Enzymatic treatment of sulfonated aromatic amines generated from reductive degradation of reactive azo dyes.

Anaerobic degradation, an effective treatment process of textile industry effluent, generates sulfonated aromatic amines, which are carcinogenic, mutagenic, and resistant to microbial degradation. These aromatic amines can be effectively removed by oxidative polymerization catalyzed by peroxidase enzyme. The amines, generated in this study from the anaerobic reduction by zero-valent iron of two reactive azo dyes (Reactive Red 2 [RR2] and Reactive Black 5 [RB5]), were successfully removed (90%) by Arthromyces ramosus peroxidase (ARP). For better understanding of the process, enzymatic treatment of two model compounds, diphenylamine (DPA) and 2-amino-8-naphthol-3,6-disulfonic acid (ANDSA), were also studied. Diphenylamine has a similar diarylamine bond as RR2. The ANDSA has a similar structure as the dye reduction products. The secondary amine bond in DPA and RR2 were oxidized by ARP. Enzymatic reaction of sulfonated aromatic amines generated soluble colored compounds, which were removed by coagulant. Optimum reaction parameters were also determined.     

Bioconcentration of nonylphenol in fathead minnows (Pimephales promelas)

Bioconcentration of p-nonylphenol (NP) by fathead minnows was determined under laboratory conditions. Fish were exposed continuously for 42 days to 0.33, 0.93 and 2.36 μgNP/l in a flow-through system. NP was Soxhlet extracted from whole fish homogenates with dichloromethane (DCM). The resulting extract was concentrated and bulk lipids removed by gel permeation and silica-gel chromatography. Compounds were identified and quantified by reverse-phase high-pressure liquid chromatography (RP-HPLC) with fluorescence detection. Mass spectrometry was used for verification of peak assignments. Bioconcentration factors (BCFs) ranged from 245 to 380.     

A Knowledge-Based Approach to the Assessment of Watershed Condition

The Ecosystem Management Decision Support (EMDS) system is an application framework for knowledge-based decision support of ecological assessments. EMDS integrates geographic information system and knowledge base system technologies to provide an analytical tool for environmental assessment and monitoring. The basic objective of EMDS is to improve the quality and completeness of environmental assessments and the efficiency with which they are performed. The USDA Forest Service and the U.S. Environmental Protection Agency have cooperatively developed an EMDS knowledge base for watershed condition assessment. Specifically, this knowledge base evaluates watershed processes, patterns, general effects of human activity, and fisheries habitat suitability. Such assessments are based on spatially explicit input data concerning current conditions and reference conditions which are subsequently interpreted by user-defined "fuzzy" membership functions. In this paper we describe basic components of our knowledge base for assessing watershed condition and illustrate its application within northern Idaho and northwestern Montana.     

Effects of Disturbance on Nitrogen Export from Forested Lands of the Chesapeake Bay Watershed

The objective of this research project is to develop, test, validate, and demonstrate an analytical framework for assessing regional-scale forest disturbance in the mid-Atlantic region by linking forest disturbance and forest nitrogen export to surface waters at multiple spatial scales. It is hypothesized that excessive nitrogen (N) leakage (export) from forested watersheds is a potentially useful, integrative "indicator" of a negative change in forest function which occurs in synchrony with changes in forest structure and species composition. Our research focuses mainly on forest disturbance associated with recent defoliations by the gypsy moth larva (Lymantria dispar) at spatial scales ranging from small watersheds to the entire Chesapeake Bay watershed. An approach for assessing the magnitude of forest disturbance and its impact on surface water quality will be based on an empirical model relating forest N leakage and gypsy moth defoliation that will be calibrated using data from 25 intensively-monitored forested watersheds in the region and tested using data from more than 60 other forested watersheds in Virginia. Ultimately, the model will be extended to the region using spatially-extensive data describing: 1) the spatial distribution of dominant forest types in the mid-Atlantic region based on both remote sensing imagery and plot-scale vegetation data; 2) the spatial pattern of gypsy moth defoliation of forested areas from aerial mapping; and 3) measurements of dissolved N concentrations in streams from synoptic water quality surveys.     

