Showing papers on "Saline water published in 1995"

Identification of groundwater solute sources using boron isotopic composition.

Abstract: In a long-term evaluation of the injection of treated wastewater into an alluvial aquifer near El Paso, TX, the boron (B) concentration and B stable isotopic values were investigated as potential intrinsic tracers of recharge-water source. The B stable isotopic values (δ 11 B) of background groundwater (14‰) and water from anthropogenic sources such as treated municipal wastewater (6-10‰) and irrigation-affected water (>40%‰) were distinctly different. The B concentrations in combination with the B stable isotope values distinguished these water types and natural saline water as sources of recharge to groundwater. Boron is suited for use as a conservative tracer in groundwater because of its high solubility in aqueous solution (predominantly as boric acid), its natural presence in nearly all water, and the lack of effects by evaporation or volatilization, by oxidation-reduction reactions, or by mineral precipitation or dissolution in all but extremely saline waters. The variability of any observed isotopic ratio in groundwater can be from several processes, such as variability in the B source, mixing, and partitioning reactions, including sorption, which cause isotopic fractionation. For rocks and minerals, a range in δ 11 B values of more than 70‰ has been reported. Water sources sampled to date have a similarly broad range. In this injection test, B concentrations in all samples were below 1 mg/L, and differences between individual sources of salinity were indistinct based on analytical concentration alone. In contrast, a hypothetical, nonlinear mixture between solutions with different δ 11 B values and different B concentrations demonstrated a detectable isotopic shift for small volume percent contributions of the source water with the largest boron concentration. The Hueco Bolson aquifer at the injection site is geologically heterogeneous, and the free water surface is more than 90 m deep. The cost to establish a sufficient density of monitoring wells to describe the flow of injected water in groundwater is prohibitive. For this and other sites, chemical and isotopic tracers such as B and δ 11 B may be used to identify the influence of various water sources with potentially adverse environmental consequences.

Geochemical Differentiation of Oil and Gas Brine from Other Saltwater Sources Contaminating Water Resources: Case Studies from Kansas and Oklahoma

Abstract: Many salinity sources other than petroleum brines have caused salinization of water resources in oil and gas fields. These include natural saltwaters from dissolution of evaporites, formation waters not associated with petroleum production, salinization of water by evapotranspiration concentration, seawater intrusion, salt mine wastes, dissolved salt used for deicing and conventional water softeners, waste leachates, and chemicals such as hydrochloric acid. Correct differentiation of these saltwater sources is necessary for application of appropriate remediation, protection, and management actions. Methods are presented that more clearly differentiate saltwater sources than previously used procedures. Conservative mixing relationships for freshwaters and suspected sources can be used to identify salinity sources and estimate chloride concentration contributions from multiple sources. The methods found most useful involve examination of changes in Br/Cl and SO4/Cl ratios with increasing chloride concentration relative to conservative mixing curves. Bromide and chloride are generally the most conservative constituents dissolved in water and often provide the most conclusive identification. Sulfate and chloride are also relatively conservative in most water resource systems, although the effects of calcium sulfate precipitation and dissolution should be considered in instances such as evapotranspiration concentration. Comparison of observed Na/Cl and (Ca + Mg)/Na ratios to those based on conservative mixing of waters can indicate the relative age of saline water and help identify recent contamination versus natural saltwaters. Cation exchange on clays decreases Na/Cl and increases (Ca + Mg)/Na ratios in saltwater recently flowing through clastic aquifers in comparison with softening often observed during long-term flushing of salinity. Case histories of natural saltwater, evapotranspiration concentration salinization, and water softener salt sources are compared to oil and gas brine contamination, including differentiation between two different brines.

Pressure and temperature conditions for methane hydrate dissociation in sodium chloride solutions.

Abstract: The pressure and temperature conditions were experimentally determined for methane hydrate dissociation in sodium chloride solutions, and an empirical equation of the conditions was obtained in the pressure range up to 18 MPa. The present results indicate that the maximum depth of oceanic sediments where methane hydrate is stable increases as water depth to seafloor increases, and that the maximum depth in saline water is smaller than that in pure water. The difference in the depth between saline and pure waters increases with decreasing the water depth, indicating that salinity of pore water affects significantly the amount of methane hydrate in oceanic sediments, in particular, beneath seafloor at relatively shallow depths.

