The Impact of Future Land Use Scenarios on Runoff Volumes in the Muskegon River Watershed

In this article we compared the response of surface water runoff to a storm event for different rates of urbanization, reforestation and riparian buffer setbacks across forty subwatersheds of the Muskegon River Watershed located in Michigan, USA. We also made these comparisons for several forecasted and one historical land use scenarios (over 140 years). Future land use scenarios to 2040 for forest regrowth, urbanization rates and stream setbacks were developed using the Land Transformation Model (LTM). Historical land use information, from 1900 at 5-year time step intervals, was created using a Backcast land use change model configured using artificial neural network and driven by agriculture and housing census information. We show that (1) controlling the rate of development is the most effective policy option to reduce runoff; (2) establishing setbacks along the mainstem are not as effective as controlling urban growth; (3) reforestation can abate some of the runoff effects from urban growth but not all; (4) land use patterns of the 1970s produced the least amount of runoff in most cases in the Muskegon River Watershed when compared to land use maps from 1900 to 2040; and, (5) future land use patterns here not always lead to increased (worse) runoff than the past. We found that while ten of the subwatersheds contained futures that were worse than any past land use configuration, twenty-five (62.5%) of the subwatersheds produced the greatest amount of runoff in 1900, shortly after the entire watershed was clear-cut. One third (14/40) of the subwatersheds contained the minimum amount of runoff in the 1960s and 1970s, a period when forest amounts were greatest and urban amounts relatively small.     

Humic acids as reducing agents: the involvement of quinoid moieties in arsenate reduction

Purpose  

Dissolved humic acids abiotically reduced inorganic arsenic to varying degrees, depending on solution pH, ionic strength, and type of humate used. The functionalities of dissolved organic matter responsible for these redox reactions remained in question, but quinoid moieties undoubtedly played an important role. It is not fully understood whether the quinoids are solely responsible for arsenate reduction, and what the kinetics of the relevant processes are.     

Determinants of exposure to fine particulate matter (PM2.5) for waiting passengers at bus stops

This research evaluates commuter exposure to particulate matter during pre-journey commute segments for passengers waiting at bus stops by investigating 840 min of simultaneous exposure levels, both inside and outside seven bus shelters in Buffalo, New York. A multivariate regression model is used to estimate the relation between exposure to particulate matter (PM_2.5 measured in μg m^?3) and three vectors of determinants: time and location, physical setting and placement, and environmental factors. Four determinants have a statistically significant effect on particulate matter: time of day, passengers’ waiting location, land use near the bus shelter, and the presence of cigarette smoking at the bus shelter. Model results suggest that exposure to PM_2.5 inside a bus shelter is 2.63 μg m^?3 (or 18 percent) higher than exposure outside a bus shelter, perhaps due in part to the presence of cigarette smoking. Morning exposure levels are 6.51 μg m^?3 (or 52 percent) higher than afternoon levels. Placement of bus stops can affect exposure to particulate matter for those waiting inside and outside of shelters: air samples at bus shelters located in building canyons have higher particulate matter than bus shelters located near open space.     

California Statewide Assessment of the Effects of Ozone on Crop Productivity

Six properties appear desirable for any set of ozone attainment criteria: (1) sufficient stringency to protect public health, (2) simplicity and understandability, (3) sensitivity to real changes in air quality, (4) stability against meteorological fluctuations, (5) use of as much data as possible, and (6) equivalence between the stringency the criteria appear to mandate, and what they actually mandate. We consider how the federal attainment criteria might be improved with respect to Properties 4 through 6 while being equally strong on 1 through 3. Whether the federal standard meets Property 1 has been the subject of debate, but our analysis would apply also to a modified standard. We show that there are subtleties in how improvements might be made. In particular, basing the attainment status on a statistic with low variance may not lead to a more stable criterion, and although it is easy to find a criterion that makes it hard for a district with bad air to reach attainment, or a district with good air to get out of attainment, it is hard to find a criterion that does both. This suggests using different criteria for districts that are out of attainment from districts that are in attainment. Initially the burden of proof would be on the district to prove that its air is of attainment quality. However, once the district has achieved attainment the burden of proof would shift; the district would remain in attainment unless there was strong evidence to the contrary. An evaluation of a set of criteria based on this idea showed improvements over the federal criteria with respect to the last three desirable properties-stability, use of data, and equivalent stringency-with some sacrifice in simplicity and sensitivity.     

