Sediment Sampling in the Proposed
by Army Corps of Engineers
3.2 SEDIMENT SAMPLING IN THE PROPOSED AND POSSIBLE FUTURE DREDGING SITES
The Dredged Material Evaluation Framework: Lower Columbia River Management Area (Corps, 1998) was used as the regulatory guidance for sediment quality evaluations in this Appendix. When Walla Walla District develops an evaluation framework specifically for the Lower Snake River Project reach and the McNary Project reach of the Columbia River, it will provide the regulatory guidance for future sediment quality evaluations within District boundaries. In June of 2000, water quality/sediment samples were collected at sites proposed for dredging in the winter of 2002 and 2003 in the Lower Snake River Reservoirs. The following tabulation outlines the number of sampling stations where data was collected.
|Reservoir Project||Number of Stations|
The number of compounds tested at each site typically ranged from about 29 to over 80 depending on the specific sampling site. The specific sample site and compounds tested for were based on locations and data previously sampled under previous pre-dredging analyses. Pre-dredging data has been collected since 1985. The following information summarizes the data that was collected in June of 2000.
The semi-volatile organic compounds, poly-nuclear aromatic hydrocarbons analyzed using EPA method 8270C were as follows: (none of these compounds were detected at levels that would require bioassay testing under the Lower Columbia Framework criteria.
List of Parameters Analyzed With Method 8270C
4-Bromophenyl phenyl ether*
Bis (2-ethylhexyl) phthalate*
Benzo (b) fluoranthene*
Benzo (k) fluoranthene*
Dibenz (a,h) anthracene*
Bis (2-chloroethyl) ether*
Benzo (a) anthracene
Bis (2-chloroxy) methane*
Butyl benzyl phthalate*
4-Chlorophenyl phenyl ether*
Bis (2-chlorolsopropyl) ether*
Benzo (a) pyrene*
Benzo (g,h,l) perylene
Ideno (1,2,3-c,d) pyrene
|*Below Detection Limits|
The semi-volatile and poly nuclear aromatic hydrocarbon compounds below detection limits were; 1,2-Dichlorobenzene; 1,2,4,5-Tetrachlorobenzene; 1,2,4-Trichlorobenzene; 1,4-Dichlorobenzene; 1-Methylnapthalene; 2,4-Dichlorophenol; 2,4-Dimethylphenol; 2,4-Dinotrotoluene; 2,4,6-Trichlorophenol; Dibenz (a, h) anthracene; 2-Chloronaphthalene; 2-Methyl-4, 6-dinitrophenol; 2-Methylnapthalene; 2-Chlorophenol; Di-n-octyl phthalate; 2-Nitrophenol; 3,3'-Dichlorobenzidine; 4-Bromophenyl phenyl ether; 4-Chloro-3-methylphenol; 4-Chlorophenyl phenyl ether; 4-Nitrophenol; Hexachlorobenzene; Hexachlorobutadiene; Hexachloroethane; Bis (2-chloroethyl) ether; Bis (2-chloroisopropyl) ether; Bis (2-chloroxy)methane; Benzo (k) flouranthene; Butyl benzyl phthalate; Diethyl phthalate; Dimethyl phthalate; Isophorone; Nitrobenzene; Phenol; Benzo (a) pyrene; 1,3-Dichlorobenzene; Bis (2chloroisopropyl) ether; 2,4 Dichlorophenol; and Bis (2-ethylhexyl) phthalate.
Acenaphthene was detected in Federal Navigation Channel but not in the Green Belt Boat Basin, Hell's Canyon Resort Marina, and the Port of Lewiston. The channel samples where detections were quantified all reported 74.6 ppb. About 1/3 of the samples rendered a measurable detection. With a screening level of 500 ppb no biological effects were anticipated.
Acenapthylene was detected in Hell's Canyon Resort Marina, Federal Navigation Channel, and Port of Clarkston. The detections reported 23 ppb, which is just above the detection limit of the method. With a screening level of 560 ppb no biological effects were anticipated.
Benzo (a) anthracene was found only in the Federal Navigation Channel and averaged 22.6 ppb. With a screening level of 1,300 ppb no biological effects were anticipated.
Benzo (b) floranthene was found in Hell's Canyon Resort Marina and the Federal Navigation Channel and averaged 44.6 ppb. There was no screen limit provided for this poly nuclear aromatic hydrocarbon.
Benzo (g, h, I) perylene was detected in the Federal Navigation Channel and averaged 17.4 ppb. With a screening level of 670 ppb no biological effects were anticipated.
