Sustainable Water Management - Sustainable Practices in Geoenvironmental Engineering - page 87

Water quality in urban runoff can also be monitored by remote sensing. Ha et al. (2003)
combined Landsat, the Korea Multi-Purpose Satellite (KOMPSAT) with two types of neu-
ral networks. Runoff, peak time, and contaminant data could be obtained to determine
water quality in an urban area. In the Netherlands, a remote sensing system was tested to
construct maps of water quality (Hakvoort et al., 2002). A hyperspectral scanner was set
up in an airplane to retrieve information on subsurface relectance spectra, speciic inher-
ent optical properties (SIOP) of the water components and the Gordon relectance model
using a matrix inversion technique. Data for both total suspended matter and chlorophyll
were obtained when circumstances were good, and reliable data mainly only for total sus-
pended matter under less ideal conditions. Information on dissolved organic matter levels
could not be obtained. The matrix inversion technique for airborne image was particularly
promising.
Signiicant advances have been made in the last decade concerning the levels of detec-
tion, information about contaminants including speciation and the speed of monitoring of
contaminants in water, as regulatory requirements become more demanding. For example,
the U.S. Groundwater Rule is being established to provide a risk-based regulatory strategy
for groundwater systems that can be sensitive to fecal contamination.
Another example is the Arsenic Rule where the rule agreed that 10 μg/L of arsenic
would be the standard from 2002 onward for drinking water (USEPA, 2012a). Drinking
water systems must comply by 2006. Analytical methods for determining the different
arsenic species include SPME and solid-phase extraction (SPE) with GS/MS, liquid chro-
matography (LC)/electrospray ionization mass spectrometry (ESI-MS), LC/ICPMS, and
ion chromatography (IC)/inductively coupled plasma mass spectrometry (ICPMS). Field
kits have also been used, particularly in Bangladesh and West Bengal. However, there have
been problems with their accuracy (Erickson, 2003).
Methyl tert -butyl ether (MTBE) has recently been of concern because of the problem of
leaking underground storage tanks, pipeline breaks, and other fuel discharges. Monitoring
of this compound is now required, with detectable values that must not exceed 20 μg/L
99% of the time (USEPA, 2012b). In a study by Williams (2001) in California from 1995 to
2000, 1.3% of all drinking water samples contained detectable levels of MTBE. More than
75% were below 13 μg/L. In Germany, Achten et al. (2002) found average levels of 88 ng/L
in well water and iltered riverbank samples. Lacorte et al. (2002) found that 7 out of 21
groundwater samples in Catalonia Spain had levels exceeding 20 to 40 μg/L. Methods
to measure MTBE have been reviewed by Richardson (2003), including headspace, purge
and trap, or solid-phase microextraction (SPME) combined with gas chromatography (GC)
or gas chromatography/mass spectrometry (GC/MS) analysis. Detection levels are in the
order of nanograms per liter range.
Following water contamination cases such as Walkerton in Ontario, Canada, where
Escherichia coli gastroenteritis occurred in 2000, the importance of analytical methods for
microorganism detection has increased. Due to the deiciencies in the standard methods
for detection of viruses, bacteria, and protozoa, particularly length of time, various new
methods have been developed. These include (a) immunoluorescent antibodies tech-
niques, (b) luorescent in situ hybridization, (c) magnetic bead cell sorting, (d) electroche-
miluminescence, (e) amperometric sensors, (f) various polymerase chain reactions (PCR),
RT-PCR, and (g) realtime PCR methods (Straub and Chandler, 2003), and (h) immuno-
magnetic separation. Richardson (2003) has also indicated that several reviews have been
published using mass spectrometric techniques for characterization of microorganisms.
Analysis of herbicides and pesticides is also of interest because of their effects on human
health and the environment. A ield kit has been evaluated by Ballesteros et al. (2001) for