Publications

Toxicity tests with Ceriodaphnia dubia were conducted to determine acute (48 h) and chronic (7-day survival and reproduction) effects of four commonly used herbicide formulations. The 48-h LC50s in decreasing order of toxicity were 14.36 mg/L (Micro-Tech®), 15.93 mg/L (Bicep®), 32.99 mg/L (Extrazine®), and 35.36 mg/L (Lexone®). Reduced reproduction was detected at concentrations below 48-h LC50s f

Concentrations of polychlorinated biphenyls (PCBs), and 2,3,7,8-tetrachlordibenzo-p-dioxin equivalents (TCDD-EQ) were determined in eggs and chicks of double-crested cormorants (DCC) which were collected in 1989 from eight locations in the Laurentian Great Lakes. The mean biomagnification factor (BMF) from forage fish to eggs was found to be 31.3. Absolute and relative concentrations as well as ra

The ethoxyresorufin O-deethylase (EROD) induction of 20 polychiorinated dibenzofurans (PCDFs) was examined in the H4IIE rat hepatoma cell bioassay. The selection of the compounds tested was based on a multivariate chemical characterization laying the groundwork for covering the whole chemical series of PCDFs. The EROD induction potency was found to vary in ED50 values from 25 to 100,000,000 pg/mg,

No abstract available.

The frequency of the 1993 flood in the upper Mississippi River Basin is characterized by applying Bulletin 17B and L-moment methods to 111 unregulated watersheds in the basin. The analysis indicated that the 1993 flood was primarily a 10- to 50-year event on unregulated watersheds less than about 50,000 square kilometers. Of the 111 stations analyzed, the L-moment and Bulletin 17B methods were use

Twenty-two bottom-sediment samples were collected from Town Lake in Austin, Texas, in 1991 and 1992 and analyzed for chlorinated insecticides by a reconnaissance-quality, electron-capture gas chromatography screening method developed by the U.S. Geological Survey (USGS). Four different chlorinated insecticides (aldrin, chlordane, dieldrin, and p,p'-DDT) and two degradation products of p,p'-DDT (p,

Landsat Thematic Mapper (TM) data were used to estimate that about 51,000 acres of crops were irrigated with water pumped from the Edwards aquifer in Uvalde and Medina Counties, Texas in 1991. Bands 2, 3,4, and 5 from a TM image for August 10,1991, were classified using the maximum-likelihood, unsupervised-classification procedure to identify the areas of crops irrigated in the two counties. Detai

Tertiary-treated wastewater currently (1991) is being injected into the Hueco bolson aquifer at a site in northeastern El Paso, Texas, to supplement the quantity of available freshwater. Hydrologic data were compiled and water-quality and bacterial data were collected from existing wells near the Hueco Bolson Recharge Project (HBRP) in August and September 1990 and 1991. Borehole tracer tests indi

Flooding of the Iowa River during July and August 1993 caused extensive contraction scour at the State Highway 99 bridge over the Iowa River at Wapello, Iowa. At least 3.3 m of piling under the footing of the second pier from the right (west) abutment were exposed. The scoured streambed did not fill in again after the flood receded, and a bathymetric survey in November 1993 showed that the streamb

For the flood of September 10, 1992, in Raven Fork, Swain County, North Carolina, a peak discharge of 460 cubic meters per second was computed by using the slope-area method. Accuracy of this determination depends on suitability of the selected reach and, in particular, selection of Manning's roughness coefficients, interpretation of the high-water marks, number and placement of cross sections, pr

No abstract available.

Water-resources data for the 1993 water year for North Carolina consist of records of stage, discharge, and water quality of streams; and stage and contents of lakes and reservoirs. This report contains discharge records for 159 gaging stations and stage and contents for 56 lakes and reservoirs; water quality for 54 gaging stations and 5 miscellaneous sites; and continuous daily tide stage for 10