Case Studies of Minimizing Plating Bath Wastes in the Electronics Products Industry

In this paper the authors report on the results of case studies carried out under the sponsorship of the U.S. EPA to determine the effectiveness of four processes designed to reduce the amount of hazardous waste from plating operations. Data reported are based on the results of actual on-site sampling of the processes and encompass effectiveness, environmental, and economic considerations. Two of the case studies evaluating the use of sodium borohydride reduction as a substitute for lime/ferrous sulfate precipitation, found that the technology was a viable substitute in one case and was marginally acceptable in another. Another case study, involving carbon adsorption removal of organic contaminants from plating bath wastes, found that this technology significantly reduced both disposal costs and waste volume. A final case study of electrolytic recovery indicated that while acid copper electroplating rinses are amenable to electrolytic recovery, other metal-bearing rinses, such as those from solder (tin/lead) plating or etching are less appropriate.     

COOPERATION IN WATER RESOURCES PROGRAMS: ALASKA'S EXAMPLE1

ABSTRACT: Alaska possesses a diversity and magnitude of water resources unmatched in any other state. With over 15% of the area of the whole United States, and 40% of the nation's total fresh water supply, but an extreme lack of basic hydrologic and climatologic data, cooperation among agencies and individuals concerned with evaluating, planning, and carrying out water resources programs is essential. Toward this end, the Inter-Agency Technical Committee for Alaska (IATCA) was established under charter from the Water Resources Council. Representation in IATCA includes virtually all Federal, State, and academic entities in Alaska having an interest in the water resources of the State. Existence of IATCA has permitted or facilitated numerous Alaskan water resources programs. Several are described briefly in this paper: A flood warning network in the Chena River basin; establishment of the Caribou-Poker Creeks Research Watershed in Central Alaska; preparation and periodic updating of the “Ten-Year Plan for Water Resources Data Acquisition”; current planning for an integrated “real-time reporting network” for hydrometeorological data within the State; and a framework for implementation of the Alaskan phase of the National Water Resources Assessment, currently in the initial phases. Accomplishments to date testify that it is indeed possible to “get it all together” in the broad field of “Water Resources” in the largest of our 50 states.     

Examination of a New Remedial Technology for Capping Contaminated Sediments: Large-Scale Laboratory Evaluation of Sediment Mixing and Cap Resistance to Erosive Forces

The potential effectiveness of a new composite-aggregate capping technology, AquaBlok^TM—in physically isolating contaminated, fine-grained sediments derived from an Ohio, Lake Erie tributary—was evaluated in the laboratory. In particular, large-scale settling-column studies were conducted to determine the degree to which composite-aggregate material penetrates into and/or mixes with the sediment, perhaps affecting the degree to which sediment could be physically isolated through capping. Additionally, large-scale flume studies were conducted to determine resistance of the composite-aggregate material to significant and long-term, fluvial-like erosive forces; the resistance of other potential capping materials was also evaluated for comparison. Experimental results indicate that the composite-aggregate material effectively isolates sediment through the formation of a continuous and relatively erosion-resistant, hydrated capping layer atop the sediments.     

CLEAN WATER ACT REAUTHORIZATION: HOW FAR HAVE WE COME?1

ABSTRACT: This paper first presents a brief review of an earlier effort to estimate the benefits associated with achieving the Clean Water Act objectives. It then discusses what would be involved in doing a retrospective benefit-cost analysis of the Clean Water Act and some information on changes in several measures of water quality over the past 20 years. The paper concludes with a summary of a recent effort to estimate the realized benefits associated with the Clean Water Act and some implications for policy. (KEY TERMS: benefits; benefit-cost analysis; costs; recreation; water pollution; water quality.)     

