Environmental letters最新文献

Analysis of the stomach contents of 97 white perch, Morone americana, taken from the effluent canal of a steam electric station (S.E.S.) and 106 white perch from adjacent Patuxent River waters indicated similar food habits from September 1970 through August 1971. However, 35% of all white perch taken from the heated effluent canal contained small pieces of coal and cinders, whereas only 3% of the river specimens contained such items in their stomachs. Fly ash and coal dust are present on the bottom of the S.E.S. canal, whereas little such material, if any, can be found on the river bottom in the study area. This suggests the canal fish were actively feeding in the heated effluent and not simply moving into the canal after feeding in the river. No significant difference (Pgreater than0.05) was found between the average wet weight stomach contents of the river and canal fish within the same mouth.

Arsenite ion, as arsenic trichloride was extracted into benzene from strongly acidified tissue homogenates. Following this, arsenite was extracted from the benzene into water, made up in 1N HCl and analyzed polarographically. Arsenate ion, left in the homogenate after arsenite extraction is isolated in exactly the same way following treatment of the homogenate with cuprous ion to reduce arsenate to arsenite ion. Treatment of the acidified homogenate with cuprous ion prior to extraction gives a homogenate which is readily analyzed for total "inorganic" arsenic. The method was efficient to a maximum level of about 20 mug inorganic arsenic since at higher levels lower recoveries were found. Analysis of a variety of marine biological specimens, with levels of total arsenic up to 40.5 ppm, indicated little of this arsenic was present in an inorganic form. Post mortem reduction of arsenate to arsenite was found to occur rapidly in fish tissue.

A study of the Flat Creek Embayment of Lake Sidney Lanier near Gainesville, Georgia revealed three genera of algae, Chlorococcum, Fragillaria and Nostoc, to be prominent in this eutrophic region of the lake. The algae was grown in phosphate-rich media and subsequently labelled with P-32. All species incorporated luxury amounts of phosphorus as determined by the uptake of P-32. The results indicate that the P-32 uptake is proportional to the surface-per-volume ratio. The higher surface-per-volume ratio resulted in greater uptake of P-32.

Nitrate analyses were performed on ground water well samples originating from sources throughout Wisconsin. The data ranged from below the analytical detection limit up to 140 mg NO3-N/1. Over nine percent of all wells sampled has nitrate concentrations in excess of 10 mg NO3-N/1. Six individual counties had more than 10 mg NO3-N/1 in at least twenty percent of the wells covered in this survey. However, data reported for over eight thousand new wells driven in 1971-1972 showed only slightly more than two percent with nitrate levels above 10 mg NO3-N/1. This reflected the trend toward drilling deeper wells which are influenced less by nitrate seepage as well as adherence to new and stricter well construction codes.

Water is polluted when it constitutes a health hazard or when its usefulness is impaired. The major sources of water pollution are municipal, manufacturing, mining, steam, electric power, cooling and agricultural. Municipal or sewage pollution forms a greater part of the man's activity and it is the immediate need of even smaller communities of today to combat sewage pollution. It is needless to stress that if an economic balance of the many varied services which a stream or a body of water is called upon to render is balanced and taken into consideration one could think of ending up in a wise management programme. In order to eliminate the existing water pollutional levels of the natural water one has to think of preventive and treatment methods. Of the various conventional and non-conventional methods of sewage treatment known today, in India, where the economic problems are complex, the waste stabilization ponds have become popular over the last two decades to let Public Health Engineers use them with confidence as a simple and reliable means of treatment of sewage and certain industrial wastes, at a fraction of the cost of conventional waste treatment plants used hitherto. A waste stabilization pond makes use of natural purification processes involved in an ecosystem through the regulating of such processes. The term "waste stabilization pond" in its simplest form is applied to a body of water, artificial or natural, employed with the intention of retaining sewage or organic waste waters until the wastes are rendered stable and inoffensive for discharge into receiving waters or on land, through physical, chemical and biological processes commonly referred to as "self-purification" and involving the symbiotic action of algae and bacteria under the influence of sunlight and air. Organic matter contained in the waste is stabilized and converted in the pond into more stable matter in the form of algal cells which find their way into the effluent and hence the term "stabilization pond".

This paper reviews some of the questions that have been asked by experts and others as to why nuclear power plants are not located or placed underground. While the safeguards and present designs make such installations unnecessary, there are some definite advantages that warrant the additional cost involved. First of all, such an arrangement does satisfy the psychological concern of a number of people and, in so doing, might gain the acceptance of the public so that such plants could be constructed in urban areas of load centers. The results of these studies are presented and some of the requirements necessary for underground installations described, including rock conditions, depth of facilities, and economics.

This paper describes the waste processing and boiler feed facilities which serve as the prototype for Union Electric Company's proposed Solid Waste Utilization System for recycling essentially all the solid waste generated in the metropolitan St. Louis area. The recently announced system, capable of processing up to 8,000 tons of raw refuse per day and estimated to cost $70 million, will be built and operated without government subsidy. Solid waste will be processed for the recovery of recyclable noncombustibles and use as a supplementary fuel to electric utility boilers.