Characterization and evaluation of phosphate microsensors to monitor internal phosphorus loading in Lake Erie sediments

Abstract

Monitoring phosphate concentration is very important to prevent and control eutrophication in natural waters. In this study, cobalt-based microsensors were modified, characterized, and tested to monitor internal soluble phosphorous (SRP) loading in lakes with improved detection limits. The effectiveness of surface modification on the performance of a cobalt-based microelectrode was fully examined by determining detection limit, response time, selectivity, interference with ions (sulfate, nitrate, and nitrite) and dissolved oxygen (DO). To assess their performance, phosphate sensors were applied to sediment samples collected from Lake Erie. SRP loading from sediments was determined under different DO conditions. After increasing the phosphate sensing area and modifying the surface, phosphate microsensors showed an increased detection limit of up to 10(-8) M concentration of phosphate ion. The phosphate microsensor also showed its ability to measure sediment SRP profiling without disturbing sediment structure, and diffusion coefficients of phosphate in sediment could be determined under both oxic and anoxic conditions. Modified phosphate sensors showed improved sensitivity and could be applied to both water and sediment samples with high spatial resolution; however, signal interferences (especially with oxygen) required consideration during sample analysis. Overall, obtained results showed that phosphate microsensors can be an effective tool for measurement of phosphate in lake water and sediment samples for SRP monitoring.

New Materials Used for the Development of Anion-Selective Electrodes—A Review

“…The maximum number of phosphates in drinking water according to the. WHO is 1 mg/L [85]. For this reason, it is extremely important to improve the methods used to detect phosphate concentrations.…”

Improvement of a Phosphate Ion-selective Microsensor Using Bis(dibromophenylstannyl)methane as a Carrier

“…The various PO4 ion-selective electrodes described so far in previous studies responded partly to HPO4 [2][3][4][5][6][7][8][9][10][11][12][13][14][15][16][17][18][19][20]26,[31][32][33][34][35] and partly to H2PO4 -. 27,35 Because of the possible interference by OH -and the fact that the fraction of each PO4 species is determined by the pH value of the solution, 28 it is not always simple to unequivocally decide based on the electrode response alone which phosphate species is being sensed.…”

“…For example, these processes occur in rhizosphere, 6 in microbial aggregates and biofilms, 7 and at the sediment-water interface. 8 Because submillimeter resolution is required for in situ analysis of such systems where steep concentration profiles of solutes occur, [9][10][11][12][13][14][15][16][17] microsensors with a micrometer-sized tip are an ideal tool for in situ analysis. The use of microsensors has improved the understanding of many biological processes in situ, such as the physiology within tissues and cells of animal 18 and plant species, 19 and the microbial processes in sediments, microbial mats, and biofilms.…”

Realtime Water Depth Logger Data as Input to PCSWMM to Estimate Tree Filter Performance

“…Pollutants found in runoff, such as nutrients from fertilizers, can cause a harmful chain reaction in the aquatic ecosystem leading to contaminated source water and ecosystem damage, as observed in the western portion of Lake Erie in recent years (Urry et al 2014). Mitigating stormwater contamination that contributes to eutrophication in natural waters is critical (Ding et al 2015). Eutrophication creates abundant growth in aquatic plants and algae blooms which lead to the depletion of oxygen in water (Behbahani et al 2013).…”