Large Volume Water Samples Research Articles

On-site preconcentration and trace metal ions determination in the Okavango Delta water system, Botswana

Microcolumns containing 8-hydroxyquinoline azo-immobilized on controlled pore glass were incorporated in a field sampler for on-site collection, isolation and preconcentration of trace metal ions in waters of the Okavango Delta, Botswana. Sequestered trace metal ions were recovered by elution with 0.5 ml of 1.5 M nitric acid, and determined by graphite furnace atomic absorption spectrometry (GFAAS). This sampling and enrichment method minimizes sample contamination, and collection of large volumes of water samples for transporting, over long distances, to analytical laboratories is avoided. Data reported comprise one of the initial surveys on trace metal ion concentrations in waters of the Okavango Delta, Botswana. In waters with more efficient mixing, dissolved metal ion concentrations found were generally low with slightly elevated levels of manganese (7–19 μg l −1), zinc (2.7–4.8 μg l −1), nickel (0.2–2.5 μg l −1) and copper (0.3–2.1 μg l −1). For each trace metal ion, concentration levels seem to reflect zones of varying water conveyance, and show no obvious temporal and spatial variations apart from a slight increment from the inlet in the upper Delta to the outlets in the lower Delta.

On-site preconcentration and trace metal ions determination in the Okavango Delta water system, Botswana

Microcolumns containing 8-hydroxyquinoline azo-immobilized on controlled pore glass were incorporated in a field sampler for on-site collection, isolation and preconcentration of trace metal ions in waters of the Okavango Delta, Botswana. Sequestered trace metal ions were recovered by elution with 0.5 ml of 1.5 M nitric acid, and determined by graphite furnace atomic absorption spectrometry (GFAAS). This sampling and enrichment method minimizes sample contamination, and collection of large volumes of water samples for transporting, over long distances, to analytical laboratories is avoided. Data reported comprise one of the initial surveys on trace metal ion concentrations in waters of the Okavango Delta, Botswana. In waters with more efficient mixing, dissolved metal ion concentrations found were generally low with slightly elevated levels of manganese (7–19 μg l −1 ), zinc (2.7–4.8 μg l −1 ), nickel (0.2–2.5 μg l −1 ) and copper (0.3–2.1 μg l −1 ). For each trace metal ion, concentration levels seem to reflect zones of varying water conveyance, and show no obvious temporal and spatial variations apart from a slight increment from the inlet in the upper Delta to the outlets in the lower Delta.

Campylobacter in waterborne epidemics in Finland

The sources for drinking water in Finland are surface water, groundwater or artificially recharged groundwater. There are approximately 1400 groundwater plants in Finland that are microbiologically at a high risk level because in most cases they do not use any disinfection treatment. Campylobacter jejuni has caused waterborne epidemics in several countries. Since the middle of the 1980s, C. jejuni has been identified as the causative agent in several waterborne outbreaks in Finland. Between 1998 and 2001, C. jejuni or C. upsaliensis caused seven reported waterborne epidemics. In these epidemics approximately 4000 people acquired the illness. Most of the outbreaks occurred in July, August , September or October. In four of them source water and net water samples were analysed for total coliforms or fecal coliforms, E. coli and campylobacters. We showed that large volumes of water samples in studies of indicator organisms (up to 5000 ml) and campylobacters (4000–20,000 ml) increased the possibility to identify faecal contamination and to detect the causative agent from suspected sources.

The Benthic Nepheloid Layer (BNL) North of the Keweenaw Peninsula in Lake Superior: Composition, Dynamics, and Role in Sediment Transport

As part of the Keweenaw Interdisciplinary Transport Experiment in Superior (KITES) project, measurements were made of the extent and the composition of the BNL in Lake Superior off the northwest coast of the Keweenaw Peninsula. Between 1998 and 2000, transmissometer profiles were obtained frequently along three transects oriented perpendicularly to the coast. Large-volume water samples were filtered, and the BNL particles were analyzed for major elements (C, N, P) and 210Pb. In 1998 and 1999, an ROV was deployed to facilitate sampling of this layer. These measurements together with ancillary data from the KITES project show that the BNL develops each summer when the lake is stably stratified and disappears in early fall as the thermocline erodes. Particles within the BNL are enriched in biogenic elements and 210Pb relative to material in surface sediments and relative to material collected in sediment traps, but are enriched in phosphorus relative to epilimnetic seston. There is a large inventory of solids suspended within the BNL (approximately 100,000 metric tons in a 20-km band along the Keweenaw Peninsula); this inventory appears quickly (1–2 weeks) in summer and disappears equally quickly via settling in fall. The large inventory of organic carbon indicates that particles are concentrated from a large area of surface waters into a considerably smaller region where the BNL exists.

