An exploration of the interaction between socio-economic productivity and water withdrawal

The term sustainability invites interest in the main factors that affect the deterioration of natural resources. Different hypotheses have been put forward concerning the relationship between water and its effect on different economic sectors. Several questions can be asked here, for example: Does a higher water withdrawal for one sector mean that this sector is adding more to the GDP or is it a sunk cost (it is the cost that should be ignored compared to the benefit of water withdrawal for an individual economic sector) compared with the benefits to the economy? Do social factors affect water withdrawal more than economic factors or are they both impacting equally? We aim to answer these questions and to shed light on different socio-economic factors that affect water withdrawal in different economic sectors. This study investigates, in depth, the interaction between humans and the environment and can be useful in monitoring the direct effect on water withdrawal from agricultural and non-agricultural sectors and on different national economic variables that act as an indicator for economic development and growth. We used simultaneous equation models in our analysis, both the three-stage least squares and the two-stage least squares to explore the relationships. For more credibility, we run the fixed and random effects of 2SLS. Our results showed the influence of trade openness and economic growth on water withdrawal for different economic sectors, and the effect of an increasing demand for water for non-agricultural purposes, which adds pressure on the agricultural sector and eventually may lead to rising food prices.     

Toxicity and biochemical impact of certain oxime carbamate pesticides against terrestrial snail,Theba pisana (Müller)

Abstract

The bran toxic baits (0.5 % w/w) of five oxime carbamate pesticides; aldicarb, aldoxycarb, methomyl, oxamyl and thiofanox were tested for their molluscicidal activity against Theba pisana snails under Laboratory conditions. In addition, the in vivo effects of these compounds on seven vital enzymes namely Acetylcholin‐esterase (AchE), glutathion‐S‐transferase (GST), glutamic oxlaoacetic transaminase (GOT), glutamic pyruvic transaminase (GPT), acid phosphatase (AcP), alkaline phosphatase (AIP), and adenosine triphosphatase (ATPase) activities of the snail tissue were also investigated after 1,3, and 5 days of exposure. The results showed that methomyl was the most potent candidate, whereas thiofanox was the least effective one against the snails. LT₅₀’s values of aldicarb, aldoxycarb, methomyl, oxamyl and thiofanox were 5.77, 4.69, 2.31, 3.97 and 6.67 days, respectively. Results of the potency of the tested pesticides against AchE activity were in harmony with the toxicity of these compounds to snails. AchE, AcP, and AIP activities were inhibited by the tested pesticides. GST activity was inhibited by aldicarb but stimulated by oxamyl and thiofanox. Methomyl and oxamyl lead to significant elevation of GOT and GPT, whereas thiofanox treated snail induced a reduction of both enzymes activities. Aldicarb and aldoxycarb caused significant induction of ATPase activity.     

尼罗河三角洲与长江三角洲重金属污染对比研究

通过对比研究尼罗河三角洲与长江三角洲重金属污染特征,结果发现前者多数重金属含量高于后者,且尼罗河三角洲富集指数EF值约为长江三角洲3倍。此外,两者重金属分布格局差异明显,尼罗河三角洲呈东西高、中间低的"马鞍形"分布。自阿斯旺建坝后,干旱气候条件和人类活动使得尼罗河三角洲泻湖演变为重金属沉积中心。与之相反,长江三角洲重金属含量向海沿程降低,季风降水和巨量水沙对污染物扩散能力较强,污染水平较低。与世界其他地区河口相比,尼罗河三角洲重金属污染属于中等水平,而长江三角洲属于中下水平。对比研究表明两三角洲重金属物污染分布规律差异与其独特的流域自然条件和人类活动方式有密切关系。     

Discovery of copper chloride cancer in ancient Egyptian polychromic wall paintings and faience: A developing archaeological disaster

We are deeply indebted to the Stiftung Volkswagenwerk for the generous financial support to conduct a detailed research program on ancient Egyptian pigments in time and space. We are grateful to the Egyptian Antiquities Organization specifically to its former Presidents Dr. Ahmed Kadry and Dr. Abdel Halim Nour El Din for their support and for the permission to collect pigment samples from various archaeological sites. During the course of this study we enjoyed the continuous encouragement of Dr. Ahmed Kadry and Dr. Abdel Halim Nour el Din and their deep understanding for the importance of the link between scientific research and Egyptology in solving archaeological problems. We also enjoyed constructive discussions with Dr. Ali Radwan Dean of the Faculty of Archaeology, Cairo University. We are also grateful to the following Directors, officials, and inspectors of the Egyptian Antiquities Organization: Dr. M. Abdel Razeq, Dr. Ali Hassan, Mr. M. Balbush, Dr. M. El Sughair, Dr. M. Saleh, Mr. M. Nasr, Mr. Ismail El Masri and other colleagues at various sites in Egypt. We are also grateful to Dr. Shawki Nakhla, Director of the Conservation Center of the Egyptian Antiquities Organization. This work has benefited from discussions with Dr. E. Martin-Pardey, Mrs. I. Blom, and Dr. A. Eggebrecht. Specifically Dr. E. Martin-Pardey laid the sampling plan for and participated in the field campaign in March 1988 and we enjoyed her egyptological support.     

