Neutralization of an extremely acidic sludge and stabilization of heavy metals in flyash aggregates

An extremely acidic, heavy metal-rich sludge (pH=-1.2) was scrubbed with a Class-F fly ash in order to simultaneously neutralize the acidity and stabilize the heavy metals contained in both wastes. This paper outlines the leaching behavior of the aggregate material generated by scrubbing. For proper fly ash/sludge ratios, the fly ash acted as an outstanding neutralizer for the acidic waste. Leaching of heavy metals from the aggregate samples was below the environmental limits within a pH range between 3 and 9. Subsequent washing of the leached aggregate with acidic CALWET solutions did not result in an additional release of heavy metals. It is proposed that coordinative bonding of the metal cations onto neutral surface sites and electrostatic adsorption led to stabilization of the heavy metals within the aggregate structure below hydrolysis pHs.     

Trace metal content in inhalable particulate matter (PM<Subscript>2.5–10</Subscript> and PM<Subscript>2.5</Subscript>) collected from historical mine waste deposits using a laboratory-based approach

Mine wastes and tailings are considered hazardous to human health because of their potential to generate large quantities of highly toxic emissions of particulate matter (PM). Human exposure to As and other trace metals in PM may occur via inhalation of airborne particulates or through ingestion of contaminated dust. This study describes a laboratory-based method for extracting PM_2.5–10 (coarse) and PM_2.5 (fine) particles from As-rich mine waste samples collected from an historical gold mining region in regional, Victoria, Australia. We also report on the trace metal and metalloid content of the coarse and fine fraction, with an emphasis on As as an element of potential concern. Laser diffraction analysis showed that the proportions of coarse and fine particles in the bulk samples ranged between 3.4–26.6 and 0.6–7.6 %, respectively. Arsenic concentrations were greater in the fine fraction (1680–26,100 mg kg^?1) compared with the coarse fraction (1210–22,000 mg kg^?1), and Co, Fe, Mn, Ni, Sb and Zn were found to be present in the fine fraction at levels around twice those occurring in the coarse. These results are of particular concern given that fine particles can accumulate in the human respiratory system. Our study demonstrates that mine wastes may be an important source of metal-enriched PM for mining communities.     

The Validation of a Passive Sampler for Indoor and Outdoor Concentrations of Volatile Organic Compounds

Abstract

Volatile organlcs compounds (VOCs) are ubiquitous in the air we breathe. The use of passive samplers to measure these concentrations can be an effective technique. When exposed for long durations, a passive sampler may be a good tool for investigating chronic exposures to chemicals in the environment. A passive sampler that was designed for occupational exposures can be used as such a tool. Laboratory validation under as many conditions as possible needs to be accomplished so as to characterize the sampler with known parameters. This paper describes the methods and results of an investigation into the validity of using a passive monitor to sample VOCs for a three-week period. Two concentration levels, two relative humidities, and five VOCs were studied. Results indicate that the samplers work best under conditions of high concentration with low relative humidity and low concentration with high relative humidity. For the passive sampler, excluding chloroform, percent deviations from the predicted values varied between ?41 and +22 percent; while the values between the passive and the active samplers varied between ?27 and +24 percent. Benzene, heptane, and perchloroethylene were sampled with equal precision and accuracy.     

Net Waste Reduction Analysis Applied to Air Pollution Control Technologies

Post-combustion air pollution control technologies were evaluated to determine total waste produced by the operation of these systems. A continuum of air pollution control technology choices providing increasing levels of control is presented and the quantity of waste produced by each air pollution control option has been calculated. In addition, this analysis accounts for waste produced indirectly by the generation of energy required for operation of the control technologies. This type of analysis can be used to select optimal control levels and to demonstrate why a goal of zero air emissions may not be environmentally desirable.     

A national system for disseminating information on victims during mass casualty incidents

Immediate provision of information to the public is vital during mass casualty incidents (MCIs). Failure to implement rapidly a communication response system may result in the public overwhelming hospitals. This paper shares Israel's experience in developing and maintaining a national system for supplying information on the location and identification of casualties. ADAM interfaces online with hospitals' patient registration systems, and allows for immediate electronic transfer of designated data. The system permits information centres to access information on which hospital has admitted identified and unidentified casualties. The latter are photographed at the entrance to the hospital and the picture is stored in ADAM. The system enables hospitals and municipalities to ensure immediate availability and accessibility of information and thus (in our belief) mitigate the concerns of family and friends. Use of such an interface system is recommended as an integral element of emergency preparedness.     

Molecular and morphometric variation in European populations of the articulate brachiopod Terebratulina retusa

Molecular and morphometric variation within and between population samples of the articulate brachiopod Terebratulina spp., collected in 1985–1987 from a Norwegian fjord, sea-lochs and coastal sites in western Scotland, the southern English Channel (Brittany) and the western Mediterranean, were measured by the analysis of variation in the lengths of mitochondrial DNA (mtDNA) fragments produced by digestion with nine restriction endonucleases and by multivariate statistical analysis of six selected morphometric parameters. Nucleotide difference within each population sample was high. Nucleotide difference between population samples from the Scottish sites, both those that are tidally contiguous and those that appear to be geographically isolated, were not significantly different from zero. Nucleotide differences between the population samples from Norway, Brittany, Scotland and the western Mediterranean were also very low. Morphometric analysis confirmed the absence of substantial differentiation.     

Some considerations in the aftermath of the WWFs anniversary celebrations in Assisi

Summary The author considers various moral, social and political issues that have become apparent from the aftermath of the WWF's twenty-fifth Anniversary Celebrations in Assisi, Italy. In particular, the difficulty of making people understand the very ethics of conservation, when their cultural history has shaped their minds quite differently, is highlighted, and this is reflected in the author's suggested subtitle for the paper, How to Love Nature Without Getting your Shoes Wet.But don't ever leave me alone with Nature, For I know too much about her not to be afraid (Alfred de Vigny)Maria Luisa Cohen is President of the Assisi Nature Council (See also,The Environmentalist, 5 (3) 227–229).