Production, Purification and Activity of an Extracellular Depolymerase from Aspergillus fumigatus

A strain of Aspergillus fumigatus, which was observed to rapidly degrade poly-3-hydroxybutyrate (PHB) in a leaf compost, was found to secrete an extracellular hydrolase when grown on PHB as the sole carbon source. Isolation and characterization of the PHB hydrolase (depolymerase) from this fungus revealed that the enzyme had a molecular weight of 57 kDa, an isoelectric point of 7.2, and a PHB hydrolysis activity maxima which occurred at 70°C and pH 8.0. Affinity labeling experiments suggested that this fungal hydrolase is a type of serine esterase. The cyclic trimers of 3-hydroxybutyrate were found to reversibly inhibit the enzymes.     

LAWS AND PROGRAMS FOR CONTROLLING NONPOINT SOURCE POLLUTION IN FOREST AREAS1

ABSTRACT: Recent federal legislation strengthened nonpoint source pollution regulations and helped to support and standardize pollution control efforts. A comprehensive review of current state and federal programs for forest areas reveals a substantial increase in agency water quality protection activities. These new efforts emphasize monitoring to assess the use and effectiveness of best management practices (BMPs). Recent monitoring reveals that BMP use is increasing and that such use typically maintains water quality within standards. However, information is generally lacking about the cost effectiveness of BMP programs. Carefully designed and executed monitoring is the key to better specification of BMPs and more cost effective water quality protection. (KEY TERMS: water quality; nonpoint source pollution; water law; watershed management; forestry; best management practices.)     

Sensitivity of SCS Models to Curve Number Variation1

ABSTRACT: The Soil Conservation Service (SCS) models, including the TR-20 computer program and the simplified methods in TR-55, are widely used in hydrologic design. The runoff curve number (CN), which is an important input parameter to SCS models, is defined in terms of land use tretments, hydrologic, condition, antecedent soil moisture, and soil type. The objective of this study was to evaluate the sensitivity of the SCS models to errors in CN estimates. The results show that the effects of CN variation decrease as the design rainfall depth increases, such as for the larger storm events. The value and use of the sensitivity curves are demonstrated using a comparison of Landsat and conventionally derived curve numbers for three watersheds in Pennsylvania.     

THE COMPLETE DRAINAGE PROGRAM - MORE THAN AN ORDINANCE1

ABSTRACT. An ever increasing number of communities throughout the nation are being forced by Federal legislation and local pressures to adopt land use and control measures related to drainage and flood protection. In many instances communities are hastily adopting ordinances and regulations which later prove difficult to administer and enforce. In addition, many of these ordinances and regulations are not producing the results originally anticipated. This paper discusses the basic elements of a drainage ordinance and evaluates the role of the ordinance in a comprehensive drainage program. This evaluation is based on the results of a two year study of drainage programs in five urban areas which produced a model urban drainage ordinance and recommendations on the administration of the ordinance. Personal interviews and local documents are used as the data base in formulating conclusions and recommendations.     

WATER SAVINGS FROM LAWN WATERING RESTRICTIONS DURING A DROUGHT YEAR,FORT COLLINS,COLORADO1

ABSTRACT: During the drought year of 1977, unusually low river flows during the summer caused the City of Fort Collins, Colorado, to institute lawn watering restrictions for six weeks as a conservation measure. Water use during the restriction period decreased 41 percent below the previous year. The effectiveness of the restrictions, however, has been unclear because abnormally wet weather also appeared to reduce evapotranspiration rates during the period the restrictions were in effect. The statistical analysis indicates that the reduction in water use due to lawn watering restrictions was 603 acre-feet and that abnormal weather reduced use by an additional 659 acre-feet during the same period. During a period of normal evapotranspiration rates, such restrictions would be expected to reduce Fort Collins municipal water usage by 19.7 percent.     

Approaches and initial findings of a state-sponsored research programme on population exposure to toxic substances

Summary Population exposure to toxic chemicals in the environment has become one of the most important, if not the most important, environmental issue of the 1980's. In response to finding high cancer mortality rates, the State of New Jersey organized an extensive program of research to determine public exposure to toxic substances in the environment. Three parts of that research are described. One focusing on toxic substances in the water has detected very low concentrations of many substances. These substances tend to be found in three distinct chemical groups: pesticides, light chlorinated hydrocarbons, and heavy metals. Gross pesticide contamination tends to occur in agricultural and forest areas; gross light chlorinated hydrocarbon pollution is in urban areas. The second component of the research is toxic substances in the air. Like the water studies, low levels of contamination have been found. Limited sampling to date has found groupings of ubiquitous organic chemicals in urban areas, two groups of specialized organic chemicals near industrial sites, and high lead levels near major highways. The third project is developing a computerized information bank about the use and disposal of 155 chemicals and will look for associations between industrial disposal practices and contamination of the environment.     

Brushland fire-management policies: A cross-impact simulation of southern California

A cross-impact simulation computer language, UW-KSIM, is presented as a potentially useful technique for assessing the consequences of resource policies. Cross-impact simulation is used to estimate trends in a set of variables that result from interactions produced from hypothesized relationships among the members of the set. This technique is illustrated with an example that simulates the likely impacts of a 20-year rotation burn policy in southern California's brushland watersheds and that compares the results to a simulated representation of the observed effects of the fire-exclusion policy. Simulated losses under the fire-exclusion policy were up to 300% higher than those produced by the rotation burn policy. Similarly, the simulated average area burned per year was reduced from 5.6% of the study area under the fire-exclusion policy to 2% of the study area under the rotation burn policy. A corresponding reduction in simulated appropriations for fighting wildfires was also demonstrated.     

IMPACT OF THERMAL STANDARDS ON POWER PLANT WATER CONSUMPTION1

Power plant water consumption (evaporative water loss) for various river temperature standards is presented for existing and proposed power plants located along the Missouri and Upper Mississippi Rivers in the MAPP geographical area. Thermodynamic and economic models are combined to evaluate the cooling related water consumption at various river thermal standards. The existing thermal standards and a number of other hypothetical thermal regulations including the extreme cases of no thermal standards and no allowable heated discharges are examined to show the dependence on thermal standards of power production related water consumption. A critical appraisal of the cost of thermal standards in terms of water consumption is thereby possible so that subjective assessments of the standards can proceed with full knowledge of the tradeoffs involved between the “water costs” of power production and environmental enhancement.     

SCS URBAN CURVE NUMBERS FROM A LANDSAT DATA BASE1

Estimating the Curve Numbers used in the Soil Conservation Service hydrologic models is a tedious and costly task. Recent advances in remote sensing and data processing have led to the development of readily available land cover data bases for many areas of the United States. This study evaluated the potential of using a Landsat data base to make the Curve Number estimation process more cost-effective and less tedious. Ten watersheds in the Washington, D.C., area were evaluated using a Landsat land cover data base developed by the U.S. Geological Survey. Results showed that these data can be useful. Predictions can be improved if ancillary data on residential lot size are included. It was concluded that this type of data base must be examined carefully before implementation.