OCCURRENCE AND EVOLUTION OF HEAVY METALS AND AS POLLUTION IN WATERS AND VEGETABLES IN PLOVDIV – ASSENOVGRAD AREA

3rd International Scientific Conference - SGEM2003, www.sgem.org, SGEM2003 Conference Proceedings/ ISBN: 954-918181-2, June 9-13, 2003, 295- 304pp

ABSTRACT

The degree of heavy metal (+As) water and vegetable contamination due to
mining and metallurgical activities in the studied area is evaluated in individual
and integral aspects. 267 ground, surface and waste water samples, according to
the proposed grid, were investigated for trace elements, 56 of them for 34
elements: Al, As, Ba, Cd, Co, Cr, Cu, Fe, Mn, Ni, Pb, Sb, Zn, Hg, Be, B, V, Sn,
Mo, Se, Ag, Te, Tl, Ti, U, Ca, Li, Mg, Sr, Bi, Ga, In, K, and Na. The analytical
work is performed with inductively coupled plasma atomic emission spectrometer
(ICP-AES) a Jobin Yvon ULTIMA 2 system, equipped with 1-m Czerny-Turner
monochromator (practical spectral bandwidth is better than 5 pm from 160 nm to
320 nm and 10 pm for 320 nm – 800 nm) and 40.68 MHz ICP. The higher
polluted ground waters with Pb, Cd and Cu are situated in the most endangered
area around the plants in the site, analogous are the results for the Zn, Fe, Mn and
As contamination, with a supplement pollution data for more distant points. Some
Tl, Hg, Se, Sb are also established. The obtained and mapped data for 30
monitoring water points show remarkable seasonal variations of pollutant
concentrations (until 3 orders for Pb and Zn). Important results are also obtained
by the monthly phisico-chemical observation. Monitoring study assures evolution
evidence. The dangerous effect of heavy metals like Pb, Cd, Cu, Zn becomes
multiplied by their interactions with other pollutants such xenobiotics. Interesting
results about the significant role of bacteria, concerning the migration and the
detoxification of the metal pollutants after interaction and biotransformation are
obtained and a possibility for bacteria based bioremediation of heavy metal and
pesticide water pollution is suggested. Some exemplary results established by the
vegetable investigations (of divided different parts) show that: 1) The heavy metal
pollution depends strongly on the aerosol emissions from the metallurgical plants,
mainly Pb and Cd; 2) The most important influence of the aerosol emissions is
trended in the WS-S direction under the influence of the predominant wind; 3) Pb
and Cd oxides or carbonates are strongly adsorbed or absorbed on the surface of
the maize leaves (washing in ultrasonic bath); 4) These and other data (the
difference between leaves and veins) show that As comes from the soil; 5) The
pollution decreases between outside and inside maize leaves 3-10 times; 6) By
carrots, pepper and maize conclusions for significant predomination of pollutants
in leaves are confirmed; 7) Rizin leaves are accumulating Pb, Cd, Zn, As, about 3
times below are the concentrations in veins; 8) Heavy metal and As concentrations
in walnuts, maize corns and carrots are in the norms. The hydrogeochemical study
and monitoring carried out is especially important, presenting possibilities for
limitation of the industrial and mining pollution and recovery of the environmental
equilibrium. The knowledge about the metal behavior in water-soil system in
evolution ensures the base for the 4-D Geographical Information System (GIS)
and for the coupled hydrogeochemical-hydrodynamical modeling of the processes
in the aim of forecast and control of the pollution dissemination.
The investigations are financial supported by NATO Science for Peace
Program in the frames of the Project NATO SfP 973 739 “WATMETAPOL”.