Sources and transformations of nitrogen compounds along the Lower Jordan River

The Lower Jordan River is located in the semiarid area of the Jordan Valley, along the border between Israel and Jordan. The implementation of the water sections of the peace treaty between Israel and Jordan and the countries' commitment to improve the ecological sustainability of the river system require a better understanding of the riverine environment. This paper investigates the sources and transformations of nitrogen compounds in the Lower Jordan River by applying a combination of physical, chemical, isotopic, and mathematical techniques. The source waters of the Lower Jordan River contain sewage, which contributes high ammonium loads to the river. Ammonium concentrations decrease from 20 to 0-5 mg N L(-1) along the first 20 km of the Lower Jordan River, while nitrate concentrations increase from nearly zero to 10-15 mg N L(-1), and delta(15)N (NO(3)) values increase from less than 5 per thousand to 15-20 per thousand. Our data analysis indicates that intensive nitrification occurs along the river, between 5 and 12 km from the Sea of Galilee, while further downstream nitrate concentration increases mostly due to an external subsurface water source that enters the river.     

Quantifying ground water inputs along the Lower Jordan River

The flow rate of the Lower Jordan River has changed dramatically during the second half of the 20th century. The diversion of its major natural sources reduced its flow rate and led to drying events during the drought years of 2000 and 2001. Under these conditions of low flow rates, the potential influence of external sources on the river discharge and chemical composition became significant. Our measurements show that the concentrations of chloride, calcium, and sodium in the river water decrease along the first 20-km section, while sulfate and magnesium concentrations increase. These variations were addressed by a recent geochemical study, suggesting that ground water inflow plays a major role. To further examine the role of ground water, we applied mass-balance calculations, using detailed flow rate measurements, water samplings, and chemical analyses along the northern (upstream) part of the river. Our flow-rate measurements showed that the river base-flow during 2000 and 2001 was 500 to 1100 L s(-1), which is about 40 times lower than the historical flow rates. Our measurements and calculations indicate that ground water input was 20 to 80% of the river water flow, and 20 to 50% of its solute mass flow. This study independently identifies the composition of possible end-members. These end-members contain high sulfate concentration and have similar chemical characteristics as were found in agricultural drains and in the "saline" Yarmouk River. Future regional development plans that include the river flow rate and chemistry should consider the interactions between the river and its shallow ground water system.     

Chemical changes in different types of coal ash during prolonged,large scale,contact with seawater

In this study, we followed the chemical changes occurring in coal ash exposed to prolonged (300 days), large scale, contact with running seawater. Four major components (Al, Ca, Mg, Fe) and seven minor and trace elements (Cd, Cr, Cu, Mn, Zn, Pb, Hg) were measured in four coal ash types: fly and bottom ash freshly obtained from coal-fired power plant, and old ash (crushed and blocks) recovered from the sea after 3-5 years contact with seawater. Changes occurred in the chemical composition of the coal ash along the experiment: Fe increased in fresh ash, Al increased in old ash and Ca increased in all ash types except old ash blocks. Cu and Hg decreased in fresh fly ash while Cr increased, Cd decreased in all ash types except bottom ash, and Mn decreased in bottom ash. Most of the changes occurred in the fresh fly ash, and not in the old ash, indicating equilibrium after prior exposure to seawater. In addition, more changes occurred in fresh fly ash than in bottom ash, emphasizing the differences between the two ash types. While the changes in the concentrations of the major elements may be an indication of the integrity of the ash matrix, the only elements of environmental significance released to the environment were Hg and Cd. However, calculated seawater concentrations were much lower than seawater quality criteria and therefore the coal ash was considered suitable for marine applications concerning seawater quality.     

Economic considerations for wastewater upgrading alternatives: an Israeli test case

Sewage effluent for land application is becoming an increasingly important source of irrigation water in many semi-arid regions of the world. Two main approaches to the use of sanitation to upgrade effluent for reuse in agriculture were analyzed: (i) sanitizing to the level required for each crop; or (ii) upgrading all effluent to the sanitary level mandated for unrestricted irrigation (<10 fecal coli/100mL). The first approach was authorized by the Israeli health authorities, who consider irrigation with secondary effluent to be complementary to the treatment process. The other approach was conceived mainly by the agricultural and environmental establishments, which debited the additional financial burden to the urban sector and/or the 'general public'. We show that upgrading all effluents in Israel to 'unrestricted irrigation quality' would cost $69 million each year for upgrading alone, in addition to the costs of treatment to the sanitary level required for each individual crop and of observing all the necessary additional precautions and boundaries. This difference in cost stems from the fact that most effluent is used for the irrigation of non-edible crops, for which partial pathogen removal is sufficient. Thus, upgrading to the sanitary level required by the most sensitive crops would be rather wasteful.     