Studies on Solvent Sublation of Trace Heavy Metals by Continuous Flow System as Ternary Complexes of 1,10-Phenanthroline and Thiocyanate Ion

A continuous flow system has been developed to determine trace Cu(II), Mn(II), Ni(II) and Zn(II) in a large volume of water samples by a solvent sublation technique. The mixed solution of 1,10-phenanthroline(phen) and thiocyanate ion was used as ligands for the formation of their ternary complexes. The continuous system was constructed in this laboratory with a peristaltic pump, a mini shaker, three mixing bottles and a flotation cell by connecting each part with a polyethylene tube. The flotation conditions such as the flow rate of sample solution and the injection rates of ligand, buffer and su rfactant solutions have been investigated to obtain the best sublation efficiencies. Each so lution flowed into the flotation cell through each polyethylene tube by the peristaltic pumps. The ternary complexes were floated and extracted into MIBK in a flotation cell of 2 L by bubbling a nitrogen gas. The absorbances of extracted analytes in MIBK were directly measured by graphite furnace-AAS. The concentrations of 1,10-phenanthroline and thiocyanate ion were 2.6 × 10 −3 M and 2.3 × 10 −2 M in the mixed solution, respectively. The pH of sample solution was adjusted to 5.0 with a buffer solution and 1%(m/v) sodium lauryl sulphate solution was added as a surfactant to support the effective flotation of the complexes. The N2 gas was bubbled at 30 mL/min for 90 minutes for 20 L of sample. Reproducible results of less than 10% RSD and recoveries of 80-120% could be obtained in real samples.

Capturing ion exchanger-bound infectious pancreatic necrosis virus—design and application for large volume water samples

A method was designed for rapid and reliable demonstration of the presence of infectious pancreatic necrosis virus retrieved from 5 l water samples. Viruses together with an added carrier protein were adsorbed to a resin of an added anion exchanger. Then the resin was collected rapidly and quantitatively through a specific device which we designed. The resin was transferred to a column from which the viruses were eluted, and subsequently further concentrated by acid precipitation, followed by SDS-polyacrylamide gel electrophoresis and Western blot analysis. Serological results were obtained within 24 h after the water sample was introduced into the laboratory. Proteins were recovered at an efficiency between 70 and 80% and the total concentration factor ranged between 150 000 and 250 000 times, depending on the requirements and the methods of choice.

Solid-phase microextraction fibre–water distribution constants of more hydrophobic organic compounds and their correlations with octanol–water partition coefficients

Fibre coating–water distribution constants ( K fw) of more hydrophobic chemicals were determined with six different solid-phase microextraction fibre types (including a polyoctylmethylsiloxane (C 8) prototype) by fibre exposure to agitated large-volume water samples lasting several days. The results obtained are comparable with K fw values obtained under dynamic conditions. Octanol–water partition coefficients ( K ow) were measured with the mixture of distributing substances to examine log K fw–log K ow relationships based on a consistent dataset. K fw values obtained with liquid polymer fibre coatings correlate reasonably well with the hydrophobicity of the test compounds (with decreasing sensitivity in the following order: 7 μm polydimethylsiloxane (PDMS)>100 μm PDMS>C 8>polyacrylate) whereas this is not the case with the PDMS–divinylbenzene (DVB) and Carbowax–DVB fibres, partially porous coatings which provide the highest K fw values for all substances tested.

Seasonality in Contaminant Concentrations in the Niagara River and Lakes Erie and Ontario

Knowing the seasonal variation of contaminant concentrations in lakes is important for designing effective monitoring studies and when comparing or combining results from different studies. However, there is a paucity of such information for the lakes covering both the entire year and the long term. Since 1986, we have collected large volume water samples for both dissolved and particulate phase contaminant analyses from stations at the head (Fort Erie—FE) and mouth (Niagara-on-the-Lake—NOTL) of the Niagara River throughout the whole year, including winter. Many of the organic contaminants measured over the period 1986 to 2001 exhibited seasonal variation. The different seasonal patterns were due to three general causes: (1) the exchange of contaminants across the air/water interface; (2) the seasonal nature of specific activities such as the application of agricultural insecticides and herbicides, and residential heating; and (3) the effect of suspended particulate material (SPM) quantity and composition on the particulate phase concentrations of contaminants. These are illustrated by the four contaminant examples (α-HCH, α-endosulfan, acenaphthylene, PCB) discussed in this paper. Where data were available for comparison, the seasonal patterns of these four contaminants in the river were generally consistent with those observed in Lakes Erie and Ontario over the period 1992 to 1995. Results suggest that the evaluation of contaminant concentrations, cycling and trends based on single temporal samples from the Great Lakes water column should be questioned. This is a significant issue given its widespread practice. Sampling Connecting Channels water may be, in general, a useful alternative to temporal lake sampling.

