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

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

2009 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, or cubic feet per second) River stage (stream elevation) Stream velocity (feet per second)

Sampling Program 2009 Convention

al Sampling Overlying

Cap: Surface

water Within Cap:

Inter-armor Sub armor

SPME – Fall 2009

Sampling Methodology Semi-annual sampling locations

24 surface water stations 22 inter-armoring water and 22 sub armoring water stations

Spring Higher flow Higher gradient Fewer flow reversals

Fall Less gradient More reversals

Seasonality of the River

Seasonality of the River

Sampling Results - SW cPAHs in surface water

All below 0.031 µg/L sediment cap performance goal; with exception of Location 15 (Spring 2009) where low level CPAHs were detected in surface water but not detected in the inter-armoring or subarmoring samples

Spring is when River has higher turbidity and higher flow.

Sampling Results - IA cPAHs in inter-armoring water

All below 0.031 µg/L sediment cap performance goal

Sampling Results - SA cPAHs in sub-armoring water

Sampling Results - SW Naphthalene in surface water

Sampling Results - IA Naphthalene in inter-armor water

Sampling Results - SA Naphthalene in sub-armor water

Sampling Results - trends Mean Total cPAH Concentration

Mea

n

Sampling Results - trends Mean Total PAHs in surface, inter- and sub-

armor water

Sampling Results – Location 10

Sampling Results – Location 10 Comparing to Portland Harbor Surface Water

Metals

Spring 2005

Fall 2005 Spring 2006

Fall 2006 Spring 2007

Fall 2007 Spring 2008

Fall 20080.00000

0.00100

0.00200

0.00300

0.00400

0.00500

0.00600

0.00700

0.00800

0.00900

0.01000 Portland Harbor: Total Zn

Portland Harbor: Total Cu

Portland Harbor: Total As

Arsenic: Surface Water

Copper: Surface Water

Arsenic: Inter-Armoring

Copper: Inter-Armoring

Arsenic: Sub-Armoring

Copper: Sub-Armoring

Arsenic Reference Criteria - 0.00014 mg/L (2007 NR-WQC Human Health)

Copper Reference Criteria - 0.009 mg/L (2007 NRWQC Aquatic Life)

Met

al C

once

ntra

tion

(mg/

L)

Note: Open symbols represent all non-detects ( i.e., the concentration represents the mean of the method detection limits).

Portland Harbor: Total As

Portland Harbor: Total Cu

Sampling Results – Location 10 Trends since remedy – cPAHs, total PAHs

Conclusions COC concentrations in surface water and sub-

armoring 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 however, SW can be elevated in Spring with High River Discharge

cPAHs decline since remedy: Not detected in SW samples since Spring 2006 (with one

exception at Location 15) ND in IA samples since Fall 2006

Concentrations trends stable to decreasing Sediment cap is protective of surface water