Vegetative delineation of coastal salt marsh boundaries

Legislation mandating the protection of wetlands, combined with current pressures to convert them to other uses, emphasize the need to determine accurately a wetland-upland boundary We investigated six methods designed to establish such a boundary based on vegetation Each method was applied to a common data set obtained from 295 quadrats along 22 transects between marsh and upland areas in 13 intertidal saline wetlands in Oregon and Washington. The multiple occurrence, joint occurrence, and five percent methods required plant species to be classified as salt marsh, upland, and non-indicator, cluster and similarity methods required no initial classification Close agreement on wetland-upland boundaries determined by the six methods suggests that preclassification of plants and collection of plant cover data may not be necessary to determine the boundary     

A human health assessment of hazardous air pollutants in Portland, OR

Ambient air samples collected from five monitoring sites in Portland, OR during July 1999 to August 2000 were analyzed for 43 hazardous air pollutants (HAP). HAP concentrations were compared to carcinogenic and non-carcinogenic benchmark levels. Carcinogenic benchmark concentrations were set at a risk level of one-in-one-million (1x10(-6)). Hazard ratios of 1.0 were used when comparing HAP concentrations to non-carcinogenic benchmarks. Emission sources (point, area, and mobile) were identified and a cumulative cancer risk and total hazard index were calculated for HAPs exceeding these health benchmark levels. Seventeen HAPs exceeded a cancer risk level of 1x10(-6) at all five monitoring sites. Nineteen HAPs exceeded this level at one or more site. Carbon tetrachloride, 1,3-butadiene, formaldehyde, and 1,1,2,2-tetrachloroethane contributed more than 50% to the upper-bound lifetime cumulative cancer risk of 2.47x10(-4). Acrolein was the only non-carcinogenic HAP with hazard ratios that exceeded 1.0 at all five sites. Mobile sources contributed the greatest percentage (68%) of HAP emissions. Additional monitoring and health assessments for HAPs in Portland, OR are warranted, including addressing issues that may have overestimated or underestimated risks in this study. Abatement strategies for HAPs that exceeded health benchmarks should be implemented to reduce potential adverse health risks.     

A NEW FLASHINESS INDEX: CHARACTERISTICS AND APPLICATIONS TO MIDWESTERN RIVERS AND STREAMS1

ABSTRACT: The term flashiness reflects the frequency and rapidity of short term changes in streamflow, especially during runoff events. Flashiness is an important component of a stream's hydrologic regime. A variety of land use and land management changes may lead to increased or decreased flashiness, often to the detriment of aquatic life. This paper presents a newly developed flashiness index, which is based on mean daily flows. The index is calculated by dividing the pathlength of flow oscillations for a time interval (i.e., the sum of the absolute values of day‐to‐day changes in mean daily flow) by total discharge during that time interval. This index has low interannual variability, relative to most flow regime indicators, and thus greater power to detect trends. Index values were calculated for 515 Midwestern streams for the 27‐year period from 1975 through 2001. Statistically significant increases were present in 22 percent of the streams, primarily in the eastern portion of the study area, while decreases were present in 9 percent, primarily in the western portion. Index values tend to decrease with increasing watershed area and with increasing unit area ground water inputs. Area compensated index values often shift at ecoregion boundaries. Potential index applications include evaluation of programs to restore more natural flow regimes.     

