SummaryHanford Site-derived pollutants are transported in surface waters in the particulate or dissolved form. Particulate transport is facilitated by sorption to minerally or organically derived material. In " fluvial systems, particulate transport is based on particle size, particle density, and water velocity. Contaminants associated with minerals are transported and deposited differently than those contaminants associated with organic carbon. In the Columbia River, sediment grain size and organic content can vary greatly from one location to another, resulting in significant differences in contaminant partitioning and transport. Previous evaluations of Columbia River sediments were typically performed on samples of bulk sediment and did not consider the physical (i.e., grain-size distribution) or chemical (i.e., organic carbon content) characteristics of a given site.A study to determine the characteristics associated with contaminant absorption was developed with the following objectives: 1) document the differences in sediment grain size and organic content and 2) determine associations between grain size, organic matter, and contaminants in sediments occurring at six established monitoring sites. Sediments at the six monitoring-site locations were analyzed for grain size, total organic carbon (TOC) content, radionuclides, metals, polycyclic aromatic hydrocarbons, polychlorinated biphenyls, and pesticides. This study demonstrated the utility of sediment grain characterization and TOC analysis in interpreting sediment-monitoring data.Grain size and organic content varied greatly among samples. Sediment from the Priest Rapids Dam monitoring sites were predominantly fine and very fine silt. Samples collected from the Hanford Reach monitoring sites were dominated by medium and fine sand, with the exception of White Bluffs Slough sediment that had nearly equal amounts of fine sand, very fine sand, and silt. The McNary Dam monitoring sites were characterized by very fine sand on the Washington shore and silt and clay on the Oregon shore. The TOC content among all sites ranged from 0.03% to 1.8296, with the higher TOC content generally associated with finer-grained sediment.This study found the majority of radionuclide concentrations to be below minimum detection levels at all sites, with the exception of 137Cs and 38U. While the highest concentrations of 137Cs and 238U were found in sediments from the McNary Dam monitoring sites, concentrations measured at the other three sites did not differ greatly. All metals were detected in each sediment sample. Sediment from the McNary Dam monitoring sites had the highest concentrations of metals, with the exception of barium, lead, and zinc. A transect across the McNary Dam monitoring sites revealed gradually increasing metals concentrations toward the Oregon shore, with a direct correlation between grain size and TOC content with metals concentrations. Organics (i.e., polycyclic aromatic hydrocarbons, polychlorinated biphenyls, and pesticides) were undetected in nearly a...
Drift prospecting surveys in New Brunswick have previously had limited success in recognizing dispersal plumes through geochemical or mineralogical analyses of tills. This study was undertaken in the Todd Mountain -Trout Lake area of central New Brunswick to define possible constraints on glacial dispersal and assist in related prospecting activities. Dispersal patterns for specific heavy minerals in the silt to fine sand (0.125 mm -0.250 mm) fraction of 63 till samples were investigated over a 12 km x 25 km area. Twelve minerals, confirmed by Scanning Electron Microscopy, were selected for study on the basis of local geology and ease of recognition.In this area of New Brunswick, eastward-trending dispersal plumes can be distinguished over short distances (<5 km) only for rare indicator minerals that characterize specific sources (e.g., coticules or zircon grains). When sampled at intervals of 100 m the mineral dispersal patterns more clearly reflect the nature and trend of units in the bedrock. Correlations between mineral content and geochemistry are poor because of glacial mixing of variable source materials. Some poor chemical correlations may also be due to weathering and hydromorphic dispersion. In this area of central New Brunswick, prospecting programs utilizing the fine-grained till fraction require close sample spacing and accurate identification of till facies.Les levds de prospection par les depots glaciaires au Nouveau-Brunswick ont auparavant rencontre des succes mitigds dans la reconnaissance des patrons de dispersion glaciaire par les analyses geochimiques ou mineralogiques des tills. La presente etude a ete entreprise dans la region mont Todd -lac T rout, dans le centre du Nouveau-Brunswick, afin de fournir des donnees sur la dispersion glaciaire et d 'assister les activites de prospection associees. Les patrons de dispersion de certains mindraux lourds dans la fraction silt a sable fin (0.125 mm -0.250 mm) de 63 dchantillons de till ont ete dtudies pour une rdgion de 12 km par 25 km. Douze mindraux, dont l'identification a ete confirmde par microscopie electronique, ont etechoisis pour l 'etude en raison du contexte geologique et de leur facilite d 'identification.Pour cette rdgion du Nouveau-Brunswick, il est possible de distinguer des patrons de dispersion de direction est, sur de courtes distances (<5 km), seulement pour de rares mindraux indicateurs caracteristiques de certaines sources (comme les grains de coticule ou de zircon). A des intervalles d'echantillonage de 100 m, les patrons de dispersion mindraux refletent plus nettement la nature et l 'orientation des unitds du socle. La correlation entre le contenu en mindraux et la composition geochimique est faible en raison du melange glaciaire de matdriaux de diverses sources. II y a de faibles correlations geochimiques qui peuvent aussi etre dues a T alteration superficielle et a la dispersion par l 'eau souterraine. Dans cette rdgion du centre du Nouveau-Brunswick, les programmes d 'exploration qui utilisent la fraction fine du till ndc...
J • Determined bioaccumulation potential of contaminants associated with test treatment composite IH-2/IH-3 Comp through 28-day exposures using the clam Macoma nasuta and the polychaete N. virens. Bioaccumulation potential was evaluated by comparing contaminants associated with tissues exposed to test treatments to tissue levels after exposure to the reference treatments IHR1 and IHR2. • Performed appropriate comparisons of results through statistical analyses to determine compliance of the proposed dredged material with Section 103 of MPRSA. WINYAH BAY iii The resultsof physical/chemicalanalyses Indicatedthat some contaminantsof concern were presentin testtreatmentsrepresentingdredgedmaterialwhencomparedto the reference treatmentsEC Ref-Comp, IHR1, and IHR2. Elevatedlevelsof polynucleararomatic hydrocarbons (PAHs) were observedin testtreatmentsIH-2, IH-3, and Samplt Rivertreatments; pesticideswere detectedonly in testtreatmentSR-1. Dioxincongenerswere presentin all test treatments,thoughthe mosttoxicformssuchas 2,3,7,8-TCDD were absent. Metalswere presentin all treatments,butonlyelevated in the Sampit Rivertest treatments. Inner Harbortest treatmentswere notanalyzedfor metalsas data from previousstudieswere available. Organotinswere presentonly In test treatment SR-1. Acute SP toxicological testsshowed no evidenceof acute toxicityof test sedimentsto A. abd/ta, R. abron/us, or N. vtrens,althoughboth A. abdlta and N. v/renstoxicological tests were not consideredvalid becauseof a <90% controlsurvival. The SPP exposureswere not acutely toxicto M. baha, M. bery///na,or L. pictus. Bloaccumulation potentialwas evaluatedthroughthe exposureof M. nasuta and N. v/rens to test treatmentIH-2/IH-3 Compand reference treatments IHR1 and IHR2 for 28 days. Statistical analyses of these data showed no evidence of significantlyelevated levels of PAHs, dioxlns,or organotinsin the tissues of these organisms. The resultsof this study Indicate that, based on the acute toxicityand bioaccumulationtests, dredged material representedby these test treatmentsis in compliancewiththe benthicbtoassay critedaor Section 227.13(c) as well as AppendixesA and B of the 1991/mp/ernentat/on Manual The resultsgenerated by this study can be used by USACE in their decision-makingprocess regardingacceptabledisposaloptionsfor the sedimentsfrom WinyahBay.
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