assessing and cleaning up contaminated sediments esr 410/510 environmental cleanup and restoration
TRANSCRIPT
![Page 1: Assessing and Cleaning Up Contaminated Sediments ESR 410/510 Environmental Cleanup and Restoration](https://reader036.vdocuments.net/reader036/viewer/2022062515/56649ce15503460f949ac945/html5/thumbnails/1.jpg)
Assessing and Cleaning Up Contaminated Sediments
ESR 410/510
Environmental Cleanup and Restoration
![Page 2: Assessing and Cleaning Up Contaminated Sediments ESR 410/510 Environmental Cleanup and Restoration](https://reader036.vdocuments.net/reader036/viewer/2022062515/56649ce15503460f949ac945/html5/thumbnails/2.jpg)
Introduction
Sediment contamination problems have been recognized for many years
Widespread concern did not appears until 1970s
Sediments of virtually all active harbors are contaminated
Also, many other major waterways such as the Great Lakes, Puget Sound, the Hudson River
![Page 3: Assessing and Cleaning Up Contaminated Sediments ESR 410/510 Environmental Cleanup and Restoration](https://reader036.vdocuments.net/reader036/viewer/2022062515/56649ce15503460f949ac945/html5/thumbnails/3.jpg)
Early Evidence of Sediment
Contamination
![Page 4: Assessing and Cleaning Up Contaminated Sediments ESR 410/510 Environmental Cleanup and Restoration](https://reader036.vdocuments.net/reader036/viewer/2022062515/56649ce15503460f949ac945/html5/thumbnails/4.jpg)
Replicate studies reveal widespread problems
![Page 5: Assessing and Cleaning Up Contaminated Sediments ESR 410/510 Environmental Cleanup and Restoration](https://reader036.vdocuments.net/reader036/viewer/2022062515/56649ce15503460f949ac945/html5/thumbnails/5.jpg)
Sediment Characterization
Grab sampling at low tide
Sediment surface showing biological activity
![Page 6: Assessing and Cleaning Up Contaminated Sediments ESR 410/510 Environmental Cleanup and Restoration](https://reader036.vdocuments.net/reader036/viewer/2022062515/56649ce15503460f949ac945/html5/thumbnails/6.jpg)
Sediment Dwelling (Benthic) Organisms
Eel GrassZostera marina
Requires abundant light and clear water. Excess algae kills it off.
![Page 7: Assessing and Cleaning Up Contaminated Sediments ESR 410/510 Environmental Cleanup and Restoration](https://reader036.vdocuments.net/reader036/viewer/2022062515/56649ce15503460f949ac945/html5/thumbnails/7.jpg)
Sediment Dwelling (Benthic) Organisms
Polychaete worms
Burrow to 20-30 cm into sediments, mixing shallow and deep sediment material and associated contaminants. (Bioturbation)
![Page 8: Assessing and Cleaning Up Contaminated Sediments ESR 410/510 Environmental Cleanup and Restoration](https://reader036.vdocuments.net/reader036/viewer/2022062515/56649ce15503460f949ac945/html5/thumbnails/8.jpg)
Sediment Dwelling (Benthic) Organisms
Nereids (Polychaeta)
![Page 9: Assessing and Cleaning Up Contaminated Sediments ESR 410/510 Environmental Cleanup and Restoration](https://reader036.vdocuments.net/reader036/viewer/2022062515/56649ce15503460f949ac945/html5/thumbnails/9.jpg)
Sediment Dwelling (Benthic) Organisms
Burrowing shrimp, Callianassa californiensis
Southern rock lobster, Jasus novahollandiae
Mole crab, Emerita analoga
![Page 10: Assessing and Cleaning Up Contaminated Sediments ESR 410/510 Environmental Cleanup and Restoration](https://reader036.vdocuments.net/reader036/viewer/2022062515/56649ce15503460f949ac945/html5/thumbnails/10.jpg)
Mole crab (Emerita)
Horseshoe crabs (Limulus polyphemus)
Sediment Dwelling (Benthic) Organisms
![Page 11: Assessing and Cleaning Up Contaminated Sediments ESR 410/510 Environmental Cleanup and Restoration](https://reader036.vdocuments.net/reader036/viewer/2022062515/56649ce15503460f949ac945/html5/thumbnails/11.jpg)
The Benthos We Eat
Rock sole
Softshell clams
Blue crab
Mussel
![Page 12: Assessing and Cleaning Up Contaminated Sediments ESR 410/510 Environmental Cleanup and Restoration](https://reader036.vdocuments.net/reader036/viewer/2022062515/56649ce15503460f949ac945/html5/thumbnails/12.jpg)
Major Contaminants of Concern in Sediments
Persistent toxic organics (pesticides, PCBs, PAHs)
Heavy metals (lead, mercury, cadmium, etc.)
