Leo Newland

Mapping micro-urban heat islands using LANDSAT TM and a GIS

Abstract LANDSAT TM satellite data and GIS software were used to map micro-urban heat islands in a portion of Dallas, Texas. Unsupervised classifications were performed on a LANDSAT subscene to extract tree cover information which was merged with TM band 6 data (thermal) to make a map showing the location of micro-urban heat islands and wooded areas. Results indicate the presence of micro-urban heat islands are resulting from the lack of tree cover related to newly developed residential neighborhoods, parking lots, business districts, apartment complexes, and shopping centers. All micro-urban heat islands were radiative in nature, with highest temperatures in the center.

Habitat-Specific Differences in Mercury Concentration in a Top Predator from a Shallow Lake

Abstract We conducted a survey of mercury contamination in largemouth bass Micropterus salmoides from Caddo Lake, Texas, and found that fish collected from forested wetland habitat had higher concentrations of mercury than those collected from open-water habitat. Habitat-specific differences in largemouth bass size, age, absolute growth rate, trophic position (based on δ15N), and horizontal food web position (based on δ13C), characteristics known to influence mercury accumulation, did not explain the observed differences in mercury contamination. Rather, habitat-related differences in mercury concentration in a primary consumer, Mississippi grass shrimp Palaemonetes kadiakensis, indicated that food webs in forested wetland habitat were more contaminated with mercury than those in open-water habitat. Spatial variation in mercury contamination within lakes and elevated mercury concentrations in forested wetlands should be of special concern not only to researchers but also to public and environmental health...

Using spot satellite data to map impervious cover for urban runoff predictions

Environment planners are constantly seeking rapid, accurate, and cost‐effective techniques to determine land cover information associated with water quality and quantity during runoff events in urban watersheds. Traditionally, this is accomplished with field surveys, aerial photographs, and/or generalized published maps. These techniques can be time consuming and labor intensive. In this study, SPOT, 10 meter‐panchromatic, satellite digital data were used to classify and map impervious cover in an urban watershed in Dallas, Texas (USA). Using the image‐derived impervious cover map and a hydrologic runoff equation, urban storm water volumes were predicted for 1990 and 1991 with an 85% accuracy when compared to actual runoff data obtained from a U.S. Geological Survey (U.S.G.S) stream gauge station.

Time-resolved leaching of cadmium and manganese from lignite and incinerator fly ash

Abstract Fly ashes from a lignite fired power plant and a municipal incinerator were leached for 3 hours using 0.1N HC1. Leachate was analyzed for Cd and Mn and plots of concentration versus time for these elements show Cd, a surface adsorbed element in the combustion process, to be rapidly removed from the ash particles in the initial four or five minutes of leaching. Manganese, a fly ash matrix element, is leached at a more constant rate as the ash praticles are dissolved. Total Cd and Mn concentrations in the incinerator fly ash are greater than total concentrations of these elements in the lignite fly ash.

The fate of organophosphorus pesticides in the environment

Abstract Organophosphorus pesticides are becoming increasingly important because of their biological activity and low potential for accumulation in the environment. Some chemical reactions of organophosphates and their mode of entrance into the environment are discussed. The role of microorganisms in determining the fate of several organophosphorus insecticides in the environment and the possible use of bacterial endospores in detoxifying contaminated soils are considered.

Integrating information for better environmental decisions.

As more is learned about the complex nature and extent of environmental impacts from progressive human disturbance, scientists, policy analysts, decision makers, educators, and communicators are increasingly joining forces to develop strategies for preserving and protecting the environment. The Eco-Informa Foundation is an educational scientific organization dedicated to promoting the collaborative development and sharing of scientific information. The Foundation participated in a recent international conference on environmental informatics through a special symposium on integrating information for better environmental decisions. Presentations focused on four general themes: (1) remote sensing and data interpretation, including through new knowledge management tools; (2) risk assessment and communication, including for radioactively contaminated facilities, introduced biological hazards, and food safety; (3) community involvement in cleanup projects; and (4) environmental education. The general context for related issues, methods and applications, and results and recommendations from those discussions are highlighted here.

