ASSESSMENT OF ORGANIC PHOSPHORUS DISTRIBUTION IN THE SEDIMENT AND WATERS OF LANGAT RIVER

To reveal the characteristics of organic phosphorus release from lake sediments and its potential impact on water quality, six lake sediments from Yunnan Plateau and the middle and lower reaches of the Yangtze River in China were selected. We studied the differences in the kinetics of dissolved organic phosphorus (DOP) and dissolved inorganic phosphorus (SRP) release from sediments. The effects of organic phosphorus morphology and dissolved organic matter (DOM) characteristics on sediment phosphorus release were investigated, and the water quality risks of sediment DOP release were discussed. The results showed that:① the release kinetics of sediment DOP and SRP were similar; both followed the second-order kinetic model, starting with a rapid release phase, followed by a slow release, and the release curve gradually leveled off and reached the maximum release. ② The release of organic phosphorus was related to organophosphorus morphology and organic matter. Active organic phosphorus (LOP) and medium active organic phosphorus (MLOP) were the DOP forms mainly released into the overlying water during the rapid release phase. The proportion of LOP and MLOP to total organic phosphorus (DTP) decreased in the late release stage, whereas the proportion of non-active organic phosphorus (NLOP) increased; further, the degree of humification and aromaticity of organic matter gradually increased with phosphorus release, and its activity decreased, resulting in a slower release rate at the later stage. ③ Compared with that of SRP, the risk of DOP release was higher, accounting for 47%-77% of the total amount of DTP. It was also found that the higher the nutrient level of the lake, the greater the release of DOP and the higher the water quality risk. Therefore, not only the release of inorganic phosphorus but also that of organic phosphorus should be of concern in the process of phosphorus release from lake sediments to prevent the underestimation of phosphorus release and water quality risk.

Molecular-weight-dependent mixing behavior of organic phosphorus and carbon in a subtropic river-estuary-bay continuum.

The amount of organic phosphorus (OP) and its distribution among different pools in lake sediments depend on biotic and abiotic processes driving OP fractionation. The key abiotic factors governing these transformation processes between different OP fractions in sediments were studied on the basis of distribution characteristics of OP pools in sediments from Lake Hulun (HLH). The results showed the order of the size of OP pools in the surface sediments from Lake Hulun to be: Re-OP (residual OP) ≫ FAOP (fulvic acid fraction) ≥ HCl-OP (OP extracted by HCl) > HAOP (humic acid fraction) ≫ LOP (labile OP); lower concentrations of LOP were found in lake surface sediments with high pH (pH > 9) of lake overlying water indicating a governing role of pH in LOP degradation in an aquatic environment. The pattern of total OP (TOP) spatial distribution showed an obvious decreasing trend from the west to the east lake districts in surface sediments from HLH, which was attributed to the inputs of dust and dry grass driven by the prevailing wind and the finer grain size in the west lake districts. However, the spatial distribution pattern of dissolved OP (DOP) in overlying water, which presented different trends with TOP and total organic carbon (TOC) in surface sediments, indicated that the biological factors and terrestrial inputs showed a joint influence on DOP distribution in HLH. The higher levels of Re-OP and lower levels of HCl-OP observed in HLH may reveal that calcium ions and their minerals were the key governing factors of OP fractionation in sediments from HLH. This work revealed the main abiotic process or mechanism driving OP fractionation in the aquatic environment helping to understand the geochemical information archived in OP pools in lake sediments.

