SOIL-PLANT-LEACHEATE CHROMIUM AS AFFECTED BY THE SOIL DISPOSAL OF TANNERY SLUDGE IN A PALEUDULT SOIL FROM ESTÂNCIA VELHA (RS) BRAZIL

Abstract

This study was carried out to evaluate the chromium concentration in soil plant and leacheate as affected by the soil disposal of two types of waste originating from primary treatment of tannery residual water in a Paleudult soil with ten percent clay from Estancia Velha, Rio Grande do Sul state, Brazil, where several tannery operation are located. Chromium tannery sludge and tannin tannery sludge contained 8.040 and 34 g kg-1 (dry weight) Cr concentration, respectively. Mineral fertilization was compared with sludge application of 15, 30 and 60 ton of sludge ha-1 originated either from tannin or chromium tanneries. One treatment with cattle manure was also included. Radish (Raphanus sativus L.) and sorghum (Sorghum vulgare Pers) were cultivated. Chromium waste concentration and soil, plant and leacheate chromium concentration were determined. Cr (VI) was not found at any part of the experiment. Application of 30 and 60 t ha-1 chromium tannery sludge in the soil increased radish tissue Cr level and it is considered above of plant maximum permitted level. Sorghum grains Cr level decreased with the application of the two types of tannery sludge in the soil as compared with the mineral fertilization. Cr concentration in soil and leacheate were considered below the maximum level defined by Brazilian environmental law.