Subterranean Aquifers Research Articles

Is organic matter a source or redox driver or both for arsenic release in groundwater?

Arsenic (As) contamination in groundwater is a global public health issue, because groundwater is the main source of drinking water worldwide. Arsenic contamination in groundwater is directly or indirectly associated with organic matter (OM). Therefore, this study investigated the role of OM in mobilization of As in the subterranean aquifers. The reduced concentrations of terminal electron acceptors (dissolved O2, NO3-, and SO42-), enhanced concentrations of dissolved organic carbon (DOC), HCO3- and NH4+ ions, and strong correlations between NH4+ and DOC indicate the reducing geochemical environment of aquifer in Bangladesh, where DOC might have originated from microbial oxidation of sedimentary OM, humic substances, surface derived terrestrial OM and petroleum. Groundwater samples exhibit variations in the concentrations of DOC (0.20–5.09mg/l), fluorescence intensity and As depending on the depth and locations of the sampling site suggesting that the aquifers have different characteristics and different sources of DOC. The DOC concentrations in the upper aquifer (up to 41m) are higher than those in the middle and lower aquifers (>55m) suggesting that the recent inflow of surface derived terrestrial OM with recharge water and petroleum in the shallow parts of the aquifer promoted the peak of high dissolved As, where older water mixes with recent recharge water containing organic carbon. Hydrogeochemical data and sediment geochemistry indicates that As mobilization from the sediment occurs through the microbial-mediated reductive dissolution of iron oxyhydroxide, where OM is the main redox driver facilitating As release into groundwater. Organic matter can strongly influence the solubility and mobility of As mainly through redox reactions, competitive adsorption, desorption and complexation reactions. Furthermore, based on the results of sediment and groundwater geochemistry, and As speciation in plant tissue, it can be concluded that OM is not only a redox driver, but also one of the sources of As in groundwater.

Evolution of blind beetles in isolated aquifers: a test of alternative modes of speciation.

Evidence is growing that not only allopatric but also sympatric speciation can be important in the evolution of species. Sympatric speciation has most convincingly been demonstrated in laboratory experiments with bacteria, but field-based evidence is limited to a few cases. The recently discovered plethora of subterranean diving beetle species in isolated aquifers in the arid interior of Australia offers a unique opportunity to evaluate alternative modes of speciation. This naturally replicated evolutionary experiment started 10-5 million years ago, when climate change forced the surface species to occupy geographically isolated subterranean aquifers. Using phylogenetic analysis, we determine the frequency of aquifers containing closely related sister species. By comparing observed frequencies with predictions from different statistical models, we show that it is very unlikely that the high number of sympatrically occurring sister species can be explained by a combination of allopatric evolution and repeated colonisations alone. Thus, diversification has occurred within the aquifers and likely involved sympatric, parapatric and/or microallopatric speciation.

Current state of knowledge regarding South America wetlands and their future under global climate change

The exact size of the wetland area of South America is not known but may comprise as much as 20% of the sub-continent, with river floodplains and intermittent interfluvial wetlands as the most prominent types. A few wetland areas have been well studied, whereas little is known about others, including some that are very large. Despite the fact that most South American countries have signed the Ramsar convention, efforts to elaborate basic data have been insufficient, thereby hindering the formulation of a wetland-friendly policy allowing the sustainable management of these areas. Until now, the low population density in many wetland areas has provided a high level of protection; however, the pressure on wetland integrity is increasing, mainly as a result of land reclamation for agriculture and animal ranching, infrastructure building, pollution, mining activities, and the construction of hydroelectric power plants. The Intergovernmental Panel on Climate Change has predicted increasing temperatures, accelerated melting of the glaciers in Patagonia and the Andes, a rise in sea level of 20–60 cm, and an increase in extreme multiannual and short-term climate events (El Niño and La Niña, heavy rains and droughts, heat waves). Precipitation may decrease slightly near the Caribbean coast as well as over large parts of Brazil, Chile, and Patagonia, but increase in Colombia, Ecuador, and Peru, around the equator, and in southeastern South America. Of even greater impact may be a change in rainfall distribution, with precipitation increasing during the rainy season and decreasing during the dry season. There is no doubt that the predicted changes in global climate will strongly affect South American wetlands, mainly those with a low hydrologic buffer capacity. However, for the coming decades, wetland destruction by wetland-unfriendly development planning will by far outweigh the negative impacts of global climate change. South American governments must bear in mind that there are many benefits that wetlands bring about for the landscape and biodiversity as well as for humans. While water availability will be the key problem for the continent’s cities and agroindustries, intact wetlands can play a major role in storing water, buffering river and stream discharges, and recharging subterranean aquifers.

