Surface water sampling

Collection of undisturbed discrete surface seawater samples from research vessels is not possible. To leave the contaminated water plume of the main vessel and to approach closer to the sea surface, suitable small tenders have to be used. Sampling is performed from the lee-side of the tender, 200m up-wind from the ship in an area not previously passed by any vessel. During sampling, the tender may be moved slowly at right angles to the direction of the prevailing surface currents. 

For surface sampling with pumping systems at fixed positions, a buoy placed at some distance from the main ship may be used. From the buoy, water is drawn via polytetrafluoro-ethylene (FIFE) tubes to a pump on the vessel. Sampling is often combined with in-line filtration. A successfully tested system which delivers about 2 L/min of sample to a working height of 2 m above the sea surface with an air supply pressure of 4 bar has been described by Harper (1987) see also Tokar et al. (1981). 

The pumping system can be used on almost all research ships, provided the vessel is equipped with a moon pool and a specific mounting plate. It combines the advantages of relatively low ship costs per sample (when passing from station to station) with the possibility of interdisciplinary studies. 

Therefore, in practice the term sea-surface microlayer has been defined as that thin layer of water that adheres to sampling devices, such as wiremesh screens (Fig. 1-3), glass plates. Teflon disks and rotating drums. For a comparison and discussion of the large variety of different surface film samplers with regard to their sampling efficiencies reference is made to Van Vleet and Williams (1980), Huhnerfuss (1981) or Hardy et al. (1988). 

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For MPN determination, sterile pipettes calibrated in 0.1-ml increments are used. Other equipment includes sterile screw-top dilution bottles containing 99 ml of water and a rack containing six sets of five lactose broth fermentation tubes. A sterile pipette is used to transfer 1.0-ml portions of the sample into each of five fermentation tubes. This is followed by dispensing 0.1 ml into a second set of five. For the next higher dilution (the third), only 0.01 ml of sample water is required. This small quantity is very difficult to pipette accurately, so 1.0 ml of sample is placed in a dilution bottle containing 99 ml of sterile water and mixed. The 1.0-ml portions containing 0.01 ml of the surface water sample are then pipetted into the third set of five tubes. The fourth set receives 0.1 ml from this same dilution bottle. The process is then carried one more step by transferring 1.0 ml from the first dilution bottle into 99 ml of water in the second for another hundredfold dilution. Portions from this dilution bottle are pipetted into the fifth and sixth tube sets. After incubation (48 h at 35 C), the tubes are examined for gas production and the number of positive reactions for each of the serial dilutions is recorded. 

Figure 13.11 shows the chromatogram obtained for a surface water sample spiked with various chorophenoxy acids at a level of 0.5 p.g 1 under the same conditions as previously and after enrichment on a Cjg column and clean-up on silica SPE cartridges. 

Figure 13.10 LC-LC chromatogram of a surface water sample spiked at 2 p.g 1 with ati azine, and its metabolites (registered at 220 nm). Conditions volume of sample injected, 2 ml clean-up time, 2.60 min ti ansfer time, 4.2 min The blank was subtracted. Peak identification is as follows 1, DIA 2, HA 3, DEA 4, atrazine. Reprinted from Journal of Chromatography, A 778, F. Hernandez et al, New method for the rapid detemiination of triazine herbicides and some of thek main metabolites in water by using coupled-column liquid cliromatography and large volume injection , pp. 171-181, copyright 1997, with permission from Elsevier Science.

Figure 13.11 Column-switcliing RPLC trace of a surface water sample spiked with eight chlorophenoxyacid herbicides at the 0.5 p-g 1 level 1, 2,4-dichlorophenoxyacetic acid 2, 4-chloro-2-methylphenoxyacetic acid 3, 2-(2,4-diclilorophenoxy) propanoic acid 4, 2-(4-cliloro-2-methylphenoxy) propanoic acid 5, 2,4,5-trichlorophenoxyacetic acid 6, 4-(2,4-dichlorophenoxy) butanoic acid 7, 4-(4-chloro-2-methylphenoxy) butanoic acid 8, 2-(2,4,5-tiichlorophenoxy) propionic acid. Reprinted from Analytica Chimica Acta, 283, J. V. Sancho-Llopis et al., Rapid method for the determination of eight chlorophenoxy acid residues in environmental water samples using off-line solid-phase extraction and on-line selective precolumn switcliing , pp. 287-296, copyright 1993, with permission from Elsevier Science.

