Environmental Engineering Reference
In-Depth Information
14.2.2  Paraquat
Paraquat is a contact-action herbicide, used to control a broad range of unwanted plants
in cereal, oilseed, fruit, and vegetable cultivations. Due to its polar and ionic nature, it
is unlikely to bioaccumulate in food chains. Paraquat is toxic to animals and man, with
mammals generally being more sensitive than birds based on the LD 50 .
Deliberate or accidental poisoning has been described in the literature for several
domestic mammal species (Bischoff et al. 1998; Philbey and Morton 2001; Berny et al. 2010;
Guitart et al. 2010a). Paraquat has also been implicated in the decline of the European
brown hare ( Lepus europaeus ) populations in Europe, and although a retrospective study
of reported incidents in France and the United Kingdom revealed that the residues of the
herbicide were detected in the stomach, urine, liver, and kidney contents of some animals,
Edwards et al. (2000) concluded that this is confirmation of exposure but not of death due
to paraquat.
14.2.3  Glyphosate
Glyphosate, currently one of the most widely used herbicides in a huge variety of agri-
cultural, lawn and garden, aquatic, and forestry situations, is an OP herbicide without
anticholinesterase activity. It is considered poorly toxic, and only a few poisoning cases
have been described in the literature (Burgat et al. 1998; Berny et al. 2010). Most of the
adverse effects of glyphosate use to wildlife are related to indirect effects on birds and
mammals (Sullivan and Sullivan 2003; Aktar et al. 2009), such as when treatment in some
zones caused dramatic decreases in the populations of native birds (MacKinnon and
Freedman 1993).
Residues of glyphosate can be detected in the viscera of herbivorous animals in amounts
that remained above 1 μg/g for the first 2 weeks after treatment, then decreased to almost
the minimum detection limit (0.10 μg/g) by day 55, with the levels in carnivorous small
mammals being distinctly lower (Newton et al. 1984), suggesting that biomagnification
does not occur.
14.3 Fungicides
The only fungicide for which extensive data on the residues in birds and mammals is
available is HCB, a classical POP with a strong tendency to accumulate in food chains and
the lipid-rich tissues of animals (Zitko 2003b).
Older inorganic fungicides that are mercury-, cadmium-, or chromium-based are con-
sidered bioaccumulative as well as very toxic and nonselective products and are mostly
prohibited today. Less problematic copper-based fungicides are still in use in many coun-
tries, although chronic copper poisoning is one of the main diseases associated with the
sudden death of sheep across the world (Plumlee 2004; Roubies et al. 2008; Guitart et al.
2010a).
Organomercurial compounds were used in agriculture as fungicidal seed dressings. In
Sweden, a widespread contamination of the environment and serious secondary poison-
ings in some mammalian predators such as red foxes ( Vulpes vulpes ), martens ( Martes mar-
tes ), and polecats ( Mustela putorius ) during the late 1950s and early 1960s because of the
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