Chemical and biological recovery from acid deposition within the Honnedaga Lake watershed,New York,USA

Honnedaga Lake in the Adirondack region of New York has sustained a heritage brook trout population despite decades of atmospheric acid deposition. Detrimental impacts from acid deposition were observed from 1920 to 1960 with the sequential loss of acid-sensitive fishes, leaving only brook trout extant in the lake. Open-lake trap net catches of brook trout declined for two decades into the late 1970s, when brook trout were considered extirpated from the lake but persisted in tributary refuges. Amendments to the Clean Air Act in 1990 mandated reductions in sulfate and nitrogen oxide emissions. By 2000, brook trout had re-colonized the lake coincident with reductions in surface-water sulfate, nitrate, and inorganic monomeric aluminum. No changes have been observed in surface-water acid-neutralizing capacity (ANC) or calcium concentration. Observed increases in chlorophyll a and decreases in water clarity reflect an increase in phytoplankton abundance. The zooplankton community exhibits low species richness, with a scarcity of acid-sensitive Daphnia and dominance by acid-tolerant copepods. Trap net surveys indicate that relative abundance of adult brook trout population has significantly increased since the 1970s. Brook trout are absent in 65 % of tributaries that are chronically acidified with ANC of <0 μeq/L and toxic aluminum levels (>2 μmol/L). Given the current conditions, a slow recovery of chemistry and biota is expected in Honnedaga Lake and its tributaries. We are exploring the potential to accelerate the recovery of brook trout abundance in Honnedaga Lake through lime applications to chronically and episodically acidified tributaries.     

Green Biomass Materials in Polyurethane Foams

Flexible polyurethane foams were prepared using naturally derived materials as alternatives to conventional auxiliary blowing agents. This research was based on the concept held by some that natural chemicals are better as a part of industrial ecology. The authors have attempted to define the foam manufacturing suitability of natural chemicals, but have not defined or defended the policy implications of such choices. Natural chemicals are often less suitable than those refined from petroleum and may then need some environmental credit related to greater discharge to be viable substitutes. Modest decreases in density (relative to foams without any auxiliary blowing agent) were obtained with the addition of solid CO₂ but other physical properties were not measured. It is unclear whether the reduction in density is a result of the phase change of CO, from solid to liquid within the polyurethane cell matrix or simply a bubbling effect of C02 in solution causing voids within the final product. Although it was anticipated that the high boiling point of limonene, from citrus peeis, would negate effectiveness as an auxiliary blowing agent, there were analogous decreases in foam density. The observed effect might be rationalized by the significant vapor pressure of limonene at temperatures lower than the boiling point. The limonene may be sweptf rom the foam system coincident with the loss of in situ generated CO₂ isoprene, naturally emitted from deciduous vegetation as well as from the combustion of carbonaceous fuels, provides a useful, if not complete, range of foam densities and may then be a partial substitute for halogenated auxiliary blowing agents. Switching from methyiene chloride to isoprene as the auxiliary blowing agent of choice would immediately decrease organic emissions from polyurethane foam plants by 20 percent (molecular weight effect). Regulation as a VOC and the residual acrid odor may be potential drawbacks to commercial utilization of isoprene.     

Performance of a woodchip filter to treat dairy soiled water

The milking process on dairy farms produces wastewaters, known as dairy soiled waters (DSW), which contain variable concentrations of nutrients. The most common method of disposal is by application to land. However, this practise can result in the pollution of nearby receiving water bodies. A laboratory study, comprising two sets of 0.5?m, 1?m and 1.5?m-deep filters loaded at two loading rates, examined the performance of woodchip filters in treating DSW. The filters comprised de-barked Sitka spruce (Picea sitchensis) woodchips. Dried DSW was reconstituted to 1% and 3% suspended solids (SS) concentrations and was applied at 28?L/m(2).d to the surface of the filters at loading rates of 280?g?SS/m(2).d and 840?g?SS/m(2).d, respectively. Filters were loaded for a maximum of 277 days. The filters achieved substantial decreases in SS (>99%), chemical oxygen demand (COD) (>97%) and total nitrogen (TN) (>89%). The dominant treatment mechanism appears to be physical filtration, but sorption and biological uptake likely also play a role. As the filters are aerobic, mineralisation and nitrification occur, but gaseous N losses are probably not significant. Woodchip shows potential as a filter medium for treating DSW, significantly decreasing the concentrations of SS, COD and TN.     

Fate of Triclosan and Methyltriclosan in soil from biosolids application

This study investigates the persistence of Triclosan (TCS), and its degradation product, Methyltriclosan (MeTCS), after land application of biosolids to an experimental agricultural plot under both till and no till. Surface soil samples (n = 40) were collected several times over a three years period and sieved to remove biosolids. Concentration of TCS in the soil gradually increased with maximum levels of 63.7 ± 14.1 ng g(-1) dry wt., far below the predicted maximum concentration of 307.5 ng g(-1) dry wt. TCS disappearance corresponded with MeTCS appearance, suggesting in situ formation. Our results suggest that soil incorporation and degradation processes are taking place simultaneously and that TCS background levels are achieved within two years. TCS half-life (t(0.5)) was determined as 104 d and MeTCS t(0.5), which was more persistent than TCS, was estimated at 443 d.     

