The Effect of EDTA and Citric acid on Soil Enzymes Activity, Substrate Induced Respiration and Pb Availability in a Contaminated Soil

Document Type : Research Article

Authors

• seyed sajjad hosseini
• Amir Lakzian
• Akram Halajnia

Ferdowsi University of Mashhad

https://doi.org/10.22067/jsw.v30i6.50232

Abstract

Introduction: Application of EDTA may increase the heavy metal availability and phytoextraction efficiency in contaminated soils. In spite of that, it might also have some adverse effects on soil biological properties. Metals as freeions are considered to be severely toxic, whereas the complexed form of these metalswith organic compounds or Fe/Mn oxides may be less available to soil microbes. However, apart from this fact, some of these compounds like EDTA and EDTA-metal complexes have low bio- chemo- and photo-degradablity and high solubility in their own characteristics andable to cause toxicity in soil environment. So more attentions have been paid to use of low molecular weight organic acids (LMWOAs) such as Citric acid because of having less unfavorable effects to the environment. Citric acid increases heavy metals solubility in soils and it also improves soil microbial activity indirectly. Soil enzymes activity is a good indicator of soil quality, and it is more suitable for monitoring the soil quality compared to physical or chemical indicators. The aims of this research were to evaluate the changes of dehydrogenase, urease and alkaline phosphomonoesterase activities, substrate-induced respiration (SIR) and Pb availability after EDTA and citric acid addition into a contaminated soil with PbCl2.
Materials and Methods: An experiment was conducted in a completely randomized design with factorial arrangement and three replications in greenhouse condition. The soil samples collected from surface horizon (0-20 cm) of the Typic haplocalsids, located in Mashhad, Iran. Soil samples were artificially contaminated with PbCl2 (500 mg Pb per kg of soil) and incubated for one months in 70 % of water holding capacity at room temperature. The experimental treatments included control, 3 and 5 mmol EDTA (EDTA3 and EDTA5) and Citric acid (CA3 and CA5) per kg of soil. Soil enzymes activity, substrate-induced respiration and Pb availability of soil samples were determined by standard methods after 7, 14, 21 and 28 days of chelates addition.
Results and Discussion: The soil texture was loam and the indigenous Pb content was 25.55 mg kg-1. The soil pH was 7.4 and electrical conductivity of saturated extraction measured 2.5 dS m-1. The soil carbonate calcium was 14% and the content of organic carbon and essential nutrients were low. The results showed that EDTA3 and EDTA5 treatments increased Pb availability by 2.17% and 10% compared to control treatment but CA3 and CA5 treatments decreased it by 3.8% and 15.7% respectively. The Pb availability in control and EDTA5 treatments did not change during the incubation time. The available Pb concentration dropped sharply during the incubation time in EDTA3, CA3 and CA5 treatments. The reduction rates in CA3 and CA5 treatments were more than EDTA3 treatment. This may be due to the high stability and low biodegradability of EDTA than biodegradable chelators and low molecular weight organic acids. The results showed that urease and dehydrogenase activities were significantly reduced in EDTA3 and EDTA5 treatments compared to control treatment. Urease and dehydrogenase activities were decreased with the increase of EDTA concentration. Alkaline phosphomonoesterase activity was not affected by the EDTA3 and EDTA5 treatments. In CA3 and CA5 treatments, dehydrogenase and alkaline phosphomonoesterase activities significantly increased with increasing the concentration of citric acid. CA5 treatment showed a prominent effect on urease activity compare to CA3 treatment. The soil enzyme activities increased with incubation time. It seems that reduction in Pb availability causes an increase of soil enzymes activities. Significant negative relationships were found between soil enzymes activities and available Pb concentration (dehydrogenase activity (r=-0.906, P

Keywords

• Citric acid
• EDTA
• Enzyme Activity
• Pb
• SIR

20.1001.1.20084757.1395.30.6.24.4

References

1- Alef K., and Nannipieri P. 1995. Methods in applied soil microbiology and biochemistry. Academic press.

2- Bremner J. M., and Mulvaney C. S. 1982. Nitrogen total. Methods of soil analysis. Part 2. Chemical and microbiological properties, (methods of soil an2), 595-624.

3- Chapman H. D. 1965. Total exchangeable bases. Methods of soil analysis. Part 2. Chemical and microbiological properties, (methods of soil anb), 902-904.

4- Do Nascimento C. W. A., Amarasiriwardena D., and Xing B. 2006. Comparison of natural organic acids and synthetic chelates at enhancing phytoextraction of metals from a multi-metal contaminated soil. Environmental Pollution, 140(1), 114-123.

