{'fraction_non_alphanumeric': 0.023809523809523808, 'fraction_numerical': 0.007549361207897794, 'mean_word_length': 4.860544217687075, 'pattern_counts': {'":': 0, '<': 0, '<?xml version=': 0, '>': 0, 'https://': 0, 'lorem ipsum': 0, 'www.': 0, 'xml': 0}, 'pii_count': 0, 'substrings_counts': 0, 'word_list_counts': {'cursed_substrings.json': 0, 'profanity_word_list.json': 0, 'sexual_word_list.json': 0, 'zh_pornsignals.json': 0}}
Heavy Metals, Resting Metabolism Rates and Breeding Parameters in Two Populations of Black-Headed Gull Larus ridibundus from the Industrially Polluted Areas of Upper Silesia, Poland

Abstract. 
 Black-headed Gulls breeding in the central part of the Upper Silesian Industrial Region (Katowice-Szopienice) in Southern Poland were compared with colony from less polluted area (Świerklaniec) situated 23 km away. Heavy metals: Cd, Pb, Zn and Cu — were determined in various organs of nestlings, fledglings and mature birds as well as egg yolks. Resting metabolic rates, hatching success and eggshell thickness were used as biomarkers of environmental exposure to industrial pollutants. The clutch size (2.97 versus 3.61) and hatching success (81.5% versus 87%) were lower in the colony from the more polluted site. The relatively high metal contents in the yolks indicate that off spring are only partially protected from toxic compounds. Gulls were able to regulate body contents of essential metals Zn and Cu, but Pb and Cd accumulated rapidly in the liver, kidneys and lungs of growing birds. Cd also accumulated in the ovaries at the similar levels as in the kidneys. Cd and Pb may have affected earlier stages of development when parents were foraged in a close vicinity of the heavily polluted area but once the young gulls had reached maturity they then foraged in distant areas. During this period they were exposed to pollutants in the same way as the gulls from the less polluted site. There was no growth impairment identified in gulls from the more polluted area, and their resting metabolism (RMR) calculated per unit of body weight was lower, indicating that energetic costs for detoxification were not as high.