[en] Following the crash of a tanker truck in the autumn of 1994, 27000 litres of petrol, paraffin and diesel oil accidentally spilt into the river Vulluelva, Norway. This report discusses the observed biological effects of the spill. The spill immediately killed the entire brown trout parr population in the lower half of the stream and 30% of the sea trout spawning population. A few weeks later, after extensive clean-up and of heavy flood, significant numbers of trout spawned within a limited river stretch in the lowest part of the stream and not in the normally more favoured spawning habitats further upstream. Analyses of the chloride content of blood plasma of parr and spawners sampled at the final phase of the spawning period showed only a few cases of stressed physiological condition. The significant variation in the observed egg survival in the river stretch preferred for spawning may be related to possible negative impacts by hydrocarbons. The study demonstrates no negative impacts on fry growth during the first season following the contamination. Mass mortality of the zoobenthos followed the oil spill in October 1994 and the populations of the dominating groups were reduced to a very low level. The recovery of zoobenthos was not complete until 9-10 months later. 62 refs., 8 figs., 11 tabs

[en] Downstream migrating salmon and steelhead (Oncoryhnchus spp.) smolts were monitored at the Rock Island Dam bypass trap from April 1--August 31, 1996. This was the twelfth consecutive year that the bypass trap was monitored. Data collected included: (1) number of fish collected by species, (2) number of fin clipped and/or Passive Integrated Transponder (PIT) tagged fish caught by species, (3) total number of fish showing signs of gas bubble trauma (GBT), (4) percent of descaled fish, and (5) daily average river flow, powerhouse number-sign 1 flow, powerhouse number-sign 2 flow and daily average spill. These data were transmitted to the Fish Passage Center (FPC), which manages the Smolt Monitoring Program throughout the Columbia River Basin. The Smolt Monitoring Program is used to manage the water budget, releasing upstream reservoir water storage allocated to supplement river flows during the downstream migration of juvenile salmonids

[en] The program described in this report studies the suitability of electrodialysis-ion exchange (EDIX) to treat aqueous streams containing heavy metals and radioactive cations in a solution containing sodium and nitrates. The goal of the program was to produce a cation stream containing sodium, heavy metals, and radioactive cations; an anion stream of nitric acid free of heavy metals and radioactive cations; and a product stream that meets discharge criteria. The experimental results, described in detail, indicated that EDIX was not a suitable process for treating wastes containing metals that formed insoluble hydroxides in a basic solution; the metals precipitate in the catholyte and feed compartments, and in the cathode membrane. The test program was therefore terminated prior to completion of all planned activities. 2 refs., 22 figs., 8 tabs

[en] Preliminary modeling efforts for the Hanford Site's Low Level Waste-Performance Assessment (LLW PA) identified ¹²⁹I, ²³⁷Np, ⁷⁹Se, ⁹⁹Tc, and ²³⁴,²³⁵,²³⁸U as posing the greatest potential health hazard. It was also determined that the outcome of these simulations was very sensitive to the parameter describing the extent to which radionuclides sorb to the subsurface matrix, i.e., the distribution coefficient (K_d). The distribution coefficient is a ratio of the radionuclide concentration associated with the solid phase to that in the liquid phase. The objectives of this study were to (1) measure iodine, neptunium, technetium, and uranium K_d values using laboratory conditions similar to those expected at the LLW PA disposal site, and (2) evaluate the effect of selected environmental parameters, such as pH, ionic strength, moisture concentration, and radio nuclide concentration, on K_d values of selected radionuclides. It is the intent of these studies to develop technically defensible K_d values for the PA. The approach taken throughout these studies was to measure the key radio nuclide K_d values as a function of several environmental parameters likely to affect their values. Such an approach provides technical defensibility by identifying the mechanisms responsible for trends in K_d values. Additionally, such studies provide valuable guidance regarding the range of K_d values likely to be encountered in the proposed disposal site

[en] Analyses of pore water from boreholes at Yucca Mountain indicate that unsaturated-zone pore water has significantly larger concentrations of chloride and dissolved solids than the saturated-zone water or perched-water bodies. Chemical compositions are of the calcium sulfate or calcium chloride types in the Paintbrush Group (Tiva Canyon, Yucca Mountain, Pah Canyon, and bedded tuffs), and sodium carbonate or bicarbonate type water in the Calico Hills Formation. Tritium profiles from boreholes at Yucca Mountain indicate tritium-concentration inversions (larger tritium concentrations are located below the smaller tritium concentration in a vertical profile) occur in many places. These inversions indicate preferential flow through fractures. Rock-gas compositions are similar to that of atmospheric air except that carbon dioxide concentrations are generally larger than those in the air. The delta carbon-13 values of gas are fairly constant from surface to 365.8 meters, indicating little interaction between the gas CO₂ and caliche in the soil. Model calculations indicate that the gas transport in the unsaturated zone at Yucca Mountain agrees well with the gas-diffusion process. Tritium-modeling results indicate that the high tritium value of about 100 tritium units in the Calico Hills Formation of UZ-16 is within limits of a piston-flow model with a water residence time of 32 to 35 years. The large variations in tritium concentrations with narrow peaks imply piston flow or preferential fracture flow rather than matrix flow. In reality, the aqueous-phase flow in the unsaturated zone is between piston and well-mixed flows but is closer to a piston flow

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