Concentrations Of Ions In Water Research Articles

Potentiometric determination of copper(II) ions based on a porphyrin derivative

AbstractA novel poly(vinyl chloride; PVC) membrane‐based Cu(II)–selective sensor has been developed using synthesized 5,10,15,20‐tetrakis(4‐methoxycarbonylphenyl)porphyrin as an ionophore. The Cu(II)–selective sensor exhibits a Nernstian response for Cu(II) ion over a wide concentration range of 1.0 × 10−5 to 1.0 × 10−1 mol L−1 with the slope of 27.0 ± 2.5 mV/decade, and a lower limit of detection of 1.88 × 10−6 mol L−1. The novel sensor shows good repeatability and high selectivity for Cu(II) ions over other mono‐, bi‐ and trivalent cations. The sensor potential response remains unaffected by pH in the range of 4.4–10.6 and exhibits a fast response time of less than 10s. Finally the developed Cu(II)–selective sensor has been successfully used as an indicator electrode in the potentiometric titration of Cu2+ against ethylenediaminetetraacetic acid and also in the determination of Cu(II) ion concentration in different water and beverage samples.

Innovative approach to the development of hydroponic green feeds

This article discusses the results of a study on the cultivation of hydroponic green feed in the laboratory, the main purpose of the study is to study the effect of humidity on the root system of the green mass, to increase the timing and dependence of the increment on temperature and humidity. The experience of using automation elements in order to develop recommendations for the implementation of automation systems and computerization of a hydroponic installation using a programmable microcontroller is analyzed. Taking into account the problems of growing green mass for use as feed for the agricultural sector, the issues of photosynthesis are considered, the results obtained and methods for measuring the concentration of free hydrogen ions in water (pH) are shown, for these purposes the water quality was monitored using Sensorex sensors, the issues of sprouting are described, as well as measuring the moisture content of the root part of the green mass and the devices used for this purpose. The article concludes that the results of the research are based on the use of various innovative solutions, this is a system of transition to digital agriculture, as a result of growing hydroponic green feeds using automation elements to control and manage the receipt of primary initial state information. This, in turn, will allow the agricultural sector to be fully automated, free up useful areas of land, increase yields and reduce production costs.

Influence of sea salt on the interfacial adhesion of bitumen–aggregate systems by molecular dynamics simulation

• Sea salt damaged bitumen’s original colloidal structure by disaggregating asphaltenes. • Saturates played the major role by most extensively diffusing to the surface of silica. • SARA fractions’ redistribution was driven by water with ions only acting as catalysts. • Number of SARA fractions in model decreased the adhesion energy in all environments. • Spatiotemporal distribution of SARA fractions at the interface determined the adhesion. This research investigated the influence of sea salt on the adhesion properties of bitumen–aggregate systems by molecular dynamics simulations in order to fundamentally understand the mechanism of damage in the seawater environment. The seawater environment was simulated by high concentrations of chloride, sodium, sulfate, magnesium, and calcium ions in water. Bitumen was represented by 3-, 4-, and 12-component models using the COMPASS force field, while the bitumen–seawater–aggregate interfacial model was discontinued by a vacuum layer of 60 Å in thickness. The results demonstrated that the presence of seawater affected the adhesion by facilitating the molecular migrations of bitumen components and by weakening the agglomeration of asphaltene. Consequently, this gradually damaged the colloidal structure of bitumen in the interfacial zone. Saturates played a dominant role in the adhesion in the seawater environment because they were the most likely to diffuse away from the silica surface. Besides the composition of bitumen, the spatiotemporal distribution of its components in the region of the interface was also identified as extremely important for the interpretation of the intrinsic factors which control the adhesion behaviour of thesesystems.

SnO2 Nanoparticles-CeO2 Nanorods Enriched with Oxygen Vacancies for Bifunctional Sensing Performances toward Toxic CO Gas and Arsenate Ions.