Phenol Biodegradation by <i>Corynebacterium glutamicum</i> Encapsulated in Electrospun Fibers

In Northern Israel, olive mills discharge liquid waste causing contamination of subterranean aquifers with phenol, rendering them albeit temporarily, unfit for both drinking and irrigation. The impact of groundwater pollution due to phenol spillage can be extensive. We developed a model system for the biodegradation of phenol-contaminated wastewater by the bacterium Corynebacterium glutamicum. Experiments consisting of suspended cultures demonstrated the native ability of this organism to utilize phenol for its metabolic pathways enabling degradation, at levels of nearly 100 ppm within 24 hours. With the use of bioinformatic data, a complete degradation pathway was constructed. Quantitative Real Time PCR analysis of the first two enzymes in this pathway revealed very distinct expression patterns and two different regulation mechanisms were postulated. Additionally, an electrospinning core-shell system was used to assemble electrospun microtubes containing bacteria on porous metallic carriers. We used these carriers as a new immobilization technique and demonstrated their significant phenol degrading capacity in a batch bioreactor configuration. This system demonstrates the feasibility of constructing a water treatment system for the management of phenol-contaminated water.

New Light on Human Prehistory in the Arabo-Persian Gulf Oasis

The emerging picture of prehistoric Arabia suggests that early modern humans were able to survive periodic hyperarid oscillations by contracting into environmental refugia around the coastal margins of the peninsula. This paper reviews new paleoenvironmental, archaeological, and genetic evidence from the Arabian Peninsula and southern Iran to explore the possibility of a demographic refugium dubbed the “Gulf Oasis,” which is posited to have been a vitally significant zone for populations residing in southwest Asia during the Late Pleistocene and Early Holocene. These data are used to assess the role of this large oasis, which, before being submerged beneath the waters of the Indian Ocean, was well watered by the Tigris, Euphrates, Karun, and Wadi Batin rivers as well as subterranean aquifers flowing beneath the Arabian subcontinent. Inverse to the amount of annual precipitation falling across the interior, reduced sea levels periodically exposed large portions of the Arabo-Persian Gulf, equal at times to ...

Microbial Atrazine Breakdown in a Karst Groundwater System and Its Effect on Ecosystem Energetics

In the absence of sunlight energy, microbial community survival in subterranean aquifers depends on integrated mechanisms of energy and nutrient scavenging. Because karst aquifers are particularly sensitive to agricultural land use impacts due to rapid and direct hydrologic connections for pollutants to enter the groundwater, we examined the fate of an exogenous pesticide (atrazine) into such an aquifer and its impact on microbial ecosystem function. Atrazine and its degradation product deethylatrazine (DEA) were detected in a fast-flowing karst aquifer underlying atrazine-impacted agricultural land. By establishing microbial cultures with sediments from a cave conduit within this aquifer, we observed two distinct pathways of microbial atrazine degradation: (i) in cave sediments previously affected by atrazine, apparent surface-derived catabolic genes allowed the microbial communities to rapidly degrade atrazine via hydroxyatrazine, to cyanuric acid, and (ii) in low-impact sediments not previously exposed to this pesticide, atrazine was also degraded by microbial activity at a much slower rate, with DEA as the primary degradation product. In sediments from both locations, atrazine affected nitrogen cycling by altering the abundance of nitrogen dissimulatory species able to use nitrogenous compounds for energy. The sum of these effects was that the presence of atrazine altered the natural microbial processes in these cave sediments, leading to an accumulation of nitrate. Such changes in microbial ecosystem dynamics can alter the ability of DEA to serve as a proxy for atrazine contamination and can negatively affect ecosystem health and water quality in karst aquifers.

