بررسی غلظت فلزات سنگین در پساب و لجن کارخانه کاشی‌سازی شهر بیرجند در سال 1389

 Background and Aim: Sewage of non-metallic and mineral industrials such as tile and ceramic contain a large amount of heavy metals (e.g. Zn, Cr, Cd, Pb) and minerals which can cause problems such as contaminating underground water and polluting the environment. Thus, the present study was done to evaluate heavy metals concentration in the effluent and sludge of the tile factory in Birjand.  Materials and Methods: In this descriptive analytical study, 36 samples were taken from six pools in June 2010 (18 samples from the effluent and 18 samples from the sludge). Analysis of the rate of the heavy metals in the samples was done on the basis of the procedures mentioned in 3010 Standard Method book.  Results: It was found that mean concentration of the heavy metals Zn, Cr, Cd, and Pb in the effluent samples was 0.135±0.235, 0.21±0.022 , 0 ,and 0.064± 0.017 mg/l respectively. These concentration levels were less than permissible standards of the Iranian Environmental Protection Agency. But, in sludge deposited on the bottom ponds, concentration of the heavy metals Zn, Cr, Cd, Pb was 3160±278.15, 1493.52±352.95, 22.18±17./55 , and 1139.11±737.5 mg/kg respectively. That is, the concentrations of Cd and Zn were less than those in the American EPA Standards, but Pb and Cr concentrations were more than EPA Standards to permit the use of sludge in the land.  Conclusion: It was revealed that in the effluent of tile and ceramic industries heavy metals concentrations are higher than environmental standards, which require more supervision and surveillance of the environmental agencies.