Copper In Seawater Research Articles

Determination of zinc, cadmium, lead and copper in sea water by means of computerized potentiometric stripping analysis

Water samples from the Arctic Sea were analyzed by the potentiometric stripping technique. Lead(II) and cadmium(II) were determined after pre-electrolysis for 32 min at—1.1 V vs. Ag/AgCl, the detection limits being 0.06 and 0.04 nM, respectively. Zinc(II) was determined after the addition of gallium(III) by pre-electrolysis for 16 min at —1.4 V vs. Ag/AgCl, the detection limit being 0.25 nM. Problems in the determination of copper(II) at the very low concentrations found in oceanic waters are outlined. The average zinc(II), cadmium(II) and lead(II) concentrations in eight different samples were 2.5, 0.16 and 0.10 nM as determined by potentiometric stripping analysis and 1.9, 0.16 and 0.09 nM as determined by solvent extraction/atomic absorption spectrometry. The advantages of this computerized technique for the analysis of sea water are discussed.

Investigations on dissolved copper—organic substances in Baltic waters

A technique for the pH-controlled isolation and separation of dissolved copper—organic substances from large amounts of seawater is described. The method has been applied in two cruises in the Bothnian and Gotland Seas of the Baltic. In both areas the correlation between the amount of isolated dissolved organic material (DOM) and the concentration of organic copper in seawater has been found to be highly significant. Under the conditions established in our experiments, organic copper fractions detected in Baltic waters were in the range of about 5% of total copper. HPLC chromatograms and UV irradiation experiments from DOM extracts strongly indicate the existence of dissolved organic-copper compounds in Baltic waters.

Effects of copper on the sabellid polychaete, Eudistylia vancouveri. II. Copper accumulation and tissue injury in the branchial crown.

Copper in seawater caused injury to the radioles (gills) of the sabellid polychaete, Eudistylia vancouveri. Light and electron microscopy showed the loss of cellular adhesion and the structural derangement that lead to cell necrosis and death. The progression of injury was related to the uptake of copper into the tissues. Copper was found by X-ray microanalysis to be localized subcellularly in membrane-bound vesicles that are similar to lysosomes. Cell breakdown may result from lysosomal labilization.

Behavioural responses of the bivalve Scrobicularia plana (da Costa) subjected to short-term copper (Cu II) concentrations

Short-term (6 h) behavioural responses and mortality of Scrobicularia exposed to low concentrations of copper in sea water (31%, S) have been investigated. Scrobicularia can detect copper at a concentration of 0·01 ppm. The initial response is valve closure resulting in a rapid drop in heart rate. In concentrations of 0·05, 0·01 and, to a lesser extent, 0·1 ppm copper added to sea water, the clams begin to interact with the polluted water after 2–3 h. In 0·5 ppm, the valves remain closed and the heart rate is maintained at a low level over the 6-h exposure period. Mortality increases with time in 0·5 ppm copper concentration, reaching 50% in 5–7 days. In 0·05 and 0·01 ppm, no mortality was recorded over this period. There is an increase in mantle cavity water calcium concentration after 6 h in 0·5 ppm, in contrast to 0·1, 0·05 and 0·01 ppm. Aspects of anaerobiosis, accumulation of heavy metals and survival are discussed in relation to the behaviour of Scrobicularia exposed to various copper concentrations.

The influence of organics on the adsorption of copper (II) on γ-Al 2O 3 in seawater, model studies with EDTA

The natural “complexing capacity” of aquatic systems was determined using titration with cupric ions. It was compared with “complexing capacity” determined in the presence of both EDTA, used as a model for organic substances, and of EDTA and γ-Al 2O 3. The γ-Al 2O 3 was used as a model for solid particles of hydrous oxide in natural waters. The adsorption isotherm of copper in seawater on γ-Al 2O 3 particles was determined with and without EDTA. For EDTA alone and for the Cu—EDTA complex, it was found that they are not adsorbed on γ-Al 2O 3 in the natural seawater. However, by adsorption on solid particles, the labile ionic Cu-complex can be removed from the seawater.

