Impact of fly ash incorporation in soil systems.

Fly ash as a soil ameliorant for improving crop production--a review.

Though in last four decades various alternate energy sources have come into the limelight, the hyperbolic use of coal as a prime energy source cannot be counterbalanced. Disposal of high amount of fly-ash from thermal power plants absorbs huge amount of water, energy and land area by ash ponds. In order to meet the growing energy demand, various environmental, economic and social problems associated with the disposal of fly-ash would continue to increase. Therefore, fly-ash management would remain a great concern of the century. Fly-ash has great potentiality in agriculture due to its efficacy in modification of soil health and crop performance. The high concentration of elements (K, Na, Zn, Ca, Mg and Fe) in fly-ash increases the yield of many agricultural crops. But compared to other sectors, the use of fly-ash in agriculture is limited. An exhaustive review of numerous studies of last four decades took place in this paper, which systematically covers the importance, scope and apprehension regarding utilization of fly-ash in agriculture. The authors concluded that though studies have established some solutions to handle the problems of radioactivity and heavy metal content in fly-ash, long-term confirmatory research and demonstration are necessary. This paper also identified some areas, like proper handling of dry ash in plants as well as in fields, ash pond management (i.e., faster decantation, recycling of water, vertical expansion rather than horizontal), monitoring of soil health, crop quality, and fate of fly-ash in time domain, where research thrust is required. Agricultural lime application contributes to global warming as Intergovernmental Panel on Climate Change (IPCC) assumes that all the carbon in agricultural lime is finally released as CO2 to the atmosphere. It is expected that use of fly-ash instead of lime in agriculture can reduce net CO2 emission, thus reduce global warming also.

Potential fly-ash utilization in agriculture: A global review

We provide an overview of research related to environmental effects of disposal of coal combustion residues (CCR) in sites in the United States. Our focus is on aspects of CCR that have the potential to negatively influence aquatic organisms and the health of aquatic ecosystems. We identify major issues of concern, as well as areas in need of further investigation. Intentional or accidental release of CCR into aquatic systems has generally been associated with deleterious environmental effects. A large number of metals and trace elements are present in CCR, some of which are rapidly accumulated to high concentrations by aquatic organisms. Moreover, a variety of biological responses have been observed in organisms following exposure to and accumulation of CCR-related contaminants. In some vertebrates and invertebrates, CCR exposure has led to numerous histopathological, behavioral, and physiological (reproductive, energetic, and endocrinological) effects. Fish kills and extirpation of some fish species have been associated with CCR release, as have indirect effects on survival and growth of aquatic animals mediated by changes in resource abundance or quality. Recovery of CCR-impacted sites can be extremely slow due to continued cycling of contaminants within the system, even in sites that only received CCR effluents for short periods of time. The literature synthesis reveals important considerations for future investigations of CCR-impacted sites. Many studies have examined biological responses to CCR with respect to Se concentrations and accumulation because of teratogenic and reproductively toxic effects known to be associated with this element. However, the complex mixture of metals and trace elements characteristic of CCR suggests that biological assessments of many CCR-contaminated habitats should examine a variety of inorganic compounds in sediments, water, and tissues before causation can be linked to individual CCR components. Most evaluations of effects of CCR in aquatic environments have focused on lentic systems and the populations of animals occupying them. Much less is known about CCR effects in lotic systems, in which the contaminants may be transported downstream, diluted or concentrated in downstream areas, and accumulated by more transient species. Although some research has examined accumulation and effects of contaminants on terrestrial and avian species that visit CCR-impacted aquatic sites, more extensive research is also needed in this area. Effects in terrestrial or semiaquatic species range from accumulation and maternal transfer of elements to complete recruitment failure, suggesting that CCR effects need to be examined both within and outside of the aquatic habitats into which CCR is released. Requiring special attention are waterfowl and amphibians that use CCR-contaminated sites during specific seasons or life stages and are highly dependent on aquatic habitat quality during those periods. Whether accidentally discharged into natural aquatic systems or present in impoundments that attract wildlife, CCR appears to present significant risks to aquatic and semiaquatic organisms. Effects may be as subtle as changes in physiology or as drastic as extirpation of entire populations. When examined as a whole, research on responses of aquatic organisms to CCR suggests that reducing the use of disposal methods that include an aquatic slurry phase may alleviate some environmental risks associated with the waste products.

