Surface water sample analysis

Fig. 6.3.7. Semi-quantitative analysis of C6-Ci2-SPC in investigated surface waters (sample batch from December 1999) (from Ref. [23]).

Mart, L., 1979b. Prevention of contamination and other accuracy risks in voltammetric trace metal analysis of natural waters. 2. Collection of surface water samples. Fres. Z. Anal. Chem., 299 97-102. 

The majority (78%) of the CWS in the 32 states use groundwater as the raw water source (Table 29.2). Thus, the two herbicides databases contain more groundwater (four to five times) than surface water samples (Tables 29.3 and 29.4). The most frequently used limits of quantification (LOQ) for the analysis of atrazine were equal to or less than 0.5ppb (1/6 of MCL) in 28 states, 0.6ppb in one state, and l.Oppb and 2.5ppb in the other two states, respectively. Prior to 1997, two states had an LOQ at the MCL of 3 ppb. The LOQs were lowered in 1997 and subsequent years to less than 1 ppb. The LOQs for simazine were equal to or less than 0.8ppb (—1/5 of MCL) in 27 of the 31 states. LOQs of l.Oppb (1/4 of MCL) and 2.0ppb (1/2 of MCL) were used in the other four states. By 2005, almost all CWS in the United States used LOQs of 0.1 ppb or lower. 

An analysis of EPA s STORET (STOrage and RETrieval) database for 1980-82 showed that based on the statistical criteria used, 2,3,7,8-TCDD was detected but at concentrations too low to be quantified in surface-water samples collected at sampling sites (Staples et al. 1985). The sampling sites in the STORET database included both ambient and pipe sites. Ambient sites included streams, lakes, ponds, wells, reservoirs, canals, estuaries, and oceans and were intended to be indicative of general U.S. waterway conditions. Pipe sites referred to municipal or industrial influents or effluents (Staples et al. 1985). 

A number of studies have speculated on diazotroph response to mineral dust Fe fertilization in the Atlantic (Mahaffey et al, 2003), and Pacific Oceans (Johnson et al, 2003). Circumstantial evidence for dust stimulation of marine diazotrophic biomass has recently been reported. A 1999 Saharan dust event coincided with increases in dissolved Fe concentrations on the west Florida shelf and a 100-fold increase in Trichodesmium biomass. N2 fixation rates were not measured, but DON concentrations doubled, presumably due to exudation by N2 fixers (Lenes et al, 2001). A recent Saharan dust addition experiment to surface water samples collected along a west African cruise transect (35°W-17°W), found a minimal increase in CO2 fixation and a large stimulation in N2 fixation, suggesting that diazotrophs were co-limited by both P and Fe (Mills et al, 2004). Note however, analysis of aerosol dust shows that while providing Fe, it also supplies P and combined N (Baker et al, 2003 Mills et al, 2004 Ridame and Guieu, 2002). 

Shen, P., Shi, Q., Hua, Z., Kong, F., Wang, Z., Zhuang, S., Chen, D. (2003). Analysis of microsystins in cyanobacteria blooms and surface water samples from Mei-lang Bay, Taihu Lake, China. Environment Int. 29, 641-647. 

In the laboratory portion of the project, the students quantify iron in real and artificial surface water samples by UV-Vis spectroscopy. The iron is complexed to the o-phenanthroline (phen) ligands in a buffered solution to create a highly colored orange complex, [Fe(phen)3] The intensity of the complex color is proportional to the concentration, following Beer s Law. Students create a standard series and prepare a surface water sample using modified standard protocols (21). We use autodispensers to dispense corrosive reagents and provide the stock iron solutions this equipment reduces exposure and ensures that the experimental work can fit within the three hour laboratory period. Students measure of the absorbance of their standard series as well as their surface water sample on a spectrometer at X = 508 nm. Students complete the experimental write-up, calculations, data analysis, and assessment during the subsequent laboratory period. 