Targeted sampling protocol as prelude to bacterial source tracking with Enterococcus faecalis

Recent studies suggest that host origin databases for bacterial source tracking (BST) must contain a large number of isolates because bacterial subspecies change with geography and time. A new targeted sampling protocol was developed as a prelude to BST to minimize these changes. The research was conducted on the Sapelo River, a tidal river on the Georgia coast. A general sampling of the river showed fecal enterococcal numbers ranging from <10 (below the limit of detection) to 990 colony-forming units (CFU) per 100 mL. Locations with high enterococcal numbers were combined with local knowledge to determine targeted sampling sites. Fecal enterococcal numbers around one site ranged from <10 to 24,000 CFU per 100 mL. Bacterial source tracking was conducted to determine if a wastewater treatment facility at the site was responsible for this contamination. The fecal indicator bacterium was Enterococcus faecalis. Ribotyping, automated with a RiboPrinter (DuPont Qualicon, Wilmington, DE), was the BST method. Thirty-seven ribotypes were observed among 83 Ent. faecalis isolates obtained from the Sapelo River and the wastewater lagoon. Sixteen ribotypes were associated with either the river or the lagoon, and only five ribotypes (14%) were shared. Nevertheless, these five ribotypes represented 39 of the 83 Ent. faecalis isolates, almost a majority (47%). These results suggest that the fecal contamination in the river came from the wastewater treatment facility. As a prelude to BST, targeted sampling minimized subspecies changes with geography and time, and eliminated the need for a permanent host origin database by restricting BST to a small geographic area and requiring sampling to be completed in one day.     

Methane emissions of beef cattle on forages: efficiency of grazing management systems

Fermentation in the rumen of cattle produces methane (CH4). Methane may play a role in global warming scenarios. The linking of grazing management strategies to more efficient beef production while reducing the CH4 emitted by beef cattle is important. The sulfur hexafluoride (SF6) tracer technique was used to determine the effects of best management practices (BMP) grazing compared with continuous grazing on CH4 production in several Louisiana forages during 1996-1998. Cows and heifers (Bos taurus) grazed common bermudagrass [Cynodon dactylon (L.) Pers.], bahiagrass (Paspalum notatum Flugge), and ryegrass (Lolium multiflorum Lam.) pastures and were wintered on bahiagrass hay with supplements of protein molasses blocks (PMB), cottonseed meal and corn (CSMC), urea and corn (URC), or limited ryegrass grazing (LRG). Daily CH4 emissions were between 89 and 180 g d(-1) for young growing heifers and 165 to 294 g d(-1) for mature Simbrah cows. Heifers on "ad lib" ryegrass in March and April produced only one-tenth the CH4 per kg of gain as heifers on LRG of 1 h. Using BMP significantly reduced the emission of CH4 per unit of animal weight gain. Management-intensive grazing (MIG) is a BMP that offers the potential for more efficient utilization of grazed forage crops via controlled rotational grazing and more efficient conversion of forage into meat and milk. Projected CH4 annual emissions in cows reflect a 22% reduction from BMP when compared with continuous grazing in this study. With the BMP application of MIG, less methane was produced per kilogram of beef gain.     

Temporal and local trends of PCDD/F levels in cow's milk in Switzerland

Levels of polychlorinated dibenzo-p-dioxins and dibenzofurans (PCDD/F) were determined in 30 Swiss cow's milk samples collected at dairy farms in the vicinity to point sources, in rural/alpine areas distant to known sources, and from tanks in large industrial milk processing plants. The contaminant concentrations in samples collected in 2001 were compared to data from analyses conducted in 1984 and 1990/1991 at the same sites. In 2001, the PCDD/F levels in milk from farms near point sources (0.63+/-0.26 ng I-TEQ/kg milk fat) are slightly but significantly higher in than milk from remote areas (0.36+/-0.09 ng I-TEQ/kg milk fat). Consumer milk collected at the processing plants had intermediary levels (0.51+/-0.19 ng I-TEQ/kg milk fat). However, milk in 2001 was significantly less contaminated than the samples collected in 1990/1991 and 1984. This trend is particularly pronounced near point sources but is also apparent in consumer milk and milk from remote areas. No geographical gradient in the atmospheric input of PCDD/F in Switzerland was found. The reduction in PCDD/F levels in dairy milk is paralleled by and correlated to the remediation of known PCDD/F emitting industries, as enforced by federal authorities.     

