The thermoluminescence of carp otoliths: A fingerprint in identification of lake pollution
This paper reports a pilot study on the thermoluminescence (TL) of carbonate minerals of carp otoliths from the heavily polluted Baiyangdian Lake (BYD) in Hebei Province and non-polluted Miyun Water Reservoir (MY) in Beijing Municipality of China. Analyses on trace elements of otoliths and water show that the heavy metal elements of BYD were much higher than those of MY, particularly on chromium (Cr), nickel (Ni), zinc (Zn) and rubidium (Rb) concentrations. These heavy metal elements could infiltrate into the otolith crystals as impurities or defeats, and were responsible for the different TL parameters and TL glow curves between BYD and MY samples. Such differences in carp otoliths would be applicable to other lakes or water reservoirs, and the TL technique could be used as "fingerprint" in identification of polluted and non-polluted lakes. Also, the TL characteristics of fish otoliths may provide a quick and qualitative means for environmental assessments in lake pollution.
Key words: Thermoluminescence, fish otolith, heavy-metal elements, lake, pollution.