Drainage sampling

From a logistical point of view, the ability to collect a single sample that represents a large area greatly reduces the number of samples needing to be collected. 

The fact that one can collect drainage samples from adjacent tributaries from sites that may only be tens of metres apart greatly reduces the amount of time spent walking between sites. Anyone that has been involved in sampling will testify to the time and effort saved by not having to walk up hills and mountains to collect samples from near watersheds as the stream effectively brings the material down the valleys to the sampler. 

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Collect two rinsing samples from the preparation tank drainage. Sampling will be performed two times, one before the start of cleaning procedure and another at the end of final rinsing water, after completion of cleaning procedure. 

Malaysia (Williams, 2001), Thailand (Williams, 2001), Philippines (Williams, 2001), Brazil (Williams, 2001 Borba, Figueiredo and Matschullat, 2003 Matschullat et al., 2000), Hungary (Odor et al., 1998), Tanzania (Bowell et al., 1995), Zimbabwe (Williams, 2001), and Switzerland (Pfeifer et al., 2004). Williams (2001) is an exceptionally broad survey of arsenic in mine drainage samples from 34 sites in Asia, Africa, and South America. The arsenic concentrations of the waters ranged from 0.005 to 72 mgL-1. Like most other mine drainage results, the majority of samples in Williams (2001) contained less than 5 mgL-1 of arsenic. The arsenic was also well oxidized. As(V) represented more than 50 % of the dissolved inorganic arsenic at 29 of the 34 sites and at least 18 of the sites had more than 95 % of their dissolved arsenic as As(V) (Williams, 2001, 269-270). The pH values of the samples ranged from 0.52 to 10. Only 3 of the 10 sites with arsenic concentrations above 1 mgL-1 had pH values below 4 (Williams, 2001, 269-270). 

The comparison reflected by the data in Figure 18 raises the question-is it possible to measure, for example, the isotopic compositions of bivalve shells, or fish, reptilian or aquatic mammalian teeth preserved within fluvial sediments to determine how high the adjacent mountains were The implication from Figure 18 is that indeed it should be possible to estimate the precipitation weighted hysometric mean elevation of drainages sampled by such materials. Application of this approach to a paleo-case is presented below. 

Figure 19. Comparison of Miocene wet season average bivalve isotopic compositions from Dettman et al. (2001) (dark gray squares) with averaged soil carbonate compositions from Bakia Khola (gray diamonds) reported by Harrison et al. (1993) from the Siwaliks. The difference between these is taken as a measure of A(818Omw) and hence can be used to estimate the precipitation weighted hypsometric mean elevations of drainages sampled by the bivalve shells. Note that in modem world the wet season amount weighted mean...

Figure 20. Estimated precipitation weighted hypsometric mean elevations of paleo-drainages sampled by bivalves in the Siwaliks based on estimated A(8lsO, ) shown in Figure 19 as a function of age. Error bars reflect model uncertainty at 2c based on A(6180 m) of the estimated precipitation weighted hypsometric mean elevations.

Bednar, A.J., J.R. Garbarino, J.F. Ranville, and T.R. Wildeman. 2002. Preserving the distribution of inorganic arsenic species in groundwater and acid mine drainage samples. Environ. Sci. Technol. 36 2213-2218. 

Figure 1.4 Selection of sampling sites, a schematic outline of drainage sampling pattern (from Salminen et al., 1998).

The Collection of Drainage Samples for Environmental Analyses from Active Stream Channels... 

Table 4.1 Explanation of terms used in drainage sampling...

Figure i, 3 Example of field form used for recording information at a drainage sample site. 

There are circumstances where the drainage sample does not represent material derived from the basin upstream of the site, and these should be dealt with at the orientation phase of the project. Such circumstances would include wind-blown material collecting in the drainage channel or exotic materials introduced to the drainage basin through anthropogenic activity. 

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