5- Epelde L., Hernandez-Allica J., Becerril J. M., Blanco F., andGarbisu C. 2008. Effects of chelates on plants and soil microbial community: comparison of EDTA and EDDS for lead phytoextraction.Science of the total environment, 401(1), 21-28.

6- Fine P., Paresh R., Beriozkin A., and Hass A. 2014. Chelant-enhanced heavy metal uptake by Eucalyptus trees under controlled deficit irrigation. Science of the Total Environment, 493, 995-1005.

7- Freitas E. V., Nascimento C. W., Souza A., and Silva F. B. 2013. Citric acid-assisted phytoextraction of lead: A field experiment. Chemosphere, 92(2), 213-217.

8- Gee G. W., Bauder J. W., and Klute A. 1986. Particle-size analysis. P. 383- 411. In Klute, A (ed.) Methods of soil analysis. Part 1. Physical and mineralogical methods. 2nd ed. American Society of Agronomy, Inc.

9- Huang J. W., Chen J., Berti W. R., and Cunningham S. D. 1997. Phytoremediation of lead-contaminated soils: role of synthetic chelates in lead phytoextraction. Environmental Science & Technology, 31(3), 800-805.

10- Jelusic M., and Lestan D. 2014. Effect of EDTA washing of metal polluted garden soils. Part I: toxicity hazards and impact on soil properties. Science of the Total Environment, 475, 132-141.

11- Kos B. 2003. Influence of a biodegradable ([S, S]-EDDS) and nondegradable (EDTA) chelate and hydrogel modified soil water sorption capacity on Pbphytoextraction and leaching. Plant and Soil, 253(2), 403-411.

12- Kos B., and Leštan D. 2004. Chelator induced phytoextraction and in situ soil washing of Cu. Environmental Pollution, 132(2), 333-339.

13- Lee J., and Sung K. 2014. Effects of chelates on soil microbial properties, plant growth and heavy metal accumulation in plants. Ecological Engineering, 73, 386-394.

14- Lindsay W. L., and Norvell W. A. 1978. Development of a DTPA soil test for zinc, iron, manganese, and copper. Soil science society of America journal, 42(3), 421-428.

15- Loeppert R. H., and Suarez L. 1996. Carbonate and gypsum. In ‘Methods of soil analysis. Part 3. Chemical methods. (Ed. DL Sparks) pp. 437–474. Soil Science Society of America: Madison, WI.

16- Luo C. L., Shen Z. G., Baker A. J., and Li X. D. 2006. A novel strategy using biodegradable EDDS for the chemically enhanced phytoextraction of soils contaminated with heavy metals. Plant and soil, 285(1-2), 67-80.

17- Luo C., Shen Z., and Li X. 2005. Enhanced phytoextraction of Cu, Pb, Zn and Cd with EDTA and EDDS. Chemosphere, 59(1), 1-11.

18- Mc Grath S.P., and Cunliffe C.H. 1985. A simplified method for the extraction of the metals Fe, Zn, Cu, Ni, Cd, Pb, Cr, Co and Mn from soils and sewage sludges. Journal of the Science of Food and Agriculture, 36(9), 794-798.

19- Meers E., Ruttens A., Hopgood M., Lesage E., and Tack F. M. G. 2005. Potential of Brassicrapa, Cannabis sativa, Helianthus annuus and Zea mays for phytoextraction of heavy metals from calcareous dredged sediment derived soils. Chemosphere, 61(4), 561-572.

20- Mühlbachova G. 2011. Soil microbial activities and heavy metal mobility in long-term contaminated soils after addition of EDTA and EDDS. Ecological Engineering, 37(7), 1064-1071.

21- Nannipieri P., Grego S., Ceccanti B., Bollag J. M., and Stotzky G. 1990. Ecological significance of the biological activity in soil. Soil biochemistry, 6, 293-355.

22- Nannipieri P., Pankhurst C. E., Doube B. M., Gupta V. V. S. R., and Grace P. R. 1994. The potential use of soil enzymes as indicators of productivity, sustainability and pollution. In (Ed. CE Pankhurst et al.) pp. 238- 244. Soil biota: management in sustainable farming systems. CSIRO Publications.

23- Nascimento C. W. A. D. 2006. Organic acids effects on desorption of heavy metals from a contaminated soil. Scientia Agricola, 63(3), 276-280.

