activity (PA), nitric oxide (NO) and hydrogen peroxide (H(2)O(2)) production during 14 days of exposure, and decreased activity and production at 21 days, with the exception of H(2)O(2) production which was high even at 21 days. Mussels exposed to untreated sewage RE also presented a high PA, NO and H(2)O(2) production and lower number of haemocytes compared to mussels from reference sites. In the bacterial challenge, mussels pre-exposed to 100% sewage died 24h after being infected with L. anguillarium, while mussels pre-exposed to 50% eliminated bacteria had a mortality rate of 30%. Mussels from the control, 12.5% and 25% groups eliminated bacteria and no mortality was observed. No significant difference was observed in bacterial clearance in mussels exposed to effluents in the RE. The lesions observed in gills in both studies were: infiltration of haemocytes in the tissue, epithelium proliferation, lamellar fusion and dilated haemolymphatic sinus. In summary, untreated municipal wastewater affected the immune system of blue mussels during 21 days of exposure and the effects were reflected in their capability to resist pathogens. And an immune modulation was observed in mussels exposed to untreated sewage in a RE, but this modulation was not reflected in the mussel's capability in eliminating pathogens.

The use of in vitro bioassays to quantify endocrine disrupting chemicals in municipal wastewater treatment plant effluents.

In vitro bioassays are widely used to detect and quantify endocrine disrupting chemicals (EDCs) in the influents and effluents of municipal wastewater treatment plants (WWTP). These assays have sometimes led to false positive or negative results, partly due to the low EDC concentrations in the samples. The objectives of the present study were: (a) to compare the estrogen screen (E-Screen) and the yeast estrogen screen (YES) bioassays using the 17beta-estradiol (E2) or its equivalence and (b) to investigate if a combination of the E-Screen and YES assays can be used to improve the accuracy of EDC detection and quantification. The E-Screen bioassay was conducted with the MCF-7 (BOS) human breast cancer cell line while the YES bioassay employed two different types of recombinant yeast. The influent and effluent samples collected from the five WWTPs operated by the Greater Vancouver Regional District (GVRD) were analyzed by both the E-Screen and the YES bioassays. Since the results of the E-Screen and YES bioassays varied by up to 4-fold on the same split sample of a nominal E2 concentration, the mean value of the E-screen and YES bioassays was used to represent the EDC activity of a given WWTP sample. Results of these studies showed that the E2 equivalent concentration in each WWTP sample was consistently higher than 1 ng/L, a concentration that may potentially cause endocrine disruption in different aquatic species. The composition of selected EDCs in a subset of effluent samples was examined using a gas chromatograph-high resolution mass spectrometer (GC-HRMS). EDC composition in 10 WWTP samples correlated with the mean endocrine disrupting activities of the E-Screen and YES bioassays. Results also indicated that secondary treatment plants are comparable to the primary treatment plants in removing EDCs from the final effluents.

Occurrence of antimicrobials in the final effluents of wastewater treatment plants in Canada.

To investigate the occurrence of antimicrobials in the final effluents from wastewater treatment plants (WWTPs) in Canada, analytical methods were developed or modified from previously described methods using solid-phase extraction followed by liquid chromatography-electrospray ionization tandem mass spectrometry. Thirty-one antimicrobials from the macrolide, quinolone, quinoxaline dioxide, sulfonamide, and tetracycline classes were investigated in the final (treated) effluents from eight WWTPs, located in five Canadian cities. Ciprofloxacin, clarithromycin, erythromycin-H20, ofloxacin, sulfamethoxazole, sulfapyridine, and tetracycline were frequently detected in the effluents. The detection of sulfapyridine in effluents is the first report of this compound in environmental samples. Antimicrobials used exclusively for veterinary applications or treatment of livestock, such as carbadox, olaquindox, and chlortetracycline were not detected in the WWTP final effluents. There appear to be differences in the relative concentrations of antimicrobials detected in WWTP final effluents in Canada relative to concentrations reported previously in northern Europe, particularly for quinolone and sulfonamide compounds. These data may reflect differences in prescription patterns in Canada and northern Europe. The antimicrobials frequently detected in WWTP effluents appear to be those prescribed heavily in Canada for medical applications, and these compounds should be considered priority compounds for monitoring in surface water near WWTP discharges. The concentrations of antimicrobials detected in WWTP final effluents did not exceed 1 microg/L; levels that are unlikely to affect the growth and survival of aquatic organisms.