Phylogenetic relationships and description of a new stygobite species ofBythinella(Mollusca, Gastropoda, Caenogastropoda, Amnicolidae) from southern France

Prié V. & Bichain J.-M. 2009. — Phylogenetic relationships and description of a new stygobite species of Bythinella (Mollusca, Gastropoda, Caenogastropoda, Amnicolidae) from southern France. Zoosystema 31 (4): 987-1000.A population of the aquatic gastropod Bythinella that does not conform to any described hypogean or epigean species of this genus was discovered in a cave stream in southern France (Folatière cave). Members of this population lacked body pigments and eyespots, which suggests adaptation to a subterranean environment. Mitochondrial COI sequences revealed two lineages within this population, separated by a genetic divergence higher than the inter-specific threshold commonly admitted for hydrobioid species. In contrast, a phylogeny based on the nuclear ITS1 gene clustered the sequenced hypogean specimens in a single clade. Moreover multivariate analyses performed on shell parameters did not enable discrimination between hypogean specimens attributed to each of these two mitochondrial lineages. The high COI variability within the same population and conflict between mtDNA and nDNA trees could be explained by a scenario of introgression by hybridization. Consequently, based on nuclear gene phylogeny, shell and anatomical characters, and ecological evidences, we hypothesize that the easily recognizable hypogean morph of the Folatière cave can be attributed to a distinct and new species — here described and named B. navacellensis n. sp. Our extensive sampling suggests that B. navacellensis n. sp. is distributed within a small delimited and cohesive area located around southern Larzac, covering c. 300 km2. Considering its distribution, restricted to a few subterranean aquifers only, B. navacellensis n. sp. can be categorised as a vulnerable species, VU D2.

Constraints in the colonization of natural and engineered subterranean igneous rock aquifers by aerobic methane‐oxidizing bacteria inferred by culture analysis

The aerobic methane-oxidizing bacteria (MOB) are suggested to be important for the removal of oxygen from subterranean aquifers that become oxygenated by natural and engineering processes. This is primarily because MOB are ubiquitous in the environment and in addition reduce oxygen efficiently. The biogeochemical factors that will control the success of the aerobic MOB in these kinds of underground aquifers remain unknown. In this study, viable and cultivable MOB occurring at natural and engineered deep granitic aquifers targeted for the disposal of spent nuclear fuel (SNF) in the Fennoscandian Shield (approximately 3-1000 m) were enumerated. The numbers were correlated with in situ salinity, methane concentrations, conductivity, pH, and depth. A mixed population habiting freshwater aquifers (approximately 3-20 m), a potential source for the inoculation of MOB into the deeper aquifers was tested for tolerance to NaCl, temperature, pH, and an ability to produce cysts and exospores. Extrapolations show that due to changing in situ parameters (salinity, conductivity, and pH), the numbers of MOB in the aquifers dropped quickly with depth. A positive correlation between the most probable numbers of MOB and methane concentrations was observed. Furthermore, the tolerance-based tests of cultured strains indicated that the MOB in the shallow aquifers thrived best in mesophilic and neutrophilic conditions as opposed to the hyperthermophilic and alkaliphilic conditions expected to develop in an engineered subterranean SNF repository. Overall, the survival of the MOB both quantitatively and physiologically in the granitic aquifers was under the strong influence of biogeochemical factors that are strongly depth-dependent.

Elucidation of endemic neurodegenerative diseases--a commentary.