Chrysene was found in the Hell's Canyon Resort Marina, Federal Navigation Channel, and Port of Lewiston. The maximum value detected was located in the Idaho portion of the Federal Navigation channel (57.3 ppb). Other areas to be dredged where chrysene was detected averaged 42.2 ppb. With a screening level of 1,400 ppb no biological effects were anticipated.
Fluoranthene was found in Hell's Canyon Resort Marina and in the Idaho portion of the Federal Navigation Channel. Hell's Canyon Resort Marina averaged 22 ppb and the Navigation Channel had a single detection at 52.7 ppb. With a screening level of 1,700 ppb no biological effects were anticipated.
Flourene was found in the Federal navigation Channel only and averaged 68.2 ppb. With a screening level of 540 ppb no biological effects were anticipated.
0 Ideno (1,2,3-c, d) pyrene was found only in Idaho, both in the Port and Navigation Channel with an average of 8.6 ppb. With a screening level of 600 ppb no biological effects were anticipated.
Napthalene was found only in the Federal Navigation Channel and averaged 49.4 ppb. With a screening level of 2,100 ppb no biological effects were anticipated.
Phenanthrene was found only in the Federal Navigation Channel and averaged 21.2 ppb. With a screening level of 2,100 ppb no biological effects were anticipated.
Pyrene was found in the Hell's Canyon Resort Marina and in the Idaho portion of the Federal Navigation Channel. The median result was 29.8 ppb with a single measurement of 68.7 ppb in the Clearwater River, Idaho. With a screening level of 2,600 ppb no biological effects were anticipated.
The dioxins and furans congeners analyzed using EPA method 8290 were as follows: (none were detected at levels which would require bioassay testing under the Lower Columbia Framework criteria.
List of Compounds Analyzed With Method 8290
Dioxin/furan congeners were found in Hell's Canyon Resort Marina and in the Washington State portion of the Federal Navigation Channel. Twenty-five sediment samples in the areas to be dredged were analyzed using EPA method 4425 (P450 Human Reporter Gene System). Of these samples, 10 reported positive detection of a "Dioxin-PAH like compound." Since all samples were pre-extracted, those samples with a positive were analyzed with the EPA 8290 test method for the confirmatory information. The following congeners were found at seven of 10 samples analyzed by high-resolution gas chromatograph mass spectrometry: Octachlorodibenzo-p-dioxin (8.0 to 162 ppt); 1,2,3,4,7,8-Heptachlorodibenzo-p-dioxin (0.7 to 22 ppt); 1,2,3,4,6,7,8- Heptachlorodibenzofuran (0.2 to 2 ppt); and Octachlorodibenzofuran (0.3 to 19 ppt). The congener 2,3,4,6,7,8-Hexachlorodibenzofuran was found in 4 of the 10 samples analyzed ranging from 0.12 to 1.15 ppt. The congener 1,2,3,6,7,8-Hexachlorodibenzo-p-dioxin found in two samples that resulted in 1.3 to 1.4 ppt respectively. No TCDD was found during this sediment chemical survey. Toxic equivalency quantification (TEQ) calculations for each sediment sample location were performed with resulting TEQs ranging from 0.018 to 0.060 ppt in the areas to be dredged. The Lower Columbia Framework uses the Puget Sound Dredged Disposal Analysis (PSDDA) guidelines for Dioxin TEQ. The screening criteria bioaccumulation trigger is currently set at 15 ppt. The sediments to be dredged by this action were 100 times less than the trigger and should have no significant impact to biota.
The Herbicide compounds analyzed using EPA method 8141 were as follows: (all were below the Lower Columbia Framework screening criteria.
List of Compounds Analyzed With Method 8141
The herbicide compounds that were below detection limits were; Diethylphosphorodithioic acid; Bolstar; Chlorpyrifos; Coumaphos; Demeton; Diazinon; Dichlorvos; Disulfoton; Ethoprop; Fensulfothion; Fenthion; Methyl parathion; Mevinphos; Parathion; Ronnel; Stirfos; Tokuthion; and Trichloronate.
The organo-phosphate pesticide compounds analyzed using EPA method 8151A were as follows: (all were below screening limits under the Lower Columbia Framework.
List of Compounds Analyzed With Method 8151A
Acifluorfen-sodium (Blazer & Tackle)
The organo-phosphate pesticide compounds below detection limits were; 2,4-D; 2,4-DB; 4-NITROANISOLE; Pentachloroanisole; Acifluorfen-sodium (Blazer & Tackle); Bentazon; Chloramben; Dalapon; Dicamba; Dichlorprop; Dinoseb; 2-(2-Methyl-4-chlorophenoxy) propian; Phorate (Thimate); Silvex; and Picloram.
