Water Total Phosphorus Research Articles

High sensitivity flow-based analysis system using a semiconductor laser and thin long flow-through cell for the determination of total phosphorus in water

A highly sensitive detection system using a semiconductor laser (SCL) and a thin long flow-through cell (TLFCT) to match flow-based analysis, such as flow injection analysis (FIA), has been developed. The SCL was a GaAlAs semiconductor laser emitting at 780 nm (5 mW), and the TLFTC, which has a 100 mm thin long light path, was made of a poly(tetrafluoroethylene) (PTFE) rod. The sensitivity was essentially improved about 10-fold in comparison to usual FIA-spectrophotometry using a 10 mm conventional flow cell. When this detection system was applied to the determination of total phosphorus (P) in water by molybdenum-blue spectrophotometry, the relative standard deviation, detection limit and linear range were 1.0% ( n = 10 at 20 μg P 1 −1), 0.6 (3 σ) and 1.0–50 μg P 1 −1, respectively, and the results for the samples were fairly consistent with those by the official method. It may also be possible to apply the present detection system to other flow-based analytical methods such as the liquid chromatography family.

Highly Sensitive Detection System Composed of a Thin, Long, Flow-Through Cell and a Semiconductor Laser for FIA Spectrophotometry and its Application to the Determination of Total Phosphorus in Water

A highly sensitive detection system, which was composed of a thin, long, flow-through cell (TLFTC) and a semiconductor laser (SCL), for flow injection analysis (FIA) spectrophotometry has been developed. The new detection system was mainly composed of a thin, long, light path (100 mm x 1.4 mm i.d.), which was made of a polytetrafluoroethylene rod as an absorption cell, along with a GaAlAs semiconductor laser emitting at 780 nm (5 mW) as a light source. With the use of the detection system, the detection sensitivity was improved by about 10 times in comparison to FIA spectrophotometry with a normal flow cell. The detection system can be useful for determinations of many trace components in samples. The determination of total phosphorus in water, with the use of molybdenum-blue photometry, was one of its applications, and the relative standard deviation, detection limit (3σ), and linear range were 1.0%, 0.6, and 1.0–50 μg P/L, respectively. The determined results for the total phosphorus in the water samples by this method were almost coincident with those obtained by the official method. The detection system may also be useful for other flow-based analytical techniques such as liquid chromatography.

Quantifying Relationships between Near-Infrared Reflectance Spectra of Lake Sediments and Water Chemistry

One of the most useful approaches to long-term monitoring of aquatic systems is the analysis of lake sediments. Biological indicators, such as diatoms, preserved in the sediments are widely used. We suggest that use of near-infrared reflectance (NIR) spectroscopy of lake sediments could become a rapid and cost-effective technique for environmental monitoring to follow long-term changes in water quality. NIR spectra of surface sediments from Swedish lakes were used to establish relationships between sediment properties and measured lake water chemistry. Predictive models for inferring total phosphorus (TP), pH, and total organic carbon (TOC) from sediment NIR data were developed using partial least squares regression. The model for inferring lake water TP (n = 33 lakes) captured 83% of the variance, while the explained variance for pH (n = 52 lakes) and TOC (n = 25 lakes) was 85 and 68%, respectively. We also used the TP model to evaluate the effect of inaccuracy in measured lake water chemistry for the model performance, i.e., the amount of explained variance. The inaccuracy in measured lake water chemistry corresponds to 10.5% of the total variance in the model. The highest possible variance to model then being 89.5%. This evaluation indicated that the obtained modeled variance almost equaled the variance possible to model, which suggests that further improvement of the models should be focused on enlargement of the calibration data set to include more lake types.

Determination of total phosphorus in waters and wastewaters by on-line UV/thermal induced digestion and flow injection analysis

An on-line flow-injection system for the determination of total phosphorus in waters and wastewaters is described. Digestion was performed using a UV photoreactor and a thermal digestion unit connected in series. The orthophosphate formed was detected as phosphomolybdenum blue after on-line filtration. Reagent and digestion conditions required to give optimal oxidation and hydrolysis of organic and condensed model compounds are reported. The flow-injection method gave complete recovery for all the model organic P compounds tested, and >85% recovery for condensed phosphates. When the proposed method was applied to a series of wastewater samples, the results obtained were in close agreement with those from a conventional batch digestion method. The technique was rapid (8 samples h −1 4 replicates), with a linear range of interest for wastewaters 0–18 mgPl −1 and a detection limit of 0.15 mgPl −1.