Excessive phosphorus (P) is considered to be the primary cause for eutrophication in fresh waterbodies and, the increasingly stringent discharge limits have pushed wastewater facilities to achieve extremely low effluent total phosphorus (TP) levels (e.g., 10-50 μg/L). Pushing the P removal to the level of limit of technology has drawn significant attention from both regulatory agencies and wastewater utilities to the removal and bioavailability of various wastewater derived phosphorus fractions such as non-reactive phosphorus (NRP) and dissolved organic phosphorus (DOP). As more advanced treatment processes have been applied to nearly completely eliminate the soluble reactive P (sRP, i.e., ortho-P), these P fractions (NRP and DOP) contribute an increasingly larger percentage and often become the dominant P fractions in the final effluents. For utilities, the concern arises from the substantial capital cost that is required to research and implement more advanced treatment technologies beyond the current practices in order to remove these P fractions. On the regulatory side, current watershed protection plans (e.g., total maximum daily loads (TMDLs)) use TP for setting limits without considering the possibility that those different P fractions may differ in their bioavailability and therefore their potential to cause eutrophication. Bioavailable P (BAP) is defined as the sum of immediately available P and the P that can transform into an available form by naturally occurring physical, chemical, and biological processes. Although rarely analyzed in routine monitoring, effluents from municipal treatment plants contain various P forms, all of which may have different availabilities to algae and other primary producers. In addition, the bioavailability of different P fraction depends on the different sources of wastewater as well as the method and incubation length of the bioassay used. Currently, little information is available about the bioavailability of various P fractions in various wastewater effluents. Particularly, there is limited information on the bioavailability of wastewater derived DOP to eutrophying phytoplankton in receiving waters. Therefore, it is critical to further identify DOP components and their bioavailability. This study investigated and assessed: • The bioavailability of various P fractions, particularly dissolved P fractions (DOP), in advanced wastewater effluents. • The nature and composition of effluent DOP and its association with effluent dissolved organic nitrogen (DON). • The link and correlation of wastewater characteristics and treatment process with bioavailable effluent DOP. Tertiary effluents from the selected representative wastewater treatment plants were collected and subjected to a detailed and comprehensive analysis for wastewater characterization, phosphorus fractions analysis, and bioavailability assays. Standard methods were employed for the phosphorus fractionation and speciation analysis. Wastewater effluent fingerprinting was performed using fluorescence spectrum and parallel factor (PARAFAC) analysis to gain insights into the nature and characteristics of the effluent organic nitrogen and phosphorus. The bioavailability of P fractions in effluents were assessed using both chemical enzymatic assays and algal bioassays. For selected effluents, simultaneous DOP and DON bioavailability assays were performed to elucidate the differential availability of wastewater effluent-derived organic nitrogen and phosphorus and their association with hydrophilic versus hydrophobic fractions. The results provided: • Information on the bioavailability of different P fractions, particularly the dissolved P fractions, in effluents from a range of advanced treatment processes/technologies. • Revealed the nature of dissolved organic phosphorus in highly treated wastewater effluents via fluorescence spectrum analysis and C/N and C/P ratio evaluations. • Elucidated the correlation between bioavailable effluent DOP and DON with different water fractions (hydrophilic versus hydrophobic), as well as with wastewater sources (humic substances versus proteinaceous matters). • Identified the potentially bioavailable P fractions in effluent and suggested possible mechanisms for their effective removal. This title belongs to WERF Research Report Series ISBN: 9781780405568 (eBook)

© The Author(s), 2013. This article is distributed under the terms of the Creative Commons Attribution License. The definitive version was published in Frontiers in Microbiology 4 (2013): 105, doi:10.3389/fmicb.2013.00105.

The critical role of Dissolved Organic Phosphorus (DOP) in supporting primary production has spurred efforts to characterize DOP composition so that insight may be gained into its bioavailability and cycling in aquatic systems. The degree to which DOP is bioavailable to primary producers will determine, in part, the extent of carbon uptake and sequestration.  Ascertaining DOP composition has proven to be an analytically challenging endeavor.  As a consequence, the DOP pool remains poorly characterized, and our predictive power relative to DOP-bioavailability, and coupled carbon cycling, remains limited. Analytical impediments to characterizing DOP composition in natural waters include its low concentration, requiring pre-concentration before compositional features can be probed via spectroscopy, and the fact that organic phosphorus compounds are not easily amenable to standard organic geochemical approaches, such as chromatographic or mass spectrophotometric methods, particularly in salt water. While 31-Phosphorus Nuclear Magnetic Resonance (31P-NMR) spectroscopy has provided intriguing information on the distribution of the 2 major DOP compound types (phosphoesters, phosphonates), the crucial question of DOP bioavailability cannot be addressed by this method. We present novel DOP molecular weight distribution and bioavailability data, generated using a coupled sequential ultrafiltration-bioavailability approach from a marine water column depth profile and locations across a gradient in phosphate concentration in the Atlantic and Pacific Oceans.  There is substantial compositional variability in the marine DOP pool, both in the pattern of DOP molecular weight distribution at different sites, as well as the distribution of bioavailable mono- and diesters of phosphate across molecular weight fractions.  In some cases, a substantial fraction of DOP in different molecular weight size classes is non-reactive to the two enzymes used to assay potential bioavailability, raising the interesting possibility of non-bioavailable DOP. The significance of recognizing that the oceanic DOP pool is compositionally heterogeneous, and variably bioavailable, lies in that fact that such information is a prerequisite to building ecosystem models that capture the influence of P biogeochemistry on primary production and carbon cycling in aquatic systems.

