Water Total Organic Carbon Research Articles

Comparison of extraction efficiencies for water-transportable phenols from different land uses

The composition and quantification of vascular plant-derived phenols in dissolved organic matter (DOM) is of importance in understanding and estimating carbon flux from soils under different land uses. Solid phase extraction (SPE) was used to extract waterborne organic matter (WBM), and thermally assisted hydrolysis (THM) using tetramethylammonium hydroxide (TMAH) was compared with gas chromatography-flame ionization detection (GC-FID) for the quantification of oxygenated aromatics in WBM, from freshwater samples from grazed grassland, woodland and moorland land uses in southwest England, UK.WBM recovered with SPE correlated with water total organic carbon (TOC) content. SPE followed by THM was shown to be the approach for isolating and quantifying water-transportable phenols. All the different land uses exported similar amounts of lignin per unit weight of OC to the drainage water. We also conclude that a significant proportion of lignin phenols is lost from soils as a component of WBM in a particulate form, so the magnitude of total phenol loss is likely greater than previously thought.

Sorption of Highly Hydrophobic Organic Chemicals to Organic Matter Relevant for Fish Bioconcentration Studies.

With regard to a potential underestimation of bioconcentration factors (BCF) in flow-through fish tests, sorption of 11 highly hydrophobic organic chemicals (HOCs) (log KOW 5.5-7.8) from different substance classes was systematically investigated for the first time in the presence of fish feed (FF) and filter residues (FR), the organic matter (OM) most relevant for fish bioconcentration studies. Sorption was investigated in batch-equilibrium experiments by solid-phase microextraction (SPME) resulting in partitioning coefficients of solid-water (Kd), total organic carbon-water (KTOC), and dissolved organic carbon-water (KDOC). Results prove a high affinity of HOCs for FF and FR supporting a significant impact on BCF studies and differing from sorption to Aldrich-humic acid (AHA) utilized as reference sorbent. Sorption is influenced by interactions between HOCs and OM characteristics. For FF, KDOC values were higher than KTOC values. Results help to assess the relevance of interaction of HOCs from different substance classes with OM relevant for BCF studies.

Seismic peak amplitude as a predictor of TOC content in shallow marine sediments

Acoustic remote sensing is a highly effective tool for exploring the seafloor of both deep and shallow marine settings. Indeed, the acoustic response depends on several physicochemical factors such as sediment grain size, bulk density, water content, and mineralogy. The objective of the present study is to assess the suitability of seismic peak amplitude as a predictor of total organic carbon (TOC) content in shallow marine sediments, based on data collected in the Cabo Frio mud belt in an upwelling zone off southeastern Brazil. These comprise records of P-wave velocity (V P) along 680 km of high-resolution single-channel seismic surveys, combined with analyses of grain size, wet bulk density, absolute water content and TOC content for four piston-cores. TOC contents of sediments from 13 box-cores served to validate the methodology. The results show well-defined positive correlations between TOC content and mean grain size (phi scale) as well as absolute water content, and negative correlations with V P, wet bulk density, and acoustic impedance. These relationships yield a regression equation by which TOC content can be satisfactorily predicted on the basis of acoustic impedance for this region: y = − 4.84 ln(x) + 40.04. Indeed, the derived TOC contents differ by only 5% from those determined by geochemical analysis. After appropriate calibration, acoustic impedance can thus be conveniently used as a predictor of large-scale spatial distributions of organic carbon enrichment in marine sediments. This not only contributes to optimizing scientific project objectives, but also enhances the cost-effectiveness of marine surveys by greatly reducing the ship time commonly required for grid sampling.

Modeling Source Water TOC Using Hydroclimate Variables and Local Polynomial Regression.

To control disinfection byproduct (DBP) formation in drinking water, an understanding of the source water total organic carbon (TOC) concentration variability can be critical. Previously, TOC concentrations in water treatment plant source waters have been modeled using streamflow data. However, the lack of streamflow data or unimpaired flow scenarios makes it difficult to model TOC. In addition, TOC variability under climate change further exacerbates the problem. Here we proposed a modeling approach based on local polynomial regression that uses climate, e.g. temperature, and land surface, e.g., soil moisture, variables as predictors of TOC concentration, obviating the need for streamflow. The local polynomial approach has the ability to capture non-Gaussian and nonlinear features that might be present in the relationships. The utility of the methodology is demonstrated using source water quality and climate data in three case study locations with surface source waters including river and reservoir sources. The models show good predictive skill in general at these locations, with lower skills at locations with the most anthropogenic influences in their streams. Source water TOC predictive models can provide water treatment utilities important information for making treatment decisions for DBP regulation compliance under future climate scenarios.

