Matter In Water Samples Research Articles

Improved water quality monitoring indicators may increase carbon storage in the oceans

Indicators related to organic matter are important when assessing aquatic environment quality. The chemical oxygen demand (COD) is widely used as a water quality reference. However, oxidizing agents used to determine the COD can oxidize refractory organic matter that is not pollutant and can persist in the ocean for thousands of years. This means the COD can misrepresent the water quality. The actual water quality can be indicated better by the biochemical oxygen demand (BOD) than the COD, but determining the BOD is time-consuming and gives variable results. In this study, the optical properties of dissolved organic matter in water samples from the Chinese coast that had been incubated for a long time or directly oxidized using COD oxidant were analyzed. The results indicated that the oxidizing agent rapidly oxidized 22.93% ± 4.96% of refractory dissolved organic matter (RDOM) that was resistant to microbial degradation, implying that RDOM made a marked contribution to the COD. Meanwhile, size-fractional fluorescence spectroscopy and COD measurements indicated that the COD of the >0.7 μm fraction and the fluorescence intensity of the protein-like component significantly positively correlated with the BOD of the bulk sample. This indicated that, for monitoring organic pollutants in coastal waters, the COD of the >0.7 μm fraction could be used as a proxy for the standard COD and that the fluorescence intensity of the protein-like component could be used as a convenient proxy for the BOD. The method can help retain recalcitrant organic matter in seawater to act as a carbon sink.

Short communication on “Differentiating with fluorescence spectroscopy the sources of dissolved organic matter in soils subjected to drying” [Zsolnay et al. Chemosphere 38, 45–50, 1999

This article is a short, but very important comment to the often used humification index (HIX), assumed to indicate the degree of biochemical degradation of dissolved organic matter in water samples. HIX is commonly calculated by dividing the fluorescence intensity detected at longer wave lengths by the intensity detected at shorter wavelengths.However, we found typos in the original article that affect the used equation directly and thus the results. We compared the different ways to calculate HIX and found a strong correlation between all results. Nevertheless, we recommend to use only equation 1, especially if data from different studies should be compared.

Bacteriological analysis of water samples and the impact of seasonal variation on microbial load

Water plays a significant role in the very existence of life in this universe. Globally, water related diseases present a major concern, to a large set of population. It thus becomes vital to check the quality of water that is being used either in domestic set up or for industrial purpose. In the present study, microbiological analysis of water sample collected from different locations such as River, Lake, Well and direct Rain water in and around Manipal, Karnataka were studied. The impact of seasonal variation on microbial load of these samples was also studied. The experimental design was carried out to estimate the number of microorganisms present and to characterise what type of organisms they are and the influence of varying seasons such as wet (monsoon) season and dry (summer) season on microbial load. Number of colonies was determined by total plate count method and growth characters and pattern were observed and noted down. Examination of motility of bacteria, Gram’s staining and different biochemical tests (IMViC) for bacteria were performed for different bacterial cultures and also the fungal staining was performed for the different fungal isolates obtained from the water samples. To check the quality of water for domestic and industrial use and to check for presence of faecal matter in water samples, the test for coliform bacteria through presumptive, confirmed and complete tests were performed. The results showed that all the water samples were safe for use as coliform organisms were not detected in the tested water samples, both in wet as well as well as dry season. The impact of seasonal variation that is the effect of dry and wet season on microbial load was also noted down. The various parameters that were examined to check for microbial load in varying seasons included difference in the number of colonies of microorganisms, their growth pattern and growth characters. From the tests conducted it was found that diverse and greater microbial load was observed in wet season compared to dry season.

Тhermodenudation on Yamal peninsula as a source of the dissolved organic matter increase in thaw lakes.

This paper is devoted to the study of thermodenudation impact on concentration of the organic matter dissolved in lake water. Summarized are results of the laboratory tests on concentration of colored dissolved organic matter in water samples collected out of the lakes in Central Yamal. Analyzed is the diff erence of colored dissolved organic matter concentration in lakes with the coasts aff ected by active thermodenudation and in lakes with undisturbed coasts. Buried peat layers discovered in the thermocirque exposures appeared to have high concentration of dissolved organic carbon. It is established that average concentration of colored dissolved organic matter is 3.5–4.5 times higher in lakes with thermocirques.

