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Efficiency of a cleanup technology to remove mercury from natural waters by means of rice husk biowaste: ecotoxicological and chemical approach


In the present work, the efficiency of rice husk to remove Hg(II) from river waters spiked with realistic environmental concentrations of this metal (μg L−1 range) was evaluated. The residual levels of Hg(II) obtained after the remediation process were compared with the guideline values for effluents discharges and water for human consumption, and the ecotoxicological effects using organisms of different trophic levels were assessed. The rice husk sorbent proved to be useful in decreasing Hg(II) contamination in river waters, by reducing the levels of Hg(II) to values of ca. 8.0 and 34 μg L−1, for an Hg(II) initial concentration of 50 and 500 μg L−1, respectively. The remediation process with rice husk biowaste was extremely efficient in river waters spiked with lower levels of Hg(II), being able to eliminate the toxicity to the exposed organisms algae Pseudokirchneriella subcapitata and rotifer Brachionus calyciflorus and ensure the total survival of Daphnia magna species. For concentrations of Hg(II) tenfold higher (500 μg L−1), the remediation process was not adequate in the detoxification process, still, the rice husk material was able to reduce considerably the toxicity to the bacteria Vibrio fischeri, algae P. subcapitata and rotifer B. calyciflorus, whose responses where fully inhibited during its exposure to the non-remediated river water. The use of a battery of bioassays with organisms from different trophic levels and whose sensitivity revealed to be different and dependent on the levels of Hg(II) contamination proved to be much more accurate in predicting the ecotoxicological hazard assessment of the detoxification process by means of rice husk biowaste.

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  1. Ahmaruzzaman M, Gupta VK (2011) Rice husk and its ash as low-cost adsorbents in water and wastewater treatment. Ind Eng Chem Res 50:13589–13613

  2. ASTM (American Society for Testing and Materials) (2002a) Standard guide for conducting acute toxicity tests on test materials with fishes, macroinvertebrates, and amphibians. E 729–96. Annual book of ASTM standards, vol 11.05. ASTM, Philadelphia

  3. AZUR Environmental (1998) Microtox® Omni Manual. Carlsbad, CA, USA

  4. Council Directive 98/83/EC on the quality of water intended for human consumption. Official Journal, 330, 0032–0054.

  5. Council Directive 98/83/EC on the quality of water intended for human consumption

  6. Demirbas A (2008) Heavy metal adsorption onto agro-based waste materials: a review. J Hazard Mater 157:220–229

  7. EC Environment Canada (1992) Biological Test Method: Growth Inhibition Test Using the Freshwater Alga Selenastrum capricornutum. Report EPS 1/RM/25, Environment Canada, Ottawa, ON, Canada.

  8. El-Said AG, Badawy NA, Garamon SE (2010) Adsorption of cadmium (II) and mercury (II) onto natural adsorbent rice husk ash (RHA) from aqueous solutions: study in single and binary system. J Am Sci 6(12):400–409 (ISSN: 1545–1003)

  9. El-Shafey EI (2010) Removal of Zn(II) and Hg(II) from aqueous solution on a carbonaceous sorbent chemically prepared from rice husk. J Hazard Mater 175:319–327

  10. Feng Q, Lin Q, Gong F, Sugita S, Shoya M (2004) Adsorption of lead and mercury by rice husk ash. J Colloid Interf Sci 278:1–8

  11. Finney DJ (1971) Probit analysis, 3rd edn. Cambridge University Press, Cambridge

  12. Gupta G, Torres N (1998) Use of fly ash in reducing toxicity of and heavy metals in wastewater effluent. J Hazard Mater 57:243–248

  13. Khalid N, Ahmad S, Kiani SN, Ahmed J (1999) Removal of mercury from aqueous solutions by adsorption to rice husks. Sep Sci Technol 34(16):3139–3153

  14. Krishnani KK, Meng X, Christodoulatos C, Boddu VM (2008) Biosorption mechanism of nine different heavy metals onto biomatrix from rice husk. J Hazard Mater 153:1222–1234

  15. Kuan C-Y, Yuen K-H (2012) Physical, chemical and physicochemical characterization of rice husk. Br Food J 114(6):853–867

  16. Lesmana SO, Febriana N, Soetaredjo FE, Sunarso J, Ismadji S (2009) Studies on potential applications of biomass for the separation of heavy metals from water and wastewater. Biochem Eng J 44:19–41

