Inhibition of aragonite precipitation from supersaturated seawater; a laboratory and field study

Berner, Robert A.; Westrich, Joseph T.; Graber, R.; Smith, J. L.; Martens, Christopher S.

doi:10.2475/ajs.278.6.816

Cited by 161 publications

(88 citation statements)

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“…Within these estuarine and coastal areas, calcium and bicarbonate concentrations are particularly high and clearly, calcium carbonate precipitation can occur. However, the precipitation of calcite and other forms of calcium carbonate may not occur within the water column because of inhibiting factors of SRP, DOC and other species such as magnesium (Berner, 1975;Berner et al, 1978;Mucci, 1986;Appelo and Postma, 1993;Drever, 1997). Within the estuarine and coastal environment, SRP and DOC pollution from the riverine sources can decline due to dilution of river water by sea water and levels may start to go below those needed to inhibit calcite precipitation within the water column.…”

Section: Associated Resultsmentioning

confidence: 99%

“…l The phosphate concentration must be sufficiently low for it not to inhibit calcium carbonate precipitation (Walter and Hanor, 1979;Mucci, 1986;House, 1986House, , 1990. l Other calcium carbonate precipitation inhibitors such as DOC (Berner et al, 1978;Suarez and Rhoades, 1982;Thomson, 1983;Inskeep and Bloom, 1986;Appelo and Postma, 1993) are below the levels where they affect the kinetics of precipitation.…”

Section: Introductionmentioning

confidence: 99%

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The potential for phosphorus pollution remediation by calcite precipitation in UK freshwaters

Neal

2001

Hydrol. Earth Syst. Sci.

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This paper examines the potential for calcium carbonate to reduce phosphate pollution in freshwaters by co-precipitation, a process known as a "self cleansing mechanism". Calcium carbonate saturation levels and phosphate concentrations (SRP -soluble reactive phosphate) across the major eastern UK river basins are examined to test for solubility controls. The study shows that calcite saturation varies for each catchment as a function of flow and biological activity rather than by direct regulation by SRP. Indeed, there is no evidence, for any of the rivers studied, that calcite solubility controls hold. However, for groundwater and groundwater-fed springs in the Chalk of the Thames basin, calcite saturation is observed with associated low SRP levels. A self-cleansing mechanism may well be operative within the Chalk due to two factors. Firstly, there is a high potential for nucleation on the calcite micro-crystals in the aquifer. Secondly, there are within aquifer reactions that remove the calcite nucleating inhibitors (SRP and dissolved organic carbon, DOC) to levels lower than those occurring within the rivers do. These inhibitors enter the catchment at very high concentrations in association with agricultural pollution (fertilizer application and animal slurry) and household contamination (e.g. sewage sources from septic tanks). Under low flow conditions, when the saturation index for calcite is at its highest, so too is the concentration of the nucleation inhibitor SRP. Companion work shows that calcite precipitation can occur at the water-sediment interface of the river and this may involve SRP removal. The data, as a whole, define an apparent bound for calcite solubility control where in the presence of nucleating centres, SRP must be less than 4 mM-P l -1 and DOC must be less than 150 mM-C l -1 : a condition that does not seem to pertain within most UK rivers.

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Section: Associated Resultsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

The potential for phosphorus pollution remediation by calcite precipitation in UK freshwaters

Neal

2001

Hydrol. Earth Syst. Sci.

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“…many researchers (Olsen and Watanabe 1959;Berner et al 1978;Suarez 1977;Levy 1981;Suarez and Rhoades 1982;Inskeep and Bloom 1986b;Baker et al 1987;Al-Kanani et al 1989;Reddy et al 1990;Miyamoto and Pingitore 1992;Suarez et al 1992). Observations of calcite supersaturation can be separated into two categories.…”

mentioning

confidence: 99%

“…When this increase in concentration is coupled with slow calcite precipitation kinetics, supersaturation results. Calcite precipitation kinetics may be retarded as a result of the blockage of precipitation sites or the presence of precipitation inhibitors such as Mg, P, and organic matter (Doner and Pratt 1968;Berner et al 1978;Suarez 1977;Levy 1981;Inskeep and Bloom 1986a and b).…”

mentioning

confidence: 99%

Calcite Supersaturation in Soil Suspensions

Amrhein¹,

Zahow²,

Suarez³

1993

Soil Science

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Calcite supersaturation in soil solutions has been attributed to errors in measuring Ca2+ and COS2-activities, metastable forms of CaC03 or soluble silicates, and organic matter mineralization. Laboratory batch suspensions of soils under controlled CO, and temperature were studied to clarify the mechanism producing calcite supersaturation. Treatments included the addition and removal of organic matter prior to reaction and the use of toluene to suppress microbial activity. The soil solutions were sampled over time and analyzed for Ca2+ and COS2-activity. Carbonate activity was determined by two methods: 1) a double titration procedure that separates non-carbonate alkalinity from carbonate alkalinity and 2) acidification and outgassing of dissolved inorganic carbon species as C02. Calcium activity was determined by two methods: 1) specific ion electrode and 2) total Ca analysis plus ion speciation modeling. Calcium-organic matter complexation was taken into account in the speciation calculations. It was found that calcite supersaturation in soil suspensions was not an artifact of inaccurate Ca2+ or COS2-activity values. Rather, calcite supersaturation occurred because rapid organic matter mineralization increased the Ca and HC03 concentrations. These elevated Ca and HC03 concentrations persisted because of the slow precipitation kinetics of calcite. Attempts to block organic matter mineralization with toluene only slowed down the reaction in the soils. Removal of organic matter with H202 resulted in Caoxalate formation, and oxidation of the oxalate to HCO,-produced elevated COS2-activities.Calcite supersaturation in natural waters and soil solutions has been reported and studied by

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“…The explanations of these observations This restriction complicates the analysis of the have mainly been focussed on surface phenom partition mechanisms (MCINTIRE, 1963; WHITE, ena including phosphate adsorption on calcium 1977). ICHIKUNI (1979) suggested an ion ex carbonate, formation of calcium phosphate, change model which indicates fluoride uptake and inhibition of calcium carbonate crystalliza by aragonite maintaining the charge balance be tion (REDDY, 1977, BERNER et al, 1978; KANEL tween fluoride and carbonate ions. In this paper and MORSE, 1978).…”

Section: Introductionmentioning

confidence: 99%

Coprecipitation of phosphate with calcite.

Ishikawa

Ichikuni

1981

Geochem. J.

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The mechanism of phosphate coprecipitation with calcite is proposed on the basis of homogeneous distribution of phosphate in the crystal at 20°C and pH 7.9-9.5. At a constant pH, phosphate content of calcite is proportional to total phosphate concentration in aqueous solution. PO' ions are uptaken into the calcite lattice, where 3 CO3 ions are replaced by 2 P04 ions in aqueous solution, as described by the ion exchange equilibrium:where S and L represent calcite and aqueous solution, respectively.

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Inhibition of aragonite precipitation from supersaturated seawater; a laboratory and field study

Cited by 161 publications

References 0 publications

The potential for phosphorus pollution remediation by calcite precipitation in UK freshwaters

The potential for phosphorus pollution remediation by calcite precipitation in UK freshwaters

Calcite Supersaturation in Soil Suspensions

Coprecipitation of phosphate with calcite.

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