Assessment of the heavy metal pollution effects on the soil respiration inthe Baix Llobregat (Catalonia, NE Spain)

A main goal of investigations is to determine could a soil respiration be a n indicator of the soil pollution. In this case a measured level of the soi l oxygen consumption depends of its pollution. It also means that the pollu tion reduces biological processes in edaphon. Investigated soil samples wer e taken from polluted and non-polluted places in the Baix Llobregat near Ba rcelona (Catalonia, NE Spain). Soil samples were taken from the top of soil (0-5 cm) without a litter. Soil analysis were done, determining percentage shares of coarse fragments, coarse sand, fine sand, coarse silt, fine silt , clay, CaCO3, organic matter as well as water pH and conductivity CE (1:5 [mS cm(-1)]). Also were determined (in mg kg(-1)) quantities of heavy metal s, as Fe, Al, Mn, Zn, Cr, Ni, V, Cu, Cd, Pb. The soil respiration was inves tigated in temperatures 15 and 30 degrees C and with controlled humidity. T he respiration in 30 degrees C is number of times greater then in 15 degree s C both for polluted and non-polluted soils. Particularly high coefficient s of correlation between the soil respiration and soil pollution in pollute d soils were obtained for Pb: r = 0.75 in 15 degrees C and r = 0.98 in 30 d egrees C; for Ba: 0.90 and 0.57; for V: 0.99 and 0.81. In non-polluted soil s highest correlation coefficients are for Pb: r = 0.70 in 15 degrees C; Fe : 0.60 and 0.72; Al: 0.68 and 0.64; Mn: 0.51 and 0.66; Ba: 0.63 and 0.61; C r: 0.94 and 0.70; Ni: 0.64 and 0.65; Cu: 0.69 and 0.48; as well as V: 0.62 in 15 degrees C; and Cd: 0.69 in 15 degrees C. This way the soil respiratio n could be a good indicator of the soil pollution.