The fate of dichlorvos in soil

Abstract Experiments were conducted to determine the factors responsible for the loss (adsorption, chemical hydrolysis, microbial degradation, etc.) of dichlorvos (2,2-dichlorovingl 0 , 0 -dimethyl phosphate) in soil perfusion systems of Houston Black clay. The rate of disappearance from the perfusate (hence the rate of dichlorvos degradation in soil) was related directly to the presence of Bacillus cereus in the perfusion system, the pH of the system, and the extent of dichlorvos adsorption. Gas liquid chromatographic analyses of the perfusates showed that dichlorvos disappearance was rapid when B . cereus was added to a previously sterilized soil perfusion system (50% in 3.9 days). Under sterile conditions, 50% of the added dichlorvos was recovered after 10 days. When B . cereus was added to a mineral salts medium containing dichlorvos as sole ccrbon source, 49% of the initial dichlorvos concentration was degraded in 4 days. The organism was not capable of utilizing dichlorvos as a sole phosphorus source. Chemical hydrolysis of dichlorvos in aqueous, buffered, soil-free systems showed that hydrolysis did not occur in very acid systems ( pH 3.3), but increased with increasing pH values (26% in 4 days at pH 6.9), and was rapid at pH 9.3 (> 99% in 2 days). The extent of dichlorvos adsorption was determined by comparing the initial loss of dichlorvos in a sterile, soil-free extract solution with the initial loss in a sterile soil perfusion system. The rapid initial disappearance of dichlorvos in the presence of sterilized soil was attributed to soil adsorption of the pesticide. After 10 days both systems contained equal concentrations (50%) of dichlorvos. Non-biological mechanisms accounted for 70% of the total degradation of dichlorvos, while bacterial degradation accounted for 30% in the soil perfusion systems.

Septic tank and agricultural non‐point source pollution within a rural watershed

This investigation addresses the problem of Non‐Point Source (NPS) pollution in the rural Lake Weatherford watershed in Parker County, Texas. This reservoir is the primary municipal water supply for the City of Weatherford, Texas. The principal method of wastewater disposal is the on‐site system or septic tanks for the small residential areas surrounding the reservoir. Sources of NPS pollution of interest in this watershed include agricultural operations as well as the residential areas. These sites were identified with the aid of aerial photography and field investigation. Suspected NPS problems were substantiated through a sampling program involving chemical and biological testing of the reservoir. Results indicate that there is significant NPS pollution contamination of Lake Weatherford from agricultural sources and seepage from on‐site wastewater disposal systems. Excessive fecal coliform and fecal streptococcus counts (>500 bacteria/100 ml) were generally associated with rainfall events and several s...

Copper, lead, mercury and zinc in periphyton from the south florida ecosystem

Periphyton samples from the Big Cypress National Preserve were analyzed for concentrations of copper, lead, zinc, mercury, and methylmercury. Concentrations of organic carbon, inorganic carbon, nitrogen, and phosphorus in periphyton samples also were determined. The samples were extracted with sodium acetate solution at a pH of 5.5 to determine exchangeable and carbonate phase metal concentrations in periphyton. Total metal concentrations in the periphyton were directly related to the degree of calcite saturation in the water column. Exchangeable and carbonate phase metal concentrations were directly related to the percent inorganic carbon in the samples. A connection between the geochemistry of trace metals and calcite precipitation and dissolution is suggested.

Global maps for GIS

Utilizing workstations or inexpensive desktop computers and GIS software, investigators are able to process and display many layers of information simultaneously for interpretation. At a GIS workstation, earth scientists, for example, are able to correlate image data with geology, soils, vegetation, topography, and subsurface information into an integrated system that can be combined and cross-referenced for composite analysis. With a properly constructed GIS, the user is able to input, rectify, merge and display multiple data sets at various scales for interpretation (CH~SMAN, 1997). GIS technology is providing more information with greater accuracy and at a lower cost than previously thought possible. Spatial data processing hardware and software have advanced to a level that is beginning to match the challenge of large area resource evaluation and planning.