Laboratory study using paper mill lime mud for agronomic benefit

Annual ryegrass (Lolium perenne L.) is an important cool-season forage grass in the southeastern US. Since large portions of soils in this region are too acidic for optimum ryegrass production, there exists an opportunity to use lime mud waste from numerous regional pulp and paper mills as an agricultural liming material. In this study, four lime mud application rates, 2.25 (L₁), 4.51 (L₂), 9.01 (L₃), and 22.50 (L₄) ton ha⁻¹, dry weight basis, and a control (L₀) were evaluated for response to ryegrass growth during the first 6 weeks to estimate an optimum application range over the testing soil for future field test. Results indicated that applied lime mud slowed ryegrass germination and seedling emergence, with differences of whole plant length among treatments L₀–L₄ significant only during the first three weeks. Differences of whole plant dry weight among treatments L₀–L₄ reduced thereafter. The initial soil pH increase due to the lime mud application dropped in treatments L₁–L₄ by the end of the 6-week experiment. The optimum lime mud application range was estimated between L₂ and L₃, which provided higher ryegrass yields (kg ha⁻¹) of 84 and 80 over 77 of the control and complied with the Code of Federal Regulation, CFR 40 Part 503 for land application.     

Ammonia modeling for assessing potential toxicity to fish species in the Rio Grande, 1989-2002.

Increasing volumes of treated and untreated human sewage discharged into rivers around the world are likely to be leading to high aquatic concentrations of toxic, unionized ammonia (NH3), with negative impacts on species and ecosystems. Tools and approaches are needed for assessing the dynamics of NH3. This paper describes a modeling approach for first-order assessment of potential NH3 toxicity in urban rivers. In this study daily dissolved NH3 concentrations in the Rio Grande of central New Mexico, USA, at the city of Albuquerque's treated sewage outfall were modeled for 1989-2002. Data for ammonium (NH4+) concentrations in the sewage and data for discharge, temperature, and pH for both sewage effluent and the river were used. We used State of New Mexico acute and chronic NH3- N concentration values (0.30 and 0.05 mg/L NH3-N, respectively) and other reported standards as benchmarks for determining NH3 toxicity in the river and for assessing potential impact on population dynamics for fish species. A critical species of concern is the Rio Grande silvery minnow (Hybognathus amarus), an endangered species in the river near Albuquerque. Results show that NH3 concentrations matched or exceeded acute levels 13%, 3%, and 4% of the time in 1989, 1991, and 1992, respectively. Modeled NH3 concentrations matched or exceeded chronic values 97%, 74%, 78%, and 11% of the time in 1989, 1991, 1992, and 1997, respectively. Exceedences ranged from 0% to 1% in later years after enhancements to the wastewater treatment plant. Modeled NH3 concentrations may differ from actual concentrations because of NH3 and NH4+ loss terms and additive terms such as mixing processes, volatilization, nitrification, sorbtion, and NH4+ uptake. We conclude that NH3 toxicity must be considered seriously for its potential ecological impacts on the Rio Grande and as a mechanism contributing to the decline of the Rio Grande fish community in general and the Rio Grande silvery minnow specifically. Conclusions drawn for the Rio Grande suggest that NH3 concentrations may be high in rivers around the world where alkaline pH values are prevalent and sewage treatment capabilities are poorly developed or absent.     

HEAVY METALS CONTENTS OF ROADSIDE MOSSES IN THE NORTHERN AND SOUTH-EASTERN REGIONS OF NIGERIA

Levels of lead, zinc, cadmium, copper and nickel were determined in roadside moss samples within towns in the northern and south-eastern regions of Nigeria. Average lead level in the south-east (59 ppm) was higher than the average for the northern region (44 ppm). Average levels of zinc, cadmium, copper and nickel did not differ significantly between the two regions, with overall averages for the entire study area being 50.9, 1.2, 11.3 and 5.6 ppm for these metals. Lead levels were poorly correlated with those of the other metals, indicating that automobile emissions may not be the main source for these metals in the moss. In comparison with a previous study of the south-west region, the results indicate a generally slightly higher level of metal pollution in the south-west region than in both the northern and south-eastern regions.     

TRACE ELEMENTS IN NORTHERN GREAT PLAINS STRIP MINE AND LIVESTOCK IMPOUNDMENT WATER1

ABSTRACT: The water from 32 strip mine water impoundments and nine livestock watering ponds in North Dakota, South Dakota, and Wyoming were analyzed for trace elements. Because of the high concentrations of trace elements in coal and bentonite clay, the possibility exists for these elements to dissolve or be suspended in the water. Strip mine ponds were not significantly higher in trace element concentrations compared to livestock ponds. All but one of the 41 ponds sampled contained elemental concentrations that would be detrimental for livestock use or aquatic life use. Cadmium and lead were the elements most frequently in excess of water quality crieria. Lead was found in the study ponds about 35 times the median concentration of North American rivers. Manganese concentrations were found to exceed iron in many ponds, which is unusual in natural waters. The potential for detrimental concentrations of trace elements in pond water must be evaluated when designing land use management plans for ponds intended to be used by livestock or aquatic life.     

A regional environmental quality management model: An assessment

The principal purpose of this paper is to discuss the research and policy lessons learned from a large environmental quality management model constructed for the Lower Delaware River Valley Region, The policy lessons involve estimates of the costs of meeting varying standards on air and water quality and the impact on those costs of certain region-wide management alternatives. The research lessons concern: (a) the desirability of considering air and water quality, and solid waste disposal, simultaneously in a single model; (b) the costs of and returns to including nonlinear models of natural systems in a regional optimization framework; and (c) the feasibility of working with constraints on the geographic distribution of the costs of environmental quality improvement within the regional, nonlinear model.