Christopher J. Lowe

PBDE and PCB accumulation in benthos near marine wastewater outfalls: the role of sediment organic carbon.

Polybrominated diphenyl ethers (PBDEs) and polychlorinated biphenyls (PCBs) were measured in sediments and benthic invertebrates near submarine municipal outfalls in Victoria and Vancouver, B.C., Canada, two areas with contrasting receiving environments. PBDE concentrations in wastewater exceeded those of the legacy PCBs by eight times at Vancouver and 35 times at Victoria. Total PBDE concentrations in benthic invertebrates were higher near Vancouver than Victoria, despite lower concentrations in sediments, and correlated with organic carbon-normalized concentrations in sediment. Principal Components Analysis indicated uptake of individual PBDE congeners was determined by sediment properties (organic carbon, grain size), while PCB congener uptake was governed by physico-chemical properties (octanol-water partitioning coefficient). Results suggest the utility of sediment quality guidelines for PBDEs and likely PCBs benefit if based on organic carbon-normalized concentrations. Also, where enhanced wastewater treatment increases the PBDEs to particulate organic carbon ratio in effluent, nearfield benthic invertebrates may face increased PBDE accumulation.

Relationship between mRNA biomarker candidates and location near a marine municipal wastewater outfall in the benthic indicator species Modiolus modiolus (L.).

The deep-sea horse mussel Modiolus modiolus (L.) is a sentinel bivalve species used for the assessment of potential biological exposure to anthropogenic contaminants in benthic environments. Using a combination of endpoints that included gross biological metrics, reproductive status, tissue contaminant load, and mRNA abundance profiles, we characterized variation in the local M. modiolus population situated in different spatial zones relative to a municipal wastewater outfall. Significant differences were observed in reproductive indicators, growth parameters, and abundance of four specific mRNA transcripts representative of stress response or membrane transport (CAT, NET/SCF6, ABCA4 and HSP70) in adductor muscle tissue of animals adjacent to the wastewater outfall. Concentrations of metals and organic chemicals in M. modiolus tissue were generally highest directly at the outfall site with much lower levels at 100-800 m from the outfall. This general pattern did not match the mRNA profiles. HSP70 and ABCA4 mRNA showed increased abundance in all regions adjacent to the municipal outfall compared to the reference site. One site group located within 100-200 m south/south-easterly of the outfall had increased levels of all four transcripts. Some mRNAs showed significant correlations with nickel, arsenic, lead, selenium, copper, and one of thirteen polycyclic aromatic hydrocarbons measured (dibenzo(a,h)-anthracene). Three mRNAs (CAT, NET/SCF6, and ABCA4) were negatively correlated with bis(2-ethylhexyl)phthalate. The data suggest that these benthic organisms are exhibiting biological responses to the outfall and support an alternate interpretation regarding dispersal of contaminants. The potential effects of emerging chemicals of concern entering the receiving environment merits further assessment.

Effect of receiving environment on the transport and fate of polybrominated diphenyl ethers near two submarine municipal outfalls

The fate of contaminants entering the marine environment through wastewater outfalls depends on the contaminants persistence and affinity for particles. However, the physical characteristics of the receiving environment, for example, current velocity and sedimentary processes, may be even more important. Because of the complexity of natural settings and the lack of appropriate comparative settings, this is not frequently evaluated quantitatively. The authors investigated the near-field accumulation of particle-reactive polybrominated diphenyl ethers (PBDEs) entering coastal waters by way of two municipal outfalls: one discharging into a high-energy, low-sedimentation environment near Victoria, BC, Canada; the other into a low-energy, high-sedimentation environment, near Vancouver, BC. The authors used ²¹⁰Pb profiles in box cores together with an advection-diffusion model to determine surface mixing and sedimentation rates, and to model the depositional history of PBDEs at these sites. Surprisingly, 88 to 99% of PBDEs were dispersed beyond the near-field at both sites, but a greater proportion of PBDEs was captured in the sediment near the Vancouver outfall where rapid burial was facilitated by inorganic sediment supplied from the nearby Fraser River. Although the discharge of PBDEs was much lower from the Victoria outfall than from Vancouver, some sediment PBDE concentrations were higher near Victoria.