Phosphorus and Metal Contaminant Transport in Two Southern Ontario Rivers: the Grand River and its Tributary, the Nith River

Abstract Water samples and suspended sediments from two southern Ontario rivers, the Grand River and its tributary, the Nith River, were analyzed to investigate the role of suspended sediments in the transport of phosphorus and metals from tributaries. Water samples were analyzed for total suspended solids, total phosphorus, total dissolved phosphorus, chloride and heavy metal concentrations. Suspended sediments were analyzed for forms of phosphorus, total and organic carbon, and heavy metals. Concentrations of total phosphorus and heavy metals in water were elevated during high flows (spring snowmelt and episodes of intensive rain events), which are characterized by high concentrations of suspended solids. On average, about half of the total phosphorus in the water (60 and 54% in the Grand and Nith rivers, respectively) was transported in the particulate form, of which about 20% is in a form that would be potentially available for biological utilization upon depletion of soluble P. Biologically inert apatite-P accounted for 25 and 19% of the total particulate P in suspended sediments from the Grand and Nith rivers, respectively, indicating that between one-fifth and one-quarter of the tributary particulate P flux is of little environmental significance. This form of particulate P showed positive correlation with discharge, indicating increased contribution of this form of P during high flows due to the channel scouring and bank erosion. This finding has important implications for the refinement of P load calculations, since it is during the wet years that P loads to the Great Lakes exceed target loads stipulated by the Great Lakes Water Quality Agreement, mainly because of increased tributary P contributions. Except for apatite-P in suspended sediments from the Grand River, no statistically significant intersite differences were found in water and sediment chemistry, suggesting that there are no important sources or sinks of available phosphorus and metals between the monitored sites. River inputs from sewage treatment plants and urban runoff appear to have little effect on water quality. The lack of significant site differentiation in suspended sediments chemistry also reflects the absence of any significant chemical and/or biological processing of particles in transit and the similarity of sediment sources.

Strategy for Phosphorus Control from Estimated Phosphorus Loads and Predicted Total Phosphorus Concentration in Penetang Bay, Georgian Bay, 1973 to 1992

Abstract Cultural eutrophication has affected Penetang Bay, in southeastern Georgian Bay, since the 1960s. External sources of phosphorus were estimated and open water total phosphorus concentration was predicted in order to establish a rationale for an effective source control strategy for the bay. Seasonal loadings are greatest in the spring due mainly to the watershed sources, with 33-58% of the total annual load entering during the March to May period. Apart from this period, the two sewage plant effluent discharges are the largest sources of phosphorus loading to the bay. On an annual basis, the largest source of phosphorus to the bay is from treated sewage effluent (60%), followed by watershed, shoreline development and urban storm water, respectively. More than 80% of the estimated total annual loads was from sewage effluent, watershed and urban storm sources alone. These sources were estimated annually for the historical period of record (1973-1992). The trophic model predicted the long-term average total phosphorus concentration ([TP]) reasonably well. Predictions of [TP]Bay for individual years were within 1-49% of the measured [TP]Bay. The model predicted [TP]Bay to within 20% of measured values for 14 of the 20 years of record. The model as applied to Penetang Bay is sensitive to changes in sewage plant effluent loading and watershed loading. Model predictions indicate that significant reductions in open water [TP] can be expected following implementation of proposed source control actions. Total loading of phosphorus to the Bay of less than 1,000 kg/year should result in open water [TP]Bay of less than 15 µg/L.

