Rivers sampling methods

This system has been employed quite successfully to process water samples in excess of 1000 L (Table III). In each of the examples cited, a 10-L column of A-7 resin was used with the exception of the Suwannee River sample, this quantity of resin was sufficient to process the entire sample without regenerating the resin. The method of Leen-heer and Noyes (10) differs from the XAD-8 method in that the filtered sample does not require adjustment to pH 2 before concentration. This... 

Monitoring is relatively easy in small wadeable streams, where two persons can sample several stations in one day. Electro-fishing in small rivers and streams provide a very robust and efficient sampling method because most fish species can be caught with high and stable efficiency. However, when the method is applied in larger and deeper (non-wadeable) rivers using a boat, the results become subject to much more variation and bias. 

Whether the Mattole River sample of Kennedy et al. Q2) contained a significant amount of Alb cannot be determined from the data they presented. Colloidal particulates that perhaps contained Ale were probably present in material passing through the 0.45 pm filter. The extraction procedure used in their experiments involved a 15 minute contact time of the 8 quinolinol reagent with the sample making it likely that some, at least, of the Alb fraction would be extracted. The method of Barnes (28) uses the same extractant but only a 10 sec. contact time, in order to minimize extraction of polymeric Al species. 

A recent application involved a quick phenol analysis from an industrial accident at a pulp and paper mill near Temiscaming, Quebec. Ottawa river samples were collected and analyzed on-site by quick test kits (Hach DR2000, method 470). Additional water samples were brought back and confirmational analyses were performed by SPME, using a polar acrylate fiber and GC/MSD. The water samples were modified with salt addition and PH adjustment. A target list of 18 phenol compounds can be detected at 10 ppb level. None of the water samples had any deteetable amounts of phenol as found by the quick screening tests. There were, however, traces of trichlorophenol (1 ppb or less) and pentachlorophenol (30 ppb or less), both well below the Quebec provincial criteria of 3 ppm (Lambert, 1999). 

The environmental sampling of waters and wastewaters provides a good illustration of many of the methods used to sample solutions. The chemical composition of surface waters, such as streams, rivers, lakes, estuaries, and oceans, is influenced by flow rate and depth. Rapidly flowing shallow streams and rivers, and shallow (<5 m) lakes are usually well mixed and show little stratification with... 

The zone elution method has been used for quantitative estimation or recovery of heavy metals in plants and vegetable juices [29], mercury (11) in river and waste waters [52], zinc in different environmental samples [46], nickel and copper in alloys [53], zirconium in Mg-Al alloys [22], cobalt, zinc, nickel, and copper in natural water and alloy samples [54], thiocyanate in spiked photogenic waste water [55], and aluminum in bauxite ores [42],... 

A monitoring system has been established to determine 90 pesticides including anilides and 10 related degradation products in river water. Pesticide residues in the water sample are collected on a PS-2 cartridge (265-mg) at a flow rate of 10 mL min, eluted with 3 mL of acetone, 3 mL of n-hexane and 3 mL of ethyl acetate successively, and determined by GC/MS. Overall recoveries ranged from 72 to 118%. Recoveries of mepronil, naproanilide, propanil and flutolanil at fortification levels of 0.1 and 2 mg kg Mn water by this method were 80-112%. The LODs were 0.01 -0.1 pg L ... 

A multi-residue method for 25 selected pesticides including propanil using an SPE disk has also been developed as a rapid screening method for organic contaminants in river, lake and seawater samples. Cig SPE disks are conditioned with 10 mL of acetone for 3 h. Water samples (1L) are allowed to percolate through the disks in order to trap the residues at a fiow rate of 50 mL min under vacuum. Residues trapped in the disks are extracted twice by eluting with 5 mL of dichloromethane-ethyl acetate (1 1, v/v). The more hydrophobic compounds (log/fow>3) seem to show no... 

Crescenzi et al. developed a multi-residue method for pesticides including propanil in drinking water, river water and groundwater based on SPE and LC/MS detection. The recoveries of the pesticides by this method were >80%. Santos etal. developed an on-line SPE method followed by LC/PAD and LC/MS detection in a simultaneous method for anilides and two degradation products (4-chloro-2-methylphenol and 2,4-dichlorophenol) of acidic herbicides in estuarine water samples. To determine the major degradation product of propanil, 3,4-dichloroaniline, the positive ion mode is needed for atmospheric pressure chemical ionization mass spectrometry (APCI/MS) detection. The LOD of 3,4-dichloroaniline by APCI/MS was 0.1-0.02 ng mL for 50-mL water samples. 

Accurate measurements of hydrogen sulfide water levels are usually complicated by the presence of other sulfide compounds. A method of determining sulfide concentration in waste water by first transforming it to hydrogen sulfide and then measuring the atomic absorption of the product yielded results ranging from 3.1 to 5.1 ppm of sulfide sulfur (Parvinen and Lajunen 1994). Total sulfide levels in samples from the Mississippi River were about 0.92 ppm, while levels in pond and well water in St. Paul, Minnesota were 1.6 and 1.9 ppm, respectively (Slooff et al. 1991). 

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