Fuel derived pollutants and boating activity patterns in the Sea of Galilee

MTBE (Methyl tert-Butyl Ether) is a fuel additive that replaced lead as an antiknock compound in internal combustion motors. Few years after its introduction, detectable levels of MTBE were found in various water bodies. MTBE has a very low taste and odor threshold and is a potential carcinogen. Another group of fuel derived toxic compounds that has been detected in water bodies is BTEX (Benzene, Toluene, Ethylbenzene and Xylene). Boating activity and allochthonous contributions from watersheds are the major sources of fuel derived pollutants in lakes. Their concentrations in lakes thus vary as a function of boating activity intensity, lake surface area and depth, weather and wind regime, land-use in the watershed, etc. The Sea of Galilee (Lake Kinneret) is the only recreational lake in Israel and an important freshwater source. In the current study, a sampling campaign was conducted in order to quantify MTBE and BTEX concentrations in Lake Kinneret, its marinas and its main contributing streams. In addition, a boating-use survey was performed in order to estimate MTBE and BTEX contribution of recreational boating. The sampling campaign revealed that, as expected, MTBE concentrations were higher than BTEX, and that near shore (i.e., marina) concentrations were higher than in-lake concentrations. Despite the clear contribution from boating, high MTBE concentrations were found following a major inflow event in winter, indicating the importance of the allochthonous contribution. The contribution from boating during summer, as measured indirectly by in-lake concentrations, is likely underestimated due to enhanced MTBE volatilization due to strong winds and high temperatures. May–September was found to be the main recreational boating season, with continued boating year round. On average, a single boat is active 23 d/y, with 84% of the watercrafts being active only during weekends and holidays. The survey further indicated that boats stay in the lake for 4.5 h on average, which conforms to the unique winds regime that limits afternoon activity due to high winds, and have an average fuel consumption of 14 L/h. The annual load of MTBE and BTEX from recreational boating in Lake Kinneret was estimated at 4430 and 6220 kg/y respectively.     

The hydrozoan coral<Emphasis Type="Italic"> Millepora dichotoma</Emphasis>: speciation or phenotypic plasticity?

This article describes ecological and biological differences between two morphs of the Red Sea fire coral Millepora dichotoma. The species is divided into two main morphs: branching and encrusting, which were found to differ both in color and morphology. Each morph has two or more sub-morphs. A total of 372 M. dichotoma colonies were examined in a census at two study sites in the Gulf of Elat. Colony size and abundance of the two morphs were found to differ significantly between sites. Experimental examination of each morph's morphological plasticity revealed different growth rates and difference in growth plasticity between the branching and the encrusting morph. Most of the fragments from the branching colonies (94%) attached to experimentally placed Plexiglas substrate, compared with much less attachment by the encrusting fragments (11%). The growth form of the branching morph on the Plexiglas switched to encrusting, spreading over and covering the substrate. When the new encrusting colony reached the edge of this substrate, it started to produce tips, and returned to growth in the classic branching form. The encrusting morph did not change its growth form. Following attachment of the original fragments of the branching morph to the substrate, 8.1% of them produced new tips. When the original branches were removed, after converting to encrusting growth form, 19% of the fragments produced new tips. The capsule size of nematocysts of the two morphs was also significantly different (t-test, P<0.05). Molecular data (ITS region) clearly demonstrate that these two M. dichotoma morphs differ considerably. Molecular evidence (srRNA) from the symbiotic zooxanthellae also shows a different pattern of clades in the hosts. The ecological, biological and molecular data thus attest to the two morphs being distinguishable. Contrary to previous reports, we consequently suggest that the two morphs of M. dichotoma found in the Gulf of Elat are actually two distinct species.Communicated by O. Kinne, Oldendorf/Luhe