In recent decades, numerous studies have been conducted on the presence of trace elements in the environment, many of which have lookedat its effects on human and animal health andon wild birds.(54) Quoted from (2),( 61), (64).
The standard limits for heavy metals have not been stated in the various organs of birds, but the measurement can be comp industrial ared with other studies. In our research, the average total concentration of trace elements in species in the industrial town Zinc-Zanjan (aggregation of male, female, live and dead species) and the final average in the lead, zinc and cadmium elements are 16.14175, 326.678625, and 1.626124 μg/g, respectively, as well as the average concentration of lead zinc and cadmium elements in the control species were obtained 1.85, 49.75, and 0.58 μg/g.
According to Janssen's study, the amount of lead in Parus major feathers was obtained 31.2 ± 230 μg/g and in Eens study, the amount of lead in blue and great tit tail feathers were obtained 15.2±640 and 1.8 ± 16.03 μg/g (38),( 23). Research studies have shown that the average concentration of lead in pigeon feathers in France, Korea, Israel, Slovakia, Brazil are 0-5 μg/g, the average concentrations of zinc in pigeons in France, Israel, and Brazil were between 90-300 μg/g and the average concentrations of cadmium in pigeons in France, Israel, and Brazil were 0.04-3 μg/g) (25),(39),(52),( 4),( 9). In a study of common buzzard in northern Italy, the mean concentrations of lead and cadmium in bird feathers were found to be 1.48 and 0.060 mg/kg dw[1], respectively (13). In a study conducted on Laughing dove, the mean lead concentration in feather was 0.01± 19.88 μg/g and for cadmium was 0.03 ± 0.87 μg/g (7). Lead for Hirundo rustica, which was collected near the contaminated area and along a highway in Maryland, USA, was found in the range of 43-820 μg/g (29). In the study of (59), the mean concentration of lead, zinc, and cadmium in great egret were obtained 0.78, 168.96, and 0.25 μg/g, respectively. In the study on E. gularis and L. heuglini, cadmium concentrations were measured at 1.16 and 1.37 μg/g, respectively, and lead concentrations were measured at 7.04 and 5.48 μg/g, respectively (49). In a study conducted on pellets of blue rock pigeon in India, the highest concentration of lead, cadmium, zinc, were found (79.6 ± 42.69 μg/g; 1.12 ± 0.60 μg/; 2250 ± 1390.16 μg/g) respectively ( 15(.
Studies on birds contaminations has shown that the amount of trace elements in gender is different.
In our study, the average concentration of trace elements of lead, zinc and cadmium, aggregation between the dead and the live, about lead element in the female and male were 16.3 and 15.9885 μg/g, the average of zinc element in the female and male were 343.201 and 310.15625 μg/g and the average concentration of cadmium element in the female and male were 1.70225 and 1.55 μg/g, respectively. In addition, the average elements in control species were the average of lead element in the female and male 2.2125 and 1.4875 μg/g, the average of zinc element in the female and male 53.5 and 46 μg/g, and the average of cadmium element in the female and male 0.7125 and 0.4475 μg/g, respectively.
in research on black ducks, the levels of metals in males were higher than in females. In Scaups, lead levels in females were significantly higher than in males (31). In a study of the Fulica atra, the average lead concentration in males was higher than females (35). By researching on the Larus genei, the average concentration of lead and cadmium in the male bird and the amount of zinc in the female bird were higher (34). In the Phalacrocorax carbo study, the amount of zinc metal in the female bird's muscle was higher than in the male (42). Research on Egretta alba has shown that there is a statistically significant difference in the average concentrations of heavy metals of lead, zinc and cadmium in the feather tissue between males and females (59). However, in the study of great tits, there was no significant difference between Cd and Pb levels between males and females. The concentration of Zn in males was higher than in females (21). In a study conducted on Ardea cinerea, the difference between the amounts of heavy metals between the genders is very small compared to other different samples (50).
[1]-Miligram/ Gram/ Dry Weight