
Evaluation of Heavy Metal levels in wild birds / Garip et al. __________________________________________________________________________
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grey heron; the concentration in two samples of the grey heron was 
0.18–2.82 ppb, lower than the concentration (6 ppb) found in the 
study conducted by Vega Benito et al. [26] in Spain. In the study, 
the As concentration of white stork was below LOD in two samples, 
4.44–25.44 ppb in two samples, and higher than that in one sample 
in the As concentrations (9.81 ± 2.09–31.68 ± 48.72 ppb) in the studies 
carried out in Spain between 1998–2008, but similar to that in one 
sample [3, 17, 21, 26, 32, 33]. When the As levels in this study were 
analysed by considering the previous information, it was found to be 
lower in the other samples except for one sample in the white stork 
which was similar. Heavy metal pollution varies according to factors 
such as environment (industrial development in the sampling sites), 
substance (chemical properties, duration of exposure, amount), and 
organisms (species, age, sex, habitat, varying dietary characteristics, 
behavior, and biomass) [2, 23, 32, 33].
In the study conducted by Carneiro et al. [4] on common buzzards 
blood samples in Spain, the Hg concentration (209.40 ± 267.28 ppb) 
was similar and higher than the concentrations of 399.53, 445.38, 
478.98 ppb in three samples in this study, while it was 32.87 ppb lower 
than one sample in this study. Hg concentrations were determined 
as (99.4 and 74.93 ± 84.64 ppb) in studies conducted by Alvárez et al. 
[23] and Carneiro et al. [31] in Spain with black kites blood samples. 
In the present study, the concentrations determined as 27.81–
2,563.61 ppb were lower in one sample and higher in three samples 
compared to the studies conducted in Spain. The Hg concentration 
(209.40 ± 267.28ppb) in the study conducted by Carneiro et al. [4] in 
the common buzzard in Spain was found to be 17.05–43.55 ppb higher 
than the concentration in the common kestrel.
The Hg concentration (43.2 ppb) in marsh harrier determined by Alvárez 
et al. [23] in Spain was lower than the present study (65.55–368.11 ppb). 
In the study, the Hg concentration in grey heron was 310.21–7,920.84 
ppb, lower than the concentrations determined by Alvárez et al. [23] in 
Spain (288 ppb). This study revealed the Hg concentration in white stork 
as 44.46–393.07 ppb; while the concentration in one sample was lower 
than the concentrations determined in the studies conducted in Spain 
(16.48 ± 1.94—153.20 ± 123 ppb), three values were determined at higher 
concentrations than the studies [23, 28, 34]. The Hg concentration in 
the present study was found to be generally higher in species other than 
common kestrels compared to previous studies. Since there was no 
study in which Hg levels were determined from blood samples in common 
kestrel, it was compared with the common buzzard, with a similar 
feeding habit. It is considered that this difference may be attributed 
to the variation between the species. Birds inhabiting aquatic habitats 
increase microbial conversion of inorganic Hg to methyl Hg, in wetland 
and marsh habitats; therefore, Hg concentrations increase in these 
birds [34]. High Hg concentrations in aquatic birds are consistent with 
other studies, as sh and zooplankton have higher Hg concentrations 
[35]. Aquatic birds are at higher risk for Hg because they feed in aquatic 
habitats [34]. The elevated Hg concentrations in predatory birds have 
been associated with the consumption of Hg–containing pesticides 
and fungicides by rodents [6]. Hg concentrations should be monitored 
continuously to avoid toxicological concerns.