Recent investigations of scrapie, Creutzfeldt-Jakob disease (CJD), and chronic wasting disease (CWD) clusters in Iceland, Slovakia and Colorado, respectively, have indicated that the soil in these regions is low in copper and higher in manganese, and it has been well-known that patients of ALS or Parkinson's disease were collectively found in the New Guinea and Papua islands, where the subterranean water (drinking water) contains much Al3+ and Mn2+ ions. Above facts suggest that these neurodegenerative diseases are closely related with the function of a metal ion. We have investigated the chemical functions of the metal ions in detail and established the unique mechanism of the oxygen activation by the transition metal ions such as iron and copper, and pointed out the notable difference in the mechanism among iron, aluminum and manganese ions. Based on these results, it has become apparent that the incorporation of Al(III) or Mn(II) in the cells induces the "iron-overload syndrome", which is mainly due to the difference in an oxygen activation mechanism between the iron ion and Al(III) or the Mn(II) ion. This syndrome highly promotes formation of hydrogen peroxide, and hydrogen peroxide thus produced can be a main factor to cause serious damages to DNA and proteins (oxidative stress), yielding a copper(II)- or manganese(II)-peptide complex and its peroxide adduct, which are the serious agents to induce the structural changes from the normal prion protein (PrP(c)) to abnormal disease-causing isoforms, PrP(Sc), or the formation of PrP 27-30 (abnormal cleavage at site 90 of the prion protein). It seems reasonable to consider that the essential origin for the transmissible spongiform encephalopathies (TSEs) should be the incorporation and accumulation of Al(III) and Mn(II) ions in the cells, and the sudden and explosive increase of scrapie and bovine spongiform encephalopathy (BSE) in the last decade may be partially due to "acid rain", because the acid rain makes Al(III) and Mn(II) ions soluble in the subterranean aquifers.

Underground storage of carbon dioxide in depleted natural gas reservoirs and in useless aquifers

Depleted reservoirs of natural gas and petroleum can provide excellent traps for carbon dioxide. Deep aquifers, which are not used due to high salinity, can host larger amount of the carbon dioxide under their high formation pressure than natural gas and oir reservoirs. Small fraction of aquifers in sedimentary basins in the world are enough to host about 87 gigaton-C of carbon dioxide. A preliminary technical and economical survey on the carbon dioxide injection system suggests that the energy requirement for carbon dioxide injection into subterranean aquifers is about 269 kWh/ton-C and that the investment and operation costs for system are 79 $/ton-C. By our preliminary cost estimation in Japan, the CO 2-emission-free electricity generation may become possible with a cost increase of 35% for natural-gas-fired power station, and of 60% for coal-fired-power station.

Quantity and Quality of Groundwater in the Campo De Dalias (Almeria, Se Spain)

The Campo de Dalías is the most economically important agricultural area in the whole of the Province of Almeria. A benign climate combined with the expertise of the market gardeners and their intensive cultivation in plastic hot-houses of out-of-season fruit and vegetables has turned a stony wasteland into an area of great productivity. The main water supply comes from a series of wells drilled into the subterranean aquifers running through the local rocks, a geometrically complex succession of Triassic limestones and dolomites, Miocene conglomerates and calcareous sandstones, Pliocene calcarenites and Quaternary gravels, sands and silts. The annual influx into the aquifers has been calculated as being around 50 Hm3, while at the present day more than 100 Hm3 are being taken out during the same period. This over exploitation of the resources is causing an inexorable descent in the water table, which is leading to marine intrusion in those aquifers nearest the sea. The main aquifer-bearing units are Balanegra and Aguadulce, composed essentially of Triassic, Alpujarride carbonates, and the Balerma-Las Marinas unit, made, up of Pliocene calcarenites. In the water from some of the wells in the Aguadulce unit more than 10,000 microS/cm have been measured at some distance from the coast, while in the Balanegra unit there are a large number of conoids below sea level, although marine intrusion is at present limited to a fairly narrow coastal strip.