![Page 13: Assessing and Cleaning Up Contaminated Sediments ESR 410/510 Environmental Cleanup and Restoration](https://reader036.vdocuments.net/reader036/viewer/2022062515/56649ce15503460f949ac945/html5/thumbnails/13.jpg)
Van Veen Hand Dredge
![Page 14: Assessing and Cleaning Up Contaminated Sediments ESR 410/510 Environmental Cleanup and Restoration](https://reader036.vdocuments.net/reader036/viewer/2022062515/56649ce15503460f949ac945/html5/thumbnails/14.jpg)
Ponar Box Corer
![Page 15: Assessing and Cleaning Up Contaminated Sediments ESR 410/510 Environmental Cleanup and Restoration](https://reader036.vdocuments.net/reader036/viewer/2022062515/56649ce15503460f949ac945/html5/thumbnails/15.jpg)
Ekman Box Corer
![Page 16: Assessing and Cleaning Up Contaminated Sediments ESR 410/510 Environmental Cleanup and Restoration](https://reader036.vdocuments.net/reader036/viewer/2022062515/56649ce15503460f949ac945/html5/thumbnails/16.jpg)
Large, Ekman-type Corer
![Page 17: Assessing and Cleaning Up Contaminated Sediments ESR 410/510 Environmental Cleanup and Restoration](https://reader036.vdocuments.net/reader036/viewer/2022062515/56649ce15503460f949ac945/html5/thumbnails/17.jpg)
Sediment Sampling:Mackereth Pneumatic Corer
![Page 18: Assessing and Cleaning Up Contaminated Sediments ESR 410/510 Environmental Cleanup and Restoration](https://reader036.vdocuments.net/reader036/viewer/2022062515/56649ce15503460f949ac945/html5/thumbnails/18.jpg)
Multi-Corer Array
![Page 19: Assessing and Cleaning Up Contaminated Sediments ESR 410/510 Environmental Cleanup and Restoration](https://reader036.vdocuments.net/reader036/viewer/2022062515/56649ce15503460f949ac945/html5/thumbnails/19.jpg)
Benthic Biota Samplers (sleds)
![Page 20: Assessing and Cleaning Up Contaminated Sediments ESR 410/510 Environmental Cleanup and Restoration](https://reader036.vdocuments.net/reader036/viewer/2022062515/56649ce15503460f949ac945/html5/thumbnails/20.jpg)
What Constitutes “Contaminated Sediments”
ALL sediments contain at least traces of metals, including some very toxic metals
Many persistent organic compounds like DDT and PCBs are globally distributed at low levels
So the mere presence of “contaminants” does not mean a sediment is contaminated by local sources or to a worrisome level.
