Sand Cap Efficacy Studies. Meg Pinza and Jay Word EcoAnalysts

Transcription

1 Sand Cap Efficacy Studies Meg Pinza and Jay Word EcoAnalysts

2 Introduction EcoAnalysts conducted a laboratory study to compare the effectiveness of sand cap amendments to reduce or inhibit movement of petroleum hydrocarbons through a sand cap layer. Study was carefully controlled in the laboratory and results were verified by chemical analysis of sand cap at the completion of the study.

3 APPROACH This study was part of a larger investigation with an emphasis on sediment contaminated with petroleum hydrocarbons. One remedial alternative option for site included wet dredging followed by sand cap over newly dredged surface. Sand caps are increasingly used at various remediation sites around the country. Compared three commercially available amended sand caps to a traditional sand cap. Laboratory trials conducted to simulate site conditions provide a unique platform for comparing technologies prior to field implementation.

4 SITE DESCRIPTION Located along the shoreline of Lake Superior active clean up site. Site Activities through time: Lumber operations A repository for solid waste, fly ash, and dredge spoils Waste water treatment plant A manufactured gas plant 1885 to 1947 Secondary wood processing plant Subject of numerous investigations. Supplemental data collected in support of Remedial Investigation/Feasibility Studies

5 STUDY OBJECTIVES Determine whether petroleum contaminated sediments migrate through a sand cap layer differently than sand cap layer amended with various treatments. Evaluate if the amended sand cap(s) provide optimal conditions for recolonization of the newly placed restorative layer by the benthic community. Three amended treatments selected for comparison to sand cap. Granular Activated Carbon SediMite Biochar

6 GRANULAR ACTIVATED CARBON (GAC) A porous form of carbon with a very large surface area available for adsorption or chemical reactions.

7 SEDIMITE An agglomerate comprised of a treatment agent (typically activated carbon), a weighting agent to enable it to sink and resist resuspension, and an inert binder.

8 BIOCHAR A proprietary blend of lower temperature char specifically formulated for remediation. For this project biochar was created by The Remediators in Port Angeles Washington

9 CONTAMINATED SEDIMENT Vertical core samples were collected, geological described, photographed and sampled for chemistry. A strong chemical odor was noted for most cores and in some cases product was seeping out of sediment interstices. Subsamples of the contaminated layer were used to create test composite.

10 Compound Concentration (ug/kg dry) % of Total SVOC Naphthalene 1,500,000 21% 2-Methylnaphthalene 1,100,000 15% 1-Methylnaphthalene 660,000 9% Biphenyl 161,000 2% Acenaphthylene 40,000 1% Acenaphthene 660,000 9% Dibenzofuran 46,000 1% Fluorene 280,000 4% Dibenzothiophene 85,000 1% Phenanthrene 860,000 12% Carbazole % Anthracene 230,000 3% C(1)-Ph/An's 377,000 5% Cyclopentaphenanthrene 80,500 1% Fluoranthene 250,000 3% CyclopentaPh/An 103,000 1% Pyrene 360,000 5% Benzo(a)anthracene 110,000 2% total Benzofluoranthenes 96,000 1% Benzo(a)fluoranthene 25,800 0% Benzo(e)pyrene 46,000 1% Benzo(a)pyrene 92,000 1% Perylene 15,600 0% Indeno(1,2,3-cd)pyrene 36,000 0% Dibenzo(a,h)anthracene % Benzo(g,h,i)perylene 45,000 1% Anthanthracene 19,400 0% Sum of SVOC 7,287, %

11 DESIGN Aquaria modified by inserting a glass weir near the water outflow port, creating two chambers. Water flowed out of the exit port through a PVC fitted with SPME fibers and resin cartridges to adsorb soluble organic compounds

12 TEST SET UP One hundred grams of contaminated sediment created from contaminated sections from several stations used as a worse case residual material.

13 SPME fibers used to determine presence of volatile PAHs in overlying water. XAD resin columns used to determine presence of semi-volatile PAHs in overlying water.

14 Analyte Clean Sand (ug) SediMite (ug) Biochar (ug) GAC (ug) Equipment Blank (ug) Naphthalene < 0.1 < 0.5 < 0.5 < 0.1 < 0.1 Acenaphthylene < 0.1 < 0.5 < 0.5 < 0.5 < 0.1 Acenaphthene < 1.5 < 4.0 < 1.0 < 2.8 < 0.1 Fluorene < 0.2 < 0.5 < 0.5 < 0.5 < 0.1 Phenanthrene < 0.5 < 0.5 < 0.5 < 0.5 < 0.1 Anthracene < < 1.0 < 0.5 < 0.1 Fluoranthene < 0.2 < 0.5 < 0.5 < 0.5 < 0.1 Pyrene < 0.2 < 0.5 < 0.5 < 0.5 < 0.1 Benzo(a)anthracene < 1.0 < 0.5 < 1.0 < 0.5 < 0.1 Chrysene < 0.2 < 0.5 < 0.5 < 0.5 < 0.1 Benzo(b)fluoranthene < 0.2 < 0.5 < 0.5 < 0.5 < 0.1 Benzo(k)fluoranthene < 0.2 < 0.5 < 0.5 < 0.5 < 0.1 Benzo(a)pyrene < 0.2 < 0.5 < 0.5 < 0.5 < 0.1 Indeno(1,2,3-cd)pyrene < 0.2 < 0.5 < 0.5 < 0.5 < 0.1 Dibenzo(a,h)anthracene < 0.2 < 0.5 < 0.5 < 0.5 < 0.1 Benzo(g,h,i)perylene < 0.2 < 0.5 < 0.5 < 0.5 < 0.1