Audits and root cause analysis

Many current audit programs are very good at determining the compliance issues at a site, but are less successful in developing long-term compliance solutions. One method for addressing these issues is the use of root cause analysis techniques. These techniques allow the facility to identify and focus on permanent solutions to compliance issues. The authors note the following: Conducting a root cause analysis is not a substantial burden on the audit team or the facility. Most information is already collected during the audit, but is not being used. Looking at the overview pattern of the root cause analysis can provide a picture of the maturity of your audit program. Pareto charts are excellent methods to convey the results of your analysis. They show both the trends of analysis and help highlight the most significant root causes.     

Revised emergency vacuum relief device sizing for atmospheric distillation systems

Conventional vacuum relief methodologies are usually protective responses; that is, they accomplish their purpose by substitution of an inert gas (usually nitrogen) for the process gases removed by an external vacuum source, or for condensable vapour collapsed by an internal process mechanism (e.g. condensation). While this approach is theoretically possible for all potential vacuum scenarios, it becomes practically impossible to implement for installations where a rapid phase change can impart near-instantaneous system pressure reductions. The procedure outlined in this paper takes a preventive approach: eliminate the source of vacuum generation before the safe lower system pressure limit is reached. For distillation and other refluxing systems, this vacuum source is usually the main overhead condenser, which is designed to collapse large volumes of condensable vapour. To eliminate the vacuum source requires elimination of the system's ability to rapidly condense vapour. This goal is accomplished by introduction of inert gas directly into the condensing system to ‘blanket’ the heat transfer surface and stop condensation. The procedure determines the rate, amount and location for introduction of inert gas. The required design data include: (i) system starting pressure, (ii) maximum allowable system vacuum, (iii) volume of the condensing system, and (iv) normal system condensing rate. By determining the rate at which the condenser removes vapour volume from the system, and designing an inert gas delivery system to meet or exceed this rate, the vacuum generation potential of the system is effectively eliminated using a much smaller quantity of inert gas than with the more traditional volume substitution methods.     

International education and sustainable development: an American experience in Bangkok,Venice and Guayaquil

Worcester Polytechnic Institute's (WPI) unique academic plan enables students to study sustainable development and the environment as part of an international educational experience. As a technological university, WPI requires students to complete an interdisciplinary project on the interaction of science or technology and society. This paper describes the environmental projects completed by WPI students, in Bangkok, Venice and Guayaquil. The lessons from WPI's experience provide a model for environmental education at other institutions. These interdisciplinary projects not only promote environmental awareness among students, but they also provide tangible assistance to regions which are developing strategies for sustainable development.     

Potential conflict between the coal and arable land resources in australia: A case for corporate responsiveness

Background information on possible surface-coal-mining operations in arable agricultural areas in Australia is provided. The major co-occurrence of the coal and arable land resources was in the Darling Downs region of Queensland and the Liverpool Plains region of New South Wales; however, coal development will probably only occur in the former region over the next decade. Analysis of the situation in the Darling Downs region, which consists of 11 Shires, found five companies conducting prefeasibility projects for surface-coal development and the size of exploration areas concerned far exceeding final mined-land disturbance estimates. Most of the land included in the prefeasibility studies was classified as arable with moderate crop restrictions requiring intensive management (classes II–IV). The total area of land that may be disturbed at some time in the future was less than 2% of the arable land in the Shires concerned. Project mutual exclusivity and ongoing rehabilitation of disturbed areas further reduce arable land out of production at any one time. It is suggested that, if self-regulation by the coal industry in Australia on rehabilitation issues is to remain a viable option in these areas, an understanding between the corporate and public sectors on the extent and limitations of its responsibilities must be obtained. The current development of a National Conservation Strategy for Australia should assist this to proceed. Research on various rehabilitation issues may be required prior to project commitment to ensure the responsibilities identified are realizable. Integrative problem-solving, incorporating audit procedures, was suggested as a suitable method to achieve these aims and corporate responsiveness was seen as a necessary first step.