![Page 21: Assessing and Cleaning Up Contaminated Sediments ESR 410/510 Environmental Cleanup and Restoration](https://reader036.vdocuments.net/reader036/viewer/2022062515/56649ce15503460f949ac945/html5/thumbnails/21.jpg)
Defining problem Contamination: The Reference Approach
Earliest scientific approach Compare levels in site samples to “natural”
or “background” levels Background levels drawn from what are
believed to be relatively “pristine” locations If samples > background, clean up
accordingly But what to compare with and how? Also, the method does not account for
mixtures of chemicals nor the “bioavailability” of the chemical
![Page 22: Assessing and Cleaning Up Contaminated Sediments ESR 410/510 Environmental Cleanup and Restoration](https://reader036.vdocuments.net/reader036/viewer/2022062515/56649ce15503460f949ac945/html5/thumbnails/22.jpg)
Bioavailability Just because a chemical is found in the
environment does not mean it is available for uptake by organisms (bioavailable)
E.g., toxic metal ions trapped inside rock particles (like ore) are not bioavailable unless the ore dissolves
Many other natural processes limit the bioavailability of certain forms, particularly with metals and with hydrophobic organic compounds
![Page 23: Assessing and Cleaning Up Contaminated Sediments ESR 410/510 Environmental Cleanup and Restoration](https://reader036.vdocuments.net/reader036/viewer/2022062515/56649ce15503460f949ac945/html5/thumbnails/23.jpg)
Bioavailability of Pb (thanks Mark)
![Page 24: Assessing and Cleaning Up Contaminated Sediments ESR 410/510 Environmental Cleanup and Restoration](https://reader036.vdocuments.net/reader036/viewer/2022062515/56649ce15503460f949ac945/html5/thumbnails/24.jpg)
Sediments Strongly Bind Many Pollutants
Sediments carry high contaminant load because pollutants “stick” to them
If a contaminant has little tendency to “stick”, then of course, it probably will not end up or persist in the sediment
But, if pollutants bind extremely well to sediments, they may pose little or no risk
So, how strong is the binding?
![Page 25: Assessing and Cleaning Up Contaminated Sediments ESR 410/510 Environmental Cleanup and Restoration](https://reader036.vdocuments.net/reader036/viewer/2022062515/56649ce15503460f949ac945/html5/thumbnails/25.jpg)
“Partitioning” of Contaminants Between Sediments and Water
Sediment particles
Interstitial or Pore Water
Dissolved chemical (mobile, available)
Adsorbed chemical (immobile, less available)
![Page 26: Assessing and Cleaning Up Contaminated Sediments ESR 410/510 Environmental Cleanup and Restoration](https://reader036.vdocuments.net/reader036/viewer/2022062515/56649ce15503460f949ac945/html5/thumbnails/26.jpg)
Equilibrium Partitoning
What’s in the interstitial water is in proportion to what’s on the solids
E.g., suppose100 molecules on the solid and 10 in the water. Double the contamination and its 200 on the solids and 20 in the water
![Page 27: Assessing and Cleaning Up Contaminated Sediments ESR 410/510 Environmental Cleanup and Restoration](https://reader036.vdocuments.net/reader036/viewer/2022062515/56649ce15503460f949ac945/html5/thumbnails/27.jpg)
Asdorption Modeling:“Organics like other Organics”
Sediments typically contain some natural organic matter (“humus”-like material)
Organic contaminants bind strongest to natural organic matter in the sediment
Binding strength depends on compound AND on organic content of the sediment
![Page 28: Assessing and Cleaning Up Contaminated Sediments ESR 410/510 Environmental Cleanup and Restoration](https://reader036.vdocuments.net/reader036/viewer/2022062515/56649ce15503460f949ac945/html5/thumbnails/28.jpg)
Predicting Binding of Organic Contaminants
“Kp” = overall partition coefficient Sed. Conc. = Kp x Water Conc. Koc = “generic” coefficient for
compound (tabulated) Kp =foc x Koc
foc is the fraction of organic carbon in sediment
![Page 29: Assessing and Cleaning Up Contaminated Sediments ESR 410/510 Environmental Cleanup and Restoration](https://reader036.vdocuments.net/reader036/viewer/2022062515/56649ce15503460f949ac945/html5/thumbnails/29.jpg)
Example:
PCB: Typical Koc = 200,000 L/kg Sediment with 2% organic content (foc =
0.02)
Sed Conc = 0.02(200,000) x Water Conc Ratio of Water Conc/Sed Conc = 1/(0.02)
(200,000) = 0.00025
Virtually ALL the PCB stays with the sediment, not in the water
![Page 30: Assessing and Cleaning Up Contaminated Sediments ESR 410/510 Environmental Cleanup and Restoration](https://reader036.vdocuments.net/reader036/viewer/2022062515/56649ce15503460f949ac945/html5/thumbnails/30.jpg)
PCB in the Columbia Slough Sediment PCB: ~30 ug/kg foc = 0.02 Calculated water PCB: <15 ng/L (parts
per trillion; below detection)
But bioconcentration occurs later: Carp tissues contain up to 850 ug/L (magnification of 57,000X !!)