Several studies have been conducted to measure methyl parathion in streams, rivers, and lakes. A U.S. Geological Survey (USGS) of western streams detected methyl parathion in five river samples taken from four states during a 14-month period in 1970 and 1971. The amount of methyl parathion detected ranged from 0.04 to 0.23 pg/L (Schultz et al. 1973). A later and more extensive USGS study analyzed water samples from major rivers of the United States four times yearly in the period of 1975-1985. Of the 2,861 water samples, 0.1% had detectable levels of methyl parathion (Gilliom et al. 1985). In a study of Arkansas surface waters, samples of lake and river/stream water were collected and analyzed over a three-year period (Senseman et al. 1997). Of the 485 samples collected, methyl parathion was found in one river/stream sample at a maximum concentration of 3.5 pg/L. Results from an EPA study in California detected methyl parathion in 3 of 18 surface drain effluent samples at concentrations of 10-190 ng/kg. Subsurface drain effluent water had concentrations of 10-170 ng/kg in 8 of 60 samples (lARC 1983). 

Acetochlor, alachlor, and metolachlor are determined in ground and surface water samples. Deuterated internal standards are added to each water sample, and analytes are extracted using an SPE column. After elution and concentration to an appropriate volume, the analytes are quantitated by GC/MS. 

The following is a general method for ground and surface water samples. Interferences in particular samples may require modification of this method. The analytical sample size is 200 mL, but the volume may be varied depending on the concentration of analytes in the sample. 

Low-level interferences are present in ground- and surface water samples. The water-methanol (4 1, v/v) wash in the SPE phase of the sample workup is intended to minimize these interferences while maintaining quantitative recovery of the analytes. A solvent blank may be injected with the samples as part of an analytical set to confirm the cleanliness of a solvent used. 

Americium has been identified in 25 groundwater samples but was not detected in any surface water samples collected from 1,585 NPL hazardous waste sites, where it was detected in some environmental media (HazDat 2001). 

In 1997, concentrations of diisopropyl methylphosphonate in onpost groundwater samples at the RMA ranged from less than the analytical reporting limit of 0.2 g/L to 1,500 g/L (USGS 1998). Concentrations of diisoproply methylphosphonate in onpost surface water samples at the RMA ranged from less than the analytical reporting limit of 0.2 g/L to 0.581 g/L. 

While variety of pharmaceutical residues have been detected in effluent and surface water samples, only few works have been reported regarding their occurrence in sewage sludge samples. 

Capillary zone electrophoresis coupled with fast cyclic voltammetric detection was developed by Zhou et al. [27] for the separation and determination of OTC, TC, and CTC antibiotics. All compounds were well separated by optimization of pH and complexation with a boric acid sodium tetraborate buffer. The detection limit using fast on-line cyclic voltammetric detection with Hg-film-microm electrode was 1.5 x 10-6 mol/L for OTC (signal to noise ratio > 2). A continuous flow manifold coupled on-line to a capillary electrophoresis system was developed by Nozal et al. [28] for determining the trace levels of OTC, TC, and DC in surface water samples. 

Another source of acrylonitrile in water is leachate from chemical waste sites. Preliminary data from the Contact Laboratory Program (CLP) Statistical Database indicates that acrylonitrile has been detected in surface water samples collected at two of 862 hazardous-waste sites (including NPL and other sites) being investigated under Superfund. The median concentration of the positive samples was 100 pg/L (CLPSD 1988). Acrylonitrile was detected in 12 groundwater samples collected at 5 sites, also at a median concentration of 100 pg/L. 

M.A. Gonzalez-Martinez, R. Puchades, A. Maquieira, JJ. Manclus and A. Montoya, Automated immu-nosensing system for 3,5,6-trichloro-2-pyridinol application to surface water samples. Anal. Chim. Acta 392,113-123 (1999). 

Surface-water samples are usually collected manually in precleaned polyethylene bottles (from a rubber or plastic boat) from the sea, lakes, and rivers. Sample collection is performed in the front of the bow of boats, against the wind. In the sea, or in larger inland lakes, sufficient distance (about 500 m) in an appropriate wind direction has to be kept between the boat and the research vessel to avoid contamination. The collection of surface water samples from the vessel itself is impossible, considering the heavy metal contamination plume surrounding each ship. Surface water samples are usually taken at 0.3-1 m depth, in order to be representive and to avoid interference by the air/water interfacial layer in which organics and consequently bound heavy metals accumulate. Usually, sample volumes between 0.5 and 21 are collected. Substantially larger volumes could not be handled in a sufficiently contamination-free manner in subsequent sample pretreatment steps. 

The method was used for routine monitoring of dinitrotoluene concentrations in seawater from Dokai Bay, Japan. Both 2,6- and 2,4-dinitrotoluene were detected. Concentrations of 2,4-dinitrotoluene in surface water samples were higher than those in bottom water samples in 8 out of 10 samples. 

