WATER REUSE FROM SEWAGE EFFLUENT BY IRRIGATION: A PERSPECTIVE FOR HAWAII1

ABSTRACT: Surrounded by an ocean, the Hawaiian Islands are limited in their natural fresh water resources. The major readily developable potable sources are the high quality ground water sources which serve both domestic uses and sugarcane irrigation although irrigation water does not require as high a quality as drinking water. The increasing overall fresh water requirements for the island of Oahu will outstrip the potential yield of fresh ground water sources, as developed by present technology, by the year 2000 according to Honolulu Board of Water Supply projections. There are water shortage regions on other islands. Water reuse from sewage effluent for irrigation will augment natural water resources, furnish supplemental or alternative fertilizer, and reduce ocean water pollution and the costs of engineering systems. In cooperative field testing from 1971 to 1975, it was demonstrated that effluent can be applied as supplemental water for furrow irrigation of sugarcane without detriment to ground water quality and sugar yield. Studies are in progress to test different dilutions of effluent and its use with chemical ripeners to improve crop yield. Sugarcane plantations on Oahu, Maui, and Kauai are in various stages of water reuse by effluent irrigation. Reuse is presently practiced for irrigation of golf courses and is being planned for forage crops in Hawaii.     

Heavy Metal Contents and Magnetic Properties of Playground Dust in Hong Kong

This study examined the levels of seven heavy metals (namelyzinc, copper, cadmium, chromium, lead, manganese and iron) andtheir associations with magnetic properties in playground dustof Hong Kong. Results showed that the playground dust containedhigh concentrations of Zn (mean = 1883 g g^-1), Cu(mean = 143 g g^-1) and Cr (mean = 263 g g^-1).Qualitative examination of dust samples under microscope indicated local traffic as one of the important pollutant sources. Magnetic measurements indicated that these anthropogenicpollutants mainly consisted of coarse-grained multidomain (MD) ferrimagnetic minerals. Superparamagnetic (SP), stable single domain (SSD) ferrimagnetic grains and non-ferrimagnetic mineralswere present in relatively small amounts. Significant correlations between heavy metals and various magnetic parametersindicated a strong affinity of heavy metals to magnetic minerals hence pointed out the potential of magnetic properties for simpleand rapid proxy indications of heavy metal pollution in playground dust.     

Acute and chronic toxicities of tributyltin to various life stages of the marine polychaete Hydroides elegans

Experiments were performed to determine the acute and chronic toxicities of tributyltin (TBT) (nominal concentrations) to polychaete Hydroides elegans. Firstly, static tests were performed to examine the lethal effect of TBT on five life stages of H. elegans. The 48-h LC(50) (95% CI) for the eggs, 2-cells, trochophores, juveniles and adults was 0.18 (0.15-0.20), 0.97 (0.77-1.23), 2.36 (2.11-2.65), 2.86 (2.63-3.12) and 4.36 (4.04-4.71) microg TBT l(-1), respectively. Secondly, a 17-d static renewal chronic test was conducted to study sensitivity of the early development (egg to juvenile) to TBT. The survivorship, percent settlement and time to reach settlement were significantly reduced at 0.01 microg TBT l(-1). Effects of TBT on the juvenile growth and maturation were also studied through a 44-d chronic test. Lower survivorship and reduced tube growth were observed only at >or= 1 microg TBT l(-1), however, only H. elegans exposed to or= 0.1 microg TBT l(-1). Our results indicate that the early development of H. elegans is highly sensitive to TBT and this polychaete can be routinely employed as a test organism for both acute and chronic ecotoxicity bioassays in tropical and subtropical regions such as southern China.     

A review on bisphenol A occurrences,health effects and treatment process via membrane technology for drinking water

Massive utilization of bisphenol A (BPA) in the industrial production of polycarbonate plastics has led to the occurrence of this compound (at μg/L to ng/L level) in the water treatment plant. Nowadays, the presence of BPA in drinking water sources is a major concern among society because BPA is one of the endocrine disruption compounds (EDCs) that can cause hazard to human health even at extremely low concentration level. Parallel to these issues, membrane technology has emerged as the most feasible treatment process to eliminate this recalcitrant contaminant via physical separation mechanism. This paper reviews the occurrences and effects of BPA toward living organisms as well as the application of membrane technology for their removal in water treatment plant. The potential applications of using polymeric membranes for BPA removal are also discussed. Literature revealed that modifying membrane surface using blending approach is the simple yet effective method to improve membrane properties with respect to BPA removal without compromising water permeability. The regeneration process helps in maintaining the performances of membrane at desired level. The application of large-scale membrane process in treatment plant shows the feasibility of the technology for removing BPA and possible future prospect in water treatment process.     

Obesity Kuznets curve hypothesis and global warming: a robust estimation under cross-section dependence

Environmental Science and Pollution Research - Obesity is a worldwide concern as it leads to adverse effects on human health. This study uses a panel of 165 countries and annual data from 2000 to...     

Local authority waste paper recovery operations: An appropriate costing system

This article reviews attempts by other workers to derive full economic evaluations of local authority waste paper recovery operations and proposals from government bodies to devise uniform costing systems for these schemes. In the light of this work a standard costing system for local authority waste paper recovery operations is proposed. Empirical data was obtained from a number of local authorities and analysed using this standard costing system. The viability of each scheme under the standard costing system and the Council's original costing system is compared.     

根际土壤中DDTs的残留与转化

通过根垫法研究DDT的五种异构体p,p‘-DDE,o,p’-DDD,p,p‘-DDD,o,p‘-DDT,p,p‘-DDT在小麦根际土壤和非根际土壤中的残留量以及DDT,DDD和DDE之间的转化．结果发现,在40d试验期间内,DDT发生缓慢降解,根际土壤中的降解略快于非根际土壤,且差别主要表现在生成DDD的厌氧过程方面．此外,根际土壤中五种DDT的异构体的可提取残留都高于非根际土壤,说明该农药的锁定过程在根际环境相对较弱．     

Individual attributes and leadership style: predicting the use of punishment and its effects

This study examined attributes of leaders that influenced their use of contingent and noncontingent punishment and the results of using punishment on leader effectiveness. Results indicated that leaders with higher levels of physical fitness and moral reasoning were more likely to use contingent punishment, while those with lower self-esteem were more likely to use noncontingent punishment. Noncontingent punishment negatively impacted leader effectiveness, while contingent punishment positively impacted leader effectiveness. © 1998 John Wiley & Sons, Ltd.