In this paper, we present a novel, one-step synthesis of SnO2 nanoparticle–CeO2 nanorod sensing material using a surfactant-mediated hydrothermal method. The bifunctional utility of the synthesized sensing material toward room-temperature sensing of CO gas and low-concentration optosensing of arsenic has been thoroughly investigated. The CeO2–SnO2 nanohybrid was characterized using sophisticated analytical techniques such as transmission electron microscopy, X-ray diffraction analysis, energy-dispersive X-ray analysis, X-ray photoelectron spectroscopy, and so forth. The CeO2–SnO2 nanohybrid-based sensor exhibited a strong response toward CO gas at room temperature. Under a low concentration (3 ppm) of CO gas, the CeO2–SnO2 sensing material showed an excellent response time of 21.1 s for 90% of the response was achieved with a higher recovery time of 59.6 s. The nanohybrid sensor showed excellent low-concentration (1 ppm) sensing behavior which is ∼6.7 times higher than that of the pristine SnO2 sensors. The synergistically enhanced sensing properties of CeO2–SnO2 nanohybrid-based sensors were discussed from the viewpoint of the CeO2–SnO2 n–n heterojunction and the effect of oxygen vacancies. Furthermore, the SnO2–CeO2 nanoheterojunction showed luminescence centers and prolonged electron–hole recombination, thereby resulting in quenching of luminescence in the presence of arsenate ions. The photoluminescence of CeO2–SnO2 is sensitive to the arsenate ion concentration in water and can be used for sensing arsenate with a limit of detection of 4.5 ppb in a wide linear range of 0 to 100 ppb.

Development of a Current Injection-Type Impedance Measurement System for Monitoring Soil Water Content and Ion Concentration.

This study was conducted with the aim of developing a circuit system that enables the measurement of the moisture content and ion concentration with a simple circuit configuration. Our previous studies have shown that soil can be represented by an equivalent circuit of a parallel circuit of resistors and capacitors. We designed a circuit that can convert the voltage transient characteristics of the soil when a current is applied to it into a square wave and output frequency information and developed an algorithm to analyze the two types of square waves and calculate R and C. Normal operation was confirmed in the range of 10 kΩ–1 MΩ for the designed circuit, and the calculation algorithm matched within a maximum error of 5%, thus confirming the validity of the program. These successfully confirmed the changes in the water content and ionic concentration. The soil moisture content measurement succeeded in measuring a maximum error of about 10%, except at one point, and the soil ion concentration measurement succeeded in measuring a maximum error of 6.6%. A new, simple, noise-resistant moisture content and ion concentration measurement circuit system with square wave output has been realized.

A smartphone-based photometric and fluorescence sensing for accurate estimation of zinc ion in water

This paper demonstrates the development of a smartphone-based analytical system to determine zinc ion (Zn2+) concentration in water. The proposed system has been designed for simultaneous sensing in photometric and fluorescence mode on a single platform. Two inbuilt sensors of the phone, namely, the ambient light sensor (ALS) and the rear camera, have been utilized to develop the proposed sensing system. For photometric-based sensing, the ALS receives the transmitted modulated signal from the sample, while the rear camera records the fluorescence signal emitted from the sample at right angle to the direction of the excitation signal. The holder for the proposed sensing system has been fabricated in a 3D printer. A custom-designed android application has been developed to convert the proposed platform into a standalone tool. Using the designed sensor, Zn2+ ion concentration of field-collected water samples has been estimated successfully. Responses of the designed platform have been compared with the standard laboratory counterparts. The limit of detection and the percentage recovery of the proposed sensor are found to be 0.1 ppm and 103.10% respectively.

A novel dual-functional coordination polymer for detection and ultra-effectively removal of Fe(III) in water

Coordination polymers (CPs) are widely used for the detection or removal of heavy metal ions in wastewater due to their excellent performance, but CPs that can simultaneously detect and remove heavy metal ions are rare. In this work, a novel dual-functional coordination polymer ([Zn8C152H112Cl4N32O24S6(H2O)4]·7H2O, Zn-CP) has been successfully designed and obtained, which can simultaneously detect and ultra-effectively remove Fe(III) ions in water, and the removal rate can be as high as 99.8%. Zn-CP has a good quenching response to Fe(III) ions, and can reduce the concentration of Fe(III) ions in water to a drinkable standard (0.3 mg/L). Even in a complex water environment, Zn-CP can still detect and ultra-effectively remove Fe(III) ions. Furthermore, Zn-CP has also been successfully synthesized on a large scale. The developed Zn-CP holds a high potential for detecting and efficiently remediating water contaminated by Fe(III) ions.

