A new subspecies of the plains pocket gopher (Geomys bursarius ozarkensis), located in the Ozark Mountains of north central Arkansas, was recently described by Elrod et al. (2000). Current range for G. b. ozarkensis was established, habitat preference was assessed by analyzing soil samples, vegetation and distance to stream and potential pocket gopher habitat within the current range was identified. A census technique was used to estimate a total density of 3, 564 pocket gophers. Through automobile and aerial survey 51 known fields of inhabitance were located extending the range slightly. Soil analyses indicated loamy sand as the most common texture with a slightly acidic pH and a broad range of values for other measured soil parameters and 21 families of vegetation were identified. All inhabited fields were located within an average of 107.2m from waterways and over 1,600 hectares of possible suitable habitat was identified.

Due to concern about diminishing landfill space, the City of Denton contracted a municipal solid waste characterization study in 1999 that would identify materials for diversion. This paper describes the results of 5 1-week waste sorting events, a scale-house analysis, a recycling participation study, a recycler profile and a similar city study. The results of the characterization studies suggest that at least 50% of each waste stream is recyclable or divertible though paper products accounted for no more than 45% by weight of any waste stream. Curbside recycling participation rate was 71% during the 6-week study period though the average weekly set-out rate was 37%. Recycling participation rates varied significantly by zip code and by home value categories but not by gender. Denton is fairly progressive in its waste management approach when compared to demographically similar cities on a 15-question assessment though recommendations for improvement have been identified.

A hydrologic model and watershed export model was used to estimate the loading of nutrients and total suspended solids from un-gaged local watersheds associated with Lake Texoma. Discharge to the reservoir from local watersheds was predicted using a modification of the curve number method in HEC Hydrologic Modeling System (HEC-HMS). Event mean concentrations were applied to land use to estimate loadings of nutrients and TSS. Total discharge from the local watersheds was estimated to be 3.02 x 107 cubic meters for a study window of March 1 to May 31, 1997, less than 10 percent of the input to the lake from the Red River and Washita River systems. Loadings were estimated to be 33,553 kg nitrogen, 4,401 kg phosphorus, and 3,423,140 kg TSS. The models and results obtained from their application appear to have potential utility for use in a water quality management decision support system for the reservoir.

Robust Vallisneria americana was cultured for restoration purposes. Preliminary studies, with various iron treatments, were conducted to ascertain the amount of phosphorous release into the water column from sediments. There was a significant difference in the amount of phosphorous released if commercial sediment was used with a low iron amendment or without an iron amendment. The second study consisted of planting V. americana on two different sediment types while supplying half of the plants with additional CO2. Plants grown on pond sediment with additional CO2 had significantly more biomass. In the third study all plants were grown on pond sediment, and half were treated with CO2. All plants that were treated with additional CO2 had significantly more biomass than those that were aerated.

The primary focus of the study was to compare dissolved organic carbon (DOC) at baseline stream flow to DOC at a higher post-rain stream flow, with a secondary focus on comparison of DOC between sites. Comparisons were also done on suspended solids at baseline flow to those of the higher post-rain flow, as well as suspended solids between sites. Significant differences did exist between DOC sampled at baseline flow and DOC in samples taken at peak flow. The study found no difference in suspended solids among sites neither on either baseflow sampling nor on the post rain event sampling.

TNT (2,4,6-trinitrotoluene) is a persistent contaminant at many military installations and poses a threat to aquatic ecosystems. Data from environmental fate and toxicity studies with TNT revealed that sediment toxicity test procedures required modification to accurately assess sediment TNT toxicity. Key modifications included aging TNT-spiked sediments 8-14 d, basing lethal dose on measured sediment concentrations of the molar sum of TNT and its main nitroaromatic (NA) transformation products (SNA), basing sublethal dose on average sediment SNA concentrations obtained from integration of sediment SNA transformation models, avoiding overlying water exchanges, and minimizing toxicity test durations. Solid phase microextraction fibers (SPMEs) were investigated as a biomimetic chemical measure of toxicity and bioavailability. Both organism and SPME concentrations provided measures of lethal dose independent of exposure scenario (TNT-spiked sediment or TNT-spiked water) for Tubifex tubifex. Among all benthic organisms tested (Chironomus tentans, Ceriodaphnia dubia, T. tubifex) and matrixes, median lethal dose (LC50) estimates based on SPME and organism concentrations ranged from 12.6 to 55.3 mmol SNA/ml polyacrylate and 83.4 to 172.3 nmol SNA/g tissue, ww, respectively. For Tubifex, LC50s (95% CI) based on SNA concentrations in sediment and SPMEs were 223 (209-238) nmol SNA/g, dw and 27.8 (26.0-29.8) mmol SNA/ml, respectively. Reproductive effects …