Effect of organic matter on the sorption of dissolved organic and inorganic phosphorus in lake sediments

Integrating random forest and isotopic tracers to optimize PMF-based source apportionment of watershed pollution.

The variability in phosphorus concentrations and the decomposition rates of organic phosphorus were measured in five selected rivers through four surveys in July and November of 2012, and February and May of 2013. After collection the water samples were incubated for 20 days in a dark incubator and the change of forms of phosphorus such as particulate organic phosphorus (POP), dissolved organic phosphorus (DOP) and dissolved inorganic phosphorus (DIP) were analyzed. By fitting the changes to two types of models, the decomposition rates of organic phosphorus were determined. The mean total organic phosphorus (TOP) decomposition rate coefficients in the studied rivers was 0.039 day-1. The average POP decomposition rate coefficient (POP?DOP?DIP model) was 0.038 day-1 while the mean DOP decomposition rate coefficient was 0.251 day-1. The decomposition rate coefficients measured in this study might be applicable for modeling of river water quality.Int. J. Agril. Res. Innov. & Tech. 5 (2): 31-36, December, 2015

A substantial part of the total phosphorus (P) in soil solution and leachates can be present as dissolved organic phosphorus (DOP). The DOP may be more mobile than inorganic orthophosphate and thus it can be an important P source for surface water eutrophication. This paper describes a series of four experiments that investigated the effects of animal waste application to sandy soil on DOP leaching. The first experiment examined the effect of storing pig slurry on DOP fractionation, using gel permeation chromatography. Experiment two and three examined the immediate and long‐term effects of animal waste application to soil in laboratory columns and outdoor maize‐grown lysimeters, respectively. In the fourth experiment concentrations of DOP and total P (TP) in soil solutions at various depths were determined in a long‐term field experiment. Results indicate that DOP in pig slurry is mainly found in high molecular weight (MW) compounds (Exp. 1). From the soil column more than 90%, and from the lysimeters more than 70% of TP leached as DOP (Exp. 2 and 3). In the lysimeter experiment (Exp. 3), leaching of TP mainly occurred in periods of low Cl and NO3 concentrations, induced by high leaching rates. This may indicate that P transport in these periods was mediated by DOC or other colloidal particles. The field experiment (Exp. 4), showed that DOP as a percentage of TP in the soil solution increased from about 10% in the topsoil to more than 70% at 70 to 80 cm depth, which was mainly due to a decrease in MRP. Thus, DOP is an important form of P in leachates and in soil solutions in the subsoil, and characterization of this DOP can improve our understanding of P leaching from soils.

Despite the significant role that dissolved organic phosphorus (DOP) plays in ecosystem productivity, efforts to characterize inputs of phosphorus (P) into lakes have largely ignored P fractions complexed to dissolved organic matter (DOM). To address this gap, we characterized DOP and DOM along a transect of a Lake Erie tributary (Kettle Creek) from the headwaters to the rivermouth and into the nearshore and offshore central basin. DOM and DOP characteristics impart a chemical fingerprint that is useful for determining source and production in aquatic ecosystems. We analyzed DOM composition and concentration (DOC; organic carbon) in addition to DOP as phosphomonoesters (MP; predominantly terrestrial in origin) and phosphodiesters (DP; microbially‐produced), along with other water quality parameters. DOM and DOC within the river were relatively invariant. While there were no consistent trends in riverine MP and DP, an impoundment on the river appeared to act as a sink for some soluble P forms and a potential source of DP. At the rivermouth, we observed a rapid decrease in DOC, DOP, and total P and a shift to more autochthonous‐like DOM, though the decrease in DP was weaker. Relative to in‐flowing river water, P pools in nearshore and offshore Lake Erie were enriched in DOP, especially DP. DOP accounted for up to 42% of total P in Kettle Creek and up to 92% in Lake Erie's central basin. Our work shows the importance of considering DOP in P management efforts as its dynamics differ from those of other, more commonly measured P forms.

