cANIMIDA Tasks 3 and 4: Sources, Concentrations, Composition, Partitioning and Dispersion Pathways for Suspended Sediments and Potential Metal Contaminants in the Coastal Beaufort Sea. Final Report

摘要

The continuation of the Arctic Nearshore Impact Monitoring in Development Area (cANIMIDA) Project was designed to determine whether offshore oil development in the coastal Beaufort Sea has had any adverse impacts on the marine environment. This report encompasses two aspects of the cANIMIDA Project, the study of suspended sediments (Task 3) and the distribution of potential metal contaminants between dissolved and particulate phases (Task 4). Samples were collected during the spring floods of May-June of 2004 and 2006 and during the open-water periods (July-August) of 2004, 2005 and 2006. The spring portion of the study was designed to investigate the flow of water, suspended sediments and dissolved and particulate metals by rivers and then trace their dispersion under ice into the coastal Beaufort Sea. The summer portion of the study was designed to investigate the distribution of suspended sediments and dissolved and particulate metals across the shelf and in the areas of active development in the open waters of the Beaufort Sea. Data from the ANIMIDA Project (1999-2002) are included in this report in some cases to help show interannual variability. During the 2 to 3 weeks of spring floods in May-June 2004 and 2006, about 60% of the annual water flow from the Kuparuk River and about one third of the annual water flow of the Sagavanirktok River were carried to the Beaufort Sea. Interannual variability in the onset date for river flow, volume at peak flow and the duration of peak flow can be significant as shown in Figure ES1a. During May-June, maximum concentrations of total suspended solids (TSS) ranged from 60 mg/L (2006) to 120 mg/L (2002) in the Kuparuk River and 244 mg/L (2002) to 609 mg/L (2001) in the Sagavanirktok River. Differences in the chemical composition of the river particles could often be related to the mineralogy of the drainage basin as, for example, the highest Ca values were found for particles in the carbonate-richer Sagavanirktok River basin and the highest Al values were found in the more clay-rich Colville River.