Six watersheds in New Hampshire were studied to determine the effects of road salt on stream water quality. Specific conductance in streams was monitored every 15 min for one year using dataloggers. Chloride concentrations were calculated from specific conductance using empirical relationships. Stream chloride concentrations were directly correlated with development in the watersheds and were inversely related to streamflow. Exceedances of the EPA water quality standard for chloride were detected in the four watersheds with the most development. The number of exceedances during a year was linearly related to the annual average concentration of chloride. Exceedances of the water quality standard were not predicted for streams with annual average concentrations less than 102 mg L(-1). Chloride was imported into three of the watersheds at rates ranging from 45 to 98 Mg Cl km(-2) yr(-1). Ninety-one percent of the chloride imported was road salt for deicing roadways and parking lots. A simple, mass balance equation was shown to predict annual average chloride concentrations from streamflow and chloride import rates to the watershed. This equation, combined with the apparent threshold for exceedances of the water quality standard, can be used for screening-level TMDLs for road salt in impaired watersheds.

41Land-based management has reduced nutrient discharges, however, many coastal waterbodies waterbodies without circulation models. The value of removed nitrogen was estimated using

Eutrophication is a challenge to coastal waters around the globe. In many places, nutrient reductions from land-based sources have not been sufficient to achieve desired water quality improvements. Bivalve shellfish have shown promise as an in-water strategy to complement land-based nutrient management. A local-scale production model was used to estimate oyster (Crassostrea virginica) harvest and bioextraction of nitrogen (N) in Great Bay Piscataqua River Estuary (GBP), New Hampshire, USA, because a system-scale ecological model was not available. Farm-scale N removal results (0.072 metric tons acre −1 year −1) were up-scaled to provide a system-wide removal estimate for current (0.61 metric tons year −1), and potential removal (2.35 metric tons year −1) at maximum possible expansion of licensed aquaculture areas. Restored reef N removal was included to provide a more complete picture. Nitrogen removal through reef sequestration was~3 times that of aquaculture. Estimated reef-associated denitrification, based on previously reported rates, removed 0.19 metric tons N year −1. When all oyster processes (aquaculture and reefs) were included, N removal was 0.33% and 0.54% of incoming N for current and expanded acres, respectively. An avoided cost approach, with wastewater treatment as the alternative management measure, was used to estimate the value of the N removed. The maximum economic value for aquaculture-based removal was $105,000 and $405,000 for current and expanded oyster areas, respectively. Combined aquaculture and reef restoration is suggested to maximize N reduction capacity while limiting use conflicts. Comparison of removal based on per oyster N content suggests much lower removal rates than model results, but model harvest estimates are similar to reported harvest. Though results are specific to GBP, the approach is transferable to estuaries that support bivalve aquaculture but do not have complex system-scale hydrodynamic or ecological models.

Abstract:Concentrations of chloride in excess of State of New Hampshire water-quality standards (230 mg/l) have been measured in watersheds adjacent to an interstate highway (I-93) in southern New Hampshire. A proposed widening plan for I-93 has raised concerns over further increases in chloride. As part of this effort, road-salt-contaminated groundwater discharge was mapped with terrain electrical conductivity (EC) electromagnetic (EM) methods in the fall of 2006 to identify potential sources of chloride during base-flow conditions to a small stream, Policy Brook. Three different EM meters were used to measure different depths below the streambed (ranging from 0 to 3 m). Results from the three meters showed similar patterns and identified several reaches where high EC groundwater may have been discharging. Based on the delineation of high (up to 350 mmhos/m) apparent terrain EC, seven-streambed piezometers were installed to sample shallow groundwater. Locations with high specific conductance in shallow groundwater (up to 2630 mmhos/m) generally matched locations with high streambed (shallow subsurface) terrain EC. A regression equation was used to convert the terrain EC of the streambed to an equivalent chloride concentration in shallow groundwater unique for this site. Utilizing the regression equation and estimates of onedimensional Darcian flow through the streambed, a maximum potential groundwater chloride load was estimated at 188 Mg of chloride per year. Changes in chloride concentration in stream water during streamflow recessions showed a linear response that indicates the dominant process affecting chloride is advective flow of chloride-enriched groundwater discharge. Published in

Quantitative descriptions of chemical, physical, and biological characteristics of estuaries are critical for developing an ecological understanding of drivers of change. Historical trends and relationships between key species of dissolved inorganic nitrogen (ammonium, nitrate/nitrite, total) from the Delta region of the San Francisco Estuary were modeled with an estuarine adaptation of the Weighted Regressions on Time, Discharge, and Season (WRTDS). Analysis of flow-normalized data revealed trends that were different from those in the observed time-series. Flow-normalized data exhibited changes in magnitude and even reversal of trends relative to the observed data. Modelled trends demonstrated that nutrient concentrations were on average higher in the last twenty years relative to the earlier periods of observation, although concentrations have been slowly declining since the mid-1990s and early 2000s. We further describe mechanisms of change with two case studies that evaluated 1) downstream changes in nitrogen following upgrades at a wastewater treatment plant, and 2) interactions between biological invaders, chlorophyll, macro-nutrients (nitrogen and silica), and flow in Suisun Bay. WRTDS results for ammonium trends showed a distinct signal as a result of upstream wastewater treatment plant upgrades, with specific reductions observed in the winter months during low-flow conditions. Results for Suisun Bay showed that chlorophyll production in early years was directly stimulated by flow, whereas the relationship with flow in later years was indirect and influenced by grazing pressure. Although these trends and potential causes of change have been described in the literature, results from WRTDS provided an approach to test alternative hypotheses of spatiotemporal drivers of nutrient dynamics in the Delta.

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This paper evaluates the operations of environmental supply-chain management atAdvanced Micro Devices (AMD), with facilities located in various countries around the world. The paper provides background on AMD's environmental practices and how they relate to greening the supply chain. Various practices and policies, as well as barriers and opportunities, are identified in this paper. The paper provides insights into how one organisation has been able to successfully and strategically align its supplier relationships with its environmental programmes.