Ecotoxicological implications of aquatic disposal of coal combustion residues in the United States: a review.

Sorption of cadmium and zinc from aqueous solutions by water hyacinth (Eichchornia crassipes).

Among traditional fossil fuel sources, coal exists in quantities capable of supplying a large portion of our future energy needs. According to the President's National Energy Plan, annual productions of 1.2 × 109 t by 1989 and 1.91 × 109 t by the year 2000 are anticipated. It appears reasonable to expect an increase in the percentage as well as the number of coal‐fired power plants. The increased use of coal will produce additional quantities of fly ash, one of the waste products of burning pulverized coal. Fly ash constitutes about 70% of the total amount of residue generated in coal‐fired power plants equipped with electrostatic precipitators or bag filters. Fly ash contains various substances of which trace metals, although present in a small fraction, are of special interest due to their cumulative build up, long life, and high toxicity to man, plants, and animals through air, water, and soil. Several estimates made by the Bureau of Mines suggest that the fly ash released into the atmosphere appears t...

Fly ash dynamics in soil‐water systems

The occurrence of strontium-90, iodine-131, and other radionuclides in milk; May, 1957, through April, 1958.

Water supply and treatment

Monthly milk samples from the milk sheds serving Atlanta, Austin, Chicago, Cincinnati, Fargo-Moorhead, New York City, Sacramento, Salt Lake City, Spokane, and St. Louis were analyzed for Ca and K content, I/sup 131/, Ba/sup 140/ s, Cs/sup 137/, Sr/sup 89/, and Sr/sup 90/. Analysis of variance applied to these data indicated geographical and seasonal variations. The average Sr/sup 90/ and Cs/sup 137/ content of milk samples from Sacramento was the lowest, while that from St. Louis was the highest. The remaining stations were grouped into one of two intermediate categories. Samples collected during early spring and fail showed higher Sr/sup 90/ and Cs/sup 137/ than at other times, probably associated with changes in seasonal feeding practices. No relationship was observed between the concentration of Sr/sup 90/ and Cs/sup 137/ in milk and publicly announced weapons tests. In contrast, a direct relationship was observed between the weapons tests and the concentration of I/sup 131/, Ba/sup 140/,, and Sr/sup 89/, which was influe nced by the half life of the radionuclides, the meteorological conditions, and the geographical location of the sampling stations with respect to the test site. Observed concentrations of radionuclides were below maximum permissible concentrations. Impracticability of estimating concentration ofmore » Sr/sup 90/ in milk, in terms of gross beta -activity or Cs/sup 137/, is discussed. (auth)« less

Radionuclides in Milk

Iodine is one of the 64 elements that make up 0.4 percent of the earth’s mass and occurs in an abundance of 0.3 p.p.m. (Chilean Iodine Educational Bureau 1956). Although there are iodine-deficient areas in the world, traces of this element can be found in practically all plant and animal life. The significance of iodine in the metabolism of animals and man has been well established. The traditional sources of iodine in the diet are primarily the marine fishes and certain vegetables and fruits, including asparagus, cabbage, green beans, potatoes, lettuce, grapes, pears, and pineapple. On the other hand, foods derived from terrestrial animal sources, such as milk, eggs, and meat, are relatively low in iodine.

Conrad P. Straub

Papers

Fly ash dynamics in soil‐water systems

The occurrence of strontium-90, iodine-131, and other radionuclides in milk; May, 1957, through April, 1958.

Water supply and treatment

Radionuclides in Milk

Iodine-131 in foods.