Impacts of Forest to Urban Land Conversion and ENSO Phase on Water Quality of a Public Water Supply Reservoir

We used coupled watershed and reservoir models to evaluate the impacts of deforestation and l Niño Southern Oscillation (ENSO) phase on drinking water quality. Source water total organic carbon (TOC) is especially important due to the potential for production of carcinogenic disinfection byproducts (DBPs). The Environmental Fluid Dynamics Code (EFDC) reservoir model is used to evaluate the difference between daily pre- and post- urbanization nutrients and TOC concentration. Post-disturbance (future) reservoir total nitrogen (TN), total phosphorus (TP), TOC and chlorophyll-a concentrations were found to be higher than pre-urbanization (base) concentrations (p < 0.05). Predicted future median TOC concentration was 1.1 mg·L−1 (41% higher than base TOC concentration) at the source water intake. Simulations show that prior to urbanization, additional water treatment was necessary on 47% of the days between May and October. However, following simulated urbanization, additional drinking water treatment might be continuously necessary between May and October. One of six ENSO indices is weakly negatively correlated with the measured reservoir TOC indicating there may be higher TOC concentrations in times of lower streamflow (La Niña). There is a positive significant correlation between simulated TN and TP concentrations with ENSO suggesting higher concentrations during El Niño.

Removal of organic matter from drinking water by single and dual media filtration: a comparative pilot study

This pilot-scale research was conducted at Ahvaz water treatment plant to investigate the performance of a dual-media filter with anthracite and silica sand layers for the removal of total organic carbon (TOC) and chemical oxygen demand (COD) as the measuring indices of organic matter in water. In addition, the performance of this dual-media filter was compared with a control single-media filter with a conventional layer. The hydraulic loading rate or water flux during the filtration was in the range of 7–14 m/h. All the experiments were carried out according to the standard methods, and the obtained results were analyzed using statistical tests such as paired-samples t-test. The average concentration of COD and TOC in the input water into the pilot was 7.93 and 2.73 mg/L, respectively. The average efficiency for TOC removal in the single-media and dual-media pilot filters at the loading rate of 7 m/h was 34.10 and 65.59%, respectively, whereas the corresponding values for COD removal in the single-media and dual-media pilot filters were 28.26 and 63.95%, respectively. Furthermore, the mean efficiency for TOC removal in the single-media and dual-media pilots at the loading rate of 14 m/h was 30.25 and 64.56%, respectively. At this loading rate, the corresponding efficiencies for COD removal in the single-media and dual-media pilot filters were 25.51 and 62.23%, respectively. The results of this research showed that the use of anthracite as a layer of dual-media filter increases the efficiency of organic matter removal compared with the single-media filter.

Evaluation of drinking water treatment combined filter backwash water recycling technology based on comet and micronucleus assay

Based on the fact that recycling of combined filter backwash water (CFBW) directly to drinking water treatment plants (WTP) is considered to be a feasible method to enhance pollutant removal efficiency, we were motivated to evaluate the genotoxicity of water samples from two pilot-scale drinking water treatment systems, one with recycling of combined backwash water, the other one with a conventional process. An integrated approach of the comet and micronucleus (MN) assays was used with zebrafish (Danio rerio) to investigate the water genotoxicity in this study. The total organic carbon (TOC), dissolved organic carbon (DOC), and trihalomethane formation potential (THMFP), of the recycling process were lower than that of the conventional process. All the results showed that there was no statistically significant difference (P>0.05) between the conventional and recycling processes, and indicated that the genotoxicity of water samples from the recycling process did not accumulate in 15day continuous recycling trial. It was worth noting that there was correlation between the concentrations of TOC, DOC, UV254, and THMFPs in water and the DNA damage score, with corresponding R2 values of 0.68, 0.63, 0.28, and 0.64. Nevertheless, both DNA strand breaks and MN frequency of all water samples after disinfection were higher than that of water samples from the two treatment units, which meant that the disinfection by-products (DBPs) formed by disinfection could increase the DNA damage. Both the comet and MN tests suggest that the recycling process did not increase the genotoxicity risk, compared to the traditional process.