A Fractal Model for Effective Excess Charge Density in Variably Saturated Fractured Rocks

AbstractEstimating hydraulic properties and monitoring water flow in fractured rocks using self‐potential observations essentially relies on our ability to model streaming potential. One of the most promising approaches for modeling electrokinetic couplings is based on the macroscopic quantification of the excess charge which is effectively transported by pore water flow. In this study, we derive a fractal model to predict the effective excess charge density for fully and partially water saturated fractured media. Fractures are conceptualized as parallel plates with a fractal pattern described by the Sierpinski carpet. From the calculation of the excess charge in a single fracture and a flux averaging upscaling procedure, we obtain closed‐form expressions for the effective excess charge density. This new analytical model explicitly depends on the fracture water ionic concentration, interface properties, water saturation, porosity and permeability. Model predictions under saturated conditions are compared to published data measured in laboratory during hydraulic fracturing. The model development also shows the independence of the excess charge from the pore shapes: when expressed in terms of hydrological parameters, one can find an expression identical to recently published models for sedimentary porous media using capillary tubes. These results extend the validity of the existing models to fractured rocks and highlight the importance of hydraulic parameters for an accurate modeling of electrokinetic couplings.

Efficient Removal of Hg(II) from Water under Mildly Acidic Conditions with Hierarchical SiO2 Monoliths Functionalized with -SH Groups.

In this work, novel adsorbents based on 3D hierarchical silica monoliths functionalized with thiol groups were used for the removal of Hg(II) ions from an acidic aqueous solution (pH 3.5). Silica monoliths were synthesized by using two different pluronic triblock polymers (P123 and F127) to study the effect of porous structure on their sorption capacity. Before and after functionalization by grafting with 3-mercaptopropyltrimethoxysilane (MPTMS), the monoliths were characterized by several techniques, and their Hg(II) removal potential was evaluated in batch experiments at 28 °C and pH 3.5, using different initial concentrations of Hg(II) ions in water (200–500 mg L−1). The thiol groups of the monoliths calcined at 550 °C showed thermal stability up to 300 °C (from TG/DTG). The functionalized monolith synthesized with P123 polymer and polyethylene glycol showed favorable hierarchical macro-mesopores for Hg(II) adsorption. M(P123)–SH exhibited 97% removal of Hg(II) at concentration 200 mg L−1. Its maximum adsorption capacity (12.2 mmol g−1) was two times higher than that of M(F127)–SH, demonstrating that the 3D hierarchical macro-mesoporosity allowing accessibility of Hg(II) to thiol groups favors the physical and chemical adsorption of Hg(II) under slightly acidic conditions.

ДОСЛІДЖЕННЯ ПРОЦЕСІВ ОЧИЩЕННЯ ВОДИ ВІД ІОНІВ МАНГАНУ ПРИ ВИКОРИСТАННІ РОЗЧИНІВ НАТРІЙ ГІПОХЛОРИТУ

The creation of effective demanganization technologies by the development of new and intensification of known processes of manganese removal from natural waters are currently of increasing importance.The search for promising ways to demanganize water to regulatory values is a topical issue for the modern water treatment domain.Recent publications of methods for extraction of manganese ions from water by sorption, membrane, ion exchange methods were reviewed. The prospects of application of oxidative methods for water demanganation are shown.The purpose of the article is to investigate the manganese ions removal methods from water during their oxidation by sodium hypochlorite and to establish the dependence of the efficiency of demanganization on the consumption of oxidizing agent and the concentration of manganese ions in water.The study presents the application of sodium hypochlorite as an oxidant in the purification of artesian water from manganese ions. It was determined in static conditions that the degree of manganese removal is affected by both its initial concentration in water and the dose of sodium hypochlorite. Water purification process is more efficient with initial manganese concentrations above 5 mg/dm3. At a manganese ion concentration 30 mg/dm3, its complete removal was achieved in 4 hours of settling at a stoichiometric ratio of manganese and sodium hypochlorite in water and at any excess of oxidant. The process of manganese ions oxidation in artesian water by sodium hypochlorite depending on its dose and contact time was studied. The dose of oxidant for the removal of manganese ions from artesian water was also determined. Thus, the research allowed to improve the methods of water purification from manganese ions during their oxidation by sodium hypochlorite and found that the water purification efficiency increased both with increasing consumption of oxidizing agent and increasing the concentration of manganese ions in water.