The list of metals analyzed using EPA method 6010 were as follows:
List of Compounds Analyzed With Method 6010
Antimony samples were all below framework reportable quantities of 1 ppm. With a screening level of 150 ppm no biological effects were anticipated. Arsenic samples were analyzed but were not reported because of problems with the contract lab. Arsenic levels averaged 5.3 ppm in the Lower Granite LSRF study samples. Since the minimum screening limit is 57 ppm, it was decided not to rerun arsenic tests in the navigation channel. The highest cadmium result was found in Federal Navigation Channel at 1.06 ppm. With a screening level of 5.1 ppm no water quality effects were anticipated. No bioaccumulation criterion is available for cadmium. Copper was detected throughout the entire range of samples. The highest result at 44.3 ppm was found in the Green Belt Boat Basin. The Hell's Canyon Resort Marina averaged 10.4 ppm. Copper was found in the other areas to be dredged but was mostly below 10 ppm. The screening level for copper was 390 ppm. The copper levels in the samples were similar to what is found in Eastern Washington background levels. No information on Idaho background levels for metals was available. Lead was present in all sediment samples. The highest concentration found was in the Federal Navigation Channel at 8.35 ppm. The Lower Columbia Framework provides a screening level of 450 ppm for lead but does not have bioaccumulation criteria for lead. Nickel was found in all sediment samples. The highest level (12.1 ppm) was detected in the Green Belt Boat Basin. With a screening limit of 140 ppm nickel was not considered to present any ecological risk. Silver was not analyzed and no data is available for this metal. Zinc sample results ranged from non-detect to 37.9 ppm in the Federal Navigation Channel as compared to a screening level of 410 ppm. Hollebeke habitat management unit averaged 34 ppm but all other sampled areas demonstrated uniformity in the distribution and abundance of zinc in the sediments. Aluminum was one of the most abundant metals found in the sediments. The highest concentration was found was in the Idaho portion of the Federal Navigation Channel (7,885 ppm). The Lower Columbia framework does not consider Aluminum to be harmful to aquatic life or humans at any level and therefore no screening level or bioaccumulation limit is set. Barium was found in all sample sites with the highest sample recorded (99.6 ppm) in the Idaho Federal Navigation Channel. Beryllium was not found above detection limits in any of the samples. Barium and Beryllium are not considered to be harmful at any concentration by the Lower Columbia framework. Calcium was found in all samples with the highest reading (3,019 ppm) in the Green Belt Boat Basin. This alkali earth element is not a contaminant, however the great abundance of the element does contribute to the explanation of the alkaline pH in the Snake River as naturally occurring. Chromium was found in all the sample stations. The highest concentrations found were in the Idaho Navigation Channel and at the Hollebeck HMU intake with a reading of 8.83 ppm and 8.81ppm respectively. The Lower Columbia framework does not consider chromium to be a contaminant and therefore no screening level or bioaccumulation trigger is provided. Cobalt was found in all samples with the highest reading found at Willow Landing at 8.29 ppm. The Lower Columbia framework does not consider cobalt to be a contaminant and therefore no screening level or bioaccumulation trigger is provided. Iron was very abundant in the sediments with approximately 1/3 of all sample measurements in excess of 10,000 ppm. Since iron is a necessary micronutrient, a trace amount of it is required for aquatic life health. Iron has no screening level. There should be more than an ample supply of this element available for most organisms. Magnesium was found in all samples with the highest quantity found in Hell's Canyon Resort Marina at 405 ppm. . The Lower Columbia framework does not consider magnesium to be a contaminant and therefore no screening level or bioaccumulation trigger is provided. Manganese concentrations were high in most samples. The highest recording was 4,009 ppm in the Hollebeke HMU. The Lower Columbia framework does not consider manganese to be a contaminant and therefore no screening level or bioaccumulation trigger is provided. Molybdenum was not found above detection limits in any of the samples. Vanadium was found in all samples tested. The highest reading was found in the Green Belt Boat Basin at 65.2 ppm. Potassium and sodium are important micronutrients for maintaining viable invertebrate communities in trace amounts. Potassium and sodium have no screening levels. Most sample results for potassium were in excess of 1,000 ppm and the sodium levels were in slight excess of 100 ppm. This ratio is considered to be normal for fresh water sediments in most cases.
All samples were sieved to determine if less than 20% silts and clays (Wentworth size classification) were present in the material. Total organic carbon percentages of sediment samples were determined using EPA method 9060. These same samples were also analyzed for their percent by weight of total dissolved solids. Table H-21 presents a comparison of the three constituent properties used to determine if further tier two chemical testing was required.
