Doctor Paul Milham

Paul MilhamDoctor Paul Milham uses strong research skills in chemistry to investigate key soil processes that underpin interactions between soil, plants, and the environment. His work on the toxic heavy metal cadmium is internationally recognised.

Dr Milham also collaborates in studies of plant nutrients, especially phosphorus, both as a mediator of the response of plants to climate change and as an environmental contaminant.

Publication of his research has included over 55 peer-reviewed journal papers (with an h-index of 12) and presentations at national and international conferences.

Dr Milham mentors young scientists (currently three PhD candidates) and contributes to the activities of the Australasian Soil and Plant Analysis Council and the National Association of Testing Authorities.


During 2012 the University provided Seed Funding to Drs Paul Holford and Paul Milham to explore interactions between bioavailable soil cadmium and halide ions.  The research builds on progress made during a study funded in the 2009−12 period (below).  The new knowledge developed has contributed to the formulation of the following IRIS application.

An IRIS application was submitted (2012) to develop collaboration on cadmium uptake plants.  This collaboration will link extensive research on the uptake of cadmium by barley at Zhejiang University in China, the research conducted by Drs Holford and Milham on the behaviour of cadmium in soil, and the capability of measuring ion fluxes created by the recent appointment of Dr Zhonghua Chen to the School of Science and Health.

Paul is part of a team of NSW DPI scientists to be awarded an ACIAR grant (2013−15) to build the capacity of villagers in North West Vietnam to increase the production of indigenous vegetables.

In 2011, the Australian Synchrotron Research Program (ASRP) funded research by Dr Milham and his collaborators at ANSTO continuing a study commenced under an earlier ASRP grant (2005), to characterise the site of cadmium binding in soils.

In 2011 the Australian Institute of Nuclear Science and Engineering funded an application by Drs Oula Ghannoum (HIE) and Paul Milham to develop tools to study the effects of climate change on N cycling in eucalypt forests.

During 2010 UWS and Applied Horticultural Research Ltd jointly funded a Partnership Grant for Drs Paul Holford (School of Science and Health) and Paul Milham to study the interaction between bioavailable soil cadmium and the chloride ion.  The knowledge generated forms the basis of novel research continued under the 2012 Seed and IRIS grants (above).

Studies on the environmental behaviour of phosphorus were funded by Dairy Australia, Land and Water Australia and an ARC Linkage Grant.

Awards and Recognition

  • Winner of the CS Piper Prize of the Royal Australian Chemical Institute (2008) and the FG Swain Award (UWS) for research on soil cadmium.
  • Elected a Fellow of the Royal Australian Chemical Institute in recognition of contributions to knowledge in the field of environmental chemistry.
  • Peer reviewer of scientific papers, editor of conference proceedings, and invited journal contributor, conference speaker and thesis examiner.
  • Elected NSW representative on the board of the Australasian Soil and Plant Analysis Council.
  • Adjunct associations with various Australian Universities, the most long-standing being with UWS.
  • Laboratory proficiency assessor for the National Association of Testing Authorities and for its sister organisation in New Zealand.
  • Past member of the board of the Australasian Soil Science Society and NSW member of the National Cadmium Management Committee.

Areas of research

Understanding the processes which control the behaviour of substances in the environment, including the:

  • behaviour of bioavailable cadmium in soils;
  • mechanism of phosphorus entrainment from soil into surface water;
  • impact of mineral nutrients on plant responses to climate change.

Current projects

Low levels of cadmium in food degrade the health of millions worldwide and may affect more than 10% of Australian children.  Most of this dietary cadmium comes from plant foods and ultimately from the bioavailable fraction of soil cadmium.  To learn how to decouple the link between bioavailable soil cadmium and its uptake by plants, Dr Milham uses partitioning, isotopic and synchrotron approaches.  He is currently studying the effects of chloride ion on the partitioning of bioavailable soil cadmium into solution, potentially leading to a new, selective assay for bioavailable cadmium and to prediction of the interplay of cadmium uptake by plants and climate change.

Nutrients moving in surface water from well-grassed, fertile pastures degrade the quality of the aquatic environment.  Phosphorus is one such nutrient and Doctor Milham contributes to research to identify and better understand the key processes that control its mobility.  There is a dearth of tools to probe these processes, and to fill that gap, he leads novel research into potential tracers for phosphate interactions in the environment based on "labelling' using stable, heavy isotopes of oxygen.

Plants require adequate phosphorus to fully respond to increased CO2 levels in the atmosphere.  This has implications for the global sequestration of carbon and consequently for future climate, because large tracts of forest currently experience marginal supplies of phosphorus.  This is true of much of Australia's native forests and Dr Milham contributes to research on this topic.