24- Neugschwandtner R. W., Tlustoš P., Komarek M., and Szakova J. 2008. Phytoextraction of Pb and Cd from a contaminated agricultural soil using different EDTA application regimes: laboratory versus field scale measures of efficiency. Geoderma, 144(3), 446-454.

25- Olsen S. R., Sommers L. E., and Page A. L. 1982. Methods of soil analysis. Part 2. Agron.Monogr, 9, 403-430.

26- Renella G., Egamberdiyeva D., Landi L., Mench M., and Nannipieri P. 2006. Microbial activity and hydrolase activities during decomposition of root exudates released by an artificial root surface in Cd-contaminated soils. Soil Biology and Biochemistry, 38(4), 702-708.

27- Saifullah Sabir M., and Ahmad H. R. 2014. Phytoremediation of Pb-Contaminated Soils Using Synthetic Chelates. In (Ed. K Hakeem et al.) pp. 397- 414. Soil Remediation and Plants: Prospects and Challenges. Academic Press.

28- Shahid M., Pinelli E., and Dumat C. 2012. Review of Pb availability and toxicity to plants in relation with metal speciation; role of synthetic and natural organic ligands. Journal of hazardous materials, 219, 1-12.

29- Sinegani A. A. S., and Ghahfarokhi I. T. The effect of application of electrokinetic and chelating agents on substrate induced respiration and bacterial and fungal populations in a multi-metal contaminated soil. 1st International Conference on Environmental Crisis and its Solutions, 13-14 Feb. 2013. Scientific and Research Branch, Khouzestan, Islamic Azad University., Kish Island-Iran

30- Tabatabai M. A., and Bremner J. M. 1969. Use of p-nitrophenyl phosphate for assay of soil phosphatase activity.Soil biology and biochemistry, 1(4), 301-307.

31- Tabatabai M. A., and Bremner J. M. 1972. Assay of urease activity in soils. Soil Biology and Biochemistry, 4(4), 479-487.

32- Tandy S., Schulin R., and Nowack B. 2006. Uptake of metals during chelant-assisted phytoextraction with EDDS related to the solubilized metal concentration. Environmental science & technology, 40(8), 2753-2758.

33- Thalmann A. 1966. The determination of the dehydrogenase activity in soil by means of TTC (triphenyltetrazolium). Soil Biol, 6, 46-49.

34- Udovic M., and Lestan D. 2009. Pb, Zn and Cd mobility, availability and fractionation in aged soil remediated by EDTA leaching. Chemosphere, 74(10), 1367-1373.

35- Ultra Jr V. U., Yano A., Iwasaki K., Tanaka S., Kang Y., and Sakurai K. 2005. Influence of chelating agent addition on copper distribution and microbial activity in soil and copper uptake by brown mustard (Brassica juncea). Soil Science & Plant Nutrition, 51(2), 193-202.

36- Usman A. R., Almaroai Y. A., Ahmad M., Vithanage M., and Ok Y. S. 2013. Toxicity of synthetic chelators and metal availability in poultry manure amended Cd, Pb and As contaminated agricultural soil. Journal of hazardous materials, 262, 1022-1030.

37- Vogeler I., Vachey A., Deurer M., and Bolan N. 2008. Impact of plants on the microbial activity in soils with high and low levels of copper. European journal of soil biology, 44(1), 92-100.

38- Walkley A., and Black I. A. 1934. An examination of the Degtjareff method for determining soil organic matter, and a proposed modification of the chromic acid titration method.Soil science, 37(1), 29-38.

39- Wu L. H., Luo Y. M., Christie P., and Wong M. H. 2003. Effects of EDTA and low molecular weight organic acids on soil solution properties of a heavy metal polluted soil. Chemosphere, 50(6), 819-822.

40- Wu L. H., Luo Y. M., Xing X. R., and Christie P. 2004. EDTA-enhanced phytoremediation of heavy metal contaminated soil with Indian mustard and associated potential leaching risk. Agriculture, Ecosystems & Environment, 102(3), 307-318.

41- Zhang F., Zhu Z., Dong Z., Cui Z., Wang H., Hu W., Zhao P., Wang P., Wei S., Li R., and Ma J. 2011. Magnetically recoverable facile nanomaterials: Synthesis, characterization and application in remediation of heavy metals. Microchemical Journal, 98(2), pp.328-333.

42- Zhang H., Zhao F.J., Sun B., Davison W., and Mcgrath S.P. 2001. A new method to measure effective soil solution concentration predicts copper availability to plants. Environmental Science & Technology, 35(12), pp.2602-2607.