EVALUATION OF THE WORTH OF ADDITIONAL DATA1

ABSTRACT .Inherent in every decision process is a certain amount of uncertainty, which is reduced with information. Perfect knowledge yields no uncertainty for a process, but perfect knowledge for hydrologic and water resource systems would require a highly excessive investment. Therefore, it is the aim of this paper to delineate a procedure that places a value on this uncertainty so that it may be compared to a cost of further investment, which would provide a basis for deciding the time at which the value of additional data does not exceed the cost of that data. A decision theory approach is employed on a hydrologic problem to formalize the steps in making a decision. Examples are given.     

Policies and regulations for Brazil’s artisanal gold mining sector: analysis and recommendations

In Brazil, artisanal and small-scale gold mining (ASGM) produces in the range of 6 tonnes of gold (Au) per annum, and employs approximately 200,000 people. Most of this mining activity is in the Amazon region, where miners have been extracting gold for more than 40 years. In the Tapajos River Basin, assessments indicate that around 99% of miners operate without the environmental and mining permits required by law. This is a result of a combination of unrealistic or lack of proper policies and regulations, lack of political will, lack of infra-structure to enforce the existing regulations and lack of incentives to miners to comply with legal requirements.In this article, we analyze a group of 20 laws, decrees and resolutions in Brazil, focusing on how idiosyncrasies in these regulations reveal gaps between policy and reality in ASGM areas. Artisanal miners operate in vast and remote areas and the government lacks the resources (personnel, vehicles, information and materials) to enforce the laws. Our analysis emphasizes the need for creating new government commitments and identifying priority areas where government agents can focus their efforts.There is no single solution for the environmental, health, technical and socio-economic problems associated with ASGM. However, a realistic approach should consider improving the level of education of miners, creating government programs to provide technical assistance in the field, simplifying administrative procedures and ensuring adequate measures for enforcement.     

Characterization of hydrocarbon pollutant burdens in petrochemical and refinery process streams

This paper describes techniques which provide for both qualitative and quantitative identification of major components in a process stream. The techniques and instrumentation have been deliberately chosen so as to be within the technical and financial reach of all but the smallecompany laboratory. The sample preparation steps consist of an initial series of extractions which isolate compounds into organic acid, base, and neutral compounds and a totally water soluble phase. Each fraction is then concentrated and subjected to thin-layer chromatography, gas chromatography, infrared spectroscopy or ultraviolet spectroscopy as appropriate. Results are given for laboratory samples, one a mixture of aniline, phenol, benzoic acid, m-nitrobenzaldehyde, 1-butanol, 2-hexanone, nonane, and cyclohexane, and the other a mixture of benzene, ethylbenzene, and styrene. Also, a qualitative analysis of a petroleum refinery desalter water is presented.     

Polychlorinated dibenzo-p-dioxins (PCDDs) and furans (PCDFs) in urban air and deposition in the United Kingdom

Polychlorinated dibenzo-p-dioxins and furans (PCDD/Fs) have been monitored in air and deposition at four UK urban sites (London, Cardiff, Manchester and Stevenage) since the beginning of 1991; data from the first 2 years are presented here. Median Σ2,3,7,8-substituted PCDD/F concentrations in air were 3.2, 4.0, 3.5 and 2.6 pg/m³ respectively for London, Cardiff, Manchester and Stevenage. Median Σ2,3,7,8-substituted PCDD/F deposition fluxes were 1.5 ng/m²/day in London, 1.4 ng/m²/day in Cardiff and Manchester and 0.79 ng/m²/day in Stevenage. Seasonal variations in the PCDD/F concentrations were observed at all sites for both air and deposition, with concentrations/fluxes generally elevated during the winter.     

Toxicity of boron to the duckweed,Spirodella polyrrhiza

Boron is an essential nutrient for plants and the potential exists for efficient removal of this element by wetland treatment systems due to accumulation by plants. To evaluate the efficacy of using Spirodella polyrrhiza to treat boron-contaminated wastewater or to be a suitable species for removing other nutrients from boron-containing wastewater the toxicity of this micronutrient was determined using standard methods. Frond production is apparently a more sensitive endpoint than either growth rate or the presence of abnormal fronds. Frond production in S. polyrrhiza was significantly reduced at 3.55 mg B/l. Significant reductions in growth rate and the percentage of abnormal (chlorotic, necrotic, and dead) fronds were observed at 18.9 and 22.4 mg B/l, respectively. The EC50 for frond production, frond growth rate, and abnormal fronds were 14.3, 11.7, and 17.7 mg B/l, respectively. S. polyrrhiza did not remove significant amounts of boron from the treatment solutions under the conditions and concentrations existing in this study. The inability of S. polyrrhiza to remove even small amounts of boron from the test solutions indicates this species is not suitable for treating boron-containing wastewater, even those with low boron concentrations.     

Continuous emissions monitoring using spark-induced breakdown spectroscopy

A new technology for monitoring airborne heavy metals on aerosols and particulates based on spark-induced breakdown spectroscopy (SIBS) was evaluated at a joint U.S. Environmental Protection Agency (EPA)/U.S. Department of Energy test at the rotary kiln incinerator simulator (RKIS) facility at EPA/Research Triangle Park, NC, in September 1997. The instrument was configured to measure lead and chromium in a simulated combustion flue gas in real time and in situ at target levels of 15 and 75 micrograms/dry standard cubic meters. Actual metal concentrations were measured during the tests using EPA Reference Method (RM) 29. The SIBS technology detected both lead and chromium at the low- and high-level concentrations. Additionally, the hardware performed without failure for more than 100 hr of operation and acquired data for 100% of the RM tests. The chromium data were well correlated with concentration increases resulting from duct operations and pressure fluctuations that are known to entrain dust.