![Page 31: Assessing and Cleaning Up Contaminated Sediments ESR 410/510 Environmental Cleanup and Restoration](https://reader036.vdocuments.net/reader036/viewer/2022062515/56649ce15503460f949ac945/html5/thumbnails/31.jpg)
Interstitial water Approach Directly sample and measure
interstitial water But does not work for sediments
above waterline (tidal zones, floodplains)
Very hard to do outside a research settling
![Page 32: Assessing and Cleaning Up Contaminated Sediments ESR 410/510 Environmental Cleanup and Restoration](https://reader036.vdocuments.net/reader036/viewer/2022062515/56649ce15503460f949ac945/html5/thumbnails/32.jpg)
Sediment Bioassays
Various means of testing in lab the organisms with sediment samples
Costly, but useful Hard to say connection to actual
system in some cases
![Page 33: Assessing and Cleaning Up Contaminated Sediments ESR 410/510 Environmental Cleanup and Restoration](https://reader036.vdocuments.net/reader036/viewer/2022062515/56649ce15503460f949ac945/html5/thumbnails/33.jpg)
Pathways for Contaminant Transport Desorption during dredging:
sediment --> water Mobilization of non-settling
particles during dredging Desorption or mobilization during
handling/dewatering Desorption or mobilization during
final confinement
![Page 34: Assessing and Cleaning Up Contaminated Sediments ESR 410/510 Environmental Cleanup and Restoration](https://reader036.vdocuments.net/reader036/viewer/2022062515/56649ce15503460f949ac945/html5/thumbnails/34.jpg)
Sediment Cleanup Options
No action: Let nature cover over or dilute contaminated sediments with fresh sedimentation Works only if all sources of
contaminant are shut off, so some “action” often required
Good only if natural processes fast enough to mitigate danger
Not good if severe imminent harm
![Page 35: Assessing and Cleaning Up Contaminated Sediments ESR 410/510 Environmental Cleanup and Restoration](https://reader036.vdocuments.net/reader036/viewer/2022062515/56649ce15503460f949ac945/html5/thumbnails/35.jpg)
Dredging as a Remediation Method Appropriate where environmental
impacts are severe Where physical disruptions like
strong currents, flooding, navigational dredging are likely to occur
Biggest problems are Resuspension of dirty sediments Severe disruption of the benthos Where to put the spoils?
![Page 36: Assessing and Cleaning Up Contaminated Sediments ESR 410/510 Environmental Cleanup and Restoration](https://reader036.vdocuments.net/reader036/viewer/2022062515/56649ce15503460f949ac945/html5/thumbnails/36.jpg)
Quantities of Dredged Sediments in the Northwest Alone
Quantities of Dredged Sediments in the Northwest Alone
250 million cubic yards from 25,000 miles of navigation channels
75 million cubic yards from permits
325 million cubic yards each year
![Page 37: Assessing and Cleaning Up Contaminated Sediments ESR 410/510 Environmental Cleanup and Restoration](https://reader036.vdocuments.net/reader036/viewer/2022062515/56649ce15503460f949ac945/html5/thumbnails/37.jpg)
How Much Dredged Material?
> 1½ feet deepover Chicago
> 5½ feet deep overWashington, D.C.
