Surface Water, Inter-Armor and Sub-Armor Sampling Program and Results

Oregon DEQ, Hart Crowser, Inc., and GSI Water Solutions

2010 McCormick & Baxter Annual Report

Sampling Program Goals:

Monitor sediment cap (and groundwater) remedy to understand performance related to minimizing releases of contaminants from sediments that might result in contamination of the Willamette River in excess of federal and state ambient water quality criteria

Fluvial system characteristics (semi-annual monitoring) Lower Willamette tidally-influenced Transition-zone water may reflect variations in:

Discharge (Q, cubic feet per second) River stage (stream elevation) Stream velocity (feet per second)

Sampling Program 2010 Spring 2010 –

Conventional Sampling Overlying Cap:

Surface water Within Cap:

Inter-armor Sub armor

Fall 2010 – SPME

Spring 2010 Sampling Locations

22 locations within sediment cap footprint Upgradient and downgradient

Seasonality of the River – Stage

FallEvent

SpringEvent

Seasonality of the River – Discharge

FallEvent

SpringEvent

Sampling Results – SW cPAHs

Sampling Results – IA cPAHs

Sampling Results – SA cPAHs

Sampling Results – SW Napthalene

Sampling Results – IA Napthalene

Sampling Results – SA Napthalene

Sampling Results - trends Mean Total cPAH Concentrations

Mea

n c

PA

H C

on

cen

trat

ion

(μ

g/L

, lo

g s

cale

)

Sampling Results - trends Mean Total PAH Concentrations

Mea

n P

AH

Co

nce

ntr

atio

n (

μg

/L,

log

sca

le)

Conclusions COC concentrations in surface water, inter-

armoring and sub-armoring samples are generally below comparison criteria with the exception of arsenic (MDL)

Detections frequencies and concentrations increase with depth (highest in SA)

Concentrations are generally lower in spring events

cPAHs declined immediately after remedy was implemented

Typically cPAHs have been below detection limits; therefore, trends cannot be identified

Sediment cap functioning as designed is protective of surface water