Effect of organic wastes on the extractability of cadmium, copper, nickel, and zinc in soil

Transcription

1 Geoderma 122 (2004) Effect of organic wastes on the extractability of cadmium, copper, nickel, and zinc in soil Ayten Karaca* Ankara University, Faculty of Agriculture, Department of Soil Science, Ankara, Turkey Available online 8 February 2004 Abstract A soil incubation experiment lasting 6 months was carried out to ascertain the effects of tobacco dust, mushroom compost, and grape marc, which contain high organic matter, on the extractable cadmium, copper, nickel, and zinc in soil. The rates of organic wastes in its moist state added were 0%, 2%, 4%, and 8% of the air-dried soil on mass basis. Soil ph was decreased significantly in soils treated with the mushroom compost and grape march during the incubation period. The addition of all three organic wastes caused a significant increase in the organic matter content of soils. The application of tobacco dust significantly increased the DTPA-extractable Cd content in soil, whereas the addition of grape marc and mushroom compost caused a significant decrease in the extractable Cd content of soils. The DTPA-extractable Cu decreased significantly with increasing rates of grape marc amendment and increased with increasing rates of tobacco dust amendment, but there was no consistent effect of mushroom compost. The amount of DTPA-extractable Ni was higher in mushroom compost added to soil than in grape marc added to soil due to higher organic matter content of grape march. The DTPA-extractable Zn increased with increasing rates of all three organic wastes amendments. D 2004 Elsevier B.V. All rights reserved. Keywords: Organic wastes; Heavy metals; ph; Organic matter 1. Introduction Application of organic wastes as a source of organic matter is a common practice to improve soil properties (Baran et al., 2001). However the use of organic wastes can lead to problems pertaining to their heavy metal content and their successive application result in heavy metal accumulation in soil. Land disposal of organic waste materials may directly or * Fax: address: akaraca@agri.ankara.edu.tr (A. Karaca). indirectly alter the heavy metal status of the soil by affecting metal solubility or dissociation kinetics (Del Castilho et al., 1993). The total heavy metal content of the soil is commonly used to indicate the degree of contamination, but the heavy metal concentration in solution mostly determines the actual environmental exposure or risk. Distribution of heavy metals between soil and solute is the key to evaluating the environmental impact of the metals. Despite the complexity of possible reactions, several important soil factors controlling the distribution of heavy metals between soil and solutes have been identified (Sposito, 1989; Temminghoff et al., 1998) /$ - see front matter D 2004 Elsevier B.V. All rights reserved. doi: /j.geoderma

2 298 A. Karaca / Geoderma 122 (2004) The sorption behavior of Cd, Cu, Ni, and Zn in soils varies from soil to soil and is influenced by soil properties, such as ph, organic matter, cation exchange capacity (CEC), and clay contents (McBride, 1989). A strong relationship between soil solution ph and metal adsorption has been demonstrated, with metal adsorption being directly proportional to ph (Elliott et al., 1986). The effects of soil ph on soil solution concentrations and extractabilities of metals have been studied. He and Singh (1993) found that peat addition increased the DTPA extractable Cd in soils due to decrease in soil ph caused by peat application. Yuan and Lavkulich (1997) and Arnesen and Singh (1999) found that the lowering of ph in peat-amended soil decreased the sorption of Cd, Cu, Zn, and Ni in the soil. Soil organic matter has been of particular interest in studies of heavy metal sorption by soils, because of its significant impact on CEC, and more importantly, the tendency of transition metal cations to form stable complexes with organic ligands (Elliott et al., 1986). Organic matter makes strong complexes with heavy metals (Krogstad, 1983). The amount of organic matter in soils affects the binding of heavy metals in soil and speciation in soil solution (Lo et al., 1992). Cadmium is a pollutant and potential toxin that has no known function in any biological organism (Wagner, 1993). Increased adsorption of Cd by soil components with increasing amounts of organic matter has been reported (Christensenn, 1984; Eriksson, 1988). High organic matter content or addition of organic matter decreases solution concentrations of Cd and Ni, but increases the extractability of Zn (McGrath et al., 1988; Arnesen and Singh, 1999). Amendment with organic matter and resulting degradation may change the soil ph and thereby indirectly affect the bioavailability of metals. Many authors have found that all type of organic wastes increased the extractability of Zn in soil (MacLean, 1976; Saviozzi et al., 1997; Arnesen and Singh (1999). The aim of the experiment described here was to study the influence of organic wastes (mushroom compost, grape marc, and tobacco dust) on the DTPA extractable Cd, Cu, Ni, and Zn in soil. Release of the metals into solution as a function of ph was also studied. 