Contaminant characterization in wetland media surrounding a pulp mill industrial effluent treatment facility

Meaghan E Quanz,Tony R Walker,Ken Oakes,Rob Willis

doi:10.1007/s11273-020-09779-0

Abstract

Three media (sediment, surface water, and dragonfly larvae tissue) were collected from wetlands surrounding an industrial effluent treatment facility prior to closure. Samples were analyzed for metals, total mercury, and polychlorinated dibenzo-p-dioxins/polychlorinated dibenzofurans (PCDD/PCDF) concentrations. Sediment and surface water concentrations were compared to provincial and federal guidelines, as well as reference wetland concentrations. Exceedances of arsenic, cadmium, chromium, copper, zinc, and PCDD/PCDF guidelines were found in deeper areas of wetlands historically contaminated from effluent, as well as wetlands exposed to current effluent inputs. Composite Libellulidae samples were collected from wetlands, and comparisons were made to reference tissue concentrations + 20%. Elevated As, Cu and Pb tissue concentrations were measured at two site wetlands, but total mercury (THg) and PCDD/PCDF reference tissue concentrations were higher than wetlands near the effluent treatment facility. Spearman rho tests identified a significant correlation between sediment and tissue Pb concentrations and between surface water and sediment THg concentrations. Results suggest relatively low ecological risk to macroinvertebrates within wetlands near the effluent treatment facility from current effluent inputs, and highlight strengths and weaknesses of federal and provincial guidelines.

Highlights

Wetland contamination from industrial activities has been an ongoing issue for decades (Moore 2008; Jones et al 2009)
This study focuses on a pulp effluent treatment facility, known as the Boat Harbour Treatment Facility, in Boat Harbour, Pictou County, Nova Scotia
total organic carbon (TOC) was highest at WL1 and WL5 at 26.7% and 35.7%, respectively, which were higher than mean REF1 TOC of 17.3%

Summary

Introduction

Wetland contamination from industrial activities has been an ongoing issue for decades (Moore 2008; Jones et al 2009). A Canadian industry with a high potential for contaminating aquatic environments is wood pulp production, attributable to the large volumes of wastewater produced (Pokhrel and Viraraghavan 2004; Munkittrick et al 2013; Hoffman et al 2017a, 2019). If pulp wastewater effluent is poorly managed, sufficient contaminants can enter aquatic environments to produce potential deleterious effects (Toczylowska-Maminska 2017). This study focuses on a pulp effluent treatment facility, known as the Boat Harbour Treatment Facility, in Boat Harbour, Pictou County, Nova Scotia. In 1967, a pulp mill, located 4 km southwest of Boat Harbour, began operation and used Boat Harbour as a treatment facility for wastewater effluent (Fig. 1)

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Discussion

Conclusion