Pesticide Residues in Birds and Mammals - Pesticides: Evaluation of Environmental Pollution - page 402

use of these compounds in agriculture and also in the wood-pulp industry were recorded
(Wren 1986; Rattner 2009). Pheasants and other seed-eating birds collected in Alberta,
Canada, where mercury seed dressings were extensively used, contained up to 5.9 μg/g
WW of mercury in the liver, which resulted in the closure of pheasant and partridge hunt-
ing areas in Alberta in 1969 (Fimreite 1970). Jefferies and French (1976) analyzed the speci-
mens of the European wood mouse taken from a wheat field that had been drilled 2 months
previously with wheat dressed with dieldrin and mercury, and found that the whole body
mercury concentrations were much higher on average (0.83 ± 0.44 μg/g WW) than those
found before and 13 days after drilling (0.04 ± 0.005 and 0.39 ± 0.04 μg/g WW, respectively).
14.3.1 Hexachlorobenzene
Due to its low acute toxicity (see Table 14.1 ), HCB was used as a fungicide for seed treat-
ment, but most countries banned its use during the last four decades (Barber et al. 2005).
The International Agency for Research on Cancer (IARC) classified this chlorinated com-
pound as possibly carcinogenic to humans (group 2B) (IARC 2010).
Currently, HCB enters the environment mostly and unintentionally as a byproduct
and waste material from the manufacture of chlorinated solvents and other chlorinated
substances and from old disposal sites (Zitko 2003b). Usually, it is considered that the
environmental levels have been globally declining in the last few decades (Mañosa et al.
2003; Braune 2007; Borrell and Aguilar 2007; Helgason et al. 2008; Vorkamp et al. 2009; Rigét
et al. 2010). Although temporal trends vary depending on the time period measured, the
media studied, and the study location, Barber et al. (2005) estimated an average half-life of
approximately 9 years, from all the published studies.
14.3.1.1 Birds
Birds have been proposed as ideal candidates for environmental monitoring and sur-
veillance purposes since they integrate the POP levels along the food web (Galassi et al.
2002; Sanpera et al. 2003; Dong et al. 2004; Dell'Omo et al. 2008; Helgason et al. 2008; van
Drooge et al. 2008; Dhananjayan and Muralidharan 2010). Although chemical monitoring
using, for example, the blood (or plasma) and tissues from living and dead birds, respec-
tively, have been reported (Herrera et al. 2000; Choi et al. 2001; Guruge et al. 2001; Alleva
et al. 2006; Sakellarides et al. 2006; Cesh et al. 2008; van Drooge et al. 2008; Elliot et al. 2009;
Martínez-López et al. 2009; Dhananjayan and Muralidharan 2010; Rajaei et al. 2010a,b;
Skarphedinsdottir et al. 2010; Dhananjayan et al. 2011), for practical and even ethical or legal
reasons, the eggs are the material of choice in the majority of studies (Jaspers et al. 2005; Van
den Steen et al. 2006, 2009a,b; García-Fernández et al. 2008).
Eggs have been considered a suitable material in the breeding areas, given that their
chemical composition mainly reflects that of the female diet during the period of egg for-
mation (Braune et al. 2001; Verreault et al. 2006; Van den Steen et al. 2009b), the contami-
nant levels found in the eggs may reveal local pollution (Aurigi et al. 2000; Galassi et al.
2002; Chu et al. 2007; Dell'Omo et al. 2008; Van den Steen et al. 2010), and they are easy
to collect and the lipid content is high (Van den Steen et al. 2009a). Compared with the
liver and other tissues of adult females, eggs tend to reflect more long-term contaminant
exposure (Braune et al. 2001; Vorkamp et al. 2004). Although, usually it is considered, for
practical purposes, that a single egg could represent statistically the entire clutch (Berny et al.
2002; Muñoz-Cifuentes et al. 2003; Dong et al. 2004; Van den Steen et al. 2006), for many
species, such as the Audouin's gull ( Larus audouinii ), there is a laying order effect on egg