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BIOGEOMON 2014
8th International Symposium
on Ecosystem Behavior
University of Bayreuth, Germany
July 13th – 17th, 2014
Book of Abstracts
Stefan Holzheu & Birgit Thies (eds.)
Bayreuther Forum Ökologie Band 119 / 2014
ISSN 0944 - 4122
268 8 Trace element and metal biogeochemistry
consumption (0.02 mg kg-1), Cocococha sediments indicate that the habitat is not affected by ASGM and Hg
concentrations in fish species of Cocococha could be used as modern reference value.
P 8.15: Poster Session 1 on Monday, 16:30-18:30
Mercury pollution levels of human and aquatic ecosystems components in the
republic of Uzbekistan
BAKHTIYOR KARIMOV1, VIGNATI DAVIDE2
1 Laboratory of Hydrobiology and Ichthyology, Institute of Gene pool of plants and animals world of
Uzbekistan AS
2 2) Water research institute, CNR Italy. Brugherio
Contact: karimov@sarkor.uz
Mercury is one of the highest priority environmental pollutants of concern. Little data are available for water,
bottom sediments and fish contamination with mercury in Uzbekistan and other Central Asian countries.
Bottom sediments and fish muscle tissues were collected during September-October 2009 from Arnasay lake
system (ALS) situated in the middle reach of Syrdarya River (SR), lower reach of Amudarya River (AR), and
in some main drainage collectors in Khorezm Region (lower reach of AR). Mercury concentrations in all
samples were determined in CNR-IRSA water research institute, Brugherio, Italy by atomic absorption
spectrometry using an AMA 254 (Automated Mercury Analyzer) instrument with a detection limit of 0,01 ng
Hg. To evaluate the possibility of human exposure to Hg, hair samples were collected from 13 volunteers in
the Tashkent and Khorezm region. Approximately 40–70 mg of freeze dried sediments, 40–55 mg of freeze
dried fish muscle tissue, and 25–50 milligrams of hair were used for the analytical determinations that were
performed in triplicate. Mercury levels in bottom sediments varied between 4.0 and 26.4 μg/kg, with
somewhat higher levels in ALS (9.6–26.4 µg/kg) than in the lower reach of AD (4.0–21 μg/kg). These values
are much lower than the Uzbekistan Maximum Permissible Levels (MPL) for soils (2100 μg/kg) and below
the Consensus-Based Threshold Effect Concentration of 180 µg/kg for sediments. Levels of mercury in fish
varied between 28.7 and 137.7 μg/kg which was also lover than the Uzbekistan MPL for fish (300 μg/kg).
Mercury content of human hair in Tashkent city varied between 42.8 and 387 (average 124) μg/kg, which
was slightly lower than in Khorezm region (21.6 to 678; average 161 μg/kg). These values are much lower
than the attention thresholds set by US EPA and WHO (1000 and 10000 μg/kg, respectively). The
comparison of mercury pollution rate of human and fish consumption levels of population gave interesting,
however expected results. It is well-known that the bioaccumulation rate of mercury in human organism
correlates positively with fish consumption level. Indeed, people in Tashkent city consume an average 1.0 kg
of fish/year and people in Italy – about 20 kg, i.e. difference is about 20 times. In turn people in Khorezm
consume 0.5 kg of fish/year which is twice lower than in Tashkent city. Although the present work did not
highlight serious mercury pollution problems in Uzbekistan, there is urgent need to start similar investigations
in the industrialised regions of the country and in other neighbouring Republics where large sources of
mercury pollution still exist. The present study was supported by the Cariplo Foundation (Italy).