Synthesis of Contaminants Data for Cook Inlet: Evaluation of Existing Data as Baseline Conditions and Recommendations for Further Monitoring (AK-21-02)

The purpose of this study was to (1) evaluate and compile regional Cook Inlet contaminant data, focusing on hydrocarbons and metals, that could be synthesized to assess Cook Inlet contaminant baseline concentrations and (2) develop an online data portal to serve historical Cook Inlet data and reports and to provide interactive data queries, downloads, mapping, and visualization capabilities. These tools will support BOEM in the development of National Environmental Policy Act (NEPA) analysis documents and Development and Production Plans (DPPs). To compile and synthesize the data, the methodology was: (1) identify and compile existing organic and inorganic contaminant data, (2) identify studies whose statistical sampling designs and analytical methods are similar and, when combined, could be representative of Cook Inlet for analysis of baseline conditions, (3) evaluate data against threshold levels and determine if contaminant baselines could be established, and (4) make the data readily available in a database portal for data queries, downloads, mapping, visualizations. Dozens of historical studies either included or evaluated Cook Inlet contaminant data, but most were decades old. Of those, a subset of 18 studies was identified whose data was accessible and could be compiled and standardized into common formats. A final subset of four studies was synthesized as representative of the Outer Continental Shelf (OCS) Cook Inlet Planning Area and were analyzed to assess Cook Inlet contaminant baselines and be compared to common thresholds. For metals, the background was highly variable, and sediment quality threshold levels were limitedly useful due to the unique naturally elevated background conditions that exist in Cook Inlet and in much of Alaska’s continental shelf sediments. For hydrocarbons, threshold levels were found to be much higher than polycyclic aromatic hydrocarbons (PAH) levels seen in Cook Inlet. Forensic chemistry assessed potential natural and anthropogenic hydrocarbon inputs. A specific hydrocarbon baseline was not identified due to background conditions and source fingerprints that varied throughout the Cook Inlet basin. Based on the review and analysis, a series of recommendations was presented on data gaps, potential future monitoring, and new tools and techniques that should be considered. The deliverable for the project include a final report, a searchable database, and online data portal where the compiled historical data can be queried, downloaded, mapped, and visualized.

USD: $324,850

2021-09-22 → 2024-09-22