Stripping polarography and the reduction of copper(II) in sea water at the hanging mercury drop electrode

An approximate but general theoretical treatment for reversible and irreversible stripping polarographic systems is presented. The treatment is based on the development of an average current (i), which at plating times exceeding 15 s. is analogous to the instantaneous current in d.c. polarography. Plots of i vs. (E – E°) are generated for reversible and irreversible waves and are discussed for the reduction of copper(II) in sea water as an example. From stripping polarography and anodic stripping voltammetry, this work indicates that the overall reduction of copper(II) at the natural pH is kinetically hindered and thus is “irreversible”. The reversibility and the determination of copper in sea water by a.s.v. can be improved by acidification and/or by the addition of ethylenediamine.

Combined effect of the chlorides of mercury and copper in sea water on the euryhaline amphipod Gammarus duebeni

The possible interactive effect of the chlorides of copper and mercury on the euryhaline amphipod Gammarus duebeni in 100% sea water was examined using the following indices: (i) 96 h LC50 values, (ii) urine production rates and (iii) degree of mercury accumulation. Both (a) the interaction of the chlorides of mercury and copper together in solution and (b) the influence of cupric chloride pre-treatment of individuals prior to exposure to mercuric chloride were investigated. Presence of a sublethal level of cupric chloride protected G. duebeni against the toxic action of mercuric chloride. Cupric chloride pretreatment was not so effective. The nature of the interaction between mercury and copper is discussed.

Behavioural responses of some marine bivalves to heightened seawater copper concentrations.

The study reported here constitutes a summary of preliminary investigations of the behavioural responses of several marine mollusc species to copper as a pollutant, and stems from the observation that the common mussel Mytilus edulis (L.) is capable of detecting and avoiding potentially lethal concentrations of copper delivered intermittently. The initial behavioural reaction of M. edulis occurs at copper concentrations of 0.02 ppM representing 0.2 ILL, the ILL taken to be 0.1 ppM copper.

Effects of temperature on the Corrosion of copper in sea water at different hydrostatic pressures

AbstractAn investigation has been made of the effect which an increasing hydrostatic pressure may have on copper corrosion at different temperatures in sea water at pH 7.8.The tests were carried out at a pressure of 1, 50, 100, 200 and 300 atm at a temperature of 5 °, 10 ° and 20 °C.The pressure set in which the tests were effected was pressurized by an hydropneumatic pump and it was fitted not only with a work electrode, but also with two Pt and one Ag‐AgCl reference electrodes for electrochemical tests.It was found that copper corrosion is always stimulated by a pressure rise and that the increased corrosion rate is accelerated by increasing temperatures.The maximum increase (71%) was obtained at T = 20 °C; D.O = 7.0 ppm and pH = 7.8 at a pressure of 150 atm.But at a temperature of approx. 5 °C, the maximum increase did not exceed 30% always at a pressure of 150 atm.The test findings also evidenced that at a temperature ≤ of 10 °C, the pressure rise did not affect the anodic process but only the cathodic reduction, whereas the anodic process too was significantly accelerated at 20 °C and the influence of the pressure was found to be more accentuated.

Potentiometric stripping analysis for zinc, cadmium. lead and copper in sea water

Analytical procedures for the determination of zinc(II), cadmium (II), lead(II) and copper(II) in sea water by potentiometric stripping analysis are described. The results are compared with those obtained by a combined solvent extraction-atomic absorption method both in the laboratory and on-board ship. The detection limits for zinc, cadmium, lead and copper are 0.03, 0.03, 0.01 and 0.02 μg l -1, respectively, for a total analysis time of about 75 min. A very thin mercury film is useful in the determination of lead and copper.