Relationships between Size Structure of Invertebrate Assemblages and Trophy and Substrate Composition in Streams

Nine stream sites, spanning the range of water total phosphorus concentrations ([TP]) found in Eastern Ontario and Western Québec, were sampled in June 1992 to describe how the size distribution of invertebrates varied along a nutrient gradient and among substrate categories ranging from sand to small boulders. Despite clear differences in the taxonomic composition among sites, the shape of the size distribution was remarkably similar in all sites. Substrate composition affected the overall abundance of invertebrates more than their size distribution. Overall density peaked on fine and coarse gravel and was lower on sand and boulders. Total abundance of invertebrates was highest in eutrophic sites ([TP] > 40 μg/L), although only organisms larger than 1 mm (approximately 1 μg dry mass) showed higher abundances in richer sites. The increase in total invertebrate abundance with increasing total phosphorus concentration suggests that these streams are phosphorus limited. Animals smaller than 1 mm long account for less than 3% of the respiration of the benthic assemblage on all substrates in our streams. Size distribution of invertebrates, although affected by substrate composition and trophy, is remarkably constant and predictable in our streams. Most of the biomass, and consequently the consumption, respiration, and secondary production, is found in relatively large invertebrates. Meiofauna is relatively rare and consequently has little direct influence on community metabolism in the streams we studied.

Chemistry of Sediment Pore Water in Aquaculture Ponds Built on Clayey Ultisols at Auburn, Alabama

AbstractThe composition of sediment pore water was determined for ponds constructed on clayey Ultisols at Auburn, Alabama. Pore water was anaerobic and contained much higher concentrations of ferrous iron (Fe2+), soluble reactive phosphorus (SRP), total phosphorus (TP), total ammonia‐nitrogen (TAN), and sulfide (S2−) than surface or bottom waters. Concentrations of SRP and TP in pore water were higher in ponds with high soil phosphorus concentrations than in a new pond with less soil phosphorus. Increased concentrations of organic matter in soil or larger inputs of feed to ponds favored greater microbial activity in soils and higher concentrations of TAN in pore water. The pH of pore water was 6.5–7.0, and pH was apparently controlled by the equilibrium: image Movement of Fe2+, SRP, and S2− from pore water into pond water apparently was prevented by the oxidized layer of soil just below the soil‐water interface. Pond managers should concentrate on maintaining this oxidized layer to reduce the tendency for toxic substances to diffuse into the pond water.

Determination of total phosphorus in waters and wastewaters by on-line microwave-induced digestion and flow-injection analysis

An on-line flow-injection system for the determination of total phosphorus in waters and wastewaters is described. Digestion was performed using a flow-through reactor in a modified domestic microwave oven, and the orthophosphate formed was detected as phosphomolybdenum blue after on-line filtration. The modifications and operation of the microwave complied with Australian Standards. Reagent and digestion conditions required to give optimal oxidation and hydrolysis of organic and condensed model species are reported. The flow-injection method gave complete recovery for almost all the model P compounds tested, with the exception of condensed phosphates. When the proposed method was applied to a series of wastewater samples, the results obtained were in close agreement with those from a conventional batch digestion method. The technique was rapid (7 samples h −1, 4 replicates), with a linear range of interest for wastewaters 0–18 mg P 1 −1, and a detection limit of 0.09 mg P 1 −1.

Semi-Micro Determination of Total Phosphorus in Fresh Waters with Perchloric Acid Digestion

Abstract A simple test-tube semi-micro method for the determination of total phosphorus in water is described. Samples are evaporated with perchloric acid at 115 °C overnight, digested at 170 °C for 40 minutes, diluted, hydrolyzed at 100 °C for 1 hour in order to decompose pyrophosphate and the liberated orthophosphate is determined without further neutralization and transfer steps by the phosphomolybdate blue method of Murphy and Riley (1962). The method can be applied directly to samples with phosphorus concentrations ranging from 4 to 1000 μg.1−1. Comparability with the classic perchloric acid and sulphuric acid—persulphate digestion methods has been demonstrated using a wide range of fresh waters.

Dynamics of a Black Crappie Population in a Heterogeneous Cooling Reservoir

Abstract Spatial and annual variation in density, growth, and size structure of black crappies Pomoxis nigromaculatus in Lake Wylie, North Carolina-South Carolina, were determined during a 5-year study. Water temperature, turbidity, total phosphorus, and nitrate+nitrite-nitrogen in Lake Wylie varied across zones and years. Significant (P < 0.0001) year or year-class × zone interactions were detected in catch rates, first-year growth, and second-year growth. Significant (P ≤ 0.0002) spatial and year-class effects on first-, second-, and third-year growth were also observed. Black crappies were attracted to the heated effluent of a power plant. First-year growth was correlated (r = 0.55; P < 0.05) with average water temperature during the growing season (April through October). Second- and third-year growth were among the fastest reported in the literature. Second-year growth was faster in areas with higher densities of threadfin shad Dorosoma petenense, which appeared to concentrate in the more nutrient-ri...