Effect of water quality and operational parameters on trihalomethanes formation potential in Dez River water, Iran

This study assesses the influence of the total organic carbon (TOC) content, chlorine quantity, water temperature, bromide ion concentration, and seasonal variations on trihalomethanes (THMs) formation potential (THMFP) in Dez River water in Iran. The water temperature and TOC content had a significant effect on THMFP. Further, the experimental results showed that increasing the concentration of bromide ions enhances the formation of dibromochloromethane and bromoform. It was found that the THMFP in Dez River water during summer times was relatively higher than 100µg/L, maximum contaminant level for THMs in drinking water. By increasing the reaction time until 80h, the THMFP was gradually increased and reached to 177.4µg/L. The most abundant fraction of natural organic matter in the river was hydrophobic acid fraction (49.4μg/L). Overall, our study demonstrated that however the THMFP of Dez River water was relatively high but a usual waterworks could effectively reduce THMFP.

Simple models to estimate historical and recent changes of total organic carbon concentrations in lakes.

Quantifying human impacts on the natural environment requires credible reconstructions of reference conditions. Anthropogenic acidification of surface waters is strongly influenced by total organic carbon (TOC) concentrations. Because both the degree of acidification and recovery are dependent on historical TOC concentrations, simple models to estimate changes in surface water TOC between reference conditions (1860) and the present day (2012) are needed. We used visible near infrared spectroscopy (VNIRS) of lake sediments to reconstruct reference condition TOC and long-term monitoring data to predict recent changes. Two empirical models were developed to predict: (i) historical TOC trends between reference conditions (1860) and peak acidification (1980) and (ii) trends in TOC between 1988 and 2012. The models were statistically robust with adj. R(2) of (i) 0.85 and (ii) 0.71, respectively. Models were driven by lake and catchment area, wetlands, historical sulfur deposition and water chemistry. Present day TOC concentrations are similar to VNIRS-reconstructed and modeled reference condition TOC in Swedish lakes. The results are valuable for understanding drivers of TOC changes in lakes and for more credible assessments of reference conditions needed for water management in Europe and elsewhere.

Dynamics of organic carbon losses by water erosion after biocrust removal

Abstract In arid and semiarid ecosystems, plant interspaces are frequently covered by communities of cyanobacteria, algae, lichens and mosses, known as biocrusts. These crusts often act as runoff sources and are involved in soil stabilization and fertility, as they prevent erosion by water and wind, fix atmospheric C and N and contribute large amounts of C to soil. Their contribution to the C balance as photosynthetically active surfaces in arid and semiarid regions is receiving growing attention. However, very few studies have explicitly evaluated their contribution to organic carbon (OC) lost from runoff and erosion, which is necessary to ascertain the role of biocrusts in the ecosystem C balance. Furthermore, biocrusts are not resilient to physical disturbances, which generally cause the loss of the biocrust and thus, an increase in runoff and erosion, dust emissions, and sediment and nutrient losses. The aim of this study was to find out the influence of biocrusts and their removal on dissolved and sediment organic carbon losses. One-hour extreme rainfall simulations (50 mm h-1) were performed on small plots set up on physical soil crusts and three types of biocrusts, representing a development gradient, and also on plots where these crusts were removed from. Runoff and erosion rates, dissolved organic carbon (DOC) and organic carbon bonded to sediments (SdOC) were measured during the simulated rain. Our results showed different SdOC and DOC for the different biocrusts and also that the presence of biocrusts substantially decreased total organic carbon (TOC) (average 1.80±1.86 g m-2) compared to physical soil crusts (7.83±3.27 g m-2). Within biocrusts, TOC losses decreased as biocrusts developed, and erosion rates were lower. Thus, erosion drove TOC losses while no significant direct relationships were found between TOC losses and runoff. In both physical crusts and biocrusts, DOC and SdOC concentrations were higher during the first minutes after runoff began and decreased over time as nutrient-enriched fine particles were washed away by runoff water. Crust removal caused a strong increase in water erosion and TOC losses. The strongest impacts on TOC losses after crust removal occurred on the lichen plots, due to the increased erosion when they were removed. DOC concentration was higher in biocrust-removed soils than in intact biocrusts, probably because OC is more strongly retained by BSC structures, but easily blown away in soils devoid of them. However, SdOC concentration was higher in intact than removed biocrusts associated with greater OC content in the top crust than in the soil once the crust is scraped off. Consequently, the loss of biocrusts leads to OC impoverishment of nutrient-limited interplant spaces in arid and semiarid areas and the reduction of soil OC heterogeneity, essential for vegetation productivity and functioning of this type of ecosystems.

