Samuel Gregory

Doctor of Philosophy, (Soil Science)
Study Completed: 2014
College of Sciences


Thesis Title
Remediation of New Zealand sheep dip sites using biochar and phytoextraction technologies

Read article at Massey Research Online: MRO icon

Historic sheep dip sites are synonymous with significantly high soil concentrations of arsenic and organochlorines. There are an estimated 50,000 contaminated sheep dip sites in New Zealand, representing what may be the country’s most significant, but understated, environmental challenge. Mr Gregory investigated whether water and food sources in proximity to these sites were being contaminated. His investigation uncovered that water sources and aquatic plants (such as watercress) were highly contaminated with arsenic. His research also focussed on whether this contamination could be remediated in a sustainable manner. By using a technique that couples biochar (a form of stable carbon similar to charcoal) with phytoextraction (a plant’s ability to extract contaminants from soil), Mr Gregory was able to show that this natural technology system can reduce the remediation time of these contaminated sites by up to 92%.

Professor Chris Anderson
Professor Michael McManus
Professor Marta Camps Arbestain