Express-techniques in study of polluted suburban streams
Water samples from streams in suburban region of new builds were analyzed in order to suggest methods and parameters for pollution monitoring. Concentrations of total nitrogen (TN) varied from 0.6 to 9.0 mg/L, ammonium – from 0 to 6.8 mg/L, total organic carbon (TOC) from 8.3 to 21.1 mg/L. Electric conductivity (EC) varied from 80 to 640 mkSm/cm, optical density at 254 nm – from 0.41 to 1.07. Increased concentrations of TN and ammonium at several sampling sites confirmed wastewater discharge from dwelling area. Polluted waters also showed higher values of electric conductivity and molar fractions for sodium and chloride ions, lower values of optical density (in range 230 – 420 nm) and TOC. Fluorescence intensity (I) was measured at excitation wavelength 230 and 270 nm, emission wavelengths 300-350 nm (protein-like fluorescence, present in wastewaters), 420 nm (humic-like fluorescence, present in natural and waste waters). Character of correlation between fluorescence intensity and TN (marker of pollution) and TOC depended on wavelengths, fluorescence signal correction and dilution of sample. Only I at 230 nm excitation and 350 nm emission for 10-fold diluted sample of water could be recommended for water monitoring. EC can be used as additional parameter in studied streams.