Wu et al. [388] carried out measurements of the enrichment of Atrazine on the micro surface water of an estuary. These authors used a micro surface water sampling technique with a 16 mesh stainless steel screen collecting bulk sampled from the top 100-150 pm of the surface. Atrazine concentration in the actual micro surface was estimated to vary in the range 150-8850 pg/1. 

McNeil VH, Cox ME (2000) Relationship between conductivity and analysed composition in a large set of natural surface-water samples, Queensland, Australia. Environ Geol 39 (12) 1325—1333... 

In addition, chemical data for 661 ground-water and 627 surface-water samples were obtained from the USGS National Water Information System database. Only subsets of all available data that included analyses for major cations, anions, and pH, and had cation-anion charge balances within 20% were utilized. 

Surface water samples were also collected at a number of sites throughout the Ruby Creek watershed although only data collected from active stream flow were utilized here. The surface water data was also categorized into background areas (n=13) and sites downstream from mineralization area (n=21). 

Median concentrations for parameters that were significantly (p=0.95) different between the background and mineralized surface water samples are presented in Table 2 under the surface water heading. There are fewer significant differences between surface water compared to ground water parameters. Be, Co, and Pb are anomalous in ground but not in surface water. This may simply be due to dilution by runoff. Both the SQFP multielement suite associated with natural ARD and the high Mo concentrations associated with mineralization clearly persist into surface water. 

The use of the Charm II RIA test to analyze tetracycline antibiotics in water (both surface and groundwater) has been reported [84, 97]. This RIA, which was initially developed to analyze tetracycline in serum, urine, and milk, was subsequently adapted to analyze water samples at concentration levels around 1 pg L-1. Thus, samples from hog lagoons, surface water samples, and ground-water samples were tested using the RIA method and the results confirmed by LC-MS. 

There is also a potential for release of endrin, endrin aldehyde, and endrin ketone to water from hazardous waste sites. Endrin has been detected in surface water samples collected at 10 of the 102 NPL sites, in groundwater samples collected at 37 of the 102 NPL sites, and in leachate samples collected at 2 of the 102 NPL sites where endrin has been detected in some environmental medium (HazDat 1996). Endrin ketone has been detected in surface water samples collected at 5 of the 37 NPL sites, in groundwater samples collected at 16 of the 37 NPL sites, and in leachate samples collected at 2 of the 37 NPL sites where endrin ketone has been detected in some environmental medium (HazDat 1996). No information was found on detections of endrin aldehyde in surface water, groundwater, or leachates at any NPL hazardous waste site (HazDat 1996)... 

No information was found in the available literature on levels of endrin aldehyde or endrin ketone in surface or groundwater. Endrin ketone has been detected in surface water samples collected at 5 of the 37 NPL sites, in groundwater samples collected at 16 of the 37 NPL sites, and in leachate samples collected at 2 of the 37 NPL sites where endrin ketone has been detected in some environmental medium however, concentrations were not reported (HazDat 1996). 

Surface water samples often contain surfactants and their metabolites. After Cis-SPE combined with selective elution [7,9,10] the metabolites, PEG and PPG, were observed in the ether fraction (PPG) or in the combined methanol-water and methanol (PEG) fractions, respectively. They could be ionised in the form of their [M + NH4]+ ions applying ESI-FIA-MS(-I-) in combination with ammonium acetate for ionisation support. ESI-LC-MS(-I-) resulted in an excellent separation of both metabolites, as presented in the total ion current (TIC) trace in Fig. 2.9.6(7) together with selected mass traces of PEG (m/z 300, 344 and 388) and PPG (m/z 442, 500, 558) (Am/z 44 and 58) in Fig. 2.9.6(l)-(6) [36],... 

Environmental detections of benzalkonium chlorides BAC homologue concentrations in wastewater samples collected from various WWTPs across the US were determined by on-line SPE-LC-ESI-MS (Table 2.12.4) [23,41], Concentration levels of BAC detected in effluents of WWTPs reached maximum levels of 36.6 xgL 1 and in surface-water samples collected downstream from different WWTP discharges detected concentrations ranged from 1.2 to 2.4 pig L 1, thus indicating its input and persistence through the wastewater treatment process. 

A further indicator giving hints on the progression of biodegradation of LAS and thereby the build-up of SPC was the peak pattern of phenyl isomers of individual SPC homologues. Since the degradation rate of a particular isomer depended on the position of the attachment of the phenyl ring on the oxidised alkyl chain [19], the peak distribution observed in the Macacu samples could be used as a marker and be compared to the one recorded from a surface water sample where a steady state in SPC breakdown was reached [17]. 

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