  17. Manusadžianas L, Balkelyte L, Sadauskas K, Blinova I, Pollumaa L, Kahru A (2003) Ecotoxicological study of Lithuanian and Estonian wastewaters: selection of the biotests, and correspondence between toxicity and chemical-based indices. Aquat Toxicol 63:27–41

  18. McWilliam RA, Baird DJ (2002) Postexposure feeding depression: a new toxicity endpoint for use in laboratory studies with Dapnhia magna. Environ Toxicol Chem 21(6):1198–1205

  19. Microbics Corporation (1992) Microtox® Manual, A Toxicity Testing Handbook.

  20. Mishra A, Tripathi BD (2008) Utilization of fly ash in adsorption of heavy metals from wastewater. Toxicol Environ Chem 90(6):1091–1097

  21. Naja G, Murphy V, Volesky B (2010) Biosorption, Metals. Encyclopedia of industrial biotechnology: bioprocess, bioseparation, and cell technology, John Wiley & Sons

  22. OECD (Organization for Economic Co-Operation and Development) (2006) Freshwater alga and cyanobacteria growth inhibition test. OECD guideline for testing of chemicals 201, Paris, France, pp 25.

  23. Pacheco PH, Gil RA, Cerutti SE, Smichowski P, Martinez L (2011) Biosorption: a new rise for elemental solid phase extraction methods-review. Talanta 85:2290–2300

  24. Rocha LS, Lopes CB, Borges JA, Duarte AC, Pereira E (2013a) Valuation of unmodified rice husk waste as an eco-friendly sorbent to remove mercury: a study using environmental realistic concentrations. Water Air Soil Pollut 224:1599

  25. Rocha LS, Lopes CB, Henriques B, Tavares DS, Borges JA, Duarte AC, Pereira E (2013b) Competitive effects on mercury removal by an agricultural waste: application to synthetic and natural spiked waters. Environ Technol 1–13. doi: 10.1080/09593330.2013.841267

  26. Rosa R, Moreira-Santos M, Lopes I, Silva L, Rebola J, Mendonça E, Picado A, Ribeiro R (2010) Comparison of a test battery for assessing the toxicity of a bleached-kraft pulp mill effluent before and after secondary treatment implementation. Environ Monit Assess 161:439–451

  27. Rotoxkit F™ Chronic Toxicity Test for Freshwater. Standard Operational Procedure. Kleimoer, Gent, Belgium. 28 pp. This assay adheres to ISO norm 20666 and AFNOR norm T90-377. (

  28. Speas D, Duffy WG (1998) Uptake of dissolved organic carbon (DOC) by Daphnia pulex. J Freshw Ecol 13(4):457–463

  29. Srivastava S, Goyal P (2010) Novel biomaterials: decontamination of toxic metals from wastewater. Environmental science and engineering, 1st ed. New York: Springer-Verlag Berlin Heidelberg.

  30. Stein JR (1973) Handbook of phycological methods, culture methods, and growth measurements. Cambridge University Press, London

  31. Sud D, Mahajan G, Kaur MP (2008) Agricultural waste material as potential adsorbent for sequestering heavy metal ions from aqueous solutions—a review. Bioresour Technol 99:6017–6027

  32. Tiwari DP, Singh DK, Saksena DN (1995) Hg(II) adsorption from aqueous solutions using rice-husk ash. J Environ Eng ASCE 121(6):479–481

  33. Uría JES, Sanz-Medel A (1998) Inorganic and methylmercury speciation in environmental samples—a review. Talanta 47:509–524

  34. USEPA (United States Environmental Protection Agency) (1994) Short-Term Methods for Estimating the Chronic Toxicity of Effluents and Receiving Waters to Freshwater Organisms. EPA 600/7-91-002. Washington, DC, EUA.

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Thanks are due to the University of Aveiro/CESAM and Fundacão para a Ciência e a Tecnologia (FCT). Luciana Rocha and Cláudia Lopes acknowledge their post-doc grants to FCT (SFRH/BPD/47166/2008 and SFRH/BPD/45156/2008). Bruno Henriques acknowledge his PhD grant to FCT (SFRH/BD/62435/2009).

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Correspondence to Luciana S. Rocha.

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Responsible editor: Céline Guéguen

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Rocha, L.S., Lopes, I., Lopes, C.B. et al. Efficiency of a cleanup technology to remove mercury from natural waters by means of rice husk biowaste: ecotoxicological and chemical approach. Environ Sci Pollut Res 21, 8146–8156 (2014).

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  • Metals
  • Natural waters
  • Ecotoxicity
  • Rice husk
  • Biosorption
  • Remediation