Mercury has been used in munitions and for other purposes on military bases. This use has,
in some cases, led to contamination of soils at the bases (Bricka et al., 1994); with the potential
for further contamination of surface and groundwaters.
Mercury contamination of soils,
surface water and groundwater is found at a former military base in southern New Jersey,
USA. The Hg content of soils ranged up to 555 mg/kg, and concentrations in some streamwater
and groundwater samples exceeded 2,000 ng/L; determining whether the Hg derives solely
from military activities is a part of ongoing investigations there (Barringer et al., 2012).
From the early-to-late 20
th
century, Hg was used in agricultural pesticides, but use of Hg
compounds decreased substantially after 1970 in the USA (Murphy & Aucott, 1999). Mercurial
compounds also were once used on golf courses in the USA, being most heavily applied in
northern States to control snow mold. On a golf course in New Hampshire, USA, Estes et al.
(1973) estimated that annual fungicide applications contributed 2.1 kg of Hg per hectare. In
Australia, sugar-cane setts were treated with a fungicide containing methoxymethylmercury
chloride before planting; concentrations of Hg from 30 to 670 ng/L were found in groundwater
underlying
cane cropland, but were interpreted as being within the range of naturally
occurring Hg concentrations in area groundwater (Brodie et al., 1984). It is apparent that not
all applications of Hg to soils result in groundwater contamination, but there are instances
where Hg can be mobilized from soils to groundwater.
In the early to mid-20
th
century, phenylmercuric acetate was used in orchards; calomel and
HgCl
2
were used on row crops; these are known to be used on sandy agricultural soils of the
Coastal Plain of southern New Jersey, USA (Murphy & Aucott, 1999). Inputs of Hg would have
been high if the federally recommended application rates of 3.4 kg/hectare for highly soluble
HgCl
2
were followed (Barringer et al., 1997 and references therein). Mobilization of Hg from
applications of mercurial compounds, enhanced by subsequent disturbance from residential
development of the land, may be the cause of elevated Hg concentrations on groundwater
downgradient from such sources. Water from wells completed in the quartz sand aquifer
beneath the former agricultural land contains Hg at concentrations exceeding 2,000 ng/L
(Barringer et al., 2005; Barringer & Szabo, 2006).
In addition to pesticides, Hg also could be introduced to soils via fertilizers. A commercial
20-20-20 fertilizer solution prepared according to manufacturer’s directions contained 280,000
ng/L of Hg (Barringer & MacLeod, 2001). Mercury was measured in several common fertilizers,
with the highest concentration (5.1 mg/kg) found in calcium superphosphate, and a lower
concentration (1.2 mg/kg) in 15-5-5 Nitrogen-Phosphorus-Potassium (NPK) fertilizer (Zhao &
Wang, 2010). Some States in the USA are acting to regulate the amount of metals permissible
in fertilizers and other agricultural chemicals (e.g. ODA, 2002).
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