Degradation of chloroform by Fenton-like treatment induced by electromagnetic fields: A case of study

The objective of this study of chloroform degradation by the first time through Fenton-like processes induced by electromagnetic fields. Fenton-like processes were carried out at natural pH with 25mg/L of H2O2 and different iron sources: i) FeCl3·6H2O (5, 50 and 100mg/L Fe3+); ii) magnetite (1g/L); iii) clay (80g/L). These treatments were driven in absence and presence of radiofrequency (RF) with an intensity of electromagnetic field of 3.68kA/m. Aqueous solution of chloroform (CHCl3) was also used to study which oxidant species are responsible for the degradation of organic matter. Because of chloroform is scavenger of primary superoxide radicals (•O2−.) and required of hydroxyl radical for their total degradation. Initial assays of ferromagnetic material/H2O2/RF processes achieved promising results in terms of DOC removal. The highest DOC removal yield (69%) in the treatment of an aqueous solution of CHCl3 was obtained by Fenton/RF treatment using 100mg/L of Fe(III) and 25mg/L of H2O2. In addition, the combination of Magnetite and Fe(III) reached notable values of CHCl3 degradation. The synergetic effect caused by the ferromagnetic properties of Magnetite and the coagulation-flocculation effect caused by iron salts at natural pH is able to reduce the organic matter in water samples. Furthermore, this treatment can be intensified by induction of RF reaching 63% of DOC removal in the CHCl3 solution.

The removal of organic precursors of DBPs during three advanced water treatment processes including ultrafiltration, biofiltration, and ozonation.

The removal efficiency of organic matter, the formation potential of trihalomethanes (THMFP), and the formation potential of haloacetic acids (HAAFP) in each unit of three advanced treatment processes were investigated in this paper. The molecular weight distribution and the components of organic matter in water samples were also determined to study the transformation of organic matter during these advanced treatments. Low-molecular-weight matter was the predominant fraction in raw water, and it could not be removed effectively by ultrafiltration and biofiltration. The dominant species of disinfection by-product formation potential (DBPFP) in raw water were chloroform and monochloroacetic acid (MCAA), with average concentrations of 107.3 and 125.9μg/L, respectively. However, the formation potential of chloroform and MCAA decreased to 36.2 and 11.5μg/L after ultrafiltration. Similarly, biological pretreatment obtained high removal efficiency for DBPFP. The total THMFP decreased from 173.8 to 81.8μg/L, and the total HAAFP decreased from 211.9 to 84.2μg/L. Separate ozonation had an adverse effect on DBPFP, especially for chlorinated HAAFP. Numerous low-molecular-weight compounds such as aldehydes, ketones, and alcohols were generated during the ozonation, which have been proven to be important precursors of HAAs. However, the ozonation/biological activated carbon (BAC) combined process had a better removal efficiency for DBPFP. The total DBPFP decreased remarkably from 338.7 to 113.3μg/L after the O3/BAC process, far below the separated BAC of process B (189.1μg/L).

Spectrophotometric Method for Determination of Ozone Residual in Water Using ABTS: 2.2’-Azino-Bis (3-Ethylbenzothiazoline-6-Sulfonate)

ABSTRACTA new spectrophotometric method for the determination of aqueous ozone in water matrices was developed. This method is based on the reaction of ozone and 2.2’-azino-bis (3-ethylbenzothiazoline-6-sulfonate), ABTS), which can be oxidized from a colorless material to a green-colored cation ABTS.+. This reaction product presents at least four peaks (415, 650, 732, 820 nm), which can be helpful in the presence of inferences from organic matter in water samples. This method is quite sensitive due to the high molar absorptivity of the product (ɛ = M−1.cm−1). The stoichiometry of the reaction of ozone with ABTS is 1:1 when ABTS is in excess. The detection limit of this ABTS method was determined to be 1.2 µg/L. The increase in absorbance due to ABTS.+ generation is linear with respect to ozone added (5 μg/L–5 mg/L) at pH 2 (controlled with phosphate buffer). The reagent ABTS reacts with ozone almost instantaneously (less than 1 sec). The product, ABTS.+, is quite stable in both pure and natural water samples if kept in the dark. This new ABTS spectrophotometric method for the determination of aqueous ozone is easy to perform and can be readily adapted for measuring other common oxidants.

