Cleanup levels for pcbs and their combustion products at an industrial facility

In 1991, a fire occurred at a foundry in western Pennsylvania. The fire started in capacitors that contained polychlorinated biphenyls (PCBs) and subsequent sampling has indicated that PCBs and products of their incomplete combustion, the polychlorinated dibenzo-p-dioxins (PCDDs) and polychlorinated dibenzofurans (PCDFs), were released as a result of the fire. This article develops and provides justification for site-specific cleanup levels for the PCBs, PCDDs, and PCDFs accidentally released into this industrial facility during the fire. Cleanup levels were calculated using standard risk assessment approaches and assumptions, and these riskbased values were compared with cleanup criteria used for other sites. Final criteria were established based on this comparison and a consideration of such site-specific factors as migration potential, industrial use patterns, and the small mass of material present.     

Cascading ecological effects of low-level phosphorus enrichment in the Florida everglades

Few studies have examined long-term ecological effects of sustained low-level nutrient enhancement on wetland biota. To determine sustained effects of phosphorus (P) addition on Everglades marshes we added P at low levels (5, 15, and 30 microg L(-1) above ambient) for 5 yr to triplicate 100-m flow-through channels in pristine marsh. A cascade of ecological responses occurred in similar sequence among treatments. Although the rate of change increased with dosing level, treatments converged to similar enriched endpoints, characterized most notably by a doubling of plant biomass and elimination of native, calcareous periphyton mats. The full sequence of biological changes occurred without an increase in water total P concentration, which remained near ambient levels until Year 5. This study indicates that Everglades marshes have a near-zero assimilative capacity for P without a state change, that ecosystem responses to enrichment accumulate over time, and that downstream P transport mainly occurs through biota rather than the water column.     

Early Effects of Atmospheric Ammonia Deposition on Calluna Vulgaris (L.) Hull Growing on an Ombrotrophic Peat Bog

This paper reports data from a field study investigating the impacts of elevated ammonia (NH₃) deposition on Calluna vulgaris growing on an ombrotrophic peat bog in S.E. Scotland. Shoot extension, foliar N concentrations, chlorophyll concentration and chlorophyll fluorescence were measured during the second growing season of exposure to a gradient of ammonia concentrations. Results indicate that NH₃ increases growth between 150–200 kg N ha^–1y^–1 cumulative deposition. Foliar N content increased significantly in response to NH₃ cumulative deposition up to 400 kg N ha^–1 y^–1 whereas chlorophyll a content significantly decreased. Measurements of Fv/Fm suggest that although NH₃ exposure altered the growth and reduced chlorophyll a, the efficiency of photosystem II was insensitive to NH₃-N deposition at this stage.     

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.     

Logging injuries for a 10-year period in Jilin Province of the People's Republic of China

PROBLEM: Logging continues to be a major source of injuries in northeast China. This paper describes logging-related injuries in the Jilin Province of the People's Republic of China. METHODS: Logging fatalities and nonfatal injuries were summarized from 1981 to 1990 in Jilin. Injury data from 1991 for the entire forestry sector in China were also analyzed. RESULTS: Fatalities were mainly from of head injuries and were caused by being struck by an object. Nonfatal injuries were most often to the lower extremities and the head and were normally caused by being struck by an object or a fall or slip. The majority of both fatal and nonfatal logging injuries occurred to workers with less than 1 year of employment and those under 35 years old. Most injuries occurred November through March in Jilin. IMPACT ON INDUSTRY: Patterns of logging injury in Jilin of China were similar, but not identical, to those described in other studies of logging injuries worldwide. Methods found to be effective in reducing logging-related injuries in other parts of the world might be used in China to reduce the injuries associated with logging.     

Sailing the Shoals of Adaptive Management: The Case of Salmon in the Pacific Northwest

/ Emerging ecosystem science builds on adaptive management as an approach to dealing with salmon problems in the Pacific Northwest. Adaptive management brings scientific and democratic processes together. However, managers, the public, resource users, and scientists differ in their views on the causes of salmon decline. Managers emphasize habitat loss and over-harvest as the primary causes; commercial fishers point to habitat loss, management practices, and predators; and the public gives greatest weight to water pollution and ocean drift nets. Scientific studies of salmon often produce results that seem contradictory or unclear to the public. For adaptive management to be effective, scientists' and the public need to better understand one another's perspectives.KEY WORDS: Perception; Fishery management; Salmon; Pacific Northwest; Science     

From concept to practice: Implementing cumulative impact assessment in New Zealand

In 1991, provisions for environmental impact assessment in New Zealand were changed significantly with the enactment of the Resource Management Act. Among other provisions, this act requires consideration of cumulative impacts in environmental assessment activities undertaken by planners in newly created regional authorities and district and city councils. The institutional context in which the act is being implemented offers both opportunities and constraints to cumulative impact assessment. A lack of methods for CIA is a recognized problem. However, methods that have been developed for environmental impact assessments can be modified to incorporate second-, third-, and fourth-order impacts as well as to identify the direction and magnitude of additive and synergistic impacts. Layered matrices and combined networks are examples of such methods. While they do not allow for scientific prediction, they do provide the practitioner with the ability to consider the cumulative impacts of decisions. This is crucial in New Zealand, where statutory requirements are ahead of established methodologies.