ALAWAT: A spatially allocated watershed model for approximating stream,sediment, and pollutant flows in Hawaii,USA

The Ala Wai Canal Watershed Model (ALAWAT) is a planning-level watershed model for approximating direct runoff, streamflow, sediment loads, and loads for up to five pollutants. ALAWAT uses raster GIS data layers including land use, SCS soil hydrologic groups, annual rainfall, and subwatershed delineations as direct model parameter inputs and can use daily total rainfall from up to ten rain gauges and streamflow from up to ten stream gauges. ALAWAT uses a daily time step and can simulate flows for up to ten-year periods and for up to 50 subwatersheds. Pollutant loads are approximated using a user-defined combination of rating curve relationships, mean event concentrations, and loading/washoff parameters for specific subwatersheds, land uses, and times of year. Using ALAWAT, annual average streamflow and baseflow relationships and urban suspended sediment loads were approximated for the Ala Wai Canal watershed (about 10,400 acres) on the island of Oahu, Hawaii. Annual average urban suspended sediments were approximated using two methods: mean event concentrations and pollutant loading and washoff. Parameters for the pollutant loading and washoff method were then modified to simulate the effect of various street sweeping intervals on sediment loads.     

Cross-taxonomic potential and spatial transferability of an umbrella species index

Validation that conservation of certain species effectively protects a high proportion of co-occurring species is rare. Our previous work has suggested that an umbrella index based on geographic distribution and life history characteristics would maximize the proportion of conspecifics protected per unit area conserved. Using bird and butterfly data from three mountain ranges in the Great Basin, we examined whether umbrella species also would confer protection to species in different taxonomic groups. Further, we addressed the spatial transferability of umbrella species by considering whether species identified as umbrellas in one mountain range would be effective umbrellas in other mountain ranges. Overall, equal proportions of species would be protected using either cross-taxonomic umbrella species or same-taxon umbrella species. Our data suggested that in a given mountain range, umbrella species identified using data from the same mountain range versus a different mountain range would be equally effective. The ability of one set of umbrella species to confer protection to co-occurring species, however, may vary among taxonomic groups and geographic regions.     

Evaluation of air quality zone classification methods based on ambient air concentration exposure

Air quality zones are used by regulatory authorities to implement ambient air standards in order to protect human health. Air quality measurements at discrete air monitoring stations are critical tools to determine whether an air quality zone complies with local air quality standards or is noncompliant. This study presents a novel approach for evaluation of air quality zone classification methods by breaking the concentration distribution of a pollutant measured at an air monitoring station into compliance and exceedance probability density functions (PDFs) and then using Monte Carlo analysis with the Central Limit Theorem to estimate long-term exposure. The purpose of this paper is to compare the risk associated with selecting one ambient air classification approach over another by testing the possible exposure an individual living within a zone may face. The chronic daily intake (CDI) is utilized to compare different pollutant exposures over the classification duration of 3 years between two classification methods. Historical data collected from air monitoring stations in Kuwait are used to build representative models of 1-hr NO₂ and 8-hr O₃ within a zone that meets the compliance requirements of each method. The first method, the “3 Strike” method, is a conservative approach based on a winner-take-all approach common with most compliance classification methods, while the second, the 99% Rule method, allows for more robust analyses and incorporates long-term trends. A Monte Carlo analysis is used to model the CDI for each pollutant and each method with the zone at a single station and with multiple stations. The model assumes that the zone is already in compliance with air quality standards over the 3 years under the different classification methodologies. The model shows that while the CDI of the two methods differs by 2.7% over the exposure period for the single station case, the large number of samples taken over the duration period impacts the sensitivity of the statistical tests, causing the null hypothesis to fail. Local air quality managers can use either methodology to classify the compliance of an air zone, but must accept that the 99% Rule method may cause exposures that are statistically more significant than the 3 Strike method.

Implications: A novel method using the Central Limit Theorem and Monte Carlo analysis is used to directly compare different air standard compliance classification methods by estimating the chronic daily intake of pollutants. This method allows air quality managers to rapidly see how individual classification methods may impact individual population groups, as well as to evaluate different pollutants based on dosage and exposure when complete health impacts are not known.