Acute,chronic and biochemical effects of chlorothalonil on <Emphasis Type="Italic">Agalychnis callidryas</Emphasis>, <Emphasis Type="Italic">Isthmohyla pseudopuma</Emphasis> and <Emphasis Type="Italic">Smilisca baudinii</Emphasis> tadpoles

Declines of amphibian populations have been a worldwide issue of concern for the scientific community during the last several decades. Efforts are being carried out to elucidate factors related to this phenomenon. Among these factors, pathogens, climate change, and environmental pollution have been suggested as possible causes. Regarding environmental pollutants, some pesticides are persistent in the environment and capable of being transported long distances from their release point. In Costa Rica, some pesticides have been detected in protected areas, at locations where amphibian populations have declined. Information about toxicity of pesticides used in Costa Rican agriculture to amphibians is still scarce, particularly for native species.Toxicity tests with chlorothalonil, a fungicide intensively used in Costa Rica, were carried out exposing tadpoles of three Costa Rican native species: Agalychnis callidryas, Isthmohyla pseudopuma, and Smilisca baudinii in order to evaluate acute and chronic toxicity as well as the biomarkers cholinesterase activity (ChE), glutathione-S transferase activity (GST), and lipid peroxidation (LPO).96-h LC₅₀: 26.6 (18.9–35.8) μg/L to A. callidryas, 25.5 (21.3–29.7) μg/L to I pseudopuma and 32.3 (26.3–39.7) μg/L to S. baudinii were determined for chlorothalonil. These three species of anurans are among the most sensitive to chlorothalonil according to the literature. Besides, GST was induced in S. baudinii after exposure to sub-lethal concentrations of chlorothalonil while evisceration occurred in S. baudinii and A. callidryas tadpoles exposed to lethal concentrations of the fungicide. Chronic exposure to sub-lethal concentrations accelerated development in S. baudinii and caused lesions in tail of S. baudinii and I. pseudopuma tadpoles. Our results demonstrate that chlorothalonil is highly toxic to native amphibian species and that low concentrations can cause biochemical responses related to phase II of biotransformation and effects on development.     

Reduction of DNA mismatch repair protein expression in airway epithelial cells of premenopausal women chronically exposed to biomass smoke

Biomass burning is a major source of indoor air pollution in rural India. This study examined whether chronic inhalation of biomass smoke causes change in the DNA mismatch repair (MMR) pathway in the airway cells. For this, airway cells exfoliated in sputum were collected from 72 premenopausal nonsmoking rural women (median age 34 years) who cooked with biomass (wood, dung, crop residues) and 68 control women who cooked with cleaner fuel liquefied petroleum gas (LPG) for the past 5 years or more. The levels of particulate matters with diameters less than 10 and 2.5 μm (PM₁₀ and PM_2.5) in indoor air were measured by real-time aerosol monitor. Benzene exposure was monitored by measuring trans,trans-muconic acid (t,t-MA) in urine by high-performance liquid chromatography with ultraviolet detector. Generation of reactive oxygen species (ROS) and level of superoxide dismutase (SOD) in airway cells were measured by flow cytometry and spectrophotometry, respectively. Immunocytochemical assay revealed lower percentage of airway epithelial cells expressing MMR proteins mutL homolog 1 (MLH1) and mutS homolog 2 (MSH2) in biomass-using women compared to LPG-using controls. Women who cooked with biomass had 6.7 times higher level of urinary t,t-MA, twofold increase in ROS generation, and 31 % depletion of SOD. Indoor air of biomass-using households had three times more particulate matters than that of controls. ROS, urinary t,t-MA, and particulate pollution in biomass-using kitchen had negative correlation, while SOD showed positive correlation with MSH2 and MLH1 expression. It appears that chronic exposure to biomass smoke reduces MMR response in airway epithelial cells, and oxidative stress plays an important role in the process.     