2. Materials and methods 2.1. Soil and organic wastes description The soil (typic xerofluvent) was a clay loam taken from an experiment field of Ankara University, Faculty of Agriculture, within 0 20 cm of the surface. The soil was air dried and passed through a 2-mm sieve. Composted grape marc (GM), mushroom compost (MC), and tobacco dust (TD) passed through a 6.35-mm sieve. The properties of the organic wastes were determined by Baran et al. (1995). Some physical and chemical properties and total and extractable heavy metal contents of the soil samples and organic wastes are given in Tables 1 and Incubation trial The rates of organic wastes in its moist state added were 0%, 2%, 4%, and 8% of the air-dried soil on mass basis. Triplicate soil samples were homogenized with dry organic wastes and filled in plastic pots (400 cm 3 in each pot). Each pot consisted of 300 g of coarsely sieved soil with various amendments. The water content of the soil was adjusted to 70% of water holding capacity. The pots were placed in an incubator at 28 jc and 70% relative humidity. Throughout the Table 1 Selected properties of the soil and organic wastes used ph EC OM C Texture % CEC N C/N 1:2.5 MS cm 1 % % Sand Silt Clay Cmolkg 1 % Soil GM TD MC GM, grape marc; TD, tobacco dust; MC, mushroom compost; OM, organic matter; CEC, cation exchange capacity.

3 A. Karaca / Geoderma 122 (2004) Table 2 Total and extractable Cd, Cu, Ni, and Zn amounts of soil and organic wastes used (mg kg 1 ) Total Cd Total Cu Total Ni Total Zn Exc. Cd Exc. Cu Exc. Ni Exc. Zn Soil GM TD MC Exc. Cd, Cu, Ni, and Zn, DTPA extractable Cd, Cu, Ni, and Zn. incubation period, water losses exceeding 10% of the initial values were compensated for by addition of distilled water. Soil samples were taken on the first day and 6 months after incubation and analyzed for ph, organic matter and DTPA extractable Cd, Zn, Cu, and Ni Sample analysis Soil ph and electrical conductivity (EC) was measured in water with a 1:2.5 ratio of soil solution according to Richards (1954). Organic matter content was determined by the method of modified Walkley and Black (Jackson, 1962). Total nitrogen was determined by using Kjeldahl method (Bremner and Mulvaney, 1982). Particle size distribution was determined according to Bouyoucos (1951). CEC was determined according to methods given in Rhoades (1982). Available heavy metals in soils and organic wastes were extracted with a DTPA solution (0.005 M DTPA M CaCl M TEA, ph 7.3), (Lindsay and Norvell, 1978). Total heavy metals in soils and organic wastes were digested in aqua regia (Baker and Amacher, 1982). All solutions with Cd, Cu, Ni, and Zn were analysed by atomic absorption spectrophotometer (AAS) with flame or graphite furnace when required. Minitab and Mstat computer programs (Software Company) were used for statistical analyses. 3. Results and discussion Soil ph decreased in soils treated with the TD and GM during the incubation period (Table 3). This decrease was especially noticeable in soils treated with TD. This material has low levels of ph. With addition MC, there was no consistent effect in the first day of incubation period. However, by the sixth month of incubation addition of MC resulted in a significant decrease in soil ph ( P >0.05). The lowest ph was determined in TD added to soil and that was followed by GM and MC added to soil, respectively. Content of organic matter increased significantly with increasing amount of all three organic wastes (Table 4). However, it was lower in the sixth month of incubation than the first day of incubation. A significant loss of organic matter occurred at all rates of added organic wastes. During the 6 months of experiment, the amount of organic matter; and probably also its properties; were altered, resulting in the adsorption of the metals to the organic ligands and to the soil surfaces (Elliott and Denneny, 1982; Japenga et al., 1992; Yuan and Lavkulich, 1997). The amount of extractable Cd was higher in MC added to soil than GM added to soils due to had higher organic matter content. Results showed that the Table 3 Soil ph values at increasing rates of organic wastes applied Time Organic Wastes Rate (%) MC 1st day 7.79Aa 7.70Ca 7.74Ba 7.80Aa 6th month 7.72Ab 7.42Bb 7.38Bb 7.19Cb LSD GM 1st day 7.79Aa 7.70Ba 7.67Ca 7.65Da 6th month 7.72Ab 7.35Bb 7.30Cb 7.03Db LSD TD 1st day 7.79Aa 7.24Ba 7.03Ca 6.85Da 6th month 7.72Ab 7.00Bb 6.87Cb 6.70Db LSD Significant differences between treatments at P < 0.05 level indicated by different letters. Upper letter in row, lower letter in column.

