Biogeochemical processes and trace element mobility in alkaline waste affected soils Cindy Louise Lockwood Submitted in accordance with the requirements for the degree of Doctor of Philosophy The University of Leeds School of Earth and Environment May 2014 The candidate confirms that the work submitted is her own, except where work which has formed part of jointly authored publications has been included. The contribution of the candidate and the other authors to the work has been explicitly indicated below. The candidate confirms that appropriate credit has been given within the thesis where reference has been made to the work of others. The work in Chapter 5 of the thesis has appeared in publication as follows: Lehoux A. P., Lockwood C. L., Mayes W. M., Stewart D. I., Mortimer R. J. G., Gruiz K., and Burke I. T. (2013) Gypsum addition to soils contaminated by red mud: Implications for aluminium, arsenic, molybdenum and vanadium solubility. Environmental Geochemistry and Health, 35(5), 643-656. I was responsible for the sampling of the soil and red mud at Ajka, the interpretation of the soil characterisation of the soil and red mud sampled above, arranging for analysis and preparing samples for XRD, XRF and TOC analysis, carrying out the experimental work (Soil pH, BET), providing laboratory assistance to the main author and assistance with the collection of data especially with regards to ICP-MS and writing of the manuscript with regards to the soil characterisation. Alizée Lehoux carried out the majority of laboratory work (except for soil characterisation, see above) and contributed to the interpretation of the data and writing of the manuscript. William Mayes acted as fieldwork support and carried out extensive manuscript review, together with the contribution of Principle Component Analysis. Douglas Stewart and Robert Mortimer acted as field work support and carried out manuscript review. Katalin Gruiz granted site access and offered advice and comments on the manuscript. Ian Burke acted as fieldwork support, MSc supervisor to Miss Lehoux and contributed considerably to the interpretation of the results together with writing the majority of the manuscript. The work in Chapter 6 of the thesis has been prepared for publication for submission as follows: Lockwood C. L., Mortimer R. J. G., Stewart D. I., Mayes, W. M., Peacock C. L., Polya D. A., Lythgoe P. R., Lehoux A. P., Gruiz K., Burke I. T. (Submitted to Applied Geochemistry, June 2014) I was responsible for the sampling the soil and red mud at Ajka, arranging for analysis and preparing samples for XRD, XRF and TOC analysis, sampling, experimental design, processing and analysis of all microcosms, data collection, interpretation of data and statistical analysis, writing the paper and preparation of all tables and figures, except where listed below. Robert Mortimer acted as field work support and manuscript review. Douglas Stewart acted as fieldwork support, carried out manuscript review and assisted with the collection of XAS data. William Mayes acted as fieldwork support, carried out manuscript review, together with the contribution of Principle Component Analysis. Caroline Peacock assisted with the collection of XAS data and offered advice and comments on the manuscript. David Polya was responsible for organising the HPLC-ICP-MS analysis and offered advice and comments on the manuscript. Paul Lythgoe carried out HPLC-ICP-MS analysis for As speciation. Alizée Lehoux provided the data for the red mud leaching batch tests. Katalin Gruiz granted site access and assisted with site orientation. Ian Burke acted as fieldwork support, assisted with collection of XAS data and interpretation of As EXAFS data and provided extensive manuscript review. The work in Chapter 7 of the thesis has been prepared for publication for submission as follows: Lockwood C. L., Stewart D. I., Mortimer R. J. G., Mayes, W. M., Gruiz K., Burke I. T., Leaching of copper and nickel in soil-water systems contaminated by red mud from Ajka, Hungary: The importance of soil organic matter. (in preparation for The Journal of Hazardous Materials, 2014) I was responsible for the sampling the soil and red mud at Ajka, arranging for analysis and preparing samples for XRD, XRF and TOC analysis, sampling, experimental design, processing and analysis of anaerobic and aerobic microcosms, data collection, interpretation and statistical analysis, writing the paper and preparation of tables and figures. Douglas Stewart acted as fieldwork support, carried out extensive manuscript review. Robert Mortimer acted as field work support and manuscript review. William Mayes acted as fieldwork support together with the contribution of Principle Component Analysis. Katalin Gruiz granted site access and assisted with site orientation. Ian Burke acted as fieldwork support and provided manuscript review. This copy has been supplied on the understanding that it is copyrighted material