Role of Suspended Matter and Dissolved Organic Substances in Behavior and Migration of Anthropogenic Radionuclides in River-Sea Aquatic Systems

Distribution of Cs, Sr, and Pu nuclides between suspended matter and the aqueous phase and the features of interaction of these radionuclides with dissolved organic matter are studied, to gain a better insight into the radionuclide behavior in the Ob and Yenisei estuaries and adjacent Kara Sea. For radionuclide speciation, the experimental study included determination of the radionuclide activities in aqueous solutions after filtration and ultrafiltration of large-volume water samples and membrane fractionation of small-volume water samples by passing the solution through a cartridge with filters of regularly decreasing pore size followed by mass-spectrometric determination of elements. In the water-soluble fraction, the 137Cs activity increases with increasing salinity, whereas that of 90Sr decreases, which can be attributed to the differences in the physicochemical behavior of the radionuclides in solutions and also to the effect of contamination sources. In seawater, suspended material can retain 1-10% of 137Cs and 90Sr. In the estuarine zones, these values can be 20-40%. More than 50% of 90Sr and 239,240Pu are associated with dissolved organic matter. In saline water this effect is less pronounced.

An improved filter elution and cell culture assay procedure for evaluating public groundwater systems for culturable enteroviruses.

Large-scale virus studies of groundwater systems require practical and sensitive procedures for both sample processing and viral assay. Filter adsorption-elution procedures have traditionally been used to process large-volume water samples for viruses. In this study, five filter elution procedures using cartridge filters were evaluated for their effectiveness in processing samples. Of the five procedures tested, the third method, which incorporated two separate beef extract elutions (one being an overnight filter immersion in beef extract), recovered 95% of seeded poliovirus compared with recoveries of 36 to 70% for the other methods. For viral enumeration, an expanded roller bottle quantal assay was evaluated using seeded poliovirus. This cytopathic-based method was considerably more sensitive than the standard plaque assay method. The roller bottle system was more economical than the plaque assay for the evaluation of comparable samples. Using roller bottles required less time and manipulation than the plaque procedure and greatly facilitated the examination of large numbers of samples. The combination of the improved filter elution procedure and the roller bottle assay for viral analysis makes large-scale virus studies of groundwater systems practical. This procedure was subsequently field tested during a groundwater study in which large-volume samples (exceeding 800 L) were processed through the filters.

Effect of solvents on the selectivity of terbutylazine imprinted polymer sorbents used in solid-phase extraction

A solid-phase extraction sample preparation method using a molecularly imprinted polymer (MIP) selective for the triazine type pesticide terbutylazine has been developed. The method involves preconcentration from large volumes of water samples on a C18 disk coupled to selective clean-up on the MIP. The method has been optimised by studying the recovery and retention of terbutylazine and some other structurally related triazine derivates as a function of the selective washing solvent used. The effect of the water content of the selective washing solvent was also investigated on the recovery of the MIP. River water samples were analysed with the coupled technique, and efficient clean-up of the samples was observed.

Detection of enteroviruses in treated drinking water

This study deals with the routine monitoring of drinking water for the presence of enteroviruses, over a period of 1 year. A rapid and simple method was employed for the simultaneous detection and typing of enteroviruses in large-volume water samples. This included an integrated cell culture/nested PCR approach, followed by restriction enzyme analysis. The two drinking water supplies studied were derived from acceptable quality surface water sources using treatment processes, which conform to international specifications for the production of safe drinking water. Enteroviruses (predominantly coxsackie B viruses) were detected in 11% and 16% of the drinking water samples from two treatment plants, respectively. This study confirms that acceptable water quality indicators do not necessarily reflect the virus content of drinking water.