To establish the influence of dissolved organic phosphorus (DOP) from different sources on the water quality of Erhai Lake in August 2014, enzymatic hydrolysis technology was used to characterize enzymatically hydrolyzable phosphorus (EHP). The results indicate that the DOP represents a significant source of the bioavailable P in the lake water and its different sources of Erhai Lake, and the bioavailability of the P pool may be underestimated by up to 55% if DOP is ignored and only the soluble-reactive phosphorus (SRP) is considered. The significant differences in DOP characteristics from the different sources may be related to the origin of the DOP, regional pollution, and environmental factors. The DOP from the sediment porewater can act as an important source of DOP in the lake water based on its high DOP content and high DOP loads from the sediment release. In addition, the highest EHP loads from the sediment release can threaten the water quality of Erhai Lake and sustain the algal blooms when they occur. Therefore, for the protection of Erhai Lake, the contributions of not only the SRP but also the DOP to the bioavailable P pool should be considered, emphasizing the eutrophication risk caused by DOP from sediments, especially in the middle section of Erhai Lake. The effects of DOP from the inflowing rivers on the water quality should also not be ignored, due to its high bioavailability.

Dissolved organic carbon, nitrogen and phosphorus in the N-E Atlantic and the N-W Mediterranean with particular reference to non-refractory fractions and degradation

Langat River in Malaysia is an important river with active development on its basin. Excess nutrients such as organic phosphorus introduced through these developments can change the trophic level of the river and by using simple and cost-effective methods, preliminary information on the status of organic phosphorus can aid in the understanding of the complex biogeochemical cycling of phosphorus in rivers. Water and sediment samples were collected from 10 points along the river. The proportion of organic phosphorus was quantified based on the fractions through sequential fractionation. The results indicate that the downstream section of the river has a high percentage of organic phosphorus (48.22%) compared to the upstream and midstream combined. The major fraction in all sites was the non-labile fraction comprising of 60–78% of the total organic phosphorus extracted. Humic acid derived from organic matter either autochthonous or allochthonous sorb organic phosphorus into the sediments and stays internal loading in the river. Moderately labile fulvic acid-bound organic phosphorus has lesser contribution in the sediments but may play an important role in increasing the dissolved phosphorus levels in the waters. Labile forms also contribute lesser in the sediments except when the river is closest to the sea due to higher sedimentation rate facilitated by tidal action. Organic phosphorus in the sediments of Langat River currently may not pose an immediate threat but presents a future risk to the ecosystem considering the river status in accumulating organic phosphorus.

The majority of C, N and P in boreal lakes are in organic form. Organically bound nutrients are released through biodegradation or photodegradation which affects the water quality, eutrophication and greenhouse gas emissions of lakes. We tested whether open land-use data combined with land-use-specific export coefficients can be used to predict total organic carbon (TOC), dissolved organic nitrogen (DON) and dissolved organic phosphorus (DOP) loading and lake water concentrations. Using data from 12 lake catchments in eastern Finland, we found that land use and management of the catchment explained a substantial proportion of the variations in TOC (r 2=0.78), DON (r 2=0.55) and DOP (r 2=0.80) concentrations between lakes. The computation does not account for in-lake processes, which are reflected as mismatch between the predicted and observed concentrations. However, this simple practical approach is useful in ranking lakes according to their water quality. The results indicated that natural sources dominate TOC, DON and DOP exports; the background leachings accounted for 57-99%, 48-96% and 55-99% of TOC, DON and DOP export, respectively. The proposed method has promise as a practical decision support tool for assessing the impacts of land use on water quality. The results showed that possibilities to control TOC, DON and DOP loading to surface waters are limited to catchments where the peatland proportion is low and anthropogenic sources significant.