4 300 A. Karaca / Geoderma 122 (2004) Table 4 Soil organic matter contents at increasing rates of organic wastes applied Time Organic Wastes Rate (%) MC 1st day 1.26 Da 2.85 Ca 4.24 Ba 5.80 Aa 6th month 1.23 Da 2.51 Cb 2.70 Bb 2.99 Ab LSD GM 1st day 1.26 Da 3.60 Ca 4.65 Ba 7.69 Aa 6th month 1.23 Da 2.55 Cb 4.50 Bb 5.50 Ab LSD TD 1st day 1.26 Da 3.85 Ca 6.19 Ba 7.90 Aa 6th month 1.23 Da 2.42 Cb 3.23 Bb 3.42 Ab LSD Significant differences between treatments at P < 0.05 level indicated by different letters. Upper letter in row, lower letter in column. MC and GM treatments caused a marked decrease, whereas TD treatment caused a marked increase in the DTPA-extractable Cd during the incubation period (Table 5, P < 0.05). Extractable Cd was highly but negatively correlated to soil ph in TD added to soils (r = 0.783, P < 0.01), however a positively correlated to soil ph in GM added to soil (r = 0.468, P < 0.05). There was no significant correlation between extractable Cd and ph in MC added to soil. Among factors controlling the adsorption of Cd in soil, ph is probably the most important (Christensenn, 1984). The effect of ph is related to its great influence on the charge and structure of the adsorbing surfaces and on the ionic composition of the soil solution (Garcia-Miragaya and Page, 1978; Abd-Elfattah and Wada, 1981). Ram and Verloo (1985) found that farmyard manure and peat soil enhanced the mobility of Cd at lower ph and decreased it at higher ph. Eriksson (1988) found that soil Cd extracted by 1 M CH 3 COONH 4 was inversely related to the amount of peat added to the soils. He and Singh (1993), who treated different type of soils with different level of peat, found that DTPAextractable Cd in the soils increased with increased addition of peat. Significant negative correlation was found between extractable Cd and organic matter content of Table 5 Concentrations of DTPA-extractable Cd, Cu, Ni and Zn (mg kg 1 ) in the soil at increasing rates of organic matter applied O.M. Cd Cd Cu Cu Ni Ni Zn Zn (%) 1st day 6th month 1st day 6th month 1st day 6th month 1st day 6th month MC Ab 0.057Aa 2.20 Aa 2.10Aa 2.90 Aa 2.50Ab 1.20 Db 1.50Da Ab 0.055ABa 2.10 ABa 2.00ABa 2.10 Ba 1.80Bb 2.10 Cb 2.90Ca Bb 0.055ABa 1.90 Ca 2.00ABa 1.90 Ca 1.74Ca 2.40 Bb 3.10Ba Cb 0.050Ba 2.00 BCa 1.90Ba 1.10 Da 1.00Da 3.70 Ab 4.30Aa LSD GM Ab 0.057Aa 2.20 Aa 2.10Aa 2.90 Aa 2.50Ab 1.20 Db 1.50Ca Bb 0.043Ba 1.80 Ba 1.90Ba 1.10 Ba 1.00Ba 1.90 Cb 2.30Ba Ba 0.041Ba 1.60 Ca 1.70Ca 0.80Ba 0.90Ba 2.10 Bb 2.40Ba Cb 0.031Ca 1.76 Db 2.10Aa 0.65 Ca 0.83Ba 2.70 Ab 2.90Aa LSD TD Cb 0.057Ba 2.20 Ba 2.10Ca 2.90 Da 2.50Db 1.20 Cb 1.50Ca Ba 0.058Ba 2.40 Ba 2.70Ba 3.10 Cb 3.40Ca 1.50 BCb 2.30Ca Aa 0.061ABa 2.50 ABb 2.90ABa 3.30 Bb 3.60Ba 1.70 Bb 2.50Ba Aa 0.063Aa 2.80 Ab 3.20Aa 3.70 Ab 4.10Aa 2.90 Ab 3.70Aa LSD Significant differences between treatments at P < 0.05 level indicated by different letters. Upper letter in row, lower letter in column.

