Trace Metals and Hydrocarbons in Sediments of the Beaufort Lagoon, Northeast Arctic Alaska, Exposed to Long-Term Natural Oil Seepage, Recent Anthropogenic Activities and Pristine Conditions

Summary

Branch: Executive

Category: Executive Agency Publications

SuDoc Class Number: I 72.

Government Author: Interior Department, Minerals Management Service

Personal Author: Naidu AS; Misra D; Kelley JJ; Blanchard A; Venkatesan MI

Series Title: BOEM Environmental Studies

Publication Title: Trace Metals and Hydrocarbons in Sediments of the Beaufort Lagoon, Northeast Arctic Alaska, Exposed to Long-Term Natural Oil Seepage, Recent Anthropogenic Activities and Pristine Conditions

Date Issued: 2005

Subject: Marine Chemistry
Water Quality
Trace Metals; Hydrocarbons; Sediments; Alaskan Arctic; Contaminants; Benthic Animals

Obligation Number: 1435-01-02-CA-85294-74464

Geographic Scope: Alaska

Report Number: 2005-041

CSE Reference: Naidu AS, Misra D, Kelley JJ, Blanchard A, Venkatesan MI (University of Alaska, Fairbanks, AK). 2005. Trace metals and hydrocarbons in sediments of the Beaufort Lagoon, northeast Arctic Alaska, exposed to long-term natural oil seepage, recent anthropogenic activities and pristine conditions. Anchorage (AK): US Department of the Interior, Minerals Management Service. 3 p. Obligation No.: 1435-01-02-CA-85294-74464. Report No.: OCS Study MMS 2005-041. URL: https://espis.boem.gov/Technical%20Summaries/3521.pdf

Abstract: There is a concern that anthropogenic contaminants discharged during petroleumrelated activities can accumulate in the Beaufort Lagoon sediments. In response to this concern concentrations of 12 metals were analyzed [copper (Cu) chromium (Cr) cadmium (Cd) nickel (Ni) vanadium (V) lead (Pb) tin (Sn) zinc (Zn) arsenic (As) barium (Ba) iron (Fe) and manganese (Mn)] in the mud fraction and total mercury (THg) and hydrocarbons [saturated compounds such as normal and isoprenoid alkanes triterpanes steranes and polycyclic aromatic hydrocarbons (PAHs)] determined in gross sediments collected at 22 locations at the lagoon and in one natural oil seep. The concentrations of the metals and hydrocarbons are generally lower than those reported for polluted marine sediments. Comparison of time-interval metal data on sandy mud (>75% mud) and mud collected in 1977 and 2003 respectively shows a significant decrease in vanadium but an increase in manganese and copper from 1977 to 2003. Presumably the differences are ascribed to disparities in the granulometry of the two sediment sets. Correlation coefficient analysis suggests that most metals are co-precipitated with iron oxy-hydroxide or occur as metalorganic complexes. There was a net increasing southeast to northwest trend in the metal concentrations which did not relate to a possible gradient from point source such as the natural oil seep or the Distant Early Warning (DEW now defunct) line station. The hydrocarbon components in the sediments are essentially of terrestrial and biogenic sources with undetectable petroleum inputs which is supported by the Organic Carbon to Nitrogen ratio (OC/N) isotope ratios of organic carbon (δ 13C) and nitrogen (δ 15N) of organic matter. There is no evidence of the contribution of petroleum hydrocarbons to the lagoon sediments from the onshore oil seeps. The overall composition of the hydrocarbon profiles is very similar to those found in our previous studies in the sediments from Elson Lagoon and near-shore regions of the Colville Delta–Prudhoe Bay–Canning Delta. We saw no impression of the natural oil seep and anthropogenic activities on the sediment trace metals and the hydrocarbon profile. The metal and hydrocarbon data will serve as a baseline which will be critical for ecological risk management of the North Slope in the context of contaminant inputs and in the better understanding of the inorganic and organic geochemistry of Arctic sediments.