In the study, the Zn concentrations were determined as 9,230.43–
19,698.93; 13,579.91–23,721.84, and 5,918.87–12,176.38 ppb in common 
buzzard, black kite, and common kestrel, respectively. When the 
concentrations in common buzzards and common kestrels were 
compared with black kites, it was found that Zn concentrations 
in black kites in Spain (3,300–5,370 ± 990 ppb) were lower in 
common kestrels except for one sample [3, 7, 21, 26]. While the Zn 
concentrations in marsh harrier and grey heron were determined 
as 14,858.10–78,594.65, 520.26–64,739.32 ppb, respectively, in the 
present study; the study by Benito et al. [26] in grey heron in Spain 
was found to be higher than the concentration (2,200 ppb) in one 
sample for grey heron, lower than three samples and lower than four 
samples for marsh harrier. It was observed that Zn concentrations 
of 10,896.28–12,616.42 ppb in white storks were compatible with 
Zn concentrations (1,900–11,218 ± 6,016ppb) in studies conducted in 
Spain [3, 17, 21, 26, 32]. 
It was observed in the present study that Cu values of 359.45–
653.19; 551.61–1,077.07, and 435.36–870.09 ppb in common buzzard, 
black kite, and common kestrel, respectively, were compatible with 
and higher than Cu concentrations (211–368.65 ± 72.78 ppb) in studies 
conducted in Spain [3, 7, 21, 26]. In the study, Cu concentrations were 
612.80–1,123.96 and 46.48–1,207.70 ppb in marsh harrier and grey 
heron, respectively, and higher than the concentration (352 ppb) in 
the study conducted by Benito et al. [26] in grey heron in Spain except 
for one sample in grey heron. The Cu concentration in white storks 
was 679.30–879.37 ppb in the study, which was compatible with the 
concentrations found in studies conducted in Spain (319.74 ± 88.34— 
10,880 ± 1,100 ppb) [3, 17, 21, 26, 32]. White storks are susceptible to the 
accumulation of various pollutants such as metals and pesticides [2]. 
It has been reported that Cu and Zn concentrations rise in white storks 
in areas where copper enterprises are located and pollution is intense 
[17, 33]. Technological advances and metal melting processes resulted 
in more accumulation of Cu in soil, surface water, and groundwater, 
which would be dangerous for the environment [20].
In the study, the Se concentrations were found to be 475.93–759.68, 
518.90–626.48, and 524.78–765.33 ppb in common buzzard, black kite, 
and common kestrel, respectively, higher than the concentration 
(359ppb) in the study conducted in Spain by Alvárez et al. [23] in black 
kites. In the study, the Se value was found to be 505.17–1,942.39 ppb in 
marsh harrier and higher than the concentration (299 ppb) in the study 
conducted by Alvárez et al. [23] in Spain. The Se concentrations in 
grey heron and white stork were 45.15–3,219.44 and 367.34–699.61 ppb, 
respectively; higher than one sample and lower than three samples in 
grey heron, and higher than all samples except one in white stork, for 
the concentrations in the studies conducted in white storks in Spain 
(382– 461.00 ±70.40 ppb) [23, 34]. No studies were found in which the 
amount of Se was determined by blood samples in common buzzards, 
common kestrels, and grey herons. For this reason, since the common 
kestrel was compared with the black kite and the grey heron was 
compared with the white stork, it is thought that this difference may 
be due to the difference between the species. The Se concentrations 
of bird species were generally higher than the values reported in the 
literature [22]. 48,000 ppb blood Se levels have been reported to be 
the temporal threshold for reproductive and survival effects [30]. 
However, the levels seen in this study are below the threshold for 
adverse reproductive outcomes. In Turkey, studies conducted by 
Temamoğullari and Dinçoğlu [36] in well water in Şanlıurfa, by Tokatli 
[37] in drinking water in the Ergene River basin, and by Yabanli and Tay 
[38] with sh muscle tissues in Muğla reported that selenium ratios 
were high. This conrmed that the high levels of Se in the present 
study were ingested by birds through soil, water, or food.
Especially young, sick, and small black kites are vulnerable to 
environmental contamination. Also, pollution has serious effects 
on the population size of black teal [7]. Researchers have reported 
that an elevation in toxic metal levels is associated with decreased 
fertility and a higher mortality rate [8]. Since black kites breed in