Aquatic ERA Full Report
Total Page:16
File Type:pdf, Size:1020Kb
April 2010 AQUATIC ECOLOGICAL RISK ASSESSMENT Report on the Sequential Analysis of Lines of Evidence for Risk from the Teck Cominco Smelter at Trail, BC Submitted to: Teck Metals Ltd. 25 Aldridge Avenue P.O. Box 1000 Trail, British Columbia V1R 4L8 REPORT Report Number: 04-1335-025 Distribution: 7 Copies Teck Metals Ltd., Trail, BC 4 Copies Golder Associates Ltd. Calgary, AB 1 Copy Intrinsik Environmental Inc., Mississauga, ON AQUATIC ECOLOGICAL RISK ASSESSMENT Abstract The Teck Cominco Metals Ltd. (now Teck Metals Ltd. but still referred to as Teck Cominco in this report, as the work reported herein was completed prior to the name change) Ecological Risk Assessment (ERA) was produced under the British Columbia Contaminated Sites Regulation (CSR). Teck Cominco elected to use a landscape perspective and to use the information to develop a risk-based Wide Area Remediation Plan. The aquatic risk assessment component of the ERA used a combination of laboratory and field-based studies of the major groups of aquatic life comprising the local food web. Interpretation of the findings was guided by a Sequential Analysis of Lines of Evidence (SALE) approach to characterize the degree of risk from smelter- related emissions. The overall approach, individual study plans and interim reports were reviewed by a Technical Advisory Committee (TAC), a Public Advisory Committee (PAC) and other external reviewers. The ERA was guided by the agreed management goal that there will be “no unacceptable residual ecological risk from past or current smelter-related emissions.” Risk management objectives for the aquatic ERA were stated as: Minimize, now and in the future, smelter operation-related direct and indirect effects within the Area Of Interest (AOI) on the diversity of aquatic plant and animal communities in the Columbia River and its tributaries. Minimize, now and in the future, smelter operation-related direct and indirect effects within the AOI on fish populations in the Columbia River and its tributaries. Prevent, now and in the future, smelter operation-related direct and indirect effects on threatened and endangered aquatic species in the AOI. The aquatic AOI encompasses a 56-km section of the Columbia River and its tributaries from downstream of the Hugh Keenleyside Dam and Brilliant Dam on the Kootenay River, and Waneta Dam on the Pend d’Oreille River, to the International Boundary. The Hugh Keenleyside, Brilliant and Waneta dams are physical barriers to fish migration, providing natural upstream endpoints for the study. Numerous tributaries ranging from small intermittent first-order streams to fourth-order streams containing important fish habitat occur within the AOI. Five creeks within the AOI (Ryan, Hanna, Murphy, China and Bear creeks) and three reference creeks (Blueberry, Norns and Deer creeks) were chosen for the screening-level assessment. Assessment Endpoints (AE) were defined for periphyton (attached algae) community composition; benthic invertebrate community composition; growth, condition, reproductive capability and population characteristics of the fish receptor species in the Columbia River; fish habitat quality in the Columbia River; fish habitat quality in the tributaries; presence, survival and reproductive success of white sturgeon in the Columbia River; and habitat quality for white sturgeon in the Columbia River. The initial list of fish receptors (mountain whitefish, rainbow trout, walleye and white sturgeon, plus groups including suckers, sculpins, dace, chubs and redside shiner) was pared to mountain whitefish, white sturgeon and prickly sculpin. White sturgeon was chosen because it is a red-listed species in British Columbia, is highly valued by residents of the AOI and is the subject of intensive study under the White Sturgeon Recovery Initiative. Mountain whitefish was chosen as the representative large-bodied fish species on the basis of the availability of April 2010 Report No. 04-1335-025 AQUATIC ECOLOGICAL RISK ASSESSMENT historic and current data on fish health, the degree of exposure to metals of this predominately bottom-feeding species, its status as a member of the salmonid family (regarded as among the most sensitive fish species), and its status as the most abundant sport fish in the AOI. Data on metal concentrations in mountain whitefish, walleye, rainbow trout and largescale sucker confirmed that mountain whitefish have higher concentrations than the other two sport fish species (rainbow trout and walleye) and similar concentrations to the bottom-feeding largescale sucker. The only exception to this is mercury, which is present in higher concentrations in walleye. This is to be expected because mercury biomagnifies, unlike any of the other potential