Concentrations and Sources of Polycyclic Aromatic Hydrocarbons in Water and Sediments from the Huaihe River, China

Surface water and sediments were collected from eleven locations on the middle region of Huaihe River to evaluate the environmental effects of urban and industrial activities. The concentrations of sixteen polycyclic aromatic hydrocarbons (PAHs) in water and sediments were between 1.2–5.1 µg/L and 72–139 ng/g, respectively. High levels of PAHs in water were recorded in comparison to those of other countries, while the concentrations in sediments were low to moderate levels. A weak positive correlation was observed (R2 = 0.49, P = 0.13) between PAHs and total organic carbon in water. However, a significant positive correlation (R2 = 0.79, P = 0.004) was found in sediments, which indicated that total organic carbon was a factor in PAH levels in sediments but not in water. The parent ratios were studied by principal component analysis that showed the PAHs from water were predominantly derived from coal combustion (34%), oil spills (49%), and vehicular emissions (17%), while the major PAH sources to sediments were coal combustion. Using the ecological toxic equivalency factor index, it was concluded that the PAHs levels may provide a potential risk in water but not in sediments.

Degradation of estrone in water and wastewater by various advanced oxidation processes

A comprehensive study was conducted to determine the relative efficacy of various advanced oxidation processes such as O3, H2O2, UV, and combinations of UV/O3, UV/H2O2 for the removal of estrone (E1) from pure water and secondary effluent. In addition to the parent compound (E1) removal, performance of the advanced oxidation processes was characterized using removal of total organic carbon (TOC), and estrogenicity of the effluent. Although E1 removal was high for all the AOPs, intermediates formed were more difficult to degrade leading to slow TOC removal. Energy calculations and cost analysis indicated that, although UV processes have low electricity cost, ozonation is the least cost option ($ 0.34/1000 gallons) when both capital and operating costs were taken into account. Ozonation also is superior to the other tested AOPs due to higher removal of TOC and estrogenicity. The rate of E1 removal decreased linearly with the background TOC in water, however, E1 degradation in the secondary effluent from a local wastewater treatment plant was not affected significantly due to the low COD values in the effluent.

Statistical significance testing of parallel pilot-scale coagulation optimization study to compare aluminum sulfate and polyaluminum chloride performance

A 14 month pilot-scale coagulation optimization study was conducted at the Peterborough Water Treatment Plant (Ontario, Canada) to compare treatment performance resulting from the application of aluminum sulfate vs. polyaluminum chloride (PACl). This paper describes results obtained from applying a statistical analysis approach to evaluate impacts on pH, turbidity, total organic carbon (TOC), ultraviolet absorbance (UVA), particle counts, chlorine residuals, filter head loss, flow rate, trihalomethanes (THMs), and nine haloacetic acids (HAA 9 ). To allow a direct comparison, parallel pilot trains were operated such that they achieved equal settled water TOC by adjusting PACl dose, (52–74% of the alum dose by weight). Settled water turbidity was significantly higher (on average 0.23 NTU) in the alum treated water when compared to PACl. For equivalent filter run-times, head loss was greater by 0.002–0.011 m h −1 when applying alum. An increase in pH by approximately 0.7 units when using PACl was observed to cause a significant increase in THM formation (10–30%).

Optimization of treatment process of Bushigan treatment plant in respect of turbidity and total organic carbon reduction

Aims: The aim of the present study was to investigate the optimization of the treatment process of Bushigan water treatment plant (South of Iran) in respect of turbidity and total organic carbon (TOC) removal. Materials and Methods: The water samples were collected from Shapoor river the influent water to Bushigan treatment plant. A conventional jar test apparatus was used to evaluate the coagulation process. Different dosages of poly aluminum chloride (PACl), powdered activated carbon (PAC) and chlorine (Cl 2 ) alone and with each other was used to determine their effects on removal of the turbidity and TOC. Results: The average of TOC and turbidity in raw water were 5.81 mg/L and 29 NTU respectively in all seasons. The study result showed that the removal efficiency of TOC and turbidity were improved with increasing the PACl and PAC dose. With the application of 12 mg/L PACl alone, the maximum TOC and turbidity removal efficiencies were 41% and 31%, respectively. At constant PACl dose, application of PAC as coagulant aid and adsorbent improved the removal efficiency of TOC and turbidity. Conclusion: The results were showed that by common water treatment method (coagulation and precipitation) using PACl as a coagulant and also PAC and Cl 2 as an adsorbent and coagulant aid, the TOC and turbidity of water reduced to below 1 mg/L. So PAC and Cl 2 can improve the coagulation process. This method can be used for water treatment plant with drinking water contain the average TOC less than 6 mg/L.

