Hawkesbury Institute for the Environment

• Publications

Doctor 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 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.

Grants

During 2012 UWS 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 Recent Journal Articles

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