Copper dissolution in sea water under mixed activation and diffusion control

A model for the dissolution of copper in sea water under mixed activation and diffusion control is presented. It is assumed that the copper is dissolving as the cuprous ion (Cu +), at a rate which is determined both by the electrode potential and by the ion concentration gradient in the electrolyte. The rate of diffusion of ions is a function of the fluid velocity and also depends upon whether the flow is laminar or turbulent. The model explains the main features previously observed for copper dissolution in sea water, viz., the increase in Tafel slope with increasing flow and the reduction in the dependence of the current on fluid velocity. A series of potentiostatic measurements of the current for a short annular electrode in a substitute sea water flow cell have been made at a variety of potentials between — 0.25 and — 0.15 V(SCE) and between fluid velocities of 0.16 and 1.6 m s −1. The theoretical model was used to separate the activation- and diffusion-affected components of the total current measured and it was shown that the activation-affected component was independent of fluid velocity, as expected, and the diffusion-affected component varied with velocity to a power of about 0.65, again as expected for turbulent flow over a short electrode. † Department of Mechanical Engineering, The City University, Northampton Square, London EC1V 0HB, England.

The Determination of Copper in Sea Water by Atomic Absorption Spectrophotometric Method with BMPP-MIBK Extraction

The Determination of Copper in Sea Water by Atomic Absorption Spectrophotometric Method with BMPP-MIBK Extraction

Copper dissolution in sea water under mixed activation and diffusion control

A model for the dissolution of copper in sea water under mixed activation and diffusion control is presented. It is assumed that the copper is dissolving as the cuprous ion (Cu +), at a rate which is determined both by the electrode potential and by the ion concentration gradient in the electrolyte. The rate of diffusion of ions is a function of the fluid velocity and also depends upon whether the flow is laminar or turbulent. The model explains the main features previously observed for copper dissolution in sea water, viz., the increase in Tafel slope with increasing flow and the reduction in the dependence of the current on fluid velocity. A series of potentiostatic measurements of the current for a short annular electrode in a substitute sea water flow cell have been made at a variety of potentials between — 0.25 and — 0.15 V(SCE) and between fluid velocities of 0.16 and 1.6 m s −1. The theoretical model was used to separate the activation- and diffusion-affected components of the total current measured and it was shown that the activation-affected component was independent of fluid velocity, as expected, and the diffusion-affected component varied with velocity to a power of about 0.65, again as expected for turbulent flow over a short electrode. † Department of Mechanical Engineering, The City University, Northampton Square, London EC1V 0HB, England.

Effects of copper on the sabellid polychaete, Eudistylia vancouveri: I. Concentration limits for copper accumulation.

Three experiments with a sabellid polychaete (Eudistylia vancouveri) show the threshold concentration for increasing copper accumulation with time to lie between 3 and 6 micrograms/L total copper in seawater during winter conditions. The branchial crown, probably the major absorptive site, concentrated more copper than the body. Accumulation was influenced by size but not by sex. Our studies indicate that the body burden of copper will increase above natural levels in areas of industrial discharge where copper levels are above the threshold limit for accumulation.

The detection of heightened sea-water copper concentrations by the mussel Mytilus edulis

An acute toxicity threshold of 0·09–0·10 ppm added copper was determined for specimens of Mytilus edulis from the Menai Strait which were exposed to copper (as CuSO4) in a flowing sea-water system.Results are presented which show that the closure response of the mussel to added copper is a three-part process. First, a sharp adduction of the shell valves is seen at a mean total copper concentration of only 0·021 ppm, then as the copper concentration rises, ‘testing’ behaviour is observed and finally the shell valves close to isolate the animal from its environment. The complete valve closure mechanism only operates at added copper concentrations of 0·2 ppm or more. The initial behavioural reaction of valve adduction at low concentration occurred at a significantly higher mean total copper concentration (0·16 ppm) in mussels which had been previously acclimated to 0·02 ppm total copper in sea water for 10 days.

