This paper describes the results of an analysis of 13.3-GHz single-polarized scatterometer data collected during NASA/MSC mission 135, flown on March 16, 1970. Data were gathered over a crude oil spill on the Gulf of Mexico (test site 128) off the Mississippi delta. With the aid of RC-8 camera photographs the scattering cross section was correlated with the extent of the oil spill. The scattering cross section at higher incidence angles (25 to 50 deg) decreased by 5-10 db in the presence of the oil spill. This was attributed to the damping by oil of small gravity and capillary waves. The composite scattering theory and the scatterometer-acquired data were used to obtain an expression of radar scattering over ocean surfaces with oil spills. The study demonstrates that the presence and extent of oil spills can be detected with high-frequency radar systems.

Detection of Oil Spills Using a 13.3-GHz Radar Scatterometer

/pdf/detection-of-oil-spills-using-a-13-3-ghz-radar-scatterometer-2qcfxq5iu6.pdf

Detection of oil spills using a 13.3-GHz radar scatterometer.

The US Geological Survey has developed an oilspill risk analysis model to aid in estimating the environmetal hazards of developing oil resources in Outer Continental Shelf (OCS) lease areas. The large, computerized model analyzes the probability of spill occurrence, as well as the likely paths or trajectories of spills in relation to the locations of recreational and biological resources which may be vulnerable. The analytical methodology can easily incorporate estimates of weathering rates, slick dispersion, and possible mitigating effects of cleanup. The probability of spill occurrence is estimated from information on the anticipated level of oil production and method and route of transport. Spill movement is modeled in Monte Carlo fashion with a sample of 500 spills per season, each transported by monthly surface-current vectors and wind velocities sampled from 3-hour wind-transition matrices. Transition matrices are baesd on historic wind records grouped in 41 wind velocity classes, and are constructed seasonally for up to six wind stations. Locations and monthly vulnerabilities of up to 31 categories of environmental resources are digitized within an 800,000 km/sup 2/ study area. Model output includes tables of conditional impact probabilities as well as probability distributions for oilspills occurring and contacting environmental resources within preselectedmore » vulnerability time horizons. The model provides the US Department of the Interior with a method for realistically assessing oilspill risks associated with OCS development. To date, it has been used in oilspill risk assessments for eight OCS lease sales with the results reported in Federal environmental impact statements. A sumary of results is presented herein. A real time version was also used to forecast the movement of oil from the 1976-1977 Argo Merchant oilspill. Additional model runs are planned for future OCS lease sales in frontier areas. 35 references, 13 figures, 10 tables.« less

The oilspill risk analysis model of the U. S. Geological Survey

Nitrate concentration in surface and groundwater is becoming a global concern. The electrodialysis is a useful separation technique that uses ion-exchange membranes to treat the solution, and these membranes can possess certain selectivity towards different ions. The objective of this work was to compare the possibility of nitrate separation form a mixed salt solution by electrodialysis using three different anion-exchange membranes (AEMs). Characteristic properties of heterogeneous AEMs are mainly defined by their composition, a mixture of a polymer matrix and an anion-exchange resin. In this work, three different kinds of anion-exchange resins with distinct functional groups (trimethylamine and dimethylethanolamine) were used to prepare AEMs, in which selectivity towards nitrate ion was compared by desalination of mixed salt solution using laboratory electrodialysis unit. The solution used was composed of NaCl, NaNO3, NaH2PO4, and Na2SO4, every salt of concentration 0.05 mol L−1. Although the properties of individual AEMs and their courses of desalination differed significantly, all membranes had higher selectivity for nitrate ions than for the remaining ones; however, their selectivity towards nitrate and chloride was very similar. The affinity relationship of the AEMs was: nitrate > chloride > dihydrogen phosphate > sulfate.

Comparison of heterogeneous anion-exchange membranes for nitrate ion removal from mixed salt solution

Accidents involving chemicals or radioactive materials represent a significant threat to the environment, public health and safety, and community well-being. In an increasingly complex and interconnected world, no community is immune from the threat posed by environmental accidents and contamination. Even communities far removed from industrial production or storage facilities can still be at risk from accidents associated with the transport of hazardous materials. While a variety of studies have been conducted on aspects of major transportation accidents, few have attempted to examine both environmental and community aspects of the problem. In contrast, this report takes an integrated approach to hazardous transportation accidents by considering environmental, safety, economic and psychosocial issues. The purpose of the project is to (1) quantify transportation-related accidents involving hazardous materials in the Alabama, and (2) identify key longer-term environmental health, public safety, and social impacts that are often overlooked after major transportation-related hazardous materials accidents. Case studies involving a train derailment, truck accident, and a pipeline explosion are discussed.

Environmental health, public safety, and social impacts associated with transportation accidents involving hazardous substances

Oceanographic observations near the Chevron spilling well off the Mississippi Delta in March 1970 revealed relative roles of various physical factors of the regional estuarine system in the behavior of oil slicks. Surface stress from the wind was most important, at speeds above 15 mph the slick orientation was generally determined by the wind direction. The wind also indirectly affected oil which was sunk by dispersant in the wind waves promoted mixing, which in turn affected the vertical stability, hence eventually the velocity profile. Wind setups and setdowns were correlated with downward and upward isopycnal movements, respectively. Both calculations and observations showed that tidal currents produced and L-shaped slick geometry when winds were below about 15 mph. The diurnal rotation of the tidal currents served to limit the excursion length of oil from the source, keeping it short of the nearest shore. The presence of fresh water from the Mississippi River in the surface layer and the consequent development of convergence lines often formed a natural barrier, preventing oil from encroaching upon the shore. Theoretical analysis using turbulent diffusion theory disclosed that the area and length of a steady-state oil slick increased with oil discharge but decreased with current speed and the lateral diffusion coefficient. Slick width increased with the rate of discharge and decreased with current speed but was independent of the diffusion coefficient. The width/length ratio of an oil slick, which was notably independent of current speed, was controlled only by the diffusion coefficient and the oil discharge. In order to be able to predict oil slick behavior, understanding of the interaction between these multiple factors is essential and, for that end, the use of a multiple-sensor array with automatic data transfer and processing capability is recommended.

/pdf/oceanographic-observations-and-theoretical-analysis-of-oil-34mplmngbs.pdf

Stephen P. Murray

Papers

Oceanographic Observations and Theoretical Analysis of Oil Slicks During the Chevron Spill, March 1970

Treatment of waste water oil mixture