Preservation of seawater samples for soluble reactive phosphate, nitrite, and nitrate plus nitrite analyses by the addition of sodium hydroxide

2017 ◽  
Vol 15 (3) ◽  
pp. 320-327 ◽  
Author(s):  
George T. F. Wong ◽  
Lisa Li-Tzu Hou ◽  
Kuo-Yuan Li
Keyword(s):  
Sodium Hydroxide ◽  
Soluble Reactive Phosphate ◽  
Reactive Phosphate ◽  
Seawater Samples

scholarly journals Effect of organic forms of phosphorus and variable concentrations of sulfide on the metabolic generation of soluble-reactive phosphate by sulfur chemolithoautotrophs: a laboratory study

2007 ◽  
Vol 1 (6) ◽  
pp. 545-550 ◽  
Author(s):  
Himadri Guhathakurta ◽  
Raka Biswas ◽  
Prabuddha Dey ◽  
Piyali Gajendra Mahapatra ◽  
Bipasha Mondal
Keyword(s):  
Laboratory Study ◽  
Soluble Reactive Phosphate ◽  
Reactive Phosphate

Nitrate applications to control phosphorus release from sediments of a shallow eutrophic estuary: an experimental evaluation

1998 ◽  
Vol 49 (6) ◽  
pp. 463 ◽  
Author(s):  
T. F. McAuliffe ◽  
R. J. Lukatelich ◽  
A. J. McComb ◽  
S. Qiu
Keyword(s):  
Dissolved Oxygen ◽  
Water Column ◽  
Oxygen Demand ◽  
Phosphorus Release ◽  
Carbon Limitation ◽  
Water Interface ◽  
Phosphate Release ◽  
Soluble Reactive Phosphate ◽  
Reactive Phosphate ◽  
Nitrate Consumption

Effects of nitrate on phosphate release from sediments of a eutrophic estuary were investigated under laboratory conditions, using reconstituted sediment–water cores. Application of nitrate (5–100 mg L-1 NO3-N) increased redox potential near the sediment–water interface from –200 mV to about 200 mV during 25 days of incubation. The effective concentration of nitrate differed between sediments, reflecting differences in sediment properties, particularly bioavailable carbon. Reduced phosphate after nitrate application is attributed mainly to: (1) increased iron (III) binding near the sediment–water interface; and (2) increased dissolved oxygen in the water column due to lowered oxygen demand, with increased oxidation of ferrous iron and substances binding soluble reactive phosphate. High nitrate concentrations (50 and 100 mg L-1 NO3-N) did not persist through a 155-day incubation, suggesting that without carbon limitation added nitrate will eventually be consumed by microbial activity, and increased phosphate release may occur. Nitrate application directly into the surface sediment increased nitrate consumption, and so was less effective than application to the water column. Frequent resuspension increased dissolved oxygen concentration, so reduced nitrate consumption and lowered concentration of soluble reactive phosphate.

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

2001 ◽  
Vol 5 (1) ◽  
pp. 119-131 ◽  
Author(s):  
C. Neal
Keyword(s):  
Calcium Carbonate ◽  
Organic Carbon ◽  
Dissolved Organic Carbon ◽  
Saturation Index ◽  
Fertilizer Application ◽  
Low Flow ◽  
Calcite Precipitation ◽  
Soluble Reactive Phosphate ◽  
Reactive Phosphate ◽  
Calcite Saturation

Abstract. 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. Keywords: calcite, calcium carbonate, phosphate, soluble reactive phosphate, dissolved organic carbon, LOIS, UK, rivers, self-cleansing mechanisms.

scholarly journals Study on Characteristics of Nitrogen and Phosphorus Loss under an Improved Subsurface Drainage

Water ◽  
2019 ◽  
Vol 11 (7) ◽  
pp. 1467 ◽  
Author(s):  
Tao ◽  
Wang ◽  
Guan ◽  
Xu ◽  
Chen ◽  
...  
Keyword(s):  
Total Nitrogen ◽  
Total Phosphorus ◽  
Nitrate Nitrogen ◽  
Subsurface Drainage ◽  
Ammonia Nitrogen ◽  
Nitrogen And Phosphorus ◽  
Phosphorus Loss ◽  
Soluble Reactive Phosphate ◽  
Reactive Phosphate ◽  
Nitrogen Concentrations