Effects of Hydrostatic Pressure on the Corrosion of Copper in Sea Water

Abstract A study has been made of the effect of hydrostatic pressure, ranging from 1 to 300 atm. (0·102 to 30·6 N.mm−2) on the corrosion of copper in sea water at pH 7·8 and at a temperature of 10°c. The experimental technique ensured that the content of dissolved oxygen in the sea water was virtually constant over the pressure range, at a value of 7·0 ppm. The same test series was also carried out in a 3·5% NaCl solution.The weight loss of the copper was found to increase with increase in pressure, both in sea water and in NaCl, and reached a maximum at a pressure of 150 atm. (∼15 N.mm−2) in both solutions. The increased pressure has no influence on the anodic dissolution process for copper, but accelerates the cathodic process. Protective films adhering to the corroded surfaces are identical for the two solutions at ambient pressure. However, at higher pressures adherent corrosion products form only in NaCl solutions. These products were found to be the same as those formed at ambient pressure.

Preconcentration of mercury, gold, and copper in sea water with lead diethyldithiocarbamate for neutron activation analysis

Lead diethyldithlocarbamate (Pb(DDC/sub 2/) has been introduced as an effective reagent for enriching mercury, gold, and copper in seawater prior to irradiation in neutron activation analysis. The aforementioned metals in seawater can be highly and selectively concentrated from a large volume of water to a small volume of CHCl/sub 3/ solution of Pb(DDC)/sub 2/. Bulk amounts of Na and Br were completely removed from the sample by this procedure. The ..gamma.. spectrum after irradiation shows only the irradiations from Hg, Au, and Cu, and thereafter their contents in seawater can be accurately determined.

Determination of copper in seawater by anodic stripping voltammetry

Copper in surface seawater has been determined using both hanging mercury drop and thin film electrodes. Total copper was found to be in the range 0.4–0.7 μg l −1 , and labile copper in the range 0.2–0.4 μg l −1 . Most of the copper present in seawater is complexed with or adsorbed on organic matter, and a smaller percentage is associated with inorganic colloids. Seawater contains both organic and inorganic compounds which will react with approximately 1×10 −8 M added ionic copper. Because of the presence of the complexing agents, peak current-copper concentration calibration curves in seawater are non-linear, and care must be exercised in using spiked results in the calculation of the copper content. The thin film electrode (TFE) is more suitable than the hanging mercury drop electrode for determining copper in seawater, although the TFE results are more dependent on deposition potential, and suffer from interference by nickel if very negative deposition potentials are used.

Determination of copper in seawater by anodic stripping voltammetry

Copper in surface seawater has been determined using both hanging mercury drop and thin film electrodes. Total copper was found to be in the range 0.4–0.7 μg l −1, and labile copper in the range 0.2–0.4 μg l −1. Most of the copper present in seawater is complexed with or adsorbed on organic matter, and a smaller percentage is associated with inorganic colloids. Seawater contains both organic and inorganic compounds which will react with approximately 1×10 −8 M added ionic copper. Because of the presence of the complexing agents, peak current-copper concentration calibration curves in seawater are non-linear, and care must be exercised in using spiked results in the calculation of the copper content. The thin film electrode (TFE) is more suitable than the hanging mercury drop electrode for determining copper in seawater, although the TFE results are more dependent on deposition potential, and suffer from interference by nickel if very negative deposition potentials are used.

Effect of the Addition of Bromides and Iodides on the Corrosion of Copper in Sea Water

The effect of additions of bromides and iodides to sea water on the corrosion of copper has been investigated. Tests were carried out in solutions containing Kl or KBr at concentrations from 10−l to 10−5 mol/l, and various alkyl halides at concentrations from 10−3 mol/l up to saturation (approx. 10−l mol/l).The inhibiting efficiency of KI varies with concentration, having a peak value (approx. 75% after 360 h immersion) at 10−2 mol/l. Inhibition is due to the formation of a layer of CuI on the copper surface. Alkyl iodides have a lower inhibitive efficiency than KI and this efficiency decreases the longer the period of immersion. The mechanism of inhibition is similar to that observed for KI.KBr has an inhibitive efficiency of 50–60% at a concentration of 10−l mol/l, but corrosion is actually accelerated at concentrations below 10−3 mol/l. The inhibiting effect is due to the action of KBr in reducing the concentration of O2 in the corrosive solution, and not to the formaiion of a protective layer of CuBr. The action of alkyl bromides is always deleterious.