![Page 38: Assessing and Cleaning Up Contaminated Sediments ESR 410/510 Environmental Cleanup and Restoration](https://reader036.vdocuments.net/reader036/viewer/2022062515/56649ce15503460f949ac945/html5/thumbnails/38.jpg)
AuthorizationAuthorization
Rivers and Harbors Act of 1899, Section 10
Clean Water Act Section 404
Marine Protection, Research, and Sanctuaries Act Section 103
![Page 39: Assessing and Cleaning Up Contaminated Sediments ESR 410/510 Environmental Cleanup and Restoration](https://reader036.vdocuments.net/reader036/viewer/2022062515/56649ce15503460f949ac945/html5/thumbnails/39.jpg)
Regulatory Authorities
U.S. National Marine Fisheries Service
U.S. Fish and Wildlife Service
U.S. Environmental Protection Agency
State Fish and Game Agencies
State Water Quality Certifying Agencies
State Coastal Zone Management Agencies
Other Federal and State Agencies
![Page 40: Assessing and Cleaning Up Contaminated Sediments ESR 410/510 Environmental Cleanup and Restoration](https://reader036.vdocuments.net/reader036/viewer/2022062515/56649ce15503460f949ac945/html5/thumbnails/40.jpg)
TIER I• Existing Data
TIER II• Physical/Chem. data• Screening Tests•Predictive models
TIER III• Toxicity Tests• Bioaccumulation Tests
TIER IV• Chronic Sublethal Tests• Steady-State Bioaccumulation Tests• Risk Assessment
EN
HA
NC
ED
RE
SOL
UT
ION
INC
RE
ASI
NG
CO
MPL
EX
ITY
/ CO
ST
![Page 41: Assessing and Cleaning Up Contaminated Sediments ESR 410/510 Environmental Cleanup and Restoration](https://reader036.vdocuments.net/reader036/viewer/2022062515/56649ce15503460f949ac945/html5/thumbnails/41.jpg)
https://www.nwp.usace.army.mil/ec/h/hr/
![Page 42: Assessing and Cleaning Up Contaminated Sediments ESR 410/510 Environmental Cleanup and Restoration](https://reader036.vdocuments.net/reader036/viewer/2022062515/56649ce15503460f949ac945/html5/thumbnails/42.jpg)
Basic Dredge Types Hydraulic
Pipeline Hopper
Mechanical Clamshell
Other / Combinations
![Page 43: Assessing and Cleaning Up Contaminated Sediments ESR 410/510 Environmental Cleanup and Restoration](https://reader036.vdocuments.net/reader036/viewer/2022062515/56649ce15503460f949ac945/html5/thumbnails/43.jpg)
Factors in Selection ofDredging Equipment Physical characteristics of sediments Quantities to be dredged Dredging depth Distance to disposal area Physical environment of and between
areas Contamination level of sediments Method of disposal Production required Types of dredges available (US or foreign)
![Page 44: Assessing and Cleaning Up Contaminated Sediments ESR 410/510 Environmental Cleanup and Restoration](https://reader036.vdocuments.net/reader036/viewer/2022062515/56649ce15503460f949ac945/html5/thumbnails/44.jpg)
Disposal of Spoils
Simple in-water disposal usually not an option for contaminated sediments
Upland disposal gets it safely out of the water but presents many problems
![Page 45: Assessing and Cleaning Up Contaminated Sediments ESR 410/510 Environmental Cleanup and Restoration](https://reader036.vdocuments.net/reader036/viewer/2022062515/56649ce15503460f949ac945/html5/thumbnails/45.jpg)
Upland Disposal
If not “hazardous” under RCRA, may be able to just pile it up on the shore
Near-shore upland sites are cheaper and can use a slurry pipeline, but may not be available (NIMBY or other limitations on land use)
If not near the shore, transportation adds big costs (truck or rail; pipeline not usually feasible)
![Page 46: Assessing and Cleaning Up Contaminated Sediments ESR 410/510 Environmental Cleanup and Restoration](https://reader036.vdocuments.net/reader036/viewer/2022062515/56649ce15503460f949ac945/html5/thumbnails/46.jpg)