Selected Journal Articles

Khan S, Milham PJ, Eltohamy KM, Hamid Y, Li F, Jin J, He M, Liang X, (2022) 'Pteris vittata plantation decrease colloidal phosphorus contents by reducing degree of phosphorus saturation in manure amended soils', Journal of Environmental Management, vol.30415, Article no.114214

Amami R, Ibrahimi K, Sher F, Milham P, Ghazouani H, Chehaibi S, Hussain Z, Iqbal HMN, (2021) 'Impacts of different tillage practices on soil water infiltration for sustainable agriculture', Sustainability (Switzerland), vol.13, no.6, Article no.3155

Minh TT, Minh TTT, Trong TD, Thuy HP, Nguyen BT, Milham PJ, (2020) 'Boron deficiency may be widespread in Brassica oleracea var. capitata L. in Lao Cai Province, North Western Vietnam', Communications in Soil Science and Plant Analysis, vol.51, no.21, pp 2726-2734

Andersson KO, Tighe MK, Guppy CN, Milham PJ, McLaren TI, Schefe CR, Lombi E, Lisle LM, Klysubun W, (2019) 'Transformation of Calcium Phosphates in Alkaline Vertisols by Acidified Incubation', Environmental Science & Technology, vol.53, no.17, pp 10131-10138

Dehigaspitiya P, Milham P, Ash GJ, Arun-Chinnappa K, Gamage D, Martin A, Nagasaka S, Seneweera S, (2019) 'Exploring natural variation of photosynthesis in a site-specific manner: evolution, progress, and prospects', Planta, vol.250, no.4, pp 1033-1050

Duan H, Ontedhu J, Milham P, Lewis JD, Tissue DT, (2019) 'Effects of elevated carbon dioxide and elevated temperature on morphological, physiological and anatomical responses of Eucalyptus tereticornis along a soil phosphorus gradient', Tree physiology, vol.39, no.11, pp 1821-1837

Morrow JL, Sa PT, Beattie GAC, Milham PJ, Riegler M, Spooner-Hart RN, Holford P, (2019) 'Additions of sugar and nitrogenous fertiliser affect plant nitrogen status and soil microbial communities', Applied Soil Ecology, vol.139, pp 47-55

Khanboluki G, Hosseini HM, Holford P, Zadeh BM, Milham PJ, (2018) 'Effect of elevated atmospheric CO2 concentration on growth and physiology of wheat and sorghum under cadmium stress', Communications in Soil Science and Plant Analysis, vol.49, no.22, pp 2867-2882

Milham PJ, Wenzel RG, Holford P, Haigh AM, Chaffer K, Hawkins CA, Humphris C, Fabien J, Conroy JP, (2018) 'Equilibrating stable Cd isotopes with acidic soils', Communications in soil science and plant analysis, vol.49, no.20, pp 2497-2506

Parks SE, Milham PJ, (2017) 'The value of on-farm rapid tests for measuring nitrate in leafy vegetables and in hydroponic solutions', Acta Horticulturae, vol.1176, pp 73-78

Andersson KO, Tighe MK, Guppy CN, Milham PJ, McLaren TI, Schefe C, Lombi E, (2016) ' XANES demonstrates the release of calcium phosphates from alkaline Vertisols to moderately acidified solution',  Environmental Science and Technology, vol.50, pp 4229-4237

Jinadasa N, Collins D, Holford P, Milham PJ, Conroy JP, (2016)  'Reactions to cadmium stress in a cadmium tolerant variety of cabbage (Brassica oleracea L.): is cadmium tolerance a desirable trait in food crops?',  Environmental Science and Pollution Research, vol.23, no.6, 5296-5306

Nagai Y, Matsumoto K, Kakinuma Y, Ujiie K, Ishimaru K, Gamage DM, Thompson M, Milham PJ, Seneweera S, Hirotsu N, (2016) 'The chromosome regions for increasing early growth in rice: role of sucrose biosynthesis and NH4 (+) uptake', Euphytica, vol.211, no.3, pp 343-352

Nakandalage N, Nicolas M, Nicolas M, Hirotsu N, Milham PJ,  Seneweera S, (2016)  'Improving rice biofortification success rates through genetic and crop management approaches in a changing environment', Frontiers in Plant Science, vol.7, Article no.764, pp 1-13

Andersson K, Tighe M, Guppy C, Milham P, McLaren T, (2015) 'Incremental acidification reveals phosphorus release dynamics in alkaline vertic soils', Geoderma, vol.259-260, pp 35–44

Chehine C, Holford P, Ghannoum O, Collins D, Conroy JP, Milham PJ, (2014) 'Transpiration influences cadmium uptake by baby leaf Spinach (Spinacia Oleracea L.)', American Journal of Agricultural and Biological Science, vol.9, no.4, pp 523-533

Paltridge NG, Palmer LJ, Milham PJ, Stangoulis JCR, (2012)  'Energy-Dispersive X-ray fluorescence analysis of zinc and iron concentration in rice and pearl millet grain',  Plant and Soil, vol.361, pp 251–260

Parks SE, Irving DE, Milham PJ, (2012)  'A critical evaluation of on-farm rapid tests for measuring nitrate in leafy vegetables',  Scientia Horticulturae, vol.134, pp. 1-6

Dougherty WJ, Mason SD, Burkitt LL, Milham PJ, (2011)  'Relationship between runoff phosphorus concentration and a novel soil phosphorus test procedure (DGT)',  Soil Research, vol.49, pp 523–528

Thomas AO, Milham PJ, Morrison RJ, Clark RG, Alvarez R, (2011)  'Persistence of the bond between P and O in POCl3 during the reaction with water',  Australian Journal of Chemistry, vol.64, pp 1360-1365

Milham PJ, Dougherty WJ, Fabien J, Rubenis G, Peverill KI, (2011)  'Stabilisation of molybdate-reactive phosphorus in 0.5 M NaHCO3 extracts of soils',  Communications in Soil Science and Plant Analysis, vol.42, pp 1143-1152

Dougherty WJ, Nicholls PJ, Milham PJ, Havilah EJ, Lawrie RA, (2008)  'Phosphorus fertilizer and grazing management effects on phosphorus in runoff from dairy pastures',  Journal of Environmental Quality, vol.37, pp 417-428