Determination of polar organophosphorus pesticides in aqueous samples by direct injection using liquid chromatography–tandem mass spectrometry

It was demonstrated that four out of six of the very polar organophosphorus pesticides (OPs), i.e. acephate, methamidophos, monocrotophos, omethoate, oxydemeton-methyl and vamidothion, could not be extracted from water using commonly available SPE cartridges. In addition, GC analysis on all six compounds was found to be troublesome due to their polar and thermolabile character. This initiated the development of an alternative highly sensitive and selective method for the determination of the above mentioned very polar OPs in water, based on LC–MS. Large volume (1 ml) water samples were directly injected onto an RP18 HPLC column with a polar endcapping. The latter was essential for obtaining retention and maintaining column performance under 100% aqueous conditions during the sampling. The compounds were ionized using atmospheric pressure chemical ionization and detected on a tandem mass spectrometer operated in multiple reaction-monitoring mode. The detection limits were in the range of 0.01–0.03 μg/l. Compared to conventional GC methods, the developed LC–MS procedure is very straightforward, fast and more reliable. This application demonstrates the applicability of LC–MS for analysis of polar OPs in surface, ground and drinking water, as a more favourable alternative to GC.

Molecular indicators of the sources and transformations of dissolved organic matter in the Mississippi river plume

The dynamics of dissolved organic matter (DOM) in the Mississippi river plume were investigated during four cruises to the region in 1990–1993. During each cruise, large-volume water samples were collected from a broad salinity gradient (0–36 psu) for the determination of dissolved organic carbon (DOC) concentrations and the isolation of DOM by tangential-flow ultrafiltration. The fraction of DOC recovered by ultrafiltration ranged from 49% in the river to 22% in the Gulf of Mexico. The ultrafiltered DOM (UDOM) was further characterized for the concentrations and compositions of combined neutral sugars and lignin-derived phenols. Concentrations of DOC ranged from 359 μM in the river during the summer to 65 μM in surface waters of the Gulf of Mexico during the winter. Mixing curves indicated minor losses of DOC at low salinities and a major source of DOC at mid salinities. Combined neutral sugars had elevated concentrations at mid salinities where plankton biomass and rates of autotrophic and heterotrophic processes were maximal, indicating that elevated concentrations of sugars and DOC were freshly-derived from plankton. In contrast, concentrations of lignin phenols in UDOM were depleted at low salinities, indicating losses due to flocculation of terrestrially-derived humic substances. The selective removal of syringyl phenols from dissolved lignin was observed in UDOM from higher salinity (>25 psu) waters, providing the first molecular evidence of the removal of terrigenous DOM from the coastal ocean due to photooxidation. Together, these molecular biomarkers indicated much greater dynamic behavior of DOM than was apparent from bulk DOC analyses, and they demonstrated that biological as well as physico-chemical processes were important in controlling the concentrations and compositions of DOM in coastal waters.

New method for rapid solid-phase extraction of large-volume water samples and its application to non-target screening of North Sea water for organic contaminants by gas chromatography–mass spectrometry

A method has been developed that allows the solid-phase extraction of microorganic compounds from large volumes of water (10 l) for non-target analysis of filtered seawater. The filtration–extraction system is operated with glass fibre filter candles and the polymeric styrene–divinylbenzene sorbent SDB-1 at flow-rates as high as 500 ml/min. Recovery studies carried out for a couple of model substances covering a wide range of polarity and chemical classes revealed a good performance of the method. Especially for polar compounds (log K OW 3.3–0.7) quantitative recovery was achieved. Limits of detection were between 0.1 and 0.7 ng/l in the full scan mode of the MS. The suitability of the method for the analysis of marine water samples is demonstrated by the non-target screening of water from the German Bight for the presence of organic contaminants. In the course of this screening a large variety of substances was identified including pesticides, industrial chemicals and pharmaceuticals. For some of the identified compounds their occurrence in marine ecosystems has not been reported before, such as dichloropyridines, carbamazepine, propyphenazone and caffeine.

Hydrogeochemistry and transport of organic contaminants in an urban watershed of Chesapeake Bay (USA)

Stream water samples were collected in the two main free-flowing branches of the Anacostia River watershed above the head of tide over a one year time period. Both the Northeast and Northwest Branches drain large suburban and urban land areas that flow into the more urbanized tidal portion of the Anacostia River within Washington, DC. Large volume (40–75 l) water samples were filtered, and the suspended particulate matter and filtrate were analyzed for polychlorinated biphenyls (PCBs), polycyclic aromatic hydrocarbons (PAHs), and organochlorine pesticides (OCPs) at sub-nanogram per liter concentrations using ultra-trace analytical methods. Higher amounts of PCBs, PAH, and OCPs in the tidal Anacostia River occurred primarily in the particulate phase during high flow events. Polycyclic aromatic hydrocarbons in the particulate phase within fluvial transport consisted primarily of pyrogenic homologues characteristic of weathered or combusted petroleum products. Fluxes were exceptionally high for PAHs which showed annual fluxes to the tidal Anacostia River comparable to those determined for the much larger mainstem Potomac River. Aromatic hydrocarbons in runoff from urban regions may serve as an important source of PAH fluxes to the tidal waters of Chesapeake Bay.

