Multivariate analysis of polycyclic aromatic hydrocarbons in sediments of Port Valdez, Alaska, 1989-2019

Sampling was conducted in Port Valdez, the site of the Valdez marine oil terminal where crude oil is loaded onto tankers for ocean shipment, to characterize sediment polycyclic aromatic hydrocarbons (PAH) concentrations arising from discharge of treated ballast-water from 1989 to 2019. Sediment PAH concentrations have declined since 1991 due to technological improvements in ballast water treatment processes and reductions in the volume of water treated. Spatial variations are associated with water depth reflecting geological and oceanographic characteristics. Comparisons between uncorrected hydrocarbon (compatible with data from 1989 to 2002) and surrogate-corrected concentrations for 2003-2019 suggest minor influence by corrections on inferences. It appears that if reliable measurements are made, the number of analytes and surrogate corrections have minimal influence for characterizing the directions and strengths of spatial and temporal change like that observed in Port Valdez. At present, PAH concentrations in the study area represent low risk for ecological effects.