The Mechanism of Removing the Organic Matter in Heavy Oil Sewage by the Electric Flocculation Method

Oily sewage is one of the wastes produced in the oil industry production process and its quantity has been increasing year by year, which influences the environment and human health severely. Electric flocculation method is one of the wide application electrochemical treatment technologies for the oily wastewater treatment at home and abroad, which has higher efficiency than other technologies at the aspect of the organic pollutants degradation. A simulative experiment device dealing with heavy oil sewage by the electric flocculation method has been designed. The mechanism of the electric flocculation method in removing organic matter of the heavy oil sewage by analyzing the change of the composition and content of the organic matter in water samples before and after the process of the electric flocculation has been studied. Research results show the carbon/tin dioxide electrode is better than the carbon/ruthenium dioxide electrode in removing organic matter; most alkanes matter in the oily wastewater have been removed in the dispersing oil form by the electric flocculation; as the current density increases, the types and quantity of the response organic matter can be improved while types of the new synthetic organics increase. At the same time, the authors provide a theory support in specific optimization of the electricity flocculation flotation in oily wastewater treatment technology and process.

Study on Mechanism of Removing the Organic Matter in Heavy Oil Sewage by the Electric Flocculation Method

Oily sewage is one of the wastes produced in the oil industry production process and its quantity has been increasing year by year, which influences the environment and human health severely. Electric flocculation method is one of the wide application electrochemical treatment technologies for the oily wastewater treatment at home and abroad, which has higher efficiency than other technologies at the aspect of the organic pollutants degradation. A simulative experiment device dealing with heavy oil sewage by the electric flocculation method has been designed in this paper. The mechanism of the electric flocculation method in removing organic matter of the heavy oil sewage by analyzing the change of the composition and content of the organic matter in water samples before and after the process of the electric flocculation has been studied. Research results show: the carbon/tin dioxide electrode is better than the carbon/ ruthenium dioxide electrode in removing organic matter; most alkanes matters in the oily wastewater have been removed in the dispersing oil form by the electric flocculation; as the current density increases, the types and quantity of the response organic matter can be improved while types of the new synthetic organics increase. At the same time, this paper provides a theory support in specific optimization of the electricity flocculation flotation in oily wastewater treatment technology and process.

Effect of biomass adaptation to biodegradation of dissolved organic carbon in water

In the present study the time of adaptation of fixed biomass for biodegradation of natural organic matter was investigated. The experiments were done in columns that are usually used for rapid determination of biodegradable dissolved organic carbon (BDOC). The biomass was adapted to samples with different concentrations of organic substances before measurements by pumping water to be investigated through the columns for several days. The time of adaptation was dependent on the initial concentration of the organic matter in the water sample. The adaptation time increased from 6 to 24h with increase of concentration of acetate solution from 2 to 10mg/l, thus adaptation rate decreased simultaneously from 0.28 to 0.11min(-1). In natural water samples with the initial concentration in the range from 4.61-10.82mg/l of dissolved organic carbon (DOC) the maximal adaptation time was less than 24h. During the adaptation period the increase in reproducibility and decrease in the standard deviation was observed. The study showed that adaptation of column to the different concentration of organic matter in water sample is necessary in order to decrease the bias in BDOC measurements when using columns tests.

Distributions of Competing Container Mosquitoes Depend on Detritus Types, Nutrient Ratios, and Food Availability.

Coexistence of competitors may result if resources are sufficiently abundant to render competition unimportant, or if species differ in resource requirements. Detritus type has been shown to affect interspecific competitive outcomes between Aedes albopictus (Skuse) and Aedes aegypti (L.) larvae under controlled conditions. We assessed the relationships among spatial distributions of detritus types, nutrients, and aquatic larvae of these species in nature. We collected mosquitoes, water, and detritus from artificial containers across 24 Florida cemeteries that varied in relative abundances of Ae. aegypti and Ae. albopictus.We measured nutrient content of fine particulate organic matter in water samples as total N, P, and C and ratios of these nutrients. We quantified food availability via a bioassay, raising individual Aedes larvae in the laboratory in standard volumes of field-collected, particulate-containing water from each cemetery. Quantities of detritus types collected in standard containers were significant predictors of nutrients and nutrient ratios. Nutrient abundances were significant predictors of relative abundance of Ae. aegypti, and of larval survival and development by both species in the bioassay. Survival and development of larvae reared in particulate-containing water from sites decreased with decreasing relative abundance of Ae. aegypti. These data suggest that N, P, and C availabilities are determined by detritus inputs to containers and that these nutrients in turn determine the feeding environment encountered by larvae, the intensity of interspecific competition among larvae, and subsequent relative abundances of species at sites. Detritus inputs, nutrients, and food availability thus seem to contribute to distributions of Ae. aegypti and Ae. albopictus in cemetery containers throughout Florida.

