Solubility of inorganic phosphorus in stream water as influenced by pH and calcium concentration

Díaz, Oscar; Reddy, K. R.; Moore, P. A.

doi:10.1016/0043-1354(94)90248-8

Cited by 145 publications

(76 citation statements)

References 16 publications

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“…According to these criteria, the average available P concentration of Beeshazar Lake (79.2 mg/kg) is able to sustain high productivity. The P fluxes depend also upon the concentration gradients between overlying water and bottom sediments [29] which is particularly pronounced in Beeshazar Lake.…”

Section: Sedimentsmentioning

confidence: 99%

“…The average nitrogen and phosphorus concentration were 3.09 g/kg and 79.2 mg/kg respectively. Unlike nitrogen and carbon, phosphorus cannot be lost from wetlands through metabolic processes and thus tends to accumulate in the bottom sediments [29]. In shallow lakes, microbial mineralization enhance nutrient recycling, this is commonly called internal nutrient loading.…”

Section: Sedimentsmentioning

confidence: 99%

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Evaluation of the Limnological Status of Beeshazar Lake, a Ramsar Site in Central Nepal

Niraula¹

2012

JWARP

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Lack of monitoring and implementation of appropriate management practices and strategies in compliance with the Ramsar Convention obligations have been contributing to severe degradation of Beeshazar Lake, a Ramsar site in central Nepal. The surface water quality and characteristics of underlying sediments were studied to determine the limnological status of the lake. Water quality in Beeshazar Lake was found less favorable to aquatic organisms, with low pH and transparency, low dissolved oxygen (DO), and high nutrient concentrations (Nitrogen and Phosphorus), challenging the conservation of critically endangered gharial, a vulnerable marsh crocodile and many fish species. The lake was found eutrophic in nature by nitrogen concentration and transparency and hyper-eutrophic by phosphorus criteria. Lake sediments were high in organic matter content and nutrient concentrations, signifying a potential internal source of nutrient loading in the overlying water. There were no significant variations in the water and sediment quality between sampling sites except for transparency, sedimentary organic matter content (OM) and total nitrogen concentration (TN). This study provided useful information for decision makers aimed to the conservation and sustainable management of the lake.

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Section: Sedimentsmentioning

confidence: 99%

Section: Sedimentsmentioning

confidence: 99%

Evaluation of the Limnological Status of Beeshazar Lake, a Ramsar Site in Central Nepal

Niraula¹

2012

JWARP

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“…However, their study indicates that the formation of hydroxyapatite was the most likely mechanism for removing P when using CaO-rich materials such as blast furnace slag. The precipitation reaction for hydroxyapatite can be simply described as follows: Yeoman et al 1988) For fresh Ca-P precipitates, the reaction may be fully reversible, and a drop in the pH and Ca concentration of the solution may result in the dissolution of precipitated Ca-P associations (see Diaz et al 1994Diaz et al , Ádám et al 2007a. Consequently, if the Ca concentration or pH (or both) of the system decreases with time, one can regard fresh Ca-P precipitates as temporary P storage compounds.…”

Section: -mentioning

confidence: 99%

Potential and limitations of phosphate retention media in water protection: A process-based review of laboratory and field-scale tests

Klimeski¹,

Chardon²,

Туртола³

et al. 2012

AFSci

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The application of phosphorus (P)-sorbing materials offers a possible solution for treating municipal wastewater and agricultural runoff. In this paper we discuss P retention and release mechanisms, and review studies on the P retention of different materials and their use as reactive media in filter beds. The main mechanisms for P retention are sorption on metal (mostly Fe or Al) hydroxide surfaces and, in alkaline conditions, the formation of Ca-P precipitates. The retention of P is strongly affected by the chemical composition of a material, its particle size and pH-related effects on sorption and precipitation both during testing and in practical operation. Laboratory tests are sensitive to solution chemistry (pH, alkalinity, ionic strength and composition, P concentration) and affected by material-to-solution ratio, contact time and agitation. Moreover, due to deviations from realistic field conditions, laboratory tests may produce imprecise estimates of the retention capacity and retention kinetics. In particular, materials that contain soluble substances (e.g., CaO) that elevate the pH of the ambient solution to high levels may in batch tests suggest a high capacity for P retention, but will most probably show much lower retention in field settings. On the other hand, materials containing metal oxides also retain P via slow reactions, and their retention capacity may be underestimated in short equilibrations. Appropriate laboratory test procedures will depend on their intended applications and material properties. Long-term field-scale tests are few in number, but some of them have shown promising results. Field-scale tests have, however, highlighted the design of the filters as a critical factor in their efficiency.

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“…Indeed some studies suggest that hydroxyapatite precipitation can only take place when the SI > 9.4 and when Ca concentrations are very high (> 100 mg L −1 ) (e.g. Diaz et al, 1994). Given that phosphorus has strong adsorption affinity to calcite (e.g.…”

Section: P Retention and Role Of Overlying Watermentioning

confidence: 99%

Phosphorus transport and retention in a channel draining an urban, tropical catchment with informal settlements

Nyenje

Meijer

Foppen

et al. 2014

Hydrol. Earth Syst. Sci.

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Abstract. Urban catchments in sub-Saharan Africa (SSA) are increasingly becoming a major source of phosphorus (P) to downstream ecosystems. This is primarily due to large inputs of untreated wastewater to urban drainage channels, especially in informal settlements (or slums). However, the processes governing the fate of P in these catchments are largely unknown. In this study, these processes are investigated. During high runoff events and a period of base flow, we collected hourly water samples (over 24 h) from a primary channel draining a 28 km 2 slum-dominated catchment in Kampala, Uganda, and from a tertiary channel draining one of the contributing slum areas (0.54 km 2 ). The samples were analysed for orthophosphate (PO 4 -P), particulate P (PP), total P (TP), suspended solids (SS) and hydrochemistry. We also collected channel bed and suspended sediments to determine their geo-available metals, sorption characteristics and the dominant phosphorus forms. Our results showed that the catchment exported high fluxes of P (0.3 kg km 2 d −1 for PO 4 -P and 0.95 for TP), which were several orders of magnitude higher than values normally reported in literature. A large proportion of P exported was particulate (56 % of TP) and we inferred that most of it was retained along the channel bed. The retained sediment P was predominantly inorganic (> 63 % of total sediment P) and consisted of mostly Ca and Fe-bound P, which were present in almost equal proportions. Ca-bound sediment P was attributed to the adsorption of P to calcite because surface water was near saturation with respect to calcite in all the events sampled. Fe-bound sediment P was attributed to the adsorption of P to iron oxides in suspended sediment during runoff events given that surface water was undersaturated with respect to iron phosphates. We also found that the bed sediments were P-saturated and showed a tendency to release P by mineralisation and desorption. During rain events, there was a flushing of PP which we attributed to the resuspension of P-rich bed sediment that accumulated in the channel during low flows. However, firstflush effects were not observed. Our findings provide useful insights into the processes governing the fate and transport of P in urban slum catchments in SSA.

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Solubility of inorganic phosphorus in stream water as influenced by pH and calcium concentration

Cited by 145 publications

References 16 publications

Evaluation of the Limnological Status of Beeshazar Lake, a Ramsar Site in Central Nepal

Evaluation of the Limnological Status of Beeshazar Lake, a Ramsar Site in Central Nepal

Potential and limitations of phosphate retention media in water protection: A process-based review of laboratory and field-scale tests

Phosphorus transport and retention in a channel draining an urban, tropical catchment with informal settlements

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