Pesticide Residues in Birds and Mammals - Pesticides: Evaluation of Environmental Pollution - page 425

proportions of α- and γ-isomers suggest metabolic degradation (Tanabe et al. 1997). In fact,
β-HCH differs largely in its physicochemical properties from all the rest of HCH isomers
(Bhatt et al. 2009). The presence of an unusually high proportion of lindane could suggest
a recent use of this pesticide, as has been observed in birds from France (Berny et al. 2002),
Spain (Herrera et al. 2000; Mañosa et al. 2003; Guitart et al. 2005; van Drooge et al. 2008;
Martínez-López et al. 2009), Greece (Sakellarides et al. 2006), Argentina (Cid et al. 2007),
India (Dhananjayan and Muralidharan 2010), Iran (Rajaei et al. 2010b), and Pakistan (Malik
et al. 2011); marine mammals from Tanzania (Mwevura et al. 2010); ring-tailed lemurs
( Lemur catta ) from Madagascar (Rainwater et al. 2009); mustelids from France (Lemarchand
et al. 2010); and bovine milk from Iran (Bayat et al. 2010).
On the other hand, endosulfan is a special case and a candidate to be included in a new
group of POPs (Weber et al. 2010). Contrary to many other OC pesticides, by the year 2010,
this insecticide had only been banned in approximately 60 countries, and India and China
are the biggest users due to its inexpensive economical cost (Lubick 2010). Commercial
endosulfan is a mixture of two isomers, namely α- and β-endosulfan, and in the environ-
ment, the cyclic sulfate group of endosulfan can be oxidized to the corresponding endo-
sulfan sulfate, which appears to be the most persistent. Residues of endosulfan, although
normally at much lower concentrations than other OC pesticides in the biota, have been
reported, and many data on the trends point to an increase in the environmental levels,
and there is a growing concern about their impact especially on the marine environment
(Li and Macdonald 2005; Muir and de Wit 2010; Weber et al. 2010).
Interestingly, mirex levels in the blood of south polar skuas ( Catharacta maccormicki )
from Antarctica were among the highest reported in birds, the mean level being 3 and
26 times higher than those in comparable species of the Arctic glaucous gull and great
black-backed gull ( Larus marinus ): 20.7 vs. 6.9 and 0.8 ng/g WW, respectively, exceeding
even p,pʹ-DDE (Bustnes et al. 2006). Mirex was also found in the eggs of African darter,
cattle egret, and other species from South Africa, where this insecticide (but also a flame
retardant) has never been registered as a pesticide (Bouwman et al. 2008). In franciscana
dolphins from Southern Brazil, Leonel et al. (2010) found that the mirex levels did not dif-
fer over the period from 1994 to 2004 or even show a slight increase; and in polar bears
from the Hudson Bay, Canada, McKinney et al. (2010) found no significant changes in the
contaminant levels between 1991 and 2007.
14.4.1.1 Birds
Several studies have reported OC concentrations in eggs from different areas of the world
in order to evaluate both temporal and spatial variations in the pollutant status of par-
ticular ecosystems and to determine the potential adverse effects on animal populations
(Mañosa et al. 2003; Muñoz-Cifuentes et al. 2003; Herkert 2004; Mateo et al. 2004; Vorkamp
et al. 2004; Buck et al. 2005; Braune 2007; Bustnes et al. 2007; Strause et al. 2007; Henny et al.
2009; Best et al. 2010; Van den Steen et al. 2010). In birds, POP insecticides may impair
reproduction (reduced egg production, eggshell thinning, decreased fertility and hatch-
ability, and others), affect the ability to compete for food and habitat, impair the capacity
to avoid predation, and contribute to reduced parental attentiveness (Peakall 1996; Berny et al.
2002; Giesy et al. 2003; Walker 2003; Fisk et al. 2005; Mineau 2005; Bernanke and Köhler
2009; Grove et al. 2009). For example, during the late 1960s and into the 1970s, instances
of reproductive failure, developmental anomalies, and population declines were reported
for the species of raptorial and fish-eating colonial water birds from the North American
Great Lakes ecosystem (Hoffman et al. 1990; Bernanke and Köhler 2009; Best et al. 2010).