Ratiometric fluorescent detection of lead ions in aquatic environment and living cells using a fluorescent peptide-based probe

Ratiometric fluorescent detection using dual emission bands is highly necessary to quantify Pb(II) in aquatic environment and live cells. We synthesized a ratiometric fluorescent peptidyl probe (1) by conjugation of a peptide receptor for Pb(II) with an excimer-forming benzothiazolylcyanovinylene fluorophore. The peptidyl probe dissolved well in aqueous solution and displayed an emission band at 538 nm (λex = 460 nm). Upon addition of Pb(II) (0–20 μM), the emission maximum shifted from 538 nm to 575 nm and the emission intensity ratio (I575 /I538) increased significantly from 0.40 to 2.26. 1 exhibited a selective ratiometric response to Pb(II) over other metal ions. 1 with a low detection limit (1.2 ppb) of Pb(II) detected nanomolar concentrations (0–500 nM) of Pb(II) ions in groundwater and tap water. The cell-permeable probe detected intracellular Pb(II) by ratiometric fluorescent images. The binding mode study using NMR, IR and CD spectroscopy, and TEM revealed that the probe formed a 1:1 complex with Pb(II) and then formed red-emissive nanoparticles and fibrils. The probe exhibited desirable detection properties such as ratiometric detection, high solubility in water, visible light excitation, high selectivity and sensitivity for Pb(II), cell-permeability, and rapid response (< 6 min).

Reusing Flowback and Produced Water with Different Salinity to Prepare Guar Fracturing Fluid

Economical and environmental concerns have forced the oil and gas industry to consider reusing flowback and produced water for fracturing operations. The major challenge is that the high-salinity of flowback water usually prevents its compatibility with several fracturing fluid additives. In this paper, the authors explored an economic and effective method to prepare guar fracturing fluids with different salinity waters. The main research idea was to use chelating agents to mask metal ions, such as calcium and magnesium, that are harmful to crosslinking. Firstly, a complexometric titration test was conducted to measure the chelating ability of three chelating agents. Secondly, through viscosity, crosslinking, and hanging tests, it was verified that the complex masking method could cope with the problem of high-valence metal ions affecting crosslinking. Thirdly, the preferred chelating agent was mixed with several other additives, including thickeners, crosslinkers, and pH regulators, to prepare the novel guar fracturing fluid. The comprehensive performances of the novel fluid system were tested such as temperature and shear resistance, friction reduction, gel-breaking performance, and core damage rate. The results show that the organophosphate chelating agent (i.e., CA-5) had the greatest ability to chelate calcium and magnesium ions. There was a good linear relationship between the dosage of CA-5 and the total molar concentration of calcium and magnesium ions in brine water. The main mechanism was that the chelating agent formed a complex with calcium and magnesium ions at a chelation ratio of 1:5. The test results of the comprehensive performance evaluation indicate that the prepared guar fracturing fluid met the requirements for field application, and the lower the salinity of the flowback water, the more it is economical and effective.

Investigating the controlling factors on salinity in soil, groundwater, and river water in a semi-arid agricultural watershed using SWAT-Salt

Soil salinity can have a significant impact on crop yield, particularly in arid and semi-arid irrigated watersheds wherein irrigation and inadequate drainage often combine to increase salt ion concentrations in soil water. To control salinity, the principal step is to identify the key environmental and hydrologic factors that govern the fate and transport of salts in these irrigated areas. To accomplish this objective, global sensitivity analysis is applied to the newly developed SWAT-Salt model, which simulates the reactive transport of 8 major salt ions (SO4, Ca, Mg, Na, K, Cl, CO3, and HCO3) in major hydrologic pathways in a watershed system. The model is applied to a saline 1118 km2 irrigated stream-aquifer system located within the Lower Arkansas River Valley in southeastern Colorado, USA. Multiple parameters including plant growth factors, stream channel factors, evaporation factors, surface runoff factors, and the initial mass concentrations of salt minerals MgSO4, MgCO3, CaSO4, CaCO3, and NaCl in the soils and in the aquifer are investigated for control on salinity in groundwater, soils, and streams. The Morris screening method is used to identify the most sensitive factors, followed by the Sobol' variance-based method to provide a final ranking and to identify interactions between factors. Results show that salt ion concentration in soils and groundwater is controlled principally by hydrologic factors (evaporation, groundwater discharge and upflux, and surface runoff factors) as well as the initial amounts of salt minerals in soils. Salt concentration in the Arkansas River is governed by similar factors, likely due to salt ion mass in the streams controlled by surface runoff and groundwater discharge from the aquifer. Results can be used in decision making regarding the most impactful land and water management strategies for controlling salinity transport and build-up in soils, both for this watershed and other similar semi-arid salinity-impacted watersheds.

