Pollution source analyses using 1-dimensional time series

Lake Holiday, a human-made recreational lake in northern Illinois, was threatened with closure due to high bacterial levels. A factorially designed experiment with multivatiate responses was developed to study and identify the main sources of pollution. Data on total coliform, fecal coliform, fecal streptococci, dissolved oxygen, pH, ammonia-N, total phosphorus, nitrate/nitrite-N were analyzed using regression models describing dam spillway loads as a function of source loads and time. The results suggest that the relationships among source, time, and load are complex, even though only two sources account for most of the lake's loading Stevens Brook, which receives the discharge from the Somonauk Sewage Treatment Plant, and Somonauk Creek, which is the major drainage, contribute high loads of bacteria and nutrients to the lake. The influent loads contributed to the lake are discharged at the dam over about 4 weeks     

Mobilization and Toxicity Potential of Aluminum from Alum Floc Deposits in Kensico Reservoir,New York

There is detailed literature on the mobilization of aluminum (Al) from soil to surface waters as a result of elevated acidic deposition to base‐poor forest watersheds. There is considerably less information on the mobilization and effects of Al from the application of alum that is used in some water supplies to control turbidity during high‐flow events. We report on the results of field measurements, laboratory sediment release experiments, and chemical equilibrium calculations conducted to evaluate the potential for the mobilization of Al from alum floc deposits in sediments of Kensico Reservoir, New York. Under ambient water quality conditions, mobilization of sediment Al is not a noteworthy concern at Kensico Reservoir. However, under experimental conditions of low pH, low acid neutralizing capacity (ANC), and low temperature, the inorganic fraction of monomeric Al can be mobilized from Kensico sediments to concentrations that would likely impair the health of aquatic organisms (>2 μmol/l). Elevated concentrations of monomeric Al were observed only when ANC decreased below 50 μeq/l, which is outside the range of values observed in Kensico during the 1997‐2007 interval (120‐460 μeq/l). Concentrations of complexing ligands are relatively low in Kensico waters (i.e., fluoride, naturally occurring organic solutes) and do not appear to substantially contribute to potential Al mobilization. For other water supplies with low ANC, the potential for sediment release of Al may exist.     

Long-term forest-floor litter dynamics in Canada's boreal forest: Comparison of two model formulations

Litter decomposition is a key component in ecosystem material cycling that determines (i) forest soil carbon (C) and nutrient content, (ii) release of carbon dioxide to the atmosphere, and (iii) generation and mass transfer of dissolved organic carbon from terrestrial to aquatic ecosystems. In this study, we provide simulations of long term forest-floor litter dynamics generated with both (i) an existing forest nutrient cycling and biomass growth model (ForNBM) with a single-pool formulation of forest-floor litter decomposition (Zhu et al., 2003. Ecol. Model. 169, 347-360), and (ii) a revised version of the model produced by substituting the single-pool formulation with a three-pool version of the formulation tested against data from litterbag experiments (FLDM; Zhang et al., 2010. Ecol. Model. 221, 1944-1953). This is done to determine the importance of subdividing the litter mass into categories of rates of decay (i.e., fast, slow, and very slow) on model accuracy. Forest-forest litter dynamics simulated with the two models are subsequently compared against field measurements collected at several northern jack pine (Pinus banksiana) stands along a southwest-northeast oriented transect (climate gradient) associated with the Boreal Forest Transect Case Study in northwest Canada. Initial comparison shows that the single-pool formulation underpredicts residual litter mass when forests are <65 years old, largely due to the improper treatment of the very slow decomposing litter component. This underprediction is resolved when the three-pool formulation is used. From a ecosystems-response point of view, the revised ForNBM (with the three-pool formulation) demonstrates that (i) forest-floor litter initially increases with forest growth and reaches a plateau once the forest matures; (ii) the forest floor stores more litter and C at the southern and warmer sites than at the northern sites; and (iii) in a similar climate regime, the forest floor stores more litter and C at productive than at nutrient-poor sites.     

A Review of the Relative Merits of Conserving,Using, or Draining Papyrus Swamps

Wetlands are a vital resource, particularly in Africa where livelihoods are closely linked to natural capital. In recent years, extensive drainage has occurred to make way for agriculture. To gain insight into whether drainage is justified, we review the value of African wetlands dominated by Cyperus papyrus in relation to use, conservation and conversion. Evidence suggests that the value derived from low-intensity, multifunctional wetland use far exceeds the value derived from swamp reclamation and generally exceeds that of conservation. At a local level, the main driver of wetland misuse appear to be a breakdown in collaborative management regimes and the main constraint on wetland use, the value of labor and selling-times. Local drivers are linked to regional factors such as the lack of coordinated wetland policies and difficulties in ensuring that legislation is absorbed by all sectors of society. We highlight opportunities for ensuring more effective collaborative management and legislation communication, which capitalize on existing governance structures. In contrast to predictions by Hardin’s Tragedy of the Commons model, we argue that effective wetland management is best achieved by preventing privatization and promoting common property management regimes. We also argue that poverty and income inequity are more important drivers of unsustainable resource use than environmental managers commonly acknowledge.     

Pesticide resurrection

Environmental Chemistry Letters -     

Taking full advantage of modelling to better assess environmental risk due to xenobiotics—the all-in-one facility MOSAIC

Environmental Science and Pollution Research - In the European Union, more than 100,000 man-made chemical substances are awaiting an environmental risk assessment (ERA). Simultaneously, ERA of...     

Optimal oil tanker size with regard to environmental impact of oil spills

This paper considers optimal tanker size in view of the environmental effects of oil spills. A model is developed that incorporates the tradeoff between small but frequent spills with many tankers, and the relatively less frequent but larger and more concentrated spills with a smaller fleet of larger ships. A procedure is suggested to incorporate the environmental impact of oil spills in the model without quantifying them in monetary units. A closed form solution set for optimal tankers size is obtained and some numerical results are presented.