and that no quotation from the thesis may be published without proper acknowledgement ©2014 The University of Leeds and Cindy Louise Lockwood The right of Cindy Louise Lockwood to be identified as the author of this work has been asserted by her in accordance with the Copyright, Designs and Patents Act 1988. Acknowledgements I would like to express my sincere thanks to Doug Stewart, Will Mayes, Rob Mortimer and Ian Burke and for their invaluable help, support and enthusiasm throughout my PhD. I would also like to thank them for all their personal advice, encouragement and for putting up with my excessive bouts of worrying. Field trips were always a great source of amusement; I’m sure that there is a joke that starts “There were four academics and a PhD student in car travelling to Budapest”. I would to thank Katalin Gruiz and her team at BME in Budapest for field support and site orientation in Hungary. I would also like to thank others who have helped me out with technical guidance and data collection including but not limited to; David Ashley, Rachel Gasior, Lesley Neve, Clare Gordon, David Elliot, Sheena Bennett, Ann Mennim, Nick Marsh, Fred Mosselmans, Tina Geraki, Alizée Lehoux and Stephen Reid. A massive massive ‘thank you’ goes to Bob Knight and Sam Allshorn, my all time PhD heros. A big thanks to members past and present of Cohen Geochemistry a.k.a. ‘Cohenites’ especially; Liane Benning, for always being interested and giving out good advice, Caroline Peacock, for beamtime help and advice, Rob Whittleston and Sarah Wallace for having done it all before me and sharing their experiences, Romain Guilbaud for helping me with a very important presentation and Jörgen Rosenqvist, my PhD therapist. Thank you to all the occupants of office 8.154 over the past 3 1/2 years especially Andy Bray, Steffi Lutz, Pieter Bots, Santiago Clerici and Daniela Meier for their willingness to help and, listen to me whinge but mainly for their tolerance of my grumpiness. A special thank you to Lizzy Moyce, Janice Littlewood and Amy Atkins – it has been an absolute pleasure, I really don’t think I could have come this far without your friendship. Outside of University Life, to my friends; Jax Spud, LB, Rads, Heather, Andy W, Guy ‘Oatcake’ Hassall, Mr. Wasif, Peaches, Tori and even Mr. Strange; my fellow Captains of the Ruptured Core Confederation, Timothy Taylor for his Championship Beers, Mr. Scratchings for his tasty pork rinds and all the whippets and rabbits on the internet - thank you all, for keeping me sane. A huge thank you to my family and extended family of Jones’, Phil, Kath and Tobes, my sister Sally, my beautiful niece Jess, my epic nephew Lucas and most of all my Mum and Dad, you have all been so supportive and I am eternally grateful. Finally, lots of love and thanks to Andy ‘The Jones’ Jones for putting up with and helping me get through this with my sense of humour intact, ‘Loving you is easy cos you make good food’. Now let’s go for a pint. This project has been funded by the UK Engineering and Physical Science Research Council (Doctoral training award EP/P505593/1) and I thank Diamond Light Source for access to beamline I18 (Grant SP7525) that contributed to the results presented in this thesis. Abstract High pH leachates can mobilise oxyanion forming elements from alkaline waste, such as iron and steel slags and bauxite ore processing residue, into the wider environment. Red mud is a highly alkaline waste product from bauxite ore processing. It contains elevated concentrations of oxyanion forming elements such as Al, As, V and Mo that are mobilised at high pH together with other trace metals including Cu and Ni. The red mud spill at Ajka, Hungary released 1 million m3 of caustic red mud into the surrounding area. As part of the initial clean-up, some thinner red mud deposits (< 5 cm) were ploughed into fields to prevent dust formation whereas wetland areas were left untreated. This study used aerobic and anaerobic batch microcosms together with XAS spectroscopy, (HPLC)-ICP-MS and solid phase extraction techniques to investigate the effects of red mud addition to unaffected soils with respect to biogeochemical processes and trace element release. Experiments were designed to be analogous to soil conditions following the remediation efforts. The results showed that the effect of red mud addition to soils was highly dependent upon soil properties, experimental pH, and total organic carbon (TOC) content. As and V were found to be persistently mobile under both aerobic and anaerobic conditions. Red mud addition to soils with a high TOC content mobilised high aqueous concentrations of organic matter complexing metals such as Cu, Ni and V under anaerobic conditions. Gypsum addition to red mud affected soils showed a reduction in aqueous oxyanion concentrations compared to soils with red mud addition alone indicating that it is potential ameliorant for red mud contaminated soils.