Impact of reservoir geochemistry on low salinity waterflooding: Global sensitivity analysis

Low salinity waterflooding (LSW) has been receiving an increasing attention in the industry as it has several advantages over alternative strategies to enhanced oil recovery (EOR), i.e. i) outperforms conventional EOR methods in terms of additional oil recovery, ii) involves lower chemical costs, iii) it is environmentally friendly, and iv) requires a relatively simple field process implementation. We quantify low salinity effect (LSE) on oil recovery upon employing a mechanistic geochemical model under parametric uncertainty. Our ultimate goal is to characterize the impact of the reservoir rock and fluid properties on the performance of LSW. To this end, we propose a geochemical model of LSW built within a commercial compositional reservoir simulator. The model is designed to account for geochemical processes recently identified through experimental and pore-scale analyses, i.e. double layer expansion, multiple ion exchange and mineral dissolution/precipitation. The geochemical model outputs were first compared with two low salinity coreflood experiments reported in the literature and then applied to predict oil recovery under parametric uncertainty. Our study encompasses the effect of formation water ionic concentrations, rock mineralogy and reservoir temperature on LSW performance. Global sensitivity indices were calculated considering reasonable intervals of variability of the studied parameters. Our analysis focuses on the total oil recovery at three different time scales: 6 months (before water breakthrough), 2 years (after water breakthrough), and 10 years (the end of the injection). The results are discussed in the frame of quantitative screening criteria development, which is necessary to assess whether a given reservoir may be a promising candidate for LSW. Our results indicate that reservoir temperature is the parameter which demonstrated the most significant impact on the LSW performance. Ion concentration also displays a significant influence on oil recovery, and we identify different chemical species in carbonate and sandstone environments. On the contrary, mineral composition shows a limited influence on oil recovery. In particular, our results show that clay presence might be not essential for LSW to be effective in sandstone reservoirs. We discuss the impact of our results in the context of experimental design aimed at an improved constraining of LSW parameterization. Our study suggests that reservoir fluid composition (e.g., concentration of Ca2+, SO42− and Na+), in addition to reservoir temperature, should be prioritized in future experimental campaigns to better understand its influence on LSW under different reservoir and operation conditions.

Role of the injected water salinity and ion concentrations on the oil recovery in carbonate reservoirs

Low salinity water flooding (LSWF) was initially considered using water with a low concentration of dissolved salts and was later extended to include modifying the ionic content of injected brines. This work investigates the effects of changing water salinity and composition along with the concentration of sulfate and iodide ions on oil recovery in carbonate reservoirs during the tertiary recovery stage. An experimental study was carried out using crude oil of 29°API, 8 core samples extracted from the Eocene carbonate reservoir (Egypt), and 6 different water salinities.The results showed additional oil recovery up to 5% of the original oil in place (OOIP) in the tertiary recovery stage with changing water salinity and water composition. Injection of high salinity (HS) and low salinity (LS) brines with high sulfate concentrations increased the incremental oil recovery by a value ranging from 1.7 to 3.8% of the OOIP. On the contrary, injection of HS and LS brines with low sulfate concentrations showed insignificant incremental oil recovery (less than 1% of the OOIP). Furthermore, injection of water with potassium iodide (KI) after injection of water with high sulfate brines showed additional oil recovery of about 1.7% of the OOIP. On the other hand, injection of water with KI after injection of water with low sulfate concentration showed insignificant incremental oil recovery (less than 0.4% of the OOIP).The concentration of sulfate in the injected water appeared to be key parameter to achieve effective waterflooding (WF) projects in carbonate reservoirs. Moreover, the results revealed that the multi-component ion exchange (MIE) mechanism seems to be the primary recovery mechanism for LSWF in carbonate reservoirs. The results and conclusions of this study can be used to develop guidelines for designing waterflooding projects in carbonate reservoirs with optimum salinity.

Adsorption Capacity of Ca2+ by Hydrochloric Acid Activated Kaolin

A high concentration of calcium ions in water is a problem as it can cause blockages in engine pipes. Adsorption is a relatively cheap and straightforward method that can be used to reduce the calcium ion content in water. Kaolin is a mineral that has a potential as an adsorbent and whose adsorption capacity can be increased by activation. This research studied the adsorption capacity of activated kaolin by hydrochloric acid against Ca2+ ions. Kaolin was chemically activated using 6 M HCl solution for 24 hours. The adsorption contact time in batches was varied with time variations of 30, 90, 150, and 180 minutes. The maximum adsorption capacity of activated kaolin to the Ca2+ was determined by varying the initial concentrations of water samples, namely 4, 7, 10, and 13 mg/L. The concentration of Ca2+ was determined by a titration method using ethylene diamine tetraacetate (EDTA). The results showed that the activation of kaolin with 6 M HCl at the optimum contact time of adsorption, namely 150 minutes, increased the percentage of adsorbed Ca ions to 2 times of that of natural kaolin, from 33.3% to 68.3%. Based on the Langmuir equation, the maximum adsorption capacity of calcium ions by activated kaolin HCl 6 M increased 1.7 times from natural kaolin to 0.346 mg/g.