Evaluation of factors for rapid development of Culex quinquefasciatus in belowground stormwater treatment devices

Water samples from 11 belowground stormwater treatment Best Management Practices (BMPs) were evaluated for their capacity to support rapid development of the West Nile virus (WNV) mosquito vector, Culex quinquefasciatus. The observed minimum development time from egg to pupa ranged from six to over 30 days. Concentrations of potential food resources (total suspended solids and the particulate organic matter in water samples) were significantly correlated to development times. In addition, the rate of immature mosquito development was both site-dependent and variable in time, suggesting that factors favorable to rapid development were strongly influenced by watershed characteristics and seasonal changes in temperature. Measured temperatures in belowground BMPs suggest that these structures may remain amenable to WNV virus activity longer each year than sites aboveground.

Reduction of natural organic matter by nanofiltration process

The objectives of this investigation were to characterize natural organic matter (NOM) in Kin-men raw water, to evaluate the performance of the nanofiltration (NF) membrane process for NOM removal, and to determine the good engineering practice (GEP) of the NF 270 membrane filtration performance. Three different samples: (1) raw water collected from the Tai Lake in Kin-men, Taiwan; (2) ultrafiltration (UF) pre-treated water; and (3) sand filtration (SF) treated water after the coagulation and sedimentation processes were employed in this study. The hydrophobic component (58%) was the predominant NOM fraction, and the NOM molecular weight was distributed broadly, i.e., lower than 1 kDa (30%), 1–5 kDa (32%) and larger than 5 kDa (38%). Hydrophobic NOM easily accumulated on the NF membrane surface and resulted in flux decline. The SF–NF was the proposed treatment process because it can reduce the NOMs effectively with lower energy consumption than UF–NF. It was noted that the dissolved organic carbon (DOC) rejection ratio was not affected by changing cross-flow velocity. However, at lower cross-flow velocity (0.15 m s −1), the reduction of organic matter in water sample was higher than that at higher cross-flow velocity (0.30 m s −1). By integrating the experimental results, it was concluded that a transmembrane pressure of 690 kPa and a cross-flow velocity of 0.30 m s −1 exhibited the GEP, yielding about 94% of both DOC and UV 254 reduction.

A high throughput chemiluminescence method for determination of chemical oxygen demand in waters

A novel and high throughput chemiluminescence (CL) method for determination of chemical oxygen demand (COD) in water sample was originally developed based on potassium permanganate–glutaraldehyde CL system. With this method, dissolved organic matter in water samples was digested by excess acid potassium permanganate, the reacted mixture solutions containing surplus KMnO 4 were added in wells of a 96-well plate, followed by injection of glutaraldehyde in the wells, and CL was then produced along with the reaction of the added glutaraldehyde with the surplus KMnO 4 and detected by a photomultiplier tube (PMT). The difference (Δ I) between the CL intensity for distilled water and that for sample water was proportional to the COD value of water sample. The calibration graph was linear in the range of 0.16–19.24 mg L −1 with a detection limit of 0.1 mg L −1. A complete analysis could be performed in 40 min including digestion and detection, giving a very high throughput of 3 × 96 samples in about 60 min. Compared with the conventional methods, this method is simple and sensitive and consumes very limited and cheap reagents. Owing to its rapid, automatic, high throughput and low cost characteristics, the presented CL method has been applied successfully to the determination of COD in real water samples ( n = 32) with satisfactory results.

Pyrolysis-GC/MS fingerprinting of environmental samples

This paper describes four recent applications of analytical pyrolysis in environmental science and engineering. In all applications, samples were analyzed in order to provide information about the origin of organic matter or changes to an organic matrix. In the first application, pyrolysis-gas chromatography/mass spectrometry (GC/MS) and pyrolysis-GC/flame ionization detection (FID) were used to help classify the origin of natural organic matter (NOM) buried in the Antarctic. In the second application, pyrolysis-GC/MS was used to compare the recalcitrance of NOM to biological degradation. In the third application, pyrolysis-GC/FID was used to quantitatively differentiate between lipogenic NOM and petroleum contamination in highly organic soil. In the fourth application, pyrolysis-GC/MS was used to fingerprint organic matter in water samples to help describe the relationship between surface water, groundwater and springs in a complex watershed. In all applications the benefits of analytical pyrolysis are still being discovered.

Relationship between the Beam Attenuation Coefficient and the Concentration of Suspended Matter in Black-Sea Waters

By using the results of simultaneous measurements of the beam attenuation coefficient and the concentration of suspended matter in water samples, we deduce the relationships between these parameters for wavelengths of 640, 660, and 677 nm. The proposed formulas are used for the evaluation of the concentration of suspended matter according to the data of optical measurements performed in cruises of research vessels. We present two maps of the distribution of suspended matter plotted for the north part of the sea in November–December 1991 and for the south part of the sea in July 1992.

