The Influence of Extraction Procedure on Ion Concentrations in Sediment Pore Water

Abstract

Sediment pore water has the potential to yield important information on sediment quality, but the influence of isolation procedures on the chemistry and toxicity are not completely known and consensus on methods used for the isolation from sediment has not been reached. To provide additional insight into the influence of collection procedures on pore water chemistry, anion (filtered only) and cation concentrations were measured in filtered and unfiltered pore water isolated from four sediments using three different procedures: dialysis, centrifugation, and vacuum. Peepers were constructed using 24-cell culture plates and cellulose membranes and vacuum extractors consisted of fused-glass air stones attached with airline tubing to 60-cc syringes. Centrifugation was accomplished at two speeds (2,500 and 10,000 g) for 30 min in a refrigerated centrifuge maintained at 4 degreesC. Only minor differences in chemical characteristics and cation and anion concentrations were found among the different collecting methods with differences being sediment-specific. Filtering of the pore water did not appreciably reduce major cation concentrations, but trace metals (Cu and Pb) were markedly reduced. Although the extraction methods evaluated produced pore waters of similar chemistries, the vacuum extractor provided the following advantages over the other methods: ease of extraction, volumes of pore water isolated, minimal preparation time, and least time required for extraction of pore water from multiple samples at one time.

Sorption of endosulphan sulphate in soil organic matter

“…At an ionic strength of 0.01, HA could not be dissolved, hence the solubility enhancement method cannot be used. The constituents of the soil pore water (ionic strength 0.01) were taken from Winger et al [20] with some modification. Soil pore water was found to be rich in alkalinity (as bicarbonate); however, due to the difficulty in manipulating pH, sodium chloride was used instead of bicarbonate.…”

“…In the present study, sorption of endosulphan sulphate in soil humic and fulvic acid was investigated at an ionic strength 0.001, which is the typical ionic strength of surface run-off, and at 0.01, which is the typical ionic strength of the soil pore water [20]. The study was first to describe the sorption of endosulphan sulphate in soil organic matters.…”

Systematic evaluation of dissolved lead sorption losses to particulate syringe filter materials

“…Taylor and Shiller (1995) point out that preloading the filter (e.g., that is, pre-rinsing the filter in order to remove contaminants) can reduce the filter's effective pore size which could also affect the soluble/ particulate percentage value. Winger et al (1998) found that concentrations of most cations in filtered pore water were slightly lower when compared to those of the same water unfiltered. They also found that the loss of trace metals (lead and copper, among others) was especially significant after filtering with a 0.45-μm nylon syringe filter.…”

Optimization of a pressurization methodology for extracting pore-water

“…Several methods have been employed to extract the sediment pore-water, including centrifugation (Ankley and Schubauer-Berigan, 1994;Carr and Chapman, 1995;Ozretich and Schults, 1998;Doig and Liber, 2000;Kelln et al, 2001), pressurization (Carr et al, 1989;Chapman, 1992, 1995;Kelln et al, 2001), suction (Bufflap and Allen, 1995;Carr and Chapman, 1995;Carr et al, 1996;Winger et al, 1998), and equilibration methods using dialysis membranes or fritted glass samplers (Jacobs, 2002;Lewandowski et al, 2002;Williamson et al, 2002). With the latter two methods (suction and dyalisis), the extraction of pore-water can be accomplished in place (Bufflap and Allen, 1995;Angelidis, 1997;Doe et al, 2003).…”