Evaluation of a continuous flow centrifuge for recovery of Cryptosporidium oocysts from large volume water samples

This study aimed to evaluate the continuous flow centrifuge (CF centrifuge) for recovering Cryptosporidium oocysts from water under realistic environmental conditions. This was achieved by taking 100 l samples from a water tank with known seeding and turbidity levels. Samples were concentrated and purified using percoll discontinuous gradients and stained using monoclonal antibody on polycarbonate membrane filters. The maximum percent recoveries were achieved at a flow rate of 0.75 l/min and centrifuge speed of 2900× g. When compared directly with cartridge filtration at a seeding level of 10 oocysts/l and low turbidity of 1 nephelometric turbidity unit (NTU), recoveries were 14.8 and 9.7% ( n=3) for the CF centrifuge and cartridge filtration respectively. At a higher turbidity of 5 NTU, recoveries were 13.0 and 9.0% respectively. These differences were not significant but the CF centrifuge sample is faster, simpler and safer to process. Its integration into flow cytometry is also evaluated. The recovery of Giardia by CF centrifugation at 10 cysts/l and 5 NTU gave a mean recovery of 37.9%.

Formula omitted] as a tracer of scavenging and particle export in the Beaufort Sea

Water column measurements of 234 Th were made at three stations in the shelf–slope regime and one offshore station in the Beaufort Sea, August–September 1995, to quantify rates of scavenging and particle export. Large-volume water samples (200–600 l) were collected in situ and dissolved and particulate 234 Th activities determined at-sea. 234 Th/ 238 U disequilibrium was evident at all locations. The distribution of the total 234 Th/ 238 U activity ratio reveals a transition, centered at the shelf break, from low values (0.4–0.6) over the shelf to elevated values approaching secular equilibrium offshore. These results further constrain the extent to which shelf scavenging and lateral transport contribute to 234 Th/ 238 U disequilibrium in the Arctic interior. Residence times of dissolved 234 Th range from ∼25–50 d in the shelf and slope waters to ∼150 d offshore, compared to ∼12–18 d for particulate 234 Th . Estimates of POC export from the upper 50 m derived from 234 Th range from ∼4–7 mmol C m −2 d −1 over the shelf to ∼1–2 mmol C m −2 d −1 in the slope waters and central Beaufort.

Determining Produced Water Originating Polycyclic Aromatic Hydrocarbons in North Sea Waters: Comparison of Sampling Techniques

A field study was carried out in the Norwegian sector of the North Sea during May and June 1997. The purpose was to measure the concentration of produced water originating polycyclic aromatic hydrocarbons (PAH) in seawater and to compare different sampling techniques for use in future monitoring programs. Three methods were used for direct water sampling: (1) in situ large volume sampling of particulate and dissolved hydrocarbons onto filters and XAD resins, (2) solid phase extraction (SPE) using polystyrene-divinylbenzene disks, (3) whole bulk water sampling. In addition, sampling by semi-permeable membrane devices (SPMDs) and blue mussels ( Mytilus edulis) was used to obtain a 4 weeks average of the concentration of the target compounds in seawater. The samples were processed and analysed by GC–MS for determination of PAH concentrations. The measured concentrations were generally found to be low, and in many cases below the limits of detection. The comparison of sampling techniques showed that blue mussels and SPMDs are suitable for measuring PAH in both near- and far-field seawater. In situ large volume water sampling was also suitable for a wide range of PAH concentrations, but this technique was limited by high break-through of the low-molecular weight compounds, such as naphthalenes. The small sampling volumes limited the SPE and whole water sampling techniques, resulting in potential detection limit problems. These grab-sampling techniques may, however, be suitable for monitoring in the near-field areas around the platforms.

Size distribution measurements of dissolved organic carbon in natural waters using ultrafiltration technique

Ultrafiltration is frequently used as a technique for size distribution measurement of dissolved organic carbon (DOC) in natural waters. Concentrations of DOC in low molecular weight size classes may be underestimated if membrane rejection is neglected. A model was developed to improve the accuracy of size distribution measurements using an ultrafiltration technique. This model can be used for a large volume water sample, which is often required for trace element analysis in environmental samples. The model was applied to the size distribution analysis of DOC in water samples from the Florida Everglades and the results were in good agreement with that obtained using the model previously reported by Logan and Jiang.