The major inflow to the Baltic Sea during January 1993

Abstract: The volume of highly saline water transported through the Great Belt (Storebaelt) and the Sound (Oresund) to the Baltic Sea is quantified directly from data measured in the Great Belt and the Sound. The measurements include current velocity, temperature and conductivity. The inflow through the Little Belt (Lillebaelt) is estimated from the volume transported through the Great Belt. The volume of highly saline water, transported into the Baltic Sea in the period January 5 to January 26, 1993, is calculated to be 154 km3. The mean water mass temperature was approximately 4 °C and the mean concentration of oxygen approximately 8 ml/l (11 mg/l). During the major inflow, the volume of water with a high salinity (more than 17 PSU) transported through the Great Belt was in a ratio of 7:6 with the volume of highly saline water transported through the Sound. Data from a survey in the Bornholm Basin with R / V Dana during the period from February 27, 1993 to March 14, 1993 are investigated to study the inflow through the western part of the Baltic.

Salt Resistance in Herbaceous Halophytes and Mangroves

Abstract: One of the now widely used definitions of halophytes is that of Jennings (1976), describing them as “the native flora of saline habitats”. This is very close to the description by Warming (1909 English Edition, 1895 Plantesamfund Danish Edition), who coined this and a larger number of still commonly used terms like hydro-, meso-, and xerophytes. According to Warming (1909), “a certain amount of soluble salts must be present before halophytic vegetation is called into existence; but the nature of the salts seems to be a matter of indifference”. Following Munns et al. (1983), such a habitat is one “containing saline water with an osmotic pressure (π) of more than 3.3 bar” (equivalent to 70 mM monovalent salts).

Feasibility of Cyclic Reuse of Saline Drainage in a Tomato-Cotton Rotation

Abstract: Use of saline drainage water for crop irrigation has been proposed as a strategy to reduce drainage volume and conserve good quality water. Over a 6-yr period, two cyclic drainage-water reuse practices were tested in a 3-yr rotation of processing tomato (Lycopersicon esculentum L.) and cotton (Gossypium hirsutum L.). In both practices, drainage water (EC i =7.4 dS m -1 and 0.74 mmol L -1 B) was applied to processing tomato after first bloom to take advantage of salt-induced enhancement of fruit quality and increased crop salt tolerance at later developmental stages. In one practice, drainage water was also applied to the following cotton crop after thinning. Nonsaline water was used for irrigation at all other times and throughout for the control. When saline water was applied once every 3 yr, yields of both crops were unaffected. Tomato yields were generallly lowest when saline water was applied 2 out of 3 yr, but saline water improved tomato fruit quality by increasing o Brix in most years. Changes in soil chemical and physical quality may limit long-term reuse. Both B and salts accumulated in the soil over time, particularly at depth (60-140 cm), whereas Se was more readily leached and showed greater fluctuations in the rootzone with irrigation treatment. Calculations using reclamation formulae estimated that for low B drainage water, the amount of drainage water used exceeded that of nonsaline water needed to return soil EC e to control levels, resulting in significant water savings. For high B drainage water, more than twice the amount of nonsaline water was needed to fully reclaim the profile than was saved by reuse. However, moderately B-tolerant crops could be successfully grown during the reclamation period, making cyclic reuse for at least 6 yr an attractive option for growers facing limited supplies of nonsaline water supplies, or as a means to reduce effluent volumes

The Effect of Zones of High Porosity and Permeability on the Configuration of the Saline-Freshwater Mixing Zone