The results obtained during the validation of the method and the analysis of at least 50 drinking and surface water samples proved the suitability of the LC-MS-MS method for the determination of the most important endocrine disrupting chemicals. 

In most cases, the extracts obtained after LLE or SPE were analyzed without including a cleanup step. Laborious cleanup steps are necessary when analysis is performed by GC-EID or GC-ECD, but nowadays the most common determination technique is GC-MSD and, due to its selectivity, there is no need for a cleanup step for surface water samples. So, the cleanup step is not part of the routine methods for phthalate water analysis. It is only necessary if high background levels or high amounts of polar substances are found in the samples, as could be the case in extracts from landfill leachates of wastewaters.Cleanup is generally performed using a polar sorbent, such as activated alumina or florisil. Lopez-Avila et al. ° have compared florisil and alumina columns to perform the cleanup step. Alumina was preferred over florisil mainly because it allows recovery of all target compounds in the elution step, while three of the 16 phthalates included in the study could not be recovered with florisil clean up. 

The analyses of environmental samples confirmed the ubiquitious presence of surfactants in surface and sea water as a result of the surfactants discharged with STP effluents. Analysis of River Elbe (Germany) water samples by GC-MS and APCl-LC-MS and MS/MS confirmed qualitatively the presence of nonpolar and polar organic pollutants of AEO, NPEO, CDEA and aromatic sulfonic acid type, respectively [226], After Cjg and/or SAX SPE anionic and non-ionic surfactants were qualitatively and quantitatively analysed in surface water samples by APCI-LC-MS in the negative or positive mode, respectively. Alkylphenol ethoxylates (APEOs) could be confirmed in river water at levels of 5.6 pg L [331]. 

Surface water samples from Southeastern regions of France and from the St. Lawrence River in Canada were monitored by APCI-LC-MS and MS/MS in the positive mode. Diuron and isoproturon were confirmed by MS/MS. Results obtained by LC-MS and ion trap LC-MS/MS were found to be comparable [374]. A substance-specific robust APCI-LC-MS/MS method using short columns for trace analysis of phenylureas was elaborated and vaUdated. Despite the low quantity of sample applied (15 mL) detection limits of < 5 pg L in full-scan and < 750 ng L in SIM mode, respectively, could be achieved. Product ion spectra were obtained from [M-i-H] parent ions and by means of a pesticide MS/MS Hbrary... 

This exercise provides an opportunity to reinforce the principles of spectrophotometry and its relationship to environmental analysis. To minimize laboratory time, the acid hydrolysis step will be eliminated and, thus, only dissolved orthophosphate will be measured. In addition to determining the phosphorus content of a surface-water sample, each student will be given an unknown sample by the instructor whose phosphorus concentration has been previously determined by anionic ion chromatography. 

Seubert, A. Schminke, G. Nowack, M. Ahter, W. Buchberger, W. Comparison of on-line couphng of ion-chromatography with atmosphere pressure ionisation mass spectrometry and with inductively coupled plasma mass spectrometry as tools for the ultra-trace analysis of bromate in surface water samples. J. Chromatogr. 2000,884, 191-196. EC contract SMT4-CT96-2134, EUR report, European Commission, No. 1960, ISBN 92-828-9401-0 Brussels. 2000. 

The methods that can be used for the determination of uranium isotopes in environmental samples were briefly surveyed (Borylo 2013). The methods were divided into radiometric methods that include different techniques of neutron activation analysis, liquid scintillation and alpha spectrometry and nonradiometric methods that include ICPMS and its variations and TIMS, and methods for assaying the amount of uranium (without isotopic composition) like ICP-OES, atomic absorption, and x-ray-based methods. The types of environmental samples listed were plants, mosses, water, soil, phosphates, sediments, and surface water. Sample preparation procedures were mentioned only in passing, stating that digestion (or mineralization) with concentrated acids (HNO3, HCl, and HE) should be followed by anion exchange on suitable resins. For alpha spectrometry, uranium was purified and deposited on steel disks (Borylo 2013). 

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