Development of a New High-Reliability Downhole Pumping System for Large Horsepowers

Summary This paper describes the design concepts incorporated in an entirely new patented hydraulically powered downhole pumping system that has been the basis for a major development program undertaken by Weir Pumps Ltd. with the support of two large oil companies and the U.K. Dept. of Energy. This system is shown to be readily adaptable to high-power artificial lift requirements for both oil and water, and typical installations for several different market applications, both onshore and offshore, are described in detail. The comprehensive laboratory and field trials of the prototype units are described, and it is shown that early expectations of a major improvement in reliability offered by the new system have been met fully by the highly successful field performance. Background Recent expansion of secondary oil recovery operations both offshore and onshore has led to the need for higher-horsepower artificial lift systems. A large proportion these systems have incorporated electric submersible pump (ESP) sets downhole, either for pumping oil or, particularly in the Middle East, for lifting water from subterranean aquifers for reinjection. Many of these applications have required considerably larger downhole pump sets than had been used previously, either because the boosted well flow rate is high or because high pumping heads are required. This large-horsepower requirement for downhole motors generally has had to be met within the diameter limitations of well casings-often 9 5/8-in. (24.5-cm) OD or less--and this has resulted in the evolution of very long submersible motors of tandem or triple tandem construction, operating in series, with high electric supply voltages. These motors, when coupled to correspondingly long seal and pump sections, have resulted in large-horsepower ESP's that are typically more than 98 ft. (30 m) long [in some cases more than 130 ft (40 m) long], very slender and flexible, and difficult to manufacture and install. Therefore, problems in operating these units could have problems in operating these units could have been expected, particularly since the environmental conditions for these high-horsepower units frequently are very adverse. In the North Sea, experience with large-horsepower ESP's so far has been fairly limited, but a typical experience of short operating life and unreliability has been reported. The report identifies the following offshore problem areas.1. The difficulty in installing the long units in deviated wells frequently results in damage to motors, potheads, and cables.2. Ingress of saline well fluid into cable connectors causes cable failure to earth.3. Ingress of well fluid into the motor through the sealing section causes motor insulation failure.4. Motor failure results from overheating because of high currents and poor cooling at startup.5. Sand erodes pump components.6. Wear rates on thrust bearings are high, particularly at flows away from the duty rating. particularly at flows away from the duty rating. 7. There are high costs associated with onsite assembly and transporting unwieldy proportions of the pump sets. JPT p. 1709

Phenolics in aquatic ecosystems: A selected review of recent literature

This review surveys the pertinent literature on phenolics in the aquatic ecosystem. Approximately 2% of the total organics manufactured in the US were phenols. Of the total phenolics produced in the US, 96% were synthetic and 4% were naturally occurring. Synthetic phenols arise from coking of coal, gas works and oil refineries, chemical plants, pesticide plants, wood preserving plants and dye manufacturing plants. Natural phenolics occur from aquatic and terrestrial vegetation and much of this is released by the pulp and paper industry. Toxicity of phenolics has been studied on selected microbes (e.g. protozoa, yeast and bacteria), algae, duckweed, and numerous invertebrates and vertebrates. Depending on the organism tested, the acute toxicity of phenol varies from 6·5 to 1840 mg/litre phenol. For other phenolics toxicity ranges from 0·084 to 555 mg/litre. The toxicity of phenolics varies with the type, position and number of substitutions on the parent molecule. Environmental factors affect the toxicity of phenolics and these include photolytic action, microbial degradation, pH, water hardness and temperature. Based on limited data, toxicity of phenolics may be less in continuous flow tests than in their sensitivity to phenolics as does the presence of oxygen. A seasonal factor may also affect the sensitivity of various fish. Starvation and lack of suitable substrate for bottom fauna increases organism sensitivity to phenol. The source of test animals may affect their sensitivity to phenolics and this effect may be due to short-term physiological acclimation and genetic selection. Studies on the biological effects of phenolics are limited and varied. Fish development and embryo survival were not affected by phenol levels less than 25 mg/litre. Amphibian embryos were sensitive to 0·5 mg/litre phenol. Pentachlorophenols inhibited fish growth at levels down to 1·74, μg/litre. Exposure of fish to phenol in concentrations as low as 4 mg/litre caused haemorrhaging at the base of the fins. Two hour exposure to 6·5 mg/litre phenol caused disruption of blood vessel walls and gill epithelium. Oedema and blood infiltration was a common effect observed in most major tissues studied from fishes exposed to phenol. Phenol, at 12·5 mg/litre, reduces the levels of neurohormones in fish exposed for 10 days. The effects of pentachlorophenol on blood glucose and blood lactate levels, and in vivo and in vitro activity levels of seven liver enzymes of eels are discussed. Pentachlorophenol, at 1·8 μg/litre, decreased assimilation conversion efficiency in underyearling salmon. Phenol also affects immunoglobin levels, blood protein levels and tissue micro-element levels. Feeding rates are affected by phenolics. Phenolics affect oxygen consumption rates and the effect may be on uncoupling of oxidative phosphorylation with a subsequent reduction of ATP formation. Many aspects of behaviour are affected by phenolics and the phases of ‘intoxication’ leading to death have been described for fish and invertebrates. Fish detoxify phenolics by forming conjugate glucuronides and sulphates. Body burdens of phenolics varied with exposure time and exposure concentration. When fish pre-exposed to phenol are transferred to clean water, body burdens drop up to 90% after three to four hours. Depuration rates for other phenolics took longer; up to 30 days for pentachlorophenol. Little research has been done on the cycling of phenol and phenolics (other than pesticides) in aquatic ecosystems. Microbial degradation will decompose phenolics rapidly if suitable bacteria are present. Other factors affecting the loss of phenolics from aquatic ecosystems include photolysis, adsorption and dilution. Phenol entering subterranean aquifers may not dilute or degrade very quickly. In one documented case well-water levels up to 200 mg/litre were measured 18 months after a spill.