Determination of total phosphorus in waters with amperometric detection by coupling of flow-injection analysis with continuous microwave oven digestion

For the determination of total phosphorus in waters by flow-injection analysis, a continuous microwave oven decomposition with subsequent amperometric detection of orthophosphate is proposed. The percentage digestion was examined for two different decomposition reagents and by varying the pH of the carrier and the length and diameter of the digestion coil. With potassium peroxodisulphate decomposition the recoveries of phosphorus vary from 91 to 100% for organic phosphorus compounds, and with perchloric acid decomposition the recoveries vary from 60 to 70% for inorganic polyphosphates. Calibration graphs are linear for up to 30 mg P l −1, the determination limit is 0.1 mg P l −1 and the precision of the method is 3% (relative standard deviation) ( n = 5) at 5 mg P l −1. The sampling rate is 20 h −1. Good recoveries of phosphorus after addition to domestic waste water sample are obtained.

Approximate Dynamic Lake Phosphorus Budget Models

Impoundments or natural lakes having short hydraulic detention times may become eutrophic through anthropogenic nutrient loading episodes. Subsequent lake recovery may be influenced by nutrient transport from the lake bottom to the water column. Order‐of‐magnitude analysis is used to derive simple mathematical models of eutrophic lake recovery. Total phosphorus concentration (P) is used as an indicator of lake water quality. Sedimentation of particulate P from the water column and cycling from lake sediments control the rate of change of lake water P in response to a step change in external P loading. The rate of P desorption from the solid phase is more important than film transport rates across the lake bottom/water column boundary. Comparisons between exact and approximate longterm predictions of lake water total phosphorus concentration generally differ by less than 0.2%. The approximate models are convenient because they are more compact in form and appear to behave similarly to an exact analytical solution to the lake model.

Variations of total phosphorus and nitrogen levels in rain water.

We have previously proposed an atomic absorption spectrophotometric method for determination of total phosphorus in water. In this paper, the proposed method was applied to the rain water collected for a year (July 1984-June 1985) from three different locations : Kobe, Amagasaki and Miki. The concentrations of total nitrogen in the water samples were also determined by a conventional method as described in the Official Gazette. Kobe, Amagasaki and Miki, situated in the southern part of Hyogo prefecture in Japan, were chosen as representatives of residential, industrial and agricultural areas, respectively. The water samples from Miki contained significantly higher concentrations of total phosphorus than those from Kobe and Amagasaki, this might be due to fertilizer used in the agricultural area. In contrast, the concentrations of total nitrogen in the samples from Amagasaki were significantly higher than those from the other two locations, which suggested that the nitrogen in rain water might be derived from air pollution with nitrogen oxides owing to motor vehicles and factories in the industrial area.

Isoetid-zoobenthos associations in acid-sensitive lakes in Ontario, Canada

The macrophyte and associated epiphytic invertebrate community were quantitatively sampled within the littoral zones of 18 oligotrophic lakes in south-central Ontario. Densities for 7 of 10 benthic taxa were significantly greater within Eriocaulon septangulare With. dominated mats compared with clusters of Lobelia dortmanna L. overlying sand beach. The microdistribution and abundance of amphipods was dependent on, and significantly correlated with, isoetid biomass. The depth distribution of littoral invertebrates was also closely associated with the attenuation of macrophyte biomass. Estimates of mean annual biomass ranged from 91.5 to 475.3 g dry wt m −2 for Eriocaulon, and from 44.9 to 192.1 g dry wt m −2 for Lobelia. Biomass showed no trend in relation to lake pH within the range 5.6–6.7, nor to total phosphorus in water from 5 to 14 mg m −3. The previously-documented decrease in abundance of several littoral zoobenthic species in conjunction with lowered pH in Haliburton-Muskoka, Ontario lakes, seems explainable by direct H + toxicity in support of laboratory work, rather than through any secondary effect ascribed to disappearance of habitable substrate.