Upland Sediment Disposal: Barview, OR
![Page 47: Assessing and Cleaning Up Contaminated Sediments ESR 410/510 Environmental Cleanup and Restoration](https://reader036.vdocuments.net/reader036/viewer/2022062515/56649ce15503460f949ac945/html5/thumbnails/47.jpg)
Barview, OR
![Page 48: Assessing and Cleaning Up Contaminated Sediments ESR 410/510 Environmental Cleanup and Restoration](https://reader036.vdocuments.net/reader036/viewer/2022062515/56649ce15503460f949ac945/html5/thumbnails/48.jpg)
Barview Slurry inlet pipe
![Page 49: Assessing and Cleaning Up Contaminated Sediments ESR 410/510 Environmental Cleanup and Restoration](https://reader036.vdocuments.net/reader036/viewer/2022062515/56649ce15503460f949ac945/html5/thumbnails/49.jpg)
Barview Variable-depth outlet weir
![Page 50: Assessing and Cleaning Up Contaminated Sediments ESR 410/510 Environmental Cleanup and Restoration](https://reader036.vdocuments.net/reader036/viewer/2022062515/56649ce15503460f949ac945/html5/thumbnails/50.jpg)
Hazardous Waste Disposal If sediment fails RCRA test, then must
either: Treat it on-site to make it pass the haz
waste test, then ship to disposal Take it off-site for treatment and disposal Ship directly it to a Subtitle C (Haz
Waste) landfill For large loads the first is the cheapest,
for smaller loads, the last 2 may be best
![Page 51: Assessing and Cleaning Up Contaminated Sediments ESR 410/510 Environmental Cleanup and Restoration](https://reader036.vdocuments.net/reader036/viewer/2022062515/56649ce15503460f949ac945/html5/thumbnails/51.jpg)
Safe In-Water Disposal: Confined Disposal Facilities
Like an “underwater landfill” Sediments are disposed in the
water but are confined inside a secure facility
Can be right next to shoreline Might be out in deeper water If you don’t move the sediments,
but just confine them in-situ, it’s called “capping”
![Page 52: Assessing and Cleaning Up Contaminated Sediments ESR 410/510 Environmental Cleanup and Restoration](https://reader036.vdocuments.net/reader036/viewer/2022062515/56649ce15503460f949ac945/html5/thumbnails/52.jpg)
Confined Disposal Alternatives
![Page 53: Assessing and Cleaning Up Contaminated Sediments ESR 410/510 Environmental Cleanup and Restoration](https://reader036.vdocuments.net/reader036/viewer/2022062515/56649ce15503460f949ac945/html5/thumbnails/53.jpg)
CONCLUSIONS
Site Assessment tells us if we have a problem that must be dealt with
We may conclude that the no-action approach may be the best
If action is required we must decide whether dredging is required or if in-situ capping will work
![Page 54: Assessing and Cleaning Up Contaminated Sediments ESR 410/510 Environmental Cleanup and Restoration](https://reader036.vdocuments.net/reader036/viewer/2022062515/56649ce15503460f949ac945/html5/thumbnails/54.jpg)
Conclusions, cont’d
Dredging has a whole lot of safety issues, especially controlling resuspended sediments
Disposal methods must be assessed with respect to safety, reliability, costs, and public acceptance
![Page 55: Assessing and Cleaning Up Contaminated Sediments ESR 410/510 Environmental Cleanup and Restoration](https://reader036.vdocuments.net/reader036/viewer/2022062515/56649ce15503460f949ac945/html5/thumbnails/55.jpg)
Conclusions, cont’d
In-situ capping can be a good alternative to dredging
But there are many situations where it is not feasible Very shallow waters Fast or unpredictable currents Powerful tides Navigational dredging Anchor weighing by large ships