Use Of A GIS Tool For Sustainable ManagementOf Aquifer 08-29 Resources In La Mancha,Spain

Geographic Information Systems enable us to manage projects as complex as the sustainable exploitation of subterranean aquifers for agricultural use. This is the case of the extensive hydrologic system 0829, located on the eastern side of La Mancha (Spain). The integration of Remote Sensing into the GIS, which allows us to identify, discriminate and study irrigated crops in the semiarid environment of this area, is done by the intersection of a classified image with the polygon layer of the rural cadastre. This union of Remote Sensing and GIS, using the rural cadastre as a geographic base, proves to be highly useful as it combines the capabilities of both tools.

Refuse Disposal, Its Significancea

AbstractApproximately 4 pounds of refuse per capita per day are produced in the United States. The term refuse, as used here, refers to the useless, unused, unwanted, or discarded solid waste materials resulting from normal community activities; refuse includes such materials as garbage, rubbish, ashes, street refuse, dead animals, and solid industrial wastes (Anon., 1958). Thus, every day our urban population produces over 400,000,000 pounds of refuse that must be disposed of by dumping on land, grinding and disposal with sewage, incineration or that must be made reusable by one or more reclamation processes. Over 1400 communities dispose of their refuse by sanitary landfill techniques, i.e., compaction and covering with compacted earth on suitable land by use of mechanical equipment such as crawler type tractors (Figure 1). Many thousands more dispose of this material in open dumps on land without the degree of sanitary control recommended by health agencies (Figure 2).Wherever refuse is deposited on land, the potential impact on surface waters or subterranean aquifers may be significant. This can be better appreciated when one considers, for example, that ordinary community refuse may have a 5‐day BOD of 14,000 to 180,000 ppm and an alkalinity (to MO as CaCO3) of 2600 to more than 23,000 ppm, as shown in Table 1 (Anon., 1952a). In one study bacteriological examination of landfill material showed an average of 740,000 coliforms per gram of refuse. The leachate from a landfill has been found to have a 5‐day BOD from 6 to more than 7000 ppm (Carpenter and Setter, 1940; McDermott, 1950).The question is, of course, what does this mean translated into terms of potential ground‐water pollution? And further, when this potential is known, what then are the practicalities involved in present disposal practices and their implications with respect to the development of existing and future ground‐water pollution problems?