5 A. Karaca / Geoderma 122 (2004) GM added to soil (r = 0.950, P < 0.01). There were no significant correlations between extractable Cd and organic matter content of MC and TD added to soil. Organic matter is considered to play an important role in reducing plant uptake of Cd from soils due to its high CEC and complexing ability. Nevertheless, the results reported in the literature are not consistent. Many authors have found that high organic matter content or addition of organic matter by organic wastes decreased the Cd concentration in solution. This effect is explained by the high CEC of organic matter and its ability to form chelate complexes with Cd. Haghiri (1974) concluded that the decreased plant Cd concentration with higher levels of organic matter added was predominantly due to the effect of increasing soil CEC. MacLean (1976) and Korcak and Fanning (1985) found a positive relationship between DTPA-extractable Cd and the amount of organic matter in soils. The concentration of Cd in all three organic wastes added to soil was higher at six months of incubation than at first day of incubation. Because of organic matter decomposition, Cd sorption was reduced in organic-wastes amended soil. Reduction in Cd sorption due to organic matter decomposition is also reported by Yuan and Lavkulich (1997) and Arnesen and Singh (1999). DTPA-extractable Cu decreased significantly with increasing rate of GM and increased with increasing rate of TD ( P < 0.05), but there was no consistent effect of MC (Table 5). Significant negative correlation was found between extractable Cu and ph in TD added to soil (r = 0.864, P < 0.01), and a positive correlation in MC added to soils (r = 0.497, P < 0.05). There was no significant correlation between extractable Cu and ph in GM added to soil. However, a significant negative correlation was found between extractable Cu and organic matter content of GM added to soil (r = 0.524, P < 0.05), and there were no significant correlations between extractable Cu and organic matter content of TD and MC added to soil. Cu was affected by ph and organic matter status, suggesting that ph and the organic contents of soils would have a great effect on the extractable Cu (Temminghoff et al., 1998). Many comparative studies have shown that soluble organic matter forms much stronger complexes with Cu than Zn (McBride, 1978). McGrath et al. (1988) found that the total Cu content was more dependent on the organic matter status, as soil and the proportion of Cu present in solution as Cu 2+ increased and as ph decreased. They also implied that extractability of Cu, however, was affected by organic matter status, suggesting that the organic matter content of soils would have a great effect on the fate of Cu whether it was applied in fertilizers, sewage sludges or other organic wastes containing Cu. Arnesen and Singh (1999) found that extractable Cu increased with increasing rate of peat, and they suggested that the lowering of ph in the peat-amended soil probably decreased the sorption of Cu in the soil. The amount of extractable Ni was higher in MC added to soil than GM added to soil due had higher organic matter content of GM. Increasing the rate of wastes addition gradually reduced the DTPA-extractable Ni in MC and GM added to soil (Table 5, P < 0.05). However, the addition of TD increased the extractable Ni. These are supported by the finding of Arnesen and Singh (1999) who found a similar effect of peat on the DTPA-extractable Ni. They suggested that the lowering of ph in the peat-amended to soil decreased the sorption of Ni in the soil and this effect became more significant after degradation of organic matter. The concentration of Ni in all three organic wastes added to soil was higher after 6 months of incubation than in the first day of incubation, but there were no significant differences between first incubation