15 Cored through cap and collected vertical segments for chemical analysis. Visual observations of biological growth or treatment/contaminant movement recorded. Samples submitted for analysis including total organic carbon and grain size

16 Core Depth 0-1 Sand SediMite Biochar GAC TOC (%) TOC(%) TOC(%) TOC(%) 0.02 U 0.02 U 0.02 U U 0.02 U 0.02 U U U U 0.02 U 0.02 U

17 Analyte (conc. ug/kg,dry) Clean Sand SediMite Biochar GAC Naphthalene < 64 < 64 2-Methylnaphthalene < Methylnaphthalene < 64 < 64 Biphenyl 120 J 12 J < 64 < 64 Acenaphthene 1200 < 63 < 64 < 64 Fluorene 520 < 63 < 64 < 64 Pentachlorophenol < 300 < 320 < 320 < 320 Dibenzothiophene 120 J < 63 < 64 < 64 Phenanthrene 2100 < Anthracene 550 < 63 < 64 < 64 C(1)-Ph/An's 920 J < 63 < 64 < 64 Cyclopentaphenanthrene 180 J < 63 < 64 < 64 Fluoranthene 620 < 63 < 64 < 64 CyclopentaPh/An 240 J < 63 < 64 < 64 Benzo(a)anthracene 270 < 63 < 64 < 64 Chrysene 250 < 63 < 64 < 64 total Benzofluoranthenes 240 < 63 < 64 < 64 Benzo(e)pyrene 140 J < 63 < 64 < 64 Benzo(a)pyrene 240 < 63 < 64 < 64 Benzo(g,h,i)perylene 120 < 63 < 64 < 64 Sum of detected SVOC

18 SUMMARY The concentration of PAH in the sand cap were more than fifty times higher than the biochar treatment and more than 20 times higher than the GAC or SediMite amendment. A restorative layer should include a sand cap amended with a carbon source. Additionally, the biochar amendment appears to enhance the carbon nutrient quality of the sand which could promote more rapid recolonization of the returning benthic community.

19 PROJECT EXAMPLES

20 FORENSICTOXICOLOGY: AVAILABILITY OF HG IN FOODWEBS Specialized field and laboratory studies conducted to determine if capping dredged surface is required to protect resident aquatic community Collected sediment cores Deployed ADCP to collect current profile Conducted SPI to look at seafloor communities Ran acute, chronic and bioaccumulation studies No acute or chronic effects of for water-column or benthic organisms and bioaccumulation to higher trophic levels below action levels Dredged material was placed at inwater disposal site with a sand cap over top. Monitoring is ongoing.

21 LABORATORY AS A CONSULTING BASED TOOL Real World scenarios by simulating site conditions Directly measures bioavailability of contaminants to aquatic systems and evaluates trophic transfer Evaluates effectiveness of alternative treatment strategies Contributing factor and toxicity identification evaluation (TIE) Uses high quality data and science-based analysis to provide sound and defensible results

22 ENVIRONMENTAL MONITORING & COMPLIANCE TESTING Provided consulting services in support of Chukchi Sea General Marine Permit: baseline study of benthic community in the Chukchi Sea before and after drilling Cluster analysis used to discern similarities and differences among communities. Created benthic atlas. Evaluated effluent discharges through compliance monitoring and toxicity identification evaluations. Provided scientific leadership for program to the client.

23 EXPERT SERVICES IN SUPPORT OF AN AGREED ORDER Provided technical support to client(s) requiring 4 years of data to be compliant with Department of Ecology agreed order. Determined whether the toxicity tests used routinely used to evaluate refinery effluent discharges were also protective of the local herring populations. Supported client in regulatory meetings with Department of Ecology to validate results of studies and provide input for future permit guidance.

24 FORENSIC ECOTOXICOLOGY LABORATORY Located in Port Gamble, WA adjacent to class AAA waters 4,000 ft 2 of space Flow through System supplies Seawater or Freshwater Automated Temperature Controlled Room (simulating arctic to tropic conditions) State (WDOE) and National (NELAP) Laboratory Accreditations Port Gamble Seattle