Reduction in Arsenic Exposure by Domestic Water Purification Devices in Shanghai Area and Related Health Risk Assessment

Domestic water purification devices (point-of-use) are important choices for people to deal with sudden drinking water contamination. Especially for sudden heavy metal and arsenic contamination, home water purification units can play a key role as a secondary line of defense. Most of the arsenic removal studies are limited to meeting the requirements of local water quality standards and few studies have been conducted on arsenic removal from household water purifiers. In this paper, the distribution characteristics of arsenic in water at the end of the pipeline network in the Shanghai water supply area have been investigated. Three types of household water purifiers, mainly with membrane separation technology, were selected to treat the simulated arsenic contamination in tap water sources. The effects of pH and inorganic salts on arsenic removal were studied in comparison to the results of coexisting ion concentrations in tap water. The results showed that the total arsenic concentrations in different tap water samples range from 0.479–1.195 µg L−1, which is lower than the limit value for arsenic concentration set by China’s drinking water standard GB 5749–2006 (10 µg L−1) and by the World Health Organization (10 µg L−1). It is found that reverse osmosis and nanofiltration water purifiers were more effective in removing As(V), with removal rate above 97.7%, and less effective in removing As(III), the rate ranging from 40.1 to 56.3%. Preliminary validation was provided for the safety of household water purifiers in securing universal and sudden drinking water contamination. Domestic water purifiers are effective in reducing the risk of arsenic exposure in drinking water.

Experimental study on the removal of the chloride ion in sea water via ultra-high lime with aluminum process

In order to study the feasibility of mixing concrete with dechlorinated sea water, ultrahigh lime with aluminum process was used in the laboratory to conduct dechlorination tests on sea water with different chloride ion concentrations. Experiments show that the ultra-high lime with aluminum process can effectively decrease the chloride ion concentration in sea water.

Using Macroelement Content to Characterize Surficial Water Quality of Artificial Reservoirs

The quality of surface waters in the territory of Poland, despite the implemented remedial measures, is mostly classified as bad. This article presents the results of research on the composition of water macroelements in 24 artificial reservoirs located in Opole province (southern Poland), searching for the reasons behind their pollution. Concentrations of the anions F−, Cl−, Br−, NO2−, NO3−, PO43− and SO42− and cations Na+, NH4+, K+, Mg2+ and Ca2+ were taken into account. An analysis of seasonal changes was carried out and, on the example of a dam reservoir (Turawa Big Reservoir), a multi-point analysis of the distribution of ion concentrations in water at the reservoir surface was also carried out. It was shown that retention and flow-through reservoirs, where the main source of pollution is the water feeding the reservoirs, are the most vulnerable to pollution. The second group consists of closed reservoirs located in industrial and agricultural areas, which are exposed to pollution from rainwater run-off and field leachate. In the case of reservoirs created in marl mining areas, a significant effect was also indicated from the chemical composition of the substrate on the formation of ionic equilibria in waters filling the excavations. The research shows that there are no hard and fast rules regarding the seasonal variability of ion concentrations during the growing season, indicating that eutrophic reservoirs show greater variability of ion concentration.Graphical

Sources of stream base flow in blanket peat covered catchments

A two year hydrological characterisation programme of relatively intact blanket peat-covered catchments, underlain by geochemically distinct substrates, investigated the influence of sub-peat materials on the runoff regimes of the first order and second order streams draining them. Semi-continuous monitoring of flow and water quality revealed a strong inverse relationship between stream flow rates and specific electrical conductance (SEC), with runoff chemistries during storm flow proving comparable in all three catchments. By contrast, differences in water quality between catchments became more pronounced at lower flow, where increased ion concentrations in stream water reflected reactions with peat substrate materials. Water table monitoring in peat at all three sites revealed groundwater levels to vary by less than 0.6 m over the investigation period. Findings suggest runoff consists of near constant inputs of higher specific electrical conductance peat substrate discharge, mixing with variable proportions of less mineralised and more compositionally variable bog water. Although making up less than 5% to total runoff, the contribution of more mineralised waters plays an important role in maintaining stream flow, particularly during prolonged dry periods, and may help explain the aquatic biodiversity encountered in blanket peat covered areas.