6 Source and Fate of Perchlorate in the Environment: A Grave …
141
be readily flushed and mobilized by introduction of percolation process. Continuous
irrigation has displaced accumulated salts to a greater depth of several meters, and
ClO 4
− is migrated from unsaturated zone to groundwater regime (Rao et al. 2007;
Scanlon et al. 2010). Recent study of Furdui et al. (2018) indicates that anthropogenic
activities trigger another atmospheric input to ClO 4
− sources that are chlorinated
solvents (e.g. methyl chloroform).
6.3.2 Synthetic Perchlorate
6.3.2.1 Production and Uses
In the 1890s, synthetic ClO 4
− was manufactured commercially for the first time in
Masebo, Sweden (Trumpolt et al. 2005). Most common industrial process used for
synthetic ClO 4
− production is use of electrolytic method using sodium chloride as
feedstock (Brown and Gu 2006). Since World War II, ClO 4
− was extensively used
as explosives and propellants. In the USA, 90% of ammonium perchlorate consumption is accounted for the military uses (Duncan et al. 2005). Synthetic NH 4 ClO 4 is
used as a propellant in solid rocket fuels (Mendiratta et al. 1996), and as a consequence, synthetic ClO 4
− producing industries are substantial industry in the USA
and Europe nowadays. Some other uses of ClO 4
− are fireworks, signal flares, white
smoke generators, matches, artillery traces, electroplating solutions, railway torpedoes, gas drying agents, lubricating oils, cloud seeding, tanning, finished leather,
electronic tubes, fabric fixes, dyes, electroplating, aluminium refining, signal and
road flares, rubber manufacture, paint and enamel production, cattle feeds and magnesium batteries (Backus et al. 2005; Cao et al. 2019; Cheng et al. 2004; Dean et al.
2004; Wilkin et al. 2007).
6.4 Fate of Perchlorate in Water
After entering into the natural water systems, fate of ClO 4
− depends on physicochemical properties of that aqueous system. Generally, ClO 4
− ions are highly soluble
in water and stable in environment. Perchlorate degrading anaerobic bacteria may
degrade ClO 4
− if the anaerobic system has exhausted electron donors as oxygen or
nitrate is depleted, and sufficient organic carbon is present. ClO 4
− accumulation at
various horizons of soil at shallow depths is observed in arid and semi-arid regions,
due to high rate of evaporation of infiltrating rainfall containing leached ClO 4
− .
ClO 4
− does not bind to soil particles, and therefore, ClO 4
− movement in soil is
largely dependent on the presence and circulation of water. If sufficient rainfall is
available, ClO 4
− may completely be leached from the soil (Trumpolt et al. 2005)
and contaminate groundwater, and ClO 4
− ions will follow the groundwater gradient
and migrate towards discharge locations (Clausen et al. 2004). But to understand
141
be readily flushed and mobilized by introduction of percolation process. Continuous
irrigation has displaced accumulated salts to a greater depth of several meters, and
ClO 4
− is migrated from unsaturated zone to groundwater regime (Rao et al. 2007;
Scanlon et al. 2010). Recent study of Furdui et al. (2018) indicates that anthropogenic
activities trigger another atmospheric input to ClO 4
− sources that are chlorinated
solvents (e.g. methyl chloroform).
6.3.2 Synthetic Perchlorate
6.3.2.1 Production and Uses
In the 1890s, synthetic ClO 4
− was manufactured commercially for the first time in
Masebo, Sweden (Trumpolt et al. 2005). Most common industrial process used for
synthetic ClO 4
− production is use of electrolytic method using sodium chloride as
feedstock (Brown and Gu 2006). Since World War II, ClO 4
− was extensively used
as explosives and propellants. In the USA, 90% of ammonium perchlorate consumption is accounted for the military uses (Duncan et al. 2005). Synthetic NH 4 ClO 4 is
used as a propellant in solid rocket fuels (Mendiratta et al. 1996), and as a consequence, synthetic ClO 4
− producing industries are substantial industry in the USA
and Europe nowadays. Some other uses of ClO 4
− are fireworks, signal flares, white
smoke generators, matches, artillery traces, electroplating solutions, railway torpedoes, gas drying agents, lubricating oils, cloud seeding, tanning, finished leather,
electronic tubes, fabric fixes, dyes, electroplating, aluminium refining, signal and
road flares, rubber manufacture, paint and enamel production, cattle feeds and magnesium batteries (Backus et al. 2005; Cao et al. 2019; Cheng et al. 2004; Dean et al.
2004; Wilkin et al. 2007).
6.4 Fate of Perchlorate in Water
After entering into the natural water systems, fate of ClO 4
− depends on physicochemical properties of that aqueous system. Generally, ClO 4
− ions are highly soluble
in water and stable in environment. Perchlorate degrading anaerobic bacteria may
degrade ClO 4
− if the anaerobic system has exhausted electron donors as oxygen or
nitrate is depleted, and sufficient organic carbon is present. ClO 4
− accumulation at
various horizons of soil at shallow depths is observed in arid and semi-arid regions,
due to high rate of evaporation of infiltrating rainfall containing leached ClO 4
− .
ClO 4
− does not bind to soil particles, and therefore, ClO 4
− movement in soil is
largely dependent on the presence and circulation of water. If sufficient rainfall is
available, ClO 4
− may completely be leached from the soil (Trumpolt et al. 2005)
and contaminate groundwater, and ClO 4
− ions will follow the groundwater gradient
and migrate towards discharge locations (Clausen et al. 2004). But to understand