Abstract: Coastal karst aquifers have highly variable distributions of porosity and permeability. The ability to assess the volume of aquifer occupied by freshwater in coastal karst aquifers is limited by both the lack of understanding of the effect that regions of cavernous porosity and permeability have on the configuration of the saline-freshwater mixing zone and by the limited knowledge of the location of the cavernous regions. A dual-density ground-water flow and solute transport model was used to explore the effect that the depth, lateral extent, and proximity to the coast of zones of high porosity and permeability has on the configuration of the saline-freshwater mixing zone. These aquifer heterogeneities tend to shift the mixing zone upward relative to the position it would have in aquifers with homogeneous porosity and permeability. Zones of high porosity and permeability located at positions shallow in the aquifer or nearer to the coast had the greatest effect. In fact, for the conditions modeled, position was more important in modifying the configuration of the mixing zone than was changing the ratio of the intrinsic permeability of the cavernous zone to the aquifer matrix from 100 to 1000. Modeling results show that ground-water flow is concentrated into the zones of high porosity and permeability and that flow configuration results in steep salinity gradients with depth. Field observations of the location of the halocline and of step changes in ground-water composition coincident with regions of cavernous porosity in coastal karst aquifers corroborate the model results. In a coastal setting with saline water intruding into an aquifer, the effect of cavernous porosity and associated high permeability is to decrease the volume of aquifer in which freshwater occurs by a greater degree than would occur in an aquifer with homogeneous porosity and permeability.

Saline groundwater in Mono Basin, California: 2. Long‐term control of lake salinity by groundwater

Abstract: Mono Lake is a perennial, closed-basin lake that has existed for at least 700 kyr. This 46-m-deep alkaline lake's present concentration is about 90,000 ppm total dissolved solids. Well logs show that beneath part of the lake, saline groundwater of concentration > 18,000 ppm extends to the bottom of the basin fill aquifer (Rogers and Dreiss, this issue). Numerical simulations indicate that redistribution of the basin's solutes between the lake and underlying saline groundwater body, driven by late Quaternary lake level changes, may be responsible for the high present-day solute content of Mono Lake. At low lake levels, the high lake concentration causes solute loss via free convection; this might occur more rapidly through faults or fractures. The saline-fresh groundwater interface position reflects a balance between the saline groundwater density and the force of inflowing fresh groundwater discharging near the shoreline. At higher lake stages, the shoreline discharge zone moves toward the basin edge, and the unrestrained saline groundwater mass subsides, drawing solutes from the lake into the basin sediments. Falling lake levels again constrict the saline groundwater beneath the lake, forcing saline water into the lake and increasing its solute content. The sediment permeability below the lake is the major control on the solute transfer rate between the lake and the groundwater reservoir. Only the larger, longer-term lake stage changes cause saline groundwater movement; depending on the assumed basin fill aquifer permeability, equilibration of the saline groundwater and lake solute content with lake stage changes requires hundreds to thousands of years. Simulations suggest that the historical conditions, where a more saline Mono Lake (50,000–90,000 ppm) overlies less concentrated groundwater (apparently ∼ 18,000 ppm), could be due to the still present impact of late Pleistocene lake high stands. Mono Lake's historical salinity data have a large scatter, but suggest a 5% decrease in the lake's solute content over the last 50 years. We estimated the diffusive solute flux into lacustrine sediments for this period from core data. The salinity data are consistent with a combination of solute diffusion into sediments and an equal, or greater, model-predicted advective solute loss to groundwater.

The role of saline formation water in crustal cycling

Abstract: Most sedimentary basins contain saline pore water. ‘Saline formation waters’ can form during burial diagenesis as the result of normal processes of water/rock interaction involving incongruent halite dissolution, bittern salt destruction, and albitization of detrital plagioclase. The kinds of Na-Ca-Cl saline formation waters typical of sedimentary basins can also result from modification of surficial brines formed by the precipitation of NaCl from evaporated seawater. As the porosity of rocks is reduced during burial, discharge of saline formation waters contributes to crustal chloride cycling, and helps explain riverine chloride loads. During burial, the dissolution of metastable detrital minerals derived from crustal rocks in corrosive, saline water transfers incompatible elements such as Li and B from the igneous crust to the sedimentary crust. Similarly, albitization transfers Ca from the crustal silicate (igneous) mineral reservoir to the crustal carbonate and aqueous (sedimentary) reservoirs. Metamorphism and then melting of albite-enriched rocks accounts for the elevated sodium contents of igneous rocks relative to sedimentary rocks. In this way average sediments have become enriched through time in Ca, Cl, Br, S, Li, and B, and depleted in Na relative to average igneous crust.