Comparison of BOD, COD, TOC and DOC as the Indicator of Organic Matter Pollution of Agricultural Surface Water in Gyeongnam Province

This survey was conducted to obtain basic data about organic matter such as BOD (Biochemical Oxygen Demand), COD (Chemical Oxygen Demand), DOC (Dissolved Organic Carbon) and TOC (Total Organic Carbon) in agricultural water in Gyeongnam province. BOD and COD are currently used for water quality indices, but adoption of TOC is being suggested. The surface water samples were collected at 39 locations in Gyeongnam province in April, July and October. Average concentrations of BOD, COD, DOC and TOC were 1.6, 3.3, 5.3 and <TEX>$5.7mg\;L^{-1}$</TEX>, respectively. In July, average concentrations of BOD and COD were 2.4 and <TEX>$3.9mg\;L^{-1}$</TEX>, respectively, showing these values were higher than other months. Average concentrations of TOC in April, July and October were 4.8, 7.4 and <TEX>$4.8mg\;L^{-1}$</TEX>, respectively. This suggested that the highest value of TOC was in July. Average decomposition efficiencies for BOD-C/TOC and COD-C/TOC were 11.4 and 23.9%, respectively. Correlation coefficient of TOC and DOC was higher by 0.995, whereas that of TOC and COD was lower by 0.763. Especially, TOC and DOC were highly related than others.

The potential role of water quality parameters on occurrence of nonylphenol and bisphenol A and identification of their discharge sources in the river ecosystems

Nonylphenol (NP) and bisphenol A (BPA) have attracted great attention due to their estrongenic activities and occurrence in different environments. This study investigated concentrations of NP and BPA in water and sediments of 16 major rivers in Taiwan to determine their association with water quality parameters on their distribution. The sources of NP and BPA discharged into river environments were also identified. The results showed that concentrations of NP and BPA were in the range of 0.02–3.94 and 0.01–44.65μgL−1 in water and 6.59–47797.69 and 0.37–491.54μgkg−1 dry weight in sediments. High levels of NP and BPA in water and sediments were measured in sampling sites near highly industrialized and urbanized areas. Construction of the sewage system and wastewater treatment plant has decreased these chemicals discharged into Love River. Dilution effects and erosion of surface sediments in the high-flow season resulted in lower concentrations of NP and BPA detected in sediments of most rivers than those in the low-flow season. Occurrence characteristics of NP and BPA in water and sediments were mainly related to organic carbon contents in sediments and several water quality parameters such as dissolved oxygen, pH, concentrations of ammonia–nitrogen and total organic carbon in water. Effluents from NP/BPA-related factories appeared to be the major discharge sources of NP and BPA. Use and waste of BPA-containing products in household activity was the another discharge source of BPA, but handling NP-containing products became an important source of NP only in the low-flow season.

Effectiveness of Air Sparging Technology in Remediation of Gaza Coastal Aquifer from Gasoline Products

Groundwater contamination becomes a great concern in many countries. One of the most important pollutants is hydrocarbons. Sources of Hydrocarbons pollutants in Gazacan be a result of accidental spills of petroleum products on the surface and uncontrolled disposal of wastewater. One of the common technologies for groundwater aquifer remediation from hydrocarbons is known as air sparging. In this study, a120 cm×100 cm×80 cmlaboratory scale aquifer model was implemented in order to investigate the effectiveness of air sparging technology in removal of petroleum products from contaminated site. Four pilot scale wells were installed at different depths and different spatial distribution. The central well was used for injecting air and the surrounding three wells were used for monitoring. The contaminated water and soil were tested for total organic carbon, lead, dissolved Oxygen and pH; one time before the start of treatment and four times through the treatment process. Total organic carbon in water and soil before air injection were 980 ppm and 0.08775 ppm, respectively. After air injection for three weeks (six hours daily) at flow rate range from 15 to20 L/min and at pressure range from 300 to 400 kPa, the concentration of pollutant was decreased to 4.0 ppm and 0.0 ppm in water and soil, respectively. Based on the results, it was clearly demonstrated that air sparging is a simple, effective and affordable technology that can be applied forGazaaquifer remediation in case of gasoline spill accidents.