Constituent Properties of Samples From the Proposed Dredging Sites
|Percent by Weight
US No. 230*
|Percent by Weight|
|Fed Navigation Channel (WA)||0.38 to 39.5||<0.1 to 2.89||<5.0 to 17.2|
|Fed Navigation Channel (ID)||0.09 to 4.87||0.12 to 12.7 (Petroleum high)||<5.0 to 21.3|
|Port of Lewiston||30.0 to 32.2||0.18||<5.0|
|Port of Clarkston||~20%||0.36||5.1|
|Hell's Gate Marina||21.7 to 31.0||2.89 to 3.17||10.9 to 21.2|
|Green Belt Boat Basin||31.0 to 37.3||1.89 to 3.13||15.1 to 21.7|
|Illia Boat Basin||>25.6%||0.44%||15.1|
|Willow Landing||19.0 to 25.5||0.66 to 1.07||30.1|
|Swallows Beach||18.0 to 38.2||>2.9||20.9 to 21.3|
|Hollebeke HMU||21.1 to 30.6||0.56 to 0.93||24.0 to 28.8|
|*The US 230 sieve separates sand and gravel from fine-grained soils such as silt or clay.|
Samples from the navigation approach dredging template recovered 99.99% by weight Wentworth-classified pebble and cobble gravels. With this information no further testing was required of these areas to be dredged.
The Herbicide Glyphosate (Roundup, Rodeo, and other trade names) and its degradation product AMPA were analyzed by high performance liquid chromatography. The breakdown product AMPA was not found above detection limits. A single Glyphosate detection of 23 ppb was discovered in the Green Belt Boat Basin. This was the only quantifiable above detection limit result out of 36 samples analyzed for Glyphosate. Although it is used very heavily in this local area, Glyphosate has a 6-month half-life and is an emergence herbicide. It is not anticipated to be present in measurable levels during the winter work window.
Total mercury was analyzed using the EPA 7471 cold vapor method. There were no mercury detections above soil detection limits (1 ppm) during this sediment quality survey. The screening criterion is less than 1 ppm (0.41ppm) but the bioaccumulation trigger is 1.5 ppm. The results do not completely identify if mercury is above screening levels or not. Since the data did not exceed bioaccumulation limits, it was not necessary to proceed with bioassay testing. Better equipment (lower detection quantification) and technique is available commercially at this time. Any future testing would use more sensitive tests (by an order of magnitude) since the screening and bioaccumulation limits are so close.
The oil and grease parameter was analyzed using EPA method 9071. The interim Lower Columbia testing framework does not consider petroleum products a contaminant and no screening levels are available from the framework. The analysis was conducted to evaluate the material's suitability as a habitat for aquatic species.
3.3 SUMMARY OF RESULTS
Ten potential areas to be dredged were evaluated in this phase II, pre-dredge sediment evaluation. In addition to the sediment evaluation, baseline summary water quality data was included in this phase II evaluation. The general water quality as measured by primary productivity was determined to be meso or hyper eutrophic since nutrient quantities are fairly or greatly abundant. The reservoir production is clearly limited by phosphorus abundance (table H-15). The primary water quality problem associated with dredging is an overabundance of ammonia in sediments and the amount readily released to the environment during the activity. The natural temperature and pH condition of the water exacerbates the ammonia problem. By dredging during a winter work window when the water temperatures are cold, there is a low risk of impacting aquatic life, their reproductive cycles, and ecology on the macro scale.
Anthropogenic organic compounds were evaluated using the EPA test methods: 8270C (semivolatile compounds), 8290 (dioxins and furans), 8141 (herbicides), 8151A (organo-phosphate pesticides), 9071 (oil and grease), and 547 (Glyphosate). These organic compounds were evaluated using the Puget Sound Sediment Disposal Procedures and the Lower Columbia (Portland District) Evaluation Framework screening and bioaccumulation limits. In addition, other protection criteria guidelines such EPA safe drinking water and EPA Protection of Aquatic Life Criterion were reviewed as well. Some dioxin and furan congeners were detected but were 100 times below the Puget Sound Disposal bioaccumulation trigger. Glyphosate was present in many samples but did not exceed drinking water standards. The other organic compound detections were PAH compounds. None of the PAH compounds were found to exceed the screening limits.
Twenty-one elemental metals were examined using EPA method 6010. For the metals that had screening and bioaccumulation limits, all results were below the recommended screening values. Manganese does not have a screening criterion under the interim protocols used. However, throughout the entire Lower Snake River, manganese was found in past and present samples in high concentrations. Mercury laboratory detection limits were very close to the bioaccumulation trigger. None of the samples evaluated for the potential areas to be dredged detected mercury. Arsenic laboratory results were not usable for this investigation. The Tier one data indicates the average arsenic concentrations were 10 times below the screening limit. Therefore, it was not necessary to repeat the tier two based on the available tier one data.
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