Shoot growth and fruit development of muskmelon under saline and non-saline soil water deficit

Abstract: In irrigated agriculture, the production of biomass and marketable yield depend largely on the quantity and salinity of the irrigation water. The sensitivity of field-grown muskmelon (Cucumis melo L. cv. “Galia”) to water deficit was compared, using non-saline (ECi= 1.2 dS m−1) and saline (ECi=6.3 dS m−1) water. Drip irrigation was applied at 2-day intervals at seven different water application rates for each water quality, including a late water-stress treatment. Neutron scattering measurements showed that the soil layers below the root zone remained dry throughout the experiment, indicating negligible deep percolation. Thus, the sum of the seasonal amount of applied water and the change in soil moisture approximated the cumulative evapotranspiration (ET). Gradual buildup of water and salt stresses resulted in small treatment effects on the size of the vegetative cover and large effects on leaf deterioration and fruit production. Crop responses to salinity may result from an osmotic component of the soil water potential or from other salt effects on the crop physiology. Relating plant data to cumulative ET allowed a distinction to be made between the effect on water availability and specific salinity effects. The relation between fruit fresh weight and ET was not sensitive to ECi. The slopes for fruit dry weights were also insensitive to ECi but the intercept was larger for saline treatments. At any given ET saline water increased fruit number, increased fruit dry matter content and decreased fruit netting, in comparison with non-saline water. The combination of salinity and soil-water deficit was detrimental to fruit quality. Saline soil-water deficit decreased the percentage of marketable (netted) fruit and caused an early end to the period of marketable fruit production. Non-saline soil-water deficit increased the percentage of marketable fruit and had no effect on the duration of the production period. Late non-saline water stress caused a pronounced increase in the percentage of marketable fruit.

Effects of water salinity, electric stress and temperature on the hydrophobicity of nylon

Abstract: The loss of hydrophobicity of nylon caused by water salinity, electric stress and temperature is investigated. The hydrophobicity is determined by measuring the contact angle using a droplet of distilled water at room temperature. To investigate the loss of hydrophobicity, nylon specimens are immersed in saline water solutions. The salinity is varied from 5 to 100,000 /spl mu/S/cm. The aging temperatures are 0, 23.5 (room temperature), 50 and 75/spl deg/C. The time of immersion is up to 336 hours. Electric field is applied in air at room temperature. From this study it is found that the contact angle of water on nylon decreases with increasing salinity of water. The contact angle decreases rapidly with increasing temperature of the saline water. The contact angle decreases with increasing time of subjecting the specimen to a fixed value of high dc electric stress in air at 23.5/spl deg/C.

Simulating Saline Water Management Strategies with Application to Arid‐Region Agroforestry

Abstract: Irrigation projects have greatly increased agricultural productivity in arid and semiarid regions, but they frequently contribute as well to saline high water tables, which must be mitigated by a drainage system. Drainage waters, sometimes contaminated by toxic elements, can lead to environmental degradation if not properly managed. One option is to irrigate salt-tolerant plants with drainage water to further increase the salt concentration while reducing the volume that would ultimately require treatment or disposal. Transient and steady-state models were used to simulate the consequences of applying saline drainage water to eucalyptus trees (Eucalyptus camaldulensis) under conditions typical to the San Joaquin Valley of California. Simulated results agreed well with limited field data. High evapotranspiration and large tree growth require application of large amounts of water, leading to large, deep percolation volumes. Degradation of soil physical properties by saline water could reduce the transmission of water through soil. This limits the quantities of irrigation water that can be applied, with consequent poor tree growth and low evapotranspiration.