Effect of magnetic ion exchange and ozonation on disinfection by-product formation

The purpose of this research was to investigate the performance of treatment with magnetic ion exchange (MIEX) resin followed by ozonation in achieving disinfection goals while controlling bromate and chlorinated disinfection by-product (DBP) formation. Three water samples were collected from raw water supplies impacted by the San Francisco Bay Delta to represent the varying levels of bromide and total organic carbon (TOC) that occur throughout the year. A fourth water was prepared by spiking bromide into a portion of one of the samples. Samples of each water were pre-treated with alum or virgin MIEX resin, and the raw and treated waters were subsequently ozonated under semi-batch conditions to assess the impact of treatment on ozone demand, ozone exposure for disinfection (“CT”), and bromate formation. Finally, aliquots of raw, coagulated, resin-treated, and ozonated waters were chlorinated in order to measure trihalomethane formation potential (THMFP). In the waters studied, MIEX resin removed 41–68% of raw water TOC, compared to 12–44% for alum. MIEX resin also reduced the bromide concentration by 20–50%. The removal of TOC by alum and MIEX resin significantly reduced the ozone demand of all waters studied, resulting in higher dissolved ozone concentrations and CT values for a given amount of ozone transferred into solution. For a given level of disinfection (CT), the amount of bromate produced by ozonation of MIEX-treated waters was similar to or slightly less than that of raw water and significantly less than that of alum-treated water. MIEX resin removed 39–85% of THMFP compared to 16–56% removal by alum. Ozonation reduced THMFP by 35–45% in all cases. This work indicates that in bromide-rich waters in which ozone disinfection is used, MIEX resin is a more appropriate treatment than alum for the removal of organic carbon, as it achieves superior TOC and THM precursor removal and decreases the production of bromate from ozone.

Riparian zone hydrology and soil water total organic carbon (TOC): implications for spatial variability and upscaling of lateral riparian TOC exports

Abstract. Groundwater flowing from hillslopes through riparian (near-stream) soils often undergoes chemical transformations that can substantially influence stream water chemistry. We used landscape analysis to predict total organic carbon (TOC) concentration profiles and groundwater levels measured in the riparian zone (RZ) of a 67 km2 catchment in Sweden. TOC exported laterally from 13 riparian soil profiles was then estimated based on the riparian flow–concentration integration model (RIM). Much of the observed spatial variability of riparian TOC concentrations in this system could be predicted from groundwater levels and the topographic wetness index (TWI). Organic riparian peat soils in forested areas emerged as hotspots exporting large amounts of TOC. These TOC fluxes were subject to considerable temporal variations caused by a combination of variable flow conditions and changing soil water TOC concentrations. Mineral riparian gley soils, on the other hand, were related to rather small TOC export rates and were characterized by relatively time-invariant TOC concentration profiles. Organic and mineral soils in RZs constitute a heterogeneous landscape mosaic that potentially controls much of the spatial variability of stream water TOC. We developed an empirical regression model based on the TWI to move beyond the plot scale and to predict spatially variable riparian TOC concentration profiles for RZs underlain by glacial till.

High potential for the formation of haloacetic acids in the Karoon River water in Iran

The impact of the total organic carbon (TOC), chlorine dosage, water temperature, reaction time, pH, and seasonal variation on the formation of haloacetic acids (HAAs) in the Karoon River in Iran was studied. The results showed that dichloroacetic acid and trichloroacetic acid were the most detected HAA5. The HAA5 formation potential (HAA5FP) levels in the Karoon River water in spring time, when the water TOC content exceeded 4 mg/L, were 1.38 times higher than during the winter season, when the water TOC content was below 3.5 mg/L. There was not a strong correlation between the HAA5FP and the residence time for the Karoon River water. For the range of the water temperatures studied, there was little variation in the HAA5FP in cold water, but in warmer water, the values of the HAA5FP varied quickly.