Pharmaceutical concentrations in screened municipal wastewaters in Victoria, British Columbia: A comparison with prescription rates and predicted concentrations.

Pharmaceuticals and personal care products (PPCPs) are emerging chemicals of concern detected in surface waters globally. Recent reviews advocate that PPCP occurrence, fate, and exposure need to be better predicted and characterized. The use of pharmaceutical prescription rates to estimate PPCP concentrations in the environment has been suggested. Concentrations of 7 pharmaceuticals (acetylsalicylic acid, diclofenac, fenoprofen, gemfibrozil, ibuprofen, ketoprofen, and naproxen) were measured in municipal wastewater using gas chromatography/ion trap-tandem mass spectroscopy (GC/IT-MS/MS). Subregional pharmaceutical prescription data were investigated to determine whether they could predict measured effluent concentrations (MECs) in wastewaters. Predicted effluent concentrations (PECs) for 5 of the 7 pharmaceuticals were within 2-fold agreement of the MECs when the fraction of parent pharmaceutical excreted was not considered. When the fraction of parent pharmaceutical excreted was considered, the respective PECs decreased, and most were within an order of magnitude of the MECs. Regression relationships of monthly PECs versus MECs were statistically significant (p < 0.05) but weak (R(2) = 0.18-0.56) for all pharmaceuticals except ketoprofen. This suggests high variability in the data and may be the result of factors influencing MECs such as the analytical methods used, wastewater sampling frequency, and methodology. The PECs were based solely on prescription rates and did not account for inputs of pharmaceuticals that had a significant over-the-counter component or were from other sources (e.g., hospitals).

Pharmaceuticals and Personal Care Products in Municipal Wastewater and the Marine Receiving Environment Near Victoria Canada

Concerns over the fate of pharmaceuticals and personal care products (PPCP) within the environment have been growing with the advent of more precise analytical methods. The discharge of municipal wastewater has been identified as a significant source of these contaminants, particularly where wastewater treatment is minimal. Here we present results from a comprehensive monitoring regime located around Victoria, BC, Canada. Samples were collected between 2009 and 2016 from a variety of sources including marine water, sediment and biota adjacent to two major untreated sewage outfalls, as well as the sewage itself. PPCP concentrations within the untreated sewage were high, and the sediment surrounding the outfalls showed corresponding contamination. However, this contamination dropped quickly with distance from the outfall such that by 800 m distance most PPCPs were below detection limits. Tissue samples of resident Northern Horse mussels (Modiolus modiolus) collected adjacent to one of the major sewage outfalls showed high single sample concentrations of the antimicrobial triclosan (317 ng g-1 dry weight), the antibiotic ciprofloxacin (176 ng g-1 dry weight), as well as the antidepressant sertraline (84.1 ng g-1 dry weight). Reference stations from around the region showed very low concentrations of contamination with almost all PPCP concentrations being below detection limits. Within the sewage, concentrations were largely stable overtime, with the exception of triclosan and triclocarban which both showed declines over the study period.

Risks of hypoxia and acidification in the high energy coastal environment near Victoria, Canada's untreated municipal sewage outfalls

Wastewater disposal often has deleterious impacts on the receiving environment. Low dissolved oxygen levels are particularly concerning. Here, we investigate the impacts on dissolved oxygen and carbon chemistry of screened municipal wastewater in the marine waters off Victoria, Canada. We analyzed data from undersea moorings, ship-based monitoring, and remotely-operated vehicle video. We used these observations to construct a two-layer model of the nearfield receiving environment. Despite the lack of advanced treatment, dissolved oxygen levels near the outfalls were well above a 62 μmol kg-1 hypoxic threshold. Furthermore, the impact on water column oxygen at the outfall is likely <2 μmol kg-1. Dissolved inorganic carbon is not elevated and pH not depressed compared to the surrounding region. Strong tidal currents and cold, well-ventilated waters give Victorias marine environment a high assimilative capacity for organic waste. However, declining oxygen levels offshore put water near the outfall at risk of future hypoxia.