and second incubation in MC added to soil. Significant negative correlations were found between extractable Ni and ph in TD and MC added to soil (r = 0.912, P < 0.01 and r = 0.556, P < 0.05, respectively), and a positive correlation in GM added to soil (r = 0.519, P < 0.05). Significant negative correlations were found between extractable Ni and organic matter content of TD and GM added to soil (r = 0.306, P < 0.1 and r = 0.800, P < 0.01, respectively). But there was no significant correlation between extractable Ni and organic matter content of MC added to soil. DTPA-extractable Zn increased with increasing rates of all three organic wastes added to soil (Table 5, P < 0.05). These results show that the different organic matter sources have about the same effect

6 302 A. Karaca / Geoderma 122 (2004) on DTPA-extractable Zn in soil. The concentration of Zn in the present study was higher after six months of incubation than in the first day of incubation, probably due to degradation of the organic matter and release of the Zn, which was complexed with organic matter in the first incubation period. Shuman (1975) found that ph, the clay content, organic matter content, and CEC influenced the adsorption of Zn by soils. Mandal and Hazra (1997) found that organic matter application and low ph arrested a decreasing trend in Zn adsorption, and increasing levels of soil organic matter increased extractability of Zn. Significant negative correlations were found between extractable Zn and ph in TD and GM added to soil (r = 0.797, P < 0.01 and r = 0.741, P < 0.01, respectively), and a positive correlation in MC added to soil (r = 0.518, P < 0.05). However, significant positive correlation was found between extractable Zn and organic matter content of GM added to soil (r = 0.811, P < 0.01). There were no significant correlations between extractable Zn and organic matter content of TD and MC added to soil. 4. Conclusion The effect of organic waste application on the extractability of Cd, Cu, Ni, and Zn in the CL soil (typic xerofluvent) depended on ph, organic matter content of the organic wastes, the metals studied and the time after its application. The application of TD increased amounts of DTPA-extractable Cd, Cu, Ni, and Zn, probably decreased ph. Increase in extractable Zn was found by the addition of GM and MC, whereas these organic wastes resulted in decreased extractable Cd and Ni. The DTPA-extractable Cu decreased with GM addition, but there was no consistent effect of MC. The concentrations of heavy metals in the present study were higher after 6 months of incubation than in the first day of incubation, probably due to degradation of the organic matter and release of the metals, which were complexed with organic matter at the beginning of incubation. Organic matter content and the ph value of the soil are relatively easy to change. Therefore, the effects of organic matter and ph on the extractability of metals deserve special attention. References Abd-Elfattah, A., Wada, K., Adsorption of Pb, Cu, Zn, Co and Cd by soils that differ in cation-exchange materials. J. Soil Sci 32, Arnesen, A.K.M., Singh, B.R., Plant uptake and DTPA-extractability of Cd, Cu, Ni and Zn in a Norwegian alum shale soil as affected by previous addition of dairy and pig manures and peat. Can. J. Soil Sci., Baker, D.E., Amacher, M.C., Nickel, copper, zinc, cadmium. In: Miller, R.H., Keeney, D.R. (Eds.), Methods of Soil Analysis, Part 2. ASA-SSSA, Madison, WI, USA, pp Baran, A., Cayci, G., Inal, A., Some physical and chemical properties of organic wastes. Pamukkale University. J. Eng. Sci. 1 (2-39), Baran, A., Cayci, G., Kutuk, C., Hartmann, R., The effect of grape marc as growing medium on growth of hypostases plant. Bioresour. Technol. 