Showing papers on "Water environment published in 1970"

Polynuclear aromatic hydrocarbons in the water environment

Abstract: Many polynuclear aromatic hydrocarbons (PAH) are known to be carcinogenic to animals and probably to man. This review is concerned with carcinogenic and non-carcinogenic PAH in the water environment, with emphasis on 3,4-benzpyrene (BP) because it is ubiquitous, is one of the most potent of the carcinogenic PAH and has been widely studied. Although PAH are formed in combustion and other high-temperature processes, there is also evidence for their endogenous formation in plants, which may explain their ubiquity therein. Although the solubility of these compounds in pure water is very low, they may be solubilized by such materials as detergents, or they may otherwise occur in aqueous solution associated with or adsorbed on to a variety of colloidal materials or biota, and thereby be transported through the water environment. A notable characteristic of PAH is their sensitivity to light.PAH have been found in industrial and municipal waste effluents, and occur in soils, ground waters and surface waters, and their sediments and biota. With the exception of filtration or sorption by activated carbon, conventional water treatment processes do not efficiently remove them, and they have been found in domestic water supplies. Because of the ubiquity of PAH in the environment, it is impossible to prevent completely man's exposure to them; nevertheless their surveillance should be continued and their concentrations in the environment should be reduced where practicable.

Effective water resources management in the urban setting

Abstract: Water resources management in the urban areas of the United States to be effective must include dimensions far beyond water supply and sewerage This paper concerns itself with those problem areas of water resource management outside of potable water supply and sanitary sewers These areas include flood plain management, greenways and blueways, storm water, vistas of waterways, and other attributes of living in or near a water-related environment The perceptions and attitudes of the concerned public and community power structure must be known in order to manage the water environment effectively Methods of measuring these perceptions and attitudes are described and ways in which the resulting citizen-resource can be tapped and used as a management device are explored

Application of PCR-Based DNA Fingerprinting Techniques for the Genetic Differentiation of Vibrio cholerae Non-01/Non-0139 Isolates from Kuching, Sarawak

Abstract: Fifty-four Vibrio cholerae non-01/non-0139 isolates were evaluated for their genetic diversity via randomly amplified polymorphic DNA-PCR (RAPD-PCR), enterobacterial repetitive intergenic consensus-PCR (ERIC-PCR) and BOX-PCR assays. Based on the various PCR fingerprints, the V. cholerae isolates were successfully differentiated into 39 types by RAPD-PCR, 43 types by ERIC-PCR, and 38 types by the BOX PCR, with the overall average polymorphic distances observed to be at 0.593, 0.527 and 0.504, respectively. The Simpson’s index of diversity of the isolates based on the fingerprinting analyses indicated that these DNA fingerprinting methods have high discriminatory power 0.986 (RAPD-PCR), 0.992 (ERIC-PCR) and 0.983 (BOX-PCR), and could be used independently or as supplements to other methods for the epidemiological investigation of the V. cholerae from water and seafood sources. The dendrograms constructed also showed that the V. cholerae isolates were clustered into several main clusters and sub-clusters, suggesting that different strains were circulating in the water environment and in the seafood sources. We conclude that molecular genotyping of V. cholerae isolates from surface water and seafood samples in Kuching, Sarawak (Malaysia) enabled high level observation of clonal diversity within V. cholerae isolates, and is directly applicable for the molecular epidemiological studies of the V. cholerae isolates.

Motion Parameters Analysis Of The Atmospheric Diving Suit

Abstract: The paper presents an atmospheric diving suit (ADS) designed to provide a practical and economical mean of conducting effective work at depths up to 300 meters. The model examination has been carried out in the aerodynamics tunnel The main aim of the examination has been to recognize suit movements and the resistant forces. The numerical analysis of the computational model has been carried out as well The convergence has been obtained for the case of the air environment. Additionally, the computer simulation has been performed for the water environment.

Man's control of water quality

Abstract: Man has certain needs for water: physiological, domestic, agricultural and industrial. These needs are not the same in quantity or quality, in location or in time, yet they must all be met to allow for mankind's full development. Man's use of water degrades its quality: by gross pollution, by residual materials which change the ecology of the water environment, and by persistent microchemical pollutants which may pose both long and short-term health hazards. Man can control water quality; but first he must measure it. The criteria of acceptable quality, particularly for the protection of public health, are continually being refined; already certain contaminants are considered a hazard at the femtogram per litre level, i.e. a million-millionth of thefamiliar p.p.m. Even when he can measure such quantities, man must protect or treat the water to maintain the required quality standards. The future will require refined micro-level measurement, toxicity and carcinogenic screening methods, and further consideration of water-distributed prophylaxis. Serious consideration must be given to new concepts in water management: multiple re-use, parallel supply systems and integrated treatment processes. MAN'S NEEDS FOR WATER Water is essential to life. Water is essential to living. Water is essential to civilization. Man's needs for water are physiological, domestic, agricultural and industrial. Fortunately these needs are not identical with regard to water quantity or quality, and they are not identical in location nor in time. These needs must be balanced so that water may be apportioned to allow for mankind's full development.