Fluoride distribution and the effect of some ions along Alexandria coastal Mediterranean seawater of Egypt

The coastal seawater of Mediterranean of Alexandria receives large amount of discharged waters containing industrial wastes, sewage, and agricultural and domestic drainage. Fluoride and some parameters were( chemical and physical) determined. The data gave indication that the content and the amount of the discharged water largely affect the chemical composition of the coastal water. Stepwise regression analysis was highly significant and the model was very fruitful, where the observed and calculated values were mostly concordant. This may indicated that there was a relation between fluoride content in cosslal seawater and its content in the discharged water.     

Abiotic degradation of imazethapyr in aqueous solution

The photodegradation of imazethapyr [2-(4,5-dihydro-4-méthyl-4-(1-méthylethyl)-5-oxo-1H-imidazol-2-yl)-5-ethyl-3-pyridinecarboxylic acid] in aqueous solution in the presence of titranium dioxide (TiO2) and humic acids (HA) at different ratios of herbicide/TiO2 and herbicide/humic acids was studied at pH 7.0. Irradiation was carried out with polychromatic light using Heraeus apparatus equipped with xenon lamp to simulate sunlight having a spectral energy distribution similar to solar irradiation (>290 nm). The concentration of remaining herbicide was followed using a High Pressure Liquid Chromatograph (HPLC) equipped with UV detector at 230 nm. In pure aqueous solution imazethapyr degrades slowly and the photodegradation leads to the formation of two metabolites labelled A and B. The presence of TiO2 caused enhancement of the degradation rate. The presence of HA induced an increase of the photodegradation of the pesticide with respect to pure aqueous solution.     

Unexpected reproductive strategy of Sardinella aurita off the coast of Venezuela

Biological sampling of Spanish sardine (Sardinella aurita Valenciennes, 1847) off the coast of Venezuela from 1956 to 1989 was used to study the reproductive strategy and migration pattern of the population. Whereas in many pelagic fishes the energy re-allocation necessary for reproduction usually occurs optimally at the end of the upwelling season when planktonic production reaches a maximum, in the present study a 5 mo delay was observed. This suggests that energy was stored as lipids early in the season and released later via metabolism for gamete production. Major reproduction did not occur in an area and at a time when offshore transport and turbulence were low, which is also unusual for a pelagic fish species. These results are discussed in terms of the life cycle of the Spanish sardine and its possible migratory patterns. The reproductive strategy of this population apparently gives priority to optimising food availability for the offspring and not to preventing eggs and larvae being transported offshore. The presence of “retention” areas could explain this unexpected strategy. Received: 4 November 1996 / Accepted: 20 December 1996     

A fouling suppression system in submerged membrane bioreactors using dielectrophoretic forces

A novel method was developed to suppress membrane fouling in submerged membrane bioreactors. The method is based on the dielectrophoretic(DEP) motion of particles in an inhomogeneous electrical field. Using a real sample of biomass as feed, the fouling-suppression performance using DEP with different electrical field intensities(60–160 V) and different frequencies(50–1000 Hz) was investigated. The fouling-suppression performance was found to relate closely with the intensity and frequency of the electrical field. A stronger electrical field was found to better recover the filtrate flux. This is because of a stronger DEP force acting on the biomass particles close to the membrane's surface. Above an intensity and frequency value of130 V and 1 k Hz, respectively the permeate flux was reduced due to an electrothermal effect.     

A fouling suppression system in submerged membrane bioreactors using dielectrophoretic forces

A novel method was developed to suppress membrane fouling in submerged membrane bioreactors. The method is based on the dielectrophoretic (DEP) motion of particles in an inhomogeneous electrical field. Using a real sample of biomass as feed, the fouling-suppression performance using DEP with different electrical field intensities (60-160 V) and different frequencies (50-1000 Hz) was investigated. The fouling-suppression performance was found to relate closely with the intensity and frequency of the electrical field. A stronger electrical field was found to better recover the filtrate flux. This is because of a stronger DEP force acting on the biomass particles close to themembrane's surface. Above an intensity and frequency value of 130 V and 1 kHz, respectively the permeate flux was reduced due to an electrothermal effect.