Chironomid-based paleosalinity reconstruction of three lakes in the south-central interior of British Columbia, Canada

Abstract: Salinity fluctuations in lakes of semi-arid regions have been recognised as indicators of paleoclimatic change, and have provided a valuable line of evidence in paleoclimatic reconstruction. In the present study, fossil remains of Chironomidae were used to reconstruct lake salinity changes from the early postglacial, through the early, mid and late Holocene. In Vahoney Lake, a transition from head capsules typical of a freshwater community (Protanpus, Sergentia, Heterotrissocladius, Cladopelma, Dicrotendipes) during the early postglacial, to those indicative of saline environments (Cricotopusl Orthocladius, Tanypus) occurred in the early Holocene. The chironomid-inferred salinity values reflected the shift from freshwater (0.031 g/l) immediately after deglaciation, to saline water (2.4 to 55.2 g/l) in subsequent periods. A less saline period was found to have occurred after about 1000 years ago, suggesting a cooler or wetter period. Results from Kilpoola Lake indicate a similar early postglacial freshwater interval with an inferred salinity less than 0.03 g/', followed by a prolonged period of higher salinities (1 to 3.5 g/l) during the Holocene. A community of chironomids including Microtendipes, Sergentia, and Heterotrissocladius (typical freshwater chironomids) were found in the basal sediments, and Cricotopusl Orthocladius and Tanypus (saline environment chironomids) were found in subsequent intervals to the present. The peak Holocene salinity occurred during a period shortly after deposition of the Mazarna ash.

Evaluation of sperm-activating solutions in Atlantic salmon Salmo salar fertilization tests

Abstract: The use of saline solutions was tested to determine their efficacy as replacements for ovarian fluid as sperm activators and to eliminate variability encountered with the use of Ovarian fluid. We tested fertilization rate of semen from eight males on Atlantic salmon Salmo salar eggs after five sperm-activating solutions and a non-activating saline were substituted for ovarian fluid. We used solutions shown acceptable for use with other salmonid species. The six solutions tested were a non sperm-activating phosphate-buffered saline (PBS, 7.2 g/L NaCl, 1.48 g/L Na2HPO4, 0.43 g/L K H2PO4), a Tris buffer (6.99 g/L NaCl, 3.63 g/L Tris and 2.42 g/L glycine), a Borax buffer (12.2 g boric acid/L in solution 1, 76 g disodium tetraborate/L combined 100:118, then 1 L combined with 3.7 L water and 18 g NaCl), and three solutions of 9.25 g/L (125 mM) NaCl buffered to pH 6.0, 7.5, and 8.9. The latter five solutions activated sperm immediately on contact, while PBS required additional water to activate sperm. The PBS solution was the least effective (mean percent eyed eggs 37.6%) for egg fertilization. The mean percent eyed eggs for the other five saline solutions (range 78% to 86%) were not significantly different. Sperm from one male provided significantly lower egg fertilization (39.6%) when compared with the other seven males (67.2–87.4% egg fertilization). Percent egg fertilization was not related to number of live sperm cells per egg. Our results show that osmotically-balanced sperm-activation solutions, even those with a pH range from 6.0 to 8.9 provide adequate media for fertilization of Atlantic salmon eggs. Fertilization in a deactivation saline and water reactivation of sperm resulted in low egg fertilization.

Comparative study of selective separation of magnesium from brine and seawater

Abstract: A highly selective, sensitive, and inexpensive procedure for the separation of magnesium from brine and seawaters is proposed. The method is based on the separation of the harmful major constituent (calcium) of saline water. This is achieved by floating both calcium and magnesium as their oleates at the pH of saline water (7.5–8.5) to avoid the effect of NaCl on the precipitation of Ca as CaSO4. The float is dissolved in HNO3/methanol, precipitated as CaSO4, and the mother liquor is refloated as pure magnesium oleate. This purity is confirmed by infrared measurements.