78, Bouyoucos, G.J., A recalibration of hydrometer for making mechanical analysis of soils. Agron. J. 43, Bremner, J.M., Mulvaney, C.S., Nitrogen-total. In: Miller, R.H., Keeney, D.R. (Eds.), Methods of Soil Analysis, Part 2. ASA-SSSA, Madison, WI, USA, pp Christensenn, T.H., Adsorption of Cd as influenced various soil properties. Water Air Soil Pollut. 21, Del Castilho, P., Chardon, W.J., Salomons, W., Influence of cattle-manure slurry application on the solubility of Cd, Cu, and Zn in a manured acidic, loamy sand soil. J. Environ. Qual. 22, Elliott, H.A., Denneny, C.M., Soil adsorption of Cd from solutions containing organic ligands. J. Environ. Qual. 22, Elliott, H.A., Liberati, M.R., Huang, C.P., Competitive adsorption of heavy metals by soils. J. Environ. Qual. 15, Eriksson, J.E., The effect of clay, organic matter and time on adsorption and plant uptake of Cd added soils. Water Air Soil Pollut. 40, Garcia-Miragaya, J., Page, A.L., Effect of ph on the extractability of heavy metal. Water Air Soil Pollut. 9, 289. Haghiri, F., Plant uptake of Cd as influenced by CEC, organic matter, Zn and soil temperature. J. Environ. Qual. 3, He, Q.B., Singh, B.R., Effect of organic matter on the distribution, extractability and uptake of Cd in soils. J. Soil Sci. 44, Jackson, M.L., Soil Chemical Analysis Prentice-Hall, Englewood Cliff, NJ, USA. Japenga, J., Dalenberg, J.W., Wiersma, D., Scheltens, S.D., Hesterberg, D., Salomons, W., Effect of liquid animal manure applications on the solubilization of heavy metals form soil. Int. J. Environ. Anal. Chem. 46, Korcak, R.F., Fanning, D.S., Availability of applied heavy metals as a function of type of soil material and metal source. Soil Sci. 140 (1), Krogstad, T., Effect of liming and decomposition on chemical composition, ion exchange and heavy metal ion selectivity in

7 A. Karaca / Geoderma 122 (2004) sphagnum peat. Scientific Reports of the Agricultural University of Norway AAS, Norway, p. 79. Lindsay, W.L., Norvell, W.A., Development of a DTPA soil test for Zn, Fe, Mn, and Cu. Soil Sci. Soc. Am. J. 42, Lo, K.S.L., Yang, W.F., Lin, Y.C., Effects of organic matter on the specific adsorption of heavy metals by soil. Toxicol. Environ. Chem. 34, MacLean, A.J., Cd in different plant species and its availability in soils as influenced by organic matter and additions of lime, Pb, Cd, and Zn. J. Soil Sci 56, Mandal, B., Hazra, G.C., Zn adsorption in soils as influenced by different soil management practices. Soil Sci. 162 (10), McBride, M.B., Transition metal bonding in humic acid: an ESR study. Soil Sci. 126 (4), McBride, M.B., Reactions controlling heavy metal solubility in soils. Adv. Soil Sci. 10, McGrath, S.P., Sanders, J.R., Shabaly, M.H., The effects of soil organic matter levels on soil solution concentrations and extractabilities of manganese, zinc and copper. Geoderma 42, Ram, N., Verloo, M., Effect of various organic materials on the mobility of heavy metals in soil. Environ. Pollut. 10, Rhoades, J.D., Cation exchange capacity. In: Miller, R.H., Keeney, D.R. (Eds.), Methods of Soil Analysis, Part 2. ASA- SSSA, Madison, WI, USA, pp Richards, L.A., Diagnosis and improvement of saline and alkali soils. U.S.D.A. Handb. 60, (USA). Saviozzi, A., Levi-Minzi, R., Riffaldi, R., Vanni, G., Laboratory studies on the application of wheat straw and pig slurry to soil and the resulting environmental implications. Agric. Ecosyst. Environ. 6, Shuman, L.M., The effect of soil properties on Zn adsorption by soils. Soil Sci. Proc. Am. Proc. 39, Sposito, G., The Chemistry of Soils Oxford Univ. Press, New York, USA. Temminghoff, E.J.M., Van Der Zee, S.E.A.T., Dehaan, F.A.M., Effects of dissolved organic matter on the mobility of copper in a contaminated sandy soil. Eur. J. Soil Sci. 49, Yuan, G., Lavkulich, L.M., Sorption behavior of Cu, Zn, and Cd in response to simulated changes in soil properties. Commun. Soil Sci. Plant Anal. 28, Wagner, G.J., Accumulation of Cd in crop plants and its consequences to human health. Adv. Agron. 51,