142
P. Sahu
the ClO 4
− contamination pattern and movement of ClO 4
− contaminated groundwater front, knowledge about local groundwater flow gradients and directions and
hydrogeological properties of the aquifer is essential (Cao et al. 2019).
6.4.1 Flow, Transport and Transformation Pathways
of Perchlorate
Nowadays, ClO 4
− can be identified and measured in micromolar range in the environment, particularly in groundwater, very easily compared to that of the past (Wagner
et al. 2006; Wendelken et al. 2006). ClO 4
− is already detected in water, soil and food,
in nanogram to milligram range, in many countries like USA, Canada, China, South
Korea and India (Her et al. 2011; Kalinski et al. 2007; Kannan et al. 2009; Nadaraja
et al. 2015; Poghosyan et al. 2014; Smith et al. 2006; Ye et al. 2012).
6.4.2 Perchlorate in Water
ClO 4
− is found even much away from its source area as sufficient rainfall may
transport ClO 4
− due to its higher water solubility. Military operations, fireworks and
industrial uses are major causes of ClO 4
− contamination of rainwater, groundwater,
surface water and drinking water.
6.4.2.1 Rainwater
Rainwater samples collected from Ireland and China show different concentrations
of ClO 4
− (Barron et al. 2006). It is observed that ClO 4
− concentrations in rainwater
of urban area are more than that of rural area, probably for air pollution (Qin et al.
2014). In areas where rainwater is the main contributor of surface water, rainwater
becomes important source of ClO 4
− contamination of surface water (Qin et al. 2014).
6.4.2.2 Surface Water
Chilean nitrate fertilizer, having high quantities of ClO 4
− , is intensively used in
agriculture, and it is a proven source of ClO 4
− contamination of surface water. Different foods are also contributor of ClO 4
− in surface water. Low concentrations (0.1–
0.5 mg L
−1 ) of ClO 4
− existed even under natural conditions as background ClO 4
−
across various environments. For example, ClO 4
− detected in Great Lakes like Lake
Ontario, Superior and Michigan of the USA is dominantly natural (Poghosyan et al.
P. Sahu
the ClO 4
− contamination pattern and movement of ClO 4
− contaminated groundwater front, knowledge about local groundwater flow gradients and directions and
hydrogeological properties of the aquifer is essential (Cao et al. 2019).
6.4.1 Flow, Transport and Transformation Pathways
of Perchlorate
Nowadays, ClO 4
− can be identified and measured in micromolar range in the environment, particularly in groundwater, very easily compared to that of the past (Wagner
et al. 2006; Wendelken et al. 2006). ClO 4
− is already detected in water, soil and food,
in nanogram to milligram range, in many countries like USA, Canada, China, South
Korea and India (Her et al. 2011; Kalinski et al. 2007; Kannan et al. 2009; Nadaraja
et al. 2015; Poghosyan et al. 2014; Smith et al. 2006; Ye et al. 2012).
6.4.2 Perchlorate in Water
ClO 4
− is found even much away from its source area as sufficient rainfall may
transport ClO 4
− due to its higher water solubility. Military operations, fireworks and
industrial uses are major causes of ClO 4
− contamination of rainwater, groundwater,
surface water and drinking water.
6.4.2.1 Rainwater
Rainwater samples collected from Ireland and China show different concentrations
of ClO 4
− (Barron et al. 2006). It is observed that ClO 4
− concentrations in rainwater
of urban area are more than that of rural area, probably for air pollution (Qin et al.
2014). In areas where rainwater is the main contributor of surface water, rainwater
becomes important source of ClO 4
− contamination of surface water (Qin et al. 2014).
6.4.2.2 Surface Water
Chilean nitrate fertilizer, having high quantities of ClO 4
− , is intensively used in
agriculture, and it is a proven source of ClO 4
− contamination of surface water. Different foods are also contributor of ClO 4
− in surface water. Low concentrations (0.1–
0.5 mg L
−1 ) of ClO 4
− existed even under natural conditions as background ClO 4
−
across various environments. For example, ClO 4
− detected in Great Lakes like Lake
Ontario, Superior and Michigan of the USA is dominantly natural (Poghosyan et al.