Due to excessive dependence on groundwater, both for irrigation
and drinking water coupled with over exploitation of ground
water, there has been an apparent tendency for the quality of
groundwater to deteriorate, which has been caused by various
toxic substances [1,2]. Nitrate (NO3
−-N) and heavy metals contamination
and the associated health concerns are among the most
common problems adversely affecting groundwater quality in the
United States and throughout the world [3–6]. The elevated levels
of nitrate in drinking water are related primarily to human health
effects such as methemoglobinemia (infantile cyanosis), neural
tube effects, or spontaneous abortions [7]. Recently, epidemiological
studies have suggested that high nitrate ingestion may also be
a contributing factor in gastric cancer [8]. In addition, cadmium
(Cd(II)) adversely affects several important enzymes and is known
to accumulate in the human kidney for a relatively long time, and
at high dose, it is also known to produce health effects on the respiratory
system [9].
Typically, environmental sampling methods for these contaminants
are accomplished by invasively collecting samples in the
field and transporting them to centralized laboratories for analyses.