A Study of Physicomechanical and Morphological Properties of Starch/Poly(vinylalcohol) Based Films

Starch/Poly(vinylalcohol) blends in two different ratios (60:40 and 50:50) were prepared with glycerol as a plasticizer. Films were cast by a solution casting method. One set of films were filled with 10 wt% of unmodified bentonite clay and another set of films were crosslinked with epichlorohydrin in an alkaline medium. The prepared film samples were subjected to X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR), mechanical characterization and scanning electron microscope (SEM). Significant changes in the tensile properties were observed depending on the different chemical constituents of the films. The presence of clay and crosslinking with epichlorohydrin were both found to have considerable effect on the morphology and mechanical property of the films. The SEM investigations, XRD analysis and FTIR studies revealed the interaction between the various chemical components of the films.     

Changes in microbiological metabolism under chemical stress

Chemical stress may alter microbiological metabolism and this, in turn, may affect the natural and engineered systems where these organisms function. The impact of chemical stress on microbiological metabolism was investigated using model chemicals 2,4-dinitrophenol (DNP), pentachlorophenol (PCP), and N-ethylmaleimide (NEM). Biological activity of Pseudomonas aeruginosa was measured in batch systems, with and without stressors at sub-lethal concentrations. Stressor DNP, between 49 and 140 mg l(-1), and PCP, at 15 and 38 mg l(-1), caused decreases in biomass growth yields, but did not inhibit substrate utilization rates. These effects increased with stressor concentrations, showing as much as a 10% yield reduction at the highest DNP concentration. This suggests that a portion of carbon and energy resources are diverted from growth and used in stress management and protection. Stressor DNP, between 300 and 700 mg l(-1), and PCP at 85 mg l(-1) caused decreases in growth yields and substrate utilization rates. This suggests an inhibition of both anabolism and catabolism. Stressor NEM was the most potent, inhibiting biological activity at concentrations as low as 2.7 mg l(-1). These findings will ultimately be useful in better monitoring and management of biological treatment operations and contaminated natural systems.     

Genetic evidence for inter-oceanic subdivision of bigeye tuna (Thunnus obesus) populations

Bigeye tuna (Thunnus obesus Lowe, 1839) are a commercially important species of tuna found in the Atlantic, Indian, and Pacific oceans. To initiate an analysis of bigeye tuna population-structure, three PCR–RFLP assays were developed based on the published mtDNA control-region sequences of four bigeye tuna. Population analyses using these three restriction assays on a total of 248 individuals resulted in an array of 13 composite haplotypes. A total of 347 nucleotides of mtDNA control-region sequence was characterized for 11 of the 13 composite haplotypes. Phylogenetic analyses demonstrated that the DNA sequences belong to two monophyletic clades. However, only one of the three restriction assays was able to discriminate between the two clades. The other two assays were confounded by excessive homoplasy. Both parallel (independent occurrences of the same nucleotide change) and convergent (different nucleotide changes within the same restriction site) changes of restriction sites were observed. These results emphasize the importance of DNA sequence-analysis for the interpretation of restriction-site polymorphism data. Analyses of the frequency distribution indicated that samples of bigeye tuna from the Atlantic Ocean were genetically distinct from those found in the Indian and Pacific oceans. Thus, these results reject the null hypothesis of a single global population of bigeye tuna. Received: 16 June 1997 / Accepted: 25 July 1998     

Pyrene remediation by Trametes maxima: an insight into secretome response and degradation pathway

Environmental Science and Pollution Research - The rapid pace of economic development has resulted in the release of several polycyclic aromatic hydrocarbons (PAHs) into the environment. Microbial...