Improved Estimation of the Dry Weight of Holopedium gibberum (Crustacea, Cladocera) Using Clutch Size, a Body Fat Index, and Lake Water Total Phosphorus Concentration

Holopedium gibberum is one of the most important species of crustacean zooplankton in Canadian Shield lakes, yet satisfactory length–weight relationships (LWR's) have not been constructed from North American populations. In this report we show that, despite assertions to the contrary, weights of individual H. gibberum can be successfully predicted from body length (L) of animals measured in a nonanaesthetized, relaxed position. We use a relationship between postabdomen length and L to show that LWR's of Ontario and Scandinavian populations of H. gibberum differ. As such differences among lakes are the rule and not the exception, it is not safe to assume that published LWR's for zooplankton are widely applicable. Consideration of clutch size (CS) and a body fat index (BFI) in addition to L significantly improved estimates of the dry weight of Holopedium from Plastic Lake in central Ontario. This model provided more accurate estimates of Holopedium dry weight in 29 test lakes than the simple LWR, i.e. it had wider applicability. Predicted weights in the test lakes were further improved by consideration of lake water total phosphorus concentrations.

Determination of total phosphorus in water by photochemical decomposition with ultraviolet irradiation

A simple and convenient photochemical decomposition method has been developed for the determination of total phosphorus in natural and sewage water. Organic phosphorus compounds and inorganic polyphosphates may be completely converted into orthophosphate in the presence of 0.3 M sulphuric acid and 0.12% potassium persulphate with 50 min irradiation. The relative standard deviations found for analysis of natural water (P 35 μ g l .) and sewage (P 2.4 mg l .) were 5.7% and 1.0% respectively. The method gives results comparable to those obtained by digestion with persulphate.

Atomic Absorption Spectrophotometric Determination of Total Phosphorus in Water and Its Application to Rain Water (Proceedings of the 12 th Symposium on Environmental Pollutants and Toxicology) (Regular Presentations)

Atomic Absorption Spectrophotometric Determination of Total Phosphorus in Water and Its Application to Rain Water (Proceedings of the 12 th Symposium on Environmental Pollutants and Toxicology) (Regular Presentations)

Heating effects on sample decomposition by peroxodisulfate for determination of total phosphorus in water.

水中の全リンの定量のためのペルオキソ二硫酸カリウムによる試料の分解に際する加熱の効果を,アデノシン二リン酸,レシチン及びトリポリリン酸塩を試料に用いて検討考察し,効果的な加熱方法を推定した.試料の分解は100～120℃で急速に進む.硫酸が存在すると,アデノシン二リン酸の分解は容易となるが,ペルオキソ二硫酸カリウムの自己分解が著しくなるためレシチンの分解は困難になる.又トリポリリン酸塩の加水分解は,ペルオキソ二硫酸カリウムの自己分解で生じる酸の存在で十分に進む.効果的な試料の分解としては,ペルオキソ二硫酸カリウムだけの添加で,なるべく速やかに120℃の高温に加熱する方法が優れていると考えられる.

The Spectrophotometric Determination of Phosphorus with o-Hydroxyhydroquinonephthalein and Iron(III)

Abstract On this basis of the coloration formed with o-hydroxyhydroquinonephthalein, an anionic dye, and iron(III) in aqueous media, trace amounts of phosphorus(as orthophosphate ion) was determined. A sample solution containing posphorus and the reagent blank in an amber-colored test tube with a stopper were heated at 40 °C for 20 min in the presence of poly(oxyethylene)sorbitan monolaurate, a nonionic surfactant, as a dispersion agent. Beer’s law was obeyed over the range of ≈1 μg/10 cm3 of phosphorus, and the apparent molar absorptivity of the complex was 2.5×105 dm3 mol−1 cm−1 at 610 nm. The present method was applied to the determination of total phosphorus in water — a sample solution containing small amounts of metal ions —, and the recovery percentage was satisfactory, about 95%. Other compounds containing phosphorus such as 5′-adenosine triphosphate could also be determined without a preliminary treatment.