chemicals of concern (PCOC); therefore, its concentration increases with successive steps in the food chain. Prickly sculpin was selected because it is a small-bodied fish with a small home range (thus its exposure can be defined within relatively narrow spatial boundaries), and because of its role as a prey item for predatory fish, its abundance along the PCOC exposure gradient from upstream to downstream of the smelter, and the relative ease of collection. Amphibians are not included as they are the subject of a separate report on wetlands. PCOC common to water and sediment in the mainstem of the Columbia River and its tributaries were: arsenic, cadmium, chromium, copper, lead, thallium and zinc. Mercury was identified as an additional PCOC for water; cobalt, iron and selenium were included as PCOC for tributaries; nickel and silver were included as PCOC for sediments. The PCOC list was derived using data from 1995 to 2001. Water quality data collected since 2001 have shown that cadmium, chromium, thallium and zinc concentrations continued to occasionally exceed water quality objectives. Exposure pathways, including atmospheric deposition from smelter emissions in the waterway and historic slag discharge into the Columbia River, were represented in two site-specific conceptual models. These models addressed direct and indirect effect of PCOC as well as physical stresses related to slag deposits. Direct effects included toxicity related reductions in growth or survival of the different receptors. Indirect effects pertain to changes in habitat quality either through loss of or changes in the relative abundance of food resources or changes in the physical environment. The Teck Cominco smelter is not the only source of stress to the aquatic environment in the AOI. A variety of land uses in the AOI produce point and non-point sources of chemical stressors (surface and groundwater flow as well as atmospheric deposition). In addition, physical stressors caused by habitat alteration or destruction occur as part of some land uses. Other sources include the Zellstoff Celgar pulp mill, flow regulation by the Hugh Keenleyside, Brilliant and Waneta dams, recreational fishing, fish management programs, linear developments (transmission corridors, roads and railroads), urban development, and agricultural land use. Assessment of Risk to Aquatic Biota in the Tributaries of the Columbia River Evaluations of water quality, sediment quality, periphyton, benthic invertebrates and fish habitat were completed as part of SALE. None of these lines provide strong evidence for metal-related risks to tributary systems. Because each of these lines indicates similar evidence of low risk from metals, there is confidence in the overall assessment of low risk from smelter-related emissions to tributary systems. Natural habitat variables are likely to be the primary determinant of periphyton and benthic invertebrate communities. Natural habitat features and anthropogenic barriers to fish movement appear to be primary factors influencing fish presence in the tributaries. Assessment of Risk to Aquatic Biota in the Mainstem Columbia River The SALE analysis indicated that the risk management objectives are being met for mountain whitefish and prickly sculpin in the AOI. Therefore, an evaluation of risk management options is not required for these April 2010 Report No. 04-1335-025 AQUATIC ECOLOGICAL RISK ASSESSMENT receptors. Periodic evaluation of prickly sculpin health measures as well as population characteristics such as age/size distribution, catch-rate and population size upstream and downstream of the smelter would provide further assurance that the prickly sculpin population in the area immediately downstream of the smelter is not being affected by exposure to smelter-related stressors. There is no compelling argument for further monitoring or evaluation of large-bodied fish species in the AOI relative to direct risks from smelter-related stressors. The SALE analysis indicated that the risk management objectives were not being met for periphyton in the near- field (New Bridge site) and the benthic invertebrate community at the Maglios and Waneta sites. Therefore, evaluation of risk management options is required for these sites. There are non smelter-related stressors in the vicinity of the New Bridge and Maglios sites. Additional data would help increase the understanding of the role of the non-smelter stressors. The role of slag in the sediment as a physical stressor versus the role of PCOC as chemical stressors may also require clarification at both sites in order to refine risk management options. The additional data could be obtained both from laboratory tests and field investigations. The temporal framework would be better understood with a quantitative evaluation