Estimation of the hydrophobic fraction of dissolved organic matter in water samples using UV photometry

In this study, we tested a simple and rapid method for the estimation of carbon in the hydrophobic fraction of dissolved organic matter (DOM) of different origin (spruce, pine, and beech litter) in soil water. The method is based on the fact that the hydrophobic fraction of DOM contains almost entirely the aromatic moieties of DOM. Thus, it showed a clearly distinct light absorption at 260 nm compared to the hydrophilic fraction. This light absorption was directly proportional to the concentration of the hydrophobic fraction. Moreover, it was independent of the concentration of the hydrophilic fraction. We compared the concentrations of hydrophobic DOM estimated by the UV method with those of the conventional fractionation using chromatographic columns of XAD-8 macroporous resin and found an excellent agreement between the two methods for both solutions from laboratory sorption experiments and field samples of forest floor leachates and subsoil porewaters. In addition, the absorption at 260 nm of hydrophobic DOM proved to be independent of pH values ranging from 2.0 to 6.5. Compared to the conventional chromatographic fractionation, the method using the UV absorption at 260 nm is less time consuming, needs a much smaller sample volume, and showed a better reproducibility. However, its use is restricted to water samples of low nitrate (<25 mg L −1) and Fe (<5 mg L −1) concentrations and, probably, with the hydrophobic fraction dominated by aromatic compounds deriving from degradation of lignin.

Effect of scavengers on the photocatalytic digestion of organic matter in water samples assisted by TiO2 in suspension for the voltammetric determination of heavy metals

The influence of electron and hole scavengers in the photocatalytic digestion of organic matter in the presence of suspended particles of TiO2 was investigated. The process, aiming at the electrochemical determination of traces of heavy metals in water samples, was followed through the recovery of the voltammetric wave of Cd(II) in the presence of EDTA, chosen as model ligand that mimics the complexing effect of natural dissolved organic matter. The accelerating power of O2, acting as electron scavenger, was confirmed. In the absence of O2, a similar function is played by nitrate ions but not, as it seems, by the analyte, Cd(II). On the other hand, CH3OH exhibits an antagonist effect as hole scavenger. This observation may explain why the acetate (from the pH buffer), used to control the medium acidity, leads to a certain reduction in the photocatalytic yield.

Partitioning of trace metals in suspended matter from the elbe estuary fractioned by a sedimentation method

The particulate matter in water samples from the freshwater region of the Elbe estuary was fractioned by its setting characteristics. The sedimenting and the permanently suspended fractions of the particulate matter were analyzed separately for trace metals (cd, Pb, Cu, Cr, Co, Ni) and organic composition. The two fractions differed significantly in organic and metal content and 13C in organic matter. Permanently suspended particles rich in riverine biogenic material contained amounts of trace metals enhanced by a factor of about three in comparison to the sedimented fraction. Also, 80% of the total particulate trace metals was transported downstream by this fraction. Along the profile of the Elbe from km 630 to km 670 a decrease in suspended particulate trace metals occurred in both fractions, which amounted to a reduction of approximately 50% between March and June. The largest decrease was detected just below Hamburg harbour and was explained by mixing of highly polluted riverine SPM with less polluted sedimenting SPM from downstream regions. The specific loading of the particulates with trace metals was linked to the particulate organic matter content which was in part degraded during the transport downstream. The adsorption characteristics of the organic matter remained quite constant both over the freshwater profile and at different times of the year and accumulation [C/Metal (g·mg −1)] varied mostly between 0.5 and 1 for Cu, Pb, Cr and Ni and 15 to 30 for Cd. The results indicate that even small changes in the perticulate matter composition might produce great differences in the total particulate tarce-metal content.

The distribution of organic matter in songkhla lake basin (SLB)

The concentrations and the distribution of organic matter in SLB (e.g. the outer part of Thale Sap Songkhla area) were examined during the period of September 1988 to September 1989. Organic matter in water samples were analyzed by gravimetry. Total organic matter and dissolved organic matter concentrations ranged from 74 to 7908 mg/L and from 23 to 7813 mg/L, respectively. Except for a set of observations which showed low concentrations during the flood season in November 1988, organic matter was regularly distributed throughout SLB. Domestic effluent and aquaculture are hypothesized as major sources of organic matter contamination. The levels of organic matter concentrations in SLB are significantly higher than would be expected for an area considered to be uncontaminated. The data also indicated a linear relationship between concentrations of suspended organic matter and suspended solids. This may be due to the organic matter associated with suspended solids.