Inter- and Intra-Annual Chemical Variability During the ice-Free Season in Lakes with Different Flushing Rates and Acid Deposition Histories

Quantifying chemical variability in different lake types is important for the assessment of both chemical and biological responses to environmental change. For monitoring programs that emphasize a large number of lakes at the expense of frequent samples, high variability may influence how representative single samples are of the average conditions of individual lakes. Intensive temporal data from long-term research sites provide a unique opportunity to assess chemical variability in lakes with different characteristics. We compared the intra- and inter-annual variability of four acidification related variables (Gran alkalinity, pH, sulphate concentration, and total base cation concentration) in four lakes with different flushing rates and acid deposition histories. Variability was highest in lakes with high flushing rates and was not influenced by historic acid deposition in our study lakes. This has implications for the amount of effort required in monitoring programs. Lakes with high flushing rates will require more frequent sampling intervals than lakes with low flushing rates. Consideration of specific lake types should be included in the design of monitoring programs.     

The distribution of polychlorinated dibenzo-p-dioxins and dibenzofurans in Jackfish Bay, Lake Superior, in relation to a kraft pulp mill effluent

Samples of whole effluent and effluent suspended solids from a kraft pulp mill and sediments and biota from Jackfish Bay, Lake Superior were analyzed for polychlorinated dibenzo-p-dioxins (CDDs) and dibenzofurans (CDFs). Tetra-CDFs (4CDF) were consistently detected in whole effluent at levels ranging between 0.3 and 1.3 ng/L. Effluent suspended solids also contained 4CDFs as well as traces of 4CDD, 5CDF, 8CDF and 8CDD. The horizontal sediment distribution suggests that the effluent was the only active source of 4CDF in the area but that 8CDD originated from a more general source such as the atmosphere. An abrupt appearance of 4CDF in the more recent sections of a core profile taken in the bay suggests that an operational change at the pulp mill resulted in the formation of 4CDFs in the mill effluent some time after 1973. Moderate values of 4CDF and low values of 4CDD were found in samples of the shrimp confirming the presence of an active source of 4CDF in Jackfish Bay.     

Perspectives and challenges in the future use of plant nutrients in tilled and mixed agricultural systems

Producing an adequate quantity of healthy food without polluting the environment is a serious challenge for future agriculture around the world. The Food 21 research program in Sweden has researched all aspects--economic, environmental, and social--of sustainable farming systems. This paper presents some of the research from that and other relevant international research programs that have focused on better nutrient-use efficiency, especially for nitrogen and phosphorus. It shows that a range of sustainable solutions to nutrient-use efficiency exists, some of which are complex but some very simple. Government policies, including subsidies; research and technology; and public acceptance of farming practices all combine to create these solutions. Participatory approaches to knowledge transfer are needed, in which scientists, policy makers, farmers, advisers, and consumers exchange information and together build sustainable farming systems.     

Di- and tribromoindoles in the common oyster (Crassostrea virginica)

The sources/origins, fate and impacts of naturally occurring organobromine compounds in the marine environment are largely unknown. Soft tissue composites of the common oyster (Crassostrea virginica) collected from coastal Georgia (USA) were analyzed for organobromines by gas chromatography. Three simple bromoindoles (BIs)--two dibromo- and one tribromo congener--were detected and their molecular formulas elucidated by electron and negative chemical ionization GC-MS. Semi-quantitative estimates of BI concentrations in these samples using GC-ECD indicated that oysters sampled in November 1999 contained 5-10 times more BIs than those sampled in August 2000 and March 2001. Although their bromine substitution patterns are presently unknown, this first ever report of bromoindoles in C. virginica, a prolific and important commercial and ecological species, underscores its potential utility as a bioindicator of organobromines in the coastal marine environment.