Infection of cotton byfusarium oxysporum f.sp.vasinfectum as affected by water stress

Abstract: Since virulence ofFusarium oxysporum f.sp.vasinfectum (FOV) on cotton (Gossypium hirsutum) is enhanced when the fungus is cultivated in a saline environment, excessively saline water must not be used for the irrigation of cotton. However, the limitations thus placed on the available water resources may lead to conditions of enforced water stress for the plant. The present study investigated whether water stress affects the susceptibility of cotton to FOV. Groups of 2-month-old cotton plants of theFusarium-susceptible Coker 304 and the moderately resistant GSC 20 varieties were maintained without watering for varying periods immediately before or after being inoculated with FOV (15 plants per group, two replications). Watering was suspended for 3, 6, 12 or 24 days before inoculation, and for 3, 6, 12 or 15 days after inoculation. After inoculation the plants were maintained in a controlled environment with a 15,000 lux, 12-h photoperiod, at 28°/24°C D/N, 20% r.h. Xylem water potential was determined in a pressure chamber. Percent infected leaf area and date of onset of wilt were the parameters used to define severity of FOV infection. There was a consistent relation between low water potential in the xylem (-7 and -20 MPa) and severity of infection, particularly when the dry period occurred after inoculation. After exposure to the lowest post-inoculation water potentials, even variety GSC 20, which is normally moderately resistant, exhibited a fairly high percent infected leaf area. This should be taken into account when the cotton grower is faced with water shortages, especially during the period from branching to flower bud break.

Salt induced changes in the growth of Chlorococcum humicolo and Scenedesmus bijugatus under nutrient limited cultures.

Abstract: Due to climatic changes in tropics, saline water bodies are often subject to natural fluctuations of salinity through precipitation, dessication, drought conditions or anthropogenic interference. Growth and persistence of algae under these conditions require physiological tolerance and/or resistant stages in the life cycle. Salinity, which ranges from 95.9-174.7 mg/L as NaCI, is considered as an important parameter for the Indradyumna pond (485 x 396 sq ft, maximum depth 5 m) of Puri, Orissa for it is located at a distance of 1 km from the Bay of Bengal. The fluctuation of salinity level of the pond has been observed during 1988-1991 mostly due to excessive use by innumerable number of pilgrims all over the year (Dash 1992). Increased salinity favors growth of cyanobacteria because this is the only group of photoautotrophic plankton taxa requiring Na + for growth (Allen and Arnon 1955). Green algal species like halotolerant planktonic algae (Hellebust and Le Gresley 1985), Chlorella, Ankistrodesmus and Scenedesmus (Kessler 1980) have also been found to be favored by increased salinity. However, the rationale of studying salinity tolerance of algae under nutrient limited conditions seems to be more appropriate in the bioassay method because it is established that the susceptibility / resistance characteristic of an algal species to external stress is nutritionally determined (Herbert and Bradley 1989; Mohapatra and Mohanty 1992). Accordingly, it was decided to see the effects of salinity stress on two indigenous phytoplankton species viz., Chlorococcum humicolo (Nag) Rabenh. and Scenedem~us bijugatus KUtz. in culture with differential nutrient enrichment using the sterile pond water as medium.

Predicting Salinization-Desalinization in Saline Water Irrigated Soils

Abstract: A mathematical model for predicting salinization-desalinization of soils has been developed. The calibration and test of the model have been carried out for a medium textured soil. The correlation coefficients between the observed and the predictedfour soil depths viz. 45, 60, 75 and 90 cm and for a period of five years (1987–92) were close to 0.84. Considering the long period for which predictions were made and the high correlation coefficients, the model appears to be a good and realistic tool for predicting soil salinization-desalinization. Application potential of the proposed model in several field problems related to management of saline water irrigated soils and use of saline waters for crop production was also explored.