Agricultural drainage plays an effective role in preventing waterlogging and salinity disasters and also is the main transport pathway for agricultural non-point source pollutants into rivers and lakes. Hence, the water quality of agricultural drainage should be a point of focus. In this paper, nitrogen and phosphorus loss under improved subsurface drainage with different filter materials (gravel, layered sand-gravel, mixed sand-gravel, straw) were studied by a three-year field experiment (2016–2018) compared with the conventional subsurface drainage. The pH values, total nitrogen, ammonia nitrogen, nitrate nitrogen, total phosphorus and soluble reactive phosphate were considered. The results showed that the nitrogen and phosphorus concentrations of drain outflow under improved subsurface drainage with gravel filter were larger than that with layered sand-gravel filter and mixed sand-gravel filter. The improved subsurface drainages with layered sand-gravel filter and mixed sand-gravel filter had an effect on reducing the ammonia nitrogen, total phosphorus and soluble reactive phosphate concentrations of the outflow. Meanwhile, the characteristics of nitrogen and phosphorus loss under the improved subsurface drainage with straw filter were different from that with layered sand-gravel filter and mixed sand-gravel filter. For the improved subsurface drainage with layered sand-gravel filter outflow, the ammonia nitrogen, total phosphorus, and soluble reactive phosphate concentrations were about 13%–78%, 38%–63%, 40%–68% less, and total nitrogen, nitrate nitrogen concentrations were 24%–80%,18%–96% more than that under conventional subsurface drainage. Meanwhile, for the improved subsurface drainage with straw filter outflow, compared with conventional subsurface drainage outflow, the percentage changes of the total nitrogen, nitrate nitrogen, ammonia nitrogen, total phosphorus and the soluble reactive phosphate concentrations were about −76%–62%, −77%–78%, −152%–−274%, −103%–−400% and −221%–−291%, respectively. Additionally, in the outflow of all subsurface drainage patterns, there were much higher total nitrogen and nitrate nitrogen concentrations which should be focused on and the agricultural water management should be adopted.

Real-Time, Online Automated System for Measurement of Water-Soluble Reactive Phosphate Ions in Atmospheric Particles

2016 ◽  
Vol 88 (14) ◽  
pp. 7163-7170 ◽  
Author(s):  
Kalliopi Violaki ◽  
Ting Fang ◽  
Nikos Mihalopoulos ◽  
Rodney Weber ◽  
Athanasios Nenes
Keyword(s):  
Real Time ◽  
Atmospheric Particles ◽  
Water Soluble ◽  
Automated System ◽  
Soluble Reactive Phosphate ◽  
Phosphate Ions ◽  
Reactive Phosphate

scholarly journals A Lab-on-Chip Analyzer for in Situ Measurement of Soluble Reactive Phosphate: Improved Phosphate Blue Assay and Application to Fluvial Monitoring

2017 ◽  
Vol 51 (17) ◽  
pp. 9989-9995 ◽  
Author(s):  
Geraldine S. Clinton-Bailey ◽  
Maxime M. Grand ◽  
Alexander D. Beaton ◽  
Adrian M. Nightingale ◽  
David R. Owsianka ◽  
...  
Keyword(s):  
In Situ Measurement ◽  
Lab On Chip ◽  
Soluble Reactive Phosphate ◽  
Reactive Phosphate ◽  
On Chip

Comparison of Acrylamide and Agar Gels by Freeze-Etching

1977 ◽  
Vol 35 ◽  
pp. 606-607
Author(s):  
Russell L. Steere ◽  
Eric F. Erbe
Keyword(s):  
Electron Microscope ◽  
Sodium Hydroxide ◽  
Sodium Hypochlorite ◽  
Chromic Acid ◽  
Distilled Water ◽  
Thin Sheets ◽  
Acid Cleaning ◽  
Agar Gels ◽  
Freeze Etching ◽  
Water Cut

Thin sheets of acrylamide and agar gels of different concentrations were prepared and washed in distilled water, cut into pieces of appropriate size to fit into complementary freeze-etch specimen holders (1) and rapidly frozen. Freeze-etching was accomplished in a modified Denton DFE-2 freeze-etch unit on a DV-503 vacuum evaporator.* All samples were etched for 10 min. at -98°C then re-cooled to -150°C for deposition of Pt-C shadow- and C replica-films. Acrylamide gels were dissolved in Chlorox (5.251 sodium hypochlorite) containing 101 sodium hydroxide, whereas agar gels dissolved rapidly in the commonly used chromic acid cleaning solutions. Replicas were picked up on grids with thin Foimvar support films and stereo electron micrographs were obtained with a JEM-100 B electron microscope equipped with a 60° goniometer stage.Characteristic differences between gels of different concentrations (Figs. 1 and 2) were sufficiently pronounced to convince us that the structures observed are real and not the result of freezing artifacts.

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