6 Source and Fate of Perchlorate in the Environment: A Grave …
143
2014). ClO 4
− salts of potassium and ammonium are the primary oxidants in pyrotechnic mixtures, and many cases of surface water contamination by ClO 4
− residue from
firework displays (Fram and Belitz 2011) are reported. For example, high concentration of ClO 4
− is observed in surface water samples in Harbour (Canada), even
four days after a firework display (Backus et al. 2005). Study of Tan et al. (2005)
reveals that ClO 4
− contamination of stream water (up to 400 µg L
−1 ) and sediment
pore water (up to 30 µg L
−1 ) in Texas (USA) attributed to a solid fuel rocket motor
manufacture that closed in 1995.
6.4.2.3 Groundwater
Soil ClO 4
− is considered as chief source of ClO 4
− in groundwater. Capillary forces
and surface tension compel dissolved ClO 4
− to be trapped within soil pores but not
to sorb to soil particle due to electrostatic repulsion (Albright et al. 2008). Biological
degradation of ClO 4
− while percolation through soil is restricted up to shallow depth
as organic matter generally decreases with greater depth, and this lack of degradation
leads to direct infiltration of ClO 4
− into the groundwater zone (Ridley and Tock
2005). For example, unsaturated zones of the arid and semi-arid southwestern United
States are an important source of ClO 4
− contamination in groundwater (Jackson et al.
2005; Parker et al. 2008; Rajagopalan et al. 2006; Rao et al. 2007). Groundwater even
shows seasonal variation in ClO 4
− levels in groundwater of Harbin, North China (Ye
et al. 2013). ClO 4
− of groundwater even has geogenic origin too. For example,
groundwater from upstream parts in the Middle Rio Grande Basin of North-Central
New Mexico contains ClO 4
− which is attributed by natural deposition (Plummer
et al. 2006). On the contrary, source of ClO 4
− contamination in groundwater of the
Po River Delta plain, Italy, is Chilean nitrate fertilizer (Mastrocicco et al. 2017).
Substantial accumulation of natural or synthetic ClO 4
− in the unsaturated zone is of
high threat as it may cause rapid increase in ClO 4
− concentration in groundwater
if artificial recharge from irrigation exceeds recharge from precipitation (Fram and
Belitz 2011).
6.4.2.4 Drinking Water
Hypochlorite solutions are used as a disinfectant in the water treatment process, and
this ClO 4
− may subsequently contaminate drinking water. For example, ArandaRodriguez et al. (Aranda-Rodriguez et al. 2017) have detected ClO 4
− concentration
in a range of 0.06 and 5.7 µg L
−1 in treated water from Canadian drinking water
treatment plants. The presence of ClO 4
− in soil may lead to acceleration in mineral dissolution process and therefore, probably enhance the concentration of toxic
heavy and/or trace metals into the soil and groundwater. Therefore, sites having high
ClO 4
− contamination in soil or groundwater generally have substantial amounts of
heavy/trace metals in it, and it could be a possible path of releasing metals to the
surface water and groundwater and finally, accumulated in living organisms both
143
2014). ClO 4
− salts of potassium and ammonium are the primary oxidants in pyrotechnic mixtures, and many cases of surface water contamination by ClO 4
− residue from
firework displays (Fram and Belitz 2011) are reported. For example, high concentration of ClO 4
− is observed in surface water samples in Harbour (Canada), even
four days after a firework display (Backus et al. 2005). Study of Tan et al. (2005)
reveals that ClO 4
− contamination of stream water (up to 400 µg L
−1 ) and sediment
pore water (up to 30 µg L
−1 ) in Texas (USA) attributed to a solid fuel rocket motor
manufacture that closed in 1995.
6.4.2.3 Groundwater
Soil ClO 4
− is considered as chief source of ClO 4
− in groundwater. Capillary forces
and surface tension compel dissolved ClO 4
− to be trapped within soil pores but not
to sorb to soil particle due to electrostatic repulsion (Albright et al. 2008). Biological
degradation of ClO 4
− while percolation through soil is restricted up to shallow depth
as organic matter generally decreases with greater depth, and this lack of degradation
leads to direct infiltration of ClO 4
− into the groundwater zone (Ridley and Tock
2005). For example, unsaturated zones of the arid and semi-arid southwestern United
States are an important source of ClO 4
− contamination in groundwater (Jackson et al.
2005; Parker et al. 2008; Rajagopalan et al. 2006; Rao et al. 2007). Groundwater even
shows seasonal variation in ClO 4
− levels in groundwater of Harbin, North China (Ye
et al. 2013). ClO 4
− of groundwater even has geogenic origin too. For example,
groundwater from upstream parts in the Middle Rio Grande Basin of North-Central
New Mexico contains ClO 4
− which is attributed by natural deposition (Plummer
et al. 2006). On the contrary, source of ClO 4
− contamination in groundwater of the
Po River Delta plain, Italy, is Chilean nitrate fertilizer (Mastrocicco et al. 2017).
Substantial accumulation of natural or synthetic ClO 4
− in the unsaturated zone is of
high threat as it may cause rapid increase in ClO 4
− concentration in groundwater
if artificial recharge from irrigation exceeds recharge from precipitation (Fram and
Belitz 2011).
6.4.2.4 Drinking Water
Hypochlorite solutions are used as a disinfectant in the water treatment process, and
this ClO 4
− may subsequently contaminate drinking water. For example, ArandaRodriguez et al. (Aranda-Rodriguez et al. 2017) have detected ClO 4
− concentration
in a range of 0.06 and 5.7 µg L
−1 in treated water from Canadian drinking water
treatment plants. The presence of ClO 4
− in soil may lead to acceleration in mineral dissolution process and therefore, probably enhance the concentration of toxic
heavy and/or trace metals into the soil and groundwater. Therefore, sites having high
ClO 4
− contamination in soil or groundwater generally have substantial amounts of
heavy/trace metals in it, and it could be a possible path of releasing metals to the
surface water and groundwater and finally, accumulated in living organisms both