The Effect of Salinity on Nitrate Leaching from Turfgrass

Abstract: SOIL SALINITY is a problem in the western United States due to the occurrence of soluble salts in many desert soils and irrigation with moderately saline water. In southern Nevada, irrigation has leached native salts below the root zone, creating a perched saline aquifer estimated at approximately 100,000 acre feet. Having an electroconductivity (EC) of 9 dS m' (approximately one fifth of seawater), this aquifer represents a potential threat to the deeper primary aquifer. As a resource, however, this aquifer contains enough water to satisfy the irrigation needs of many of the existing golf courses in Las Vegas for the next 20 years. If properly managed, this water supply could be used as an alternative or supplemental irrigation source, decreasing the demand on high-quality water while reducing the potential for contamination of the primary aquifer. One concern about the use of saline water for turf irrigation, and the focus of our study, is that salinity might increase nitrate (N) leaching from turf. Since nitrogen is the most heavily used nutrient in turfgrass management, this concern is justified. In the case where N application exceeds the ability of the turfgrass to absorb the nitrogen, excess N could move from the soil-plant system into water supplies. The degradation of lakes and streams, the possible permanent contamination of groundwaters, and possible health hazards related to waters high in nitrate are all consequences of inefficient or improper use of nitrogen fertilizers. Numerous studies have documented the effects of environmental factors and management practices on nitrate leaching from turfgrasses. For example, Brown et al. (2) measured concentrations of nitrate as high as 74 ppm N in the leachate below bermudagrass following application of ammonium nitrate, with total leaching loss of 23% of the applied N. For comparison, 10 ppm N03-N is considered the maximum for safe drinking water. Snyder et al. (9) found peak N03-N concentrations between 20 and 40 ppm N in

The success of elutriate tests in extended prediction of water quality after a dredging operation under freshwater and saline conditions.

Abstract: Dredging simulation by elutriate tests accurately predicted concentrations of Hg, Cu, Mn and Fe released to the water column from contaminated sediment to within 1 order of magnitude. Hg and Cu concentrations increased by up to 7-fold after dredging, but declined to background concentrations within 48 h. Maximum loadings of Hg and Cu coincided with Fe and total organic carbon (TOC) water column concentrations, suggesting Hg and Cu are adsorbed onto particulates of Fe oxides and organic material. Seasonal changes in redox potential and temperature did not significantly affect metal release from sediments. Saline water did not cause significant increases in contaminant release from sediments to the water column over that observed for freshwater. Water quality standards of 1 µg l−1 Hg and 28 µg l−1 Cu as annual averages were not breached by dredging operations. Long-term effects of dredging on Hg and Cu availability, due to deposition of contaminated material as surficial sediments, is, however, of concern.

A Marine Pollution Study of Northeast Coastal Water Off Taiwan Island

Abstract: The coastal water of northeast Taiwan island, called ‘Yin-Yang Hai’ for its distinct yellow colour compared with blue offshore water, was investigated from 1989 to 1990 by the authors. Biological study showed the dominant species of plankton to be Copepoda, Cladocera, planktonic eggs and Diatoma. Dominant species of benthos were young crabs, Amphipoda and Annelida, with Amphipoda usually occurring in heavily polluted areas. Heavy metal data showed that the concentration of copper was high. the copper and iron concentration in algae of the intertidal zone was also high. the concentrations of iron and copper in inshore water were also higher than in offshore water. By comparison of the pH and salinity distribution of this area, we conclude that this coastal water has been polluted by acid waste water from coastal industry. the suspended solids concentration in sea water is high. Flocculation occurring at the boundary of fresh and saline water might be a reason for the distinct yellow colour of the ...

Pineapple yield and quality on a banana soil of the Canary Islands irrigated with acid and saline water

Abstract: Pineapple (Ananas comosus L. Merr) plants, cultivar 'Red Spanish', were grown in a greenhouse in 300-L containers, with soil from a banana plantation, and irrigated with saline and acid waters. Essential chemical soil characteristics were a pH of 6.9, electrical conductivity (EC) 1.26 dS m -1 , and available nutrient status 188 ppm P, 11.95 meq (100-g) -1 Ca, 5.35 meq (100-g) -1 Mg, 3.96 meq (100-g) -1 K, and 2.17 meq (100-g) -1 Na. Irrigation water treatments consisted of control (tap water) ; 7, 14, 21, and 28 meq L -1 NaCl ; 10, 15, 20, and 25 meq L -1 NaHCO 3 ; and 75 meq L -1 H 2 SO 4 . Sodium chloride at levels of 14 meq L -1 and above in water affected fruit yield and quality adversely. Neither acid water nor bicarbonated waters had any effect on the fruit, except for the highest level of NaHCO 3 .