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Item Contributions to contamination dynamics, assessment and remediation of the environment : application for the degree of Doctor of Science DSc from Massey University, Palmerston North, New Zealand(Massey University, 2015) Naidu, RavendraEnvironmental contamination is a massive problem for Australia and, indeed, globally. It has serious impacts on: • human health; • the health and sustainability of our natural environment; and • the economy. Historical environmental contamination will be a toxic legacy for Australians for decades to come. There are over 160,000 potentially contaminated sites in Australia. Remediation is currently costing companies and owners of contaminated sites in excess of $3 billion per annum, with the number of sites remediated being less than 5%. Cases of poisoning by substances such as arsenic, lead, asbestos, pesticides etc. are in the news almost daily, while large areas of valuable land (for example in China) cannot be used because of past contamination. Surface and subsurface soil and its groundwater environment is a complex and heterogeneous system. Once contaminants have come into contact with these systems, assessment and remediation is difficult and extremely challenging. Australia has not yet developed the affordable solutions, the preventative technologies and advanced regulatory frameworks to address this huge problem and curb its spread. Professor Naidu, a PhD graduate of Massey University, recognised environmental contamination as a major challenge confronting the community, owners of contaminated sites and regulatory bodies as early as the 1990s - before Australia even had its National Environment Protection Measure in, place. Recognising the gap in knowledge on contaminants, he commenced a research and technology development program providing initial leadership in Australia and later internationally by heading Commission 3.5 (2002 to 2010) which focused on Soil Degradation and Reclamation. He also raised in excess of $500 million to establish a Co-operative Research Centre for Contamination Assessment and Remediation of the Environment (CRC CARE) - the only National Centre of Excellence that focuses on contamination and remediation. The research undertaken within this Centre is prioritised through extensive consultation and participation by end-users. Since commencing research on contaminants, Professor Naidu has enhanced our understanding of risks posed by contaminants in the environment, their fate and behaviour in soil and groundwater, and techniques for assessing and remediating contaminated sites. These areas are grouped, in this thesis, into five overlapping areas of research: • Measurement; • Fate and dynamics; • Bioavailability; • Food Chain and • Remediation. The key elements of these five themes, and their contribution to knowledge, form Chapters 2-6 of the thesis. Professor Naidu's awards and honours are summarised in his curriculum vitae.Item Use of turnips to reduce potassium accumulation on areas receiving farm dairy effluent : a thesis presented in partial fulfilment of the requirements for the degree of Master of Applied Science in Soil Science at Massey University, Palmerston North, New Zealand(Massey University, 2006) Salazar, MonicaLand treatment of farm dairy effluent (FDE) on small areas of intensive of dairy farms has enriched soils with nutrients particularly K. Solving the problem solely by increasing the area allocated for land treatment requires large investment in pump, pipes and irrigator infrastructure. A less costly strategy, of sowing and grazing a summer turnip on the land treatment area in order to redistribute K to the pasture area is evaluated in this thesis. A survey (February 2006) showed that in the Manawatu region turnip crop yields (8 to 17t DM.ha⁻¹) provided profitable feed for dairy cows, were a suitable re-grassing strategy and if harvested, removed 350 to 700 kg K ha⁻¹ from the soil. In the summer of 2005/06, a turnip (Brassica rapa cv. Barkant) trial was established after permanent pasture on a Pallic soil (pH 6.5, Olsen P 35.2 ug. g⁻¹, exchangeable K⁺ 0.7, Ca²⁺ 6.3, Mg²⁺ 1.4 me/ 100 g soil). The following treatments pre-plant fertiliser only (38 kg N ha⁻¹, 25 kg P ha⁻¹) and 25 kg K ha⁻¹), pre-plant fertiliser plus side-dressed urea at 40 DAS (46 kg N ha⁻¹) and pre-plant fertiliser plus 5 x 10 mm FDE applications (57kgha⁻¹) all produced similar final dry matter yields (8 t DM ha⁻¹) at 100 days after sowing (DAS). Leaf was the largest component of dry matter and had higher K concentrations (4.6 and 6.8% K in the control and FDE treatments respectively) than bulb (3 and 4 %K in the control and FDE treatments respectively). The ratio of leaf to bulb dry matter however varied for each different treatment. Side-dressed urea and FDE treatments produced the largest leaf biomass and reached maximum yields earlier by 75 DAS and 64 DAS, respectively and generated more K removal at harvest (339, 428 & 537 kg K ha-⁻ at 75 DAS and 316, 372 & 490 kg K ha-⁻ at 100 DAS for pre-plant only, urea & FDE treatments, respectively). The lack of yield response to N partially resulted from crop uptake of between 107 and 114 kg N ha-⁻ from mineralisable soil N. The dynamic N crop model N-able predicted that extra side-dressed N would not increase turnip yield but in the absence of pre-plant N (38 kg N ha-⁻) the turnips would yield 7.4 t DM ha-⁻ at 100 DAS. The use of the N-able model demonstrated a need for a decision support model to assist farmers in choosing appropriate N fertiliser application rates. A simple model was created to simulate how the grazing cow can transfer K from turnip paddocks (part of a FDE treatment block) to other parts of the farm. The model simulation of 490 cows on a mixed diet of 4kg DM turnips and 12 kg DM pasture predicted that the grazing of turnips (8t DM ha-⁻ crop) would result in the net transfer of significant quantities (>170 kg K ha-⁻) of K from land growing turnips to other parts of the farm. To cause net transfer to occur the allocated turnip dry matter must be grazed in the shortest time possible and the cows returned to pasture after short milking times.Item Bioremediation of contaminated soil : a thesis presented in partial fulfilment of the requirements for the degree of Master of Technology in Environmental Engineering at Massey University(Massey University, 1997) Wotherspoon, Robert JasonThe release of contaminants into the environment is inevitable. Contaminants are released through manufacture and use of products and as a result of treatment and disposal of wastes. Upon release to the environment, contaminants move and respond to a number of interrelated natural and man made factors. Penta-chloro-phenol (PCP) is one such contaminant that has been released into the environment and is known to have serious long term environmental effects. The objective of this study was to determine the effectiveness of biological processes to remediate soil contaminated with Penta-chloro-phenol (PCP). This thesis reviews mechanisms by which soil is contaminated, processes available to remediate soils, and in particular, process requirements for successful bioremediation. The abilities of bacteria to degrade PCP from soil contaminated with PCP was evaluated. Solid phase and slurry phase experiments were examined for their effect on PCP concentration over a four month period at the Department of Technology. Massey University. The objectives of this study were (1) To determine if aeration and inoculation of soil in-situ could produce significant removal of PCP. (2) Determine the effect of concentration on bioremediation rates. (3) Compare in-situ treatment with bio-slurry treatments. The experiments showed that it is possible to remove up to 95% of PCP from contaminated soil by inoculation with bacteria. Inoculum size and aeration were shown to be critical factors in affecting the rate of degradation. The larger the initial inoculum the greater the rate of degradation. Without aeration the inoculum was unable to significantly degrade PCP. The bio-slurry confirmed that PCP could be removed readily from soil to an aqueous state. In an aqueous state PCP is degraded at a faster rate than when it is incorporated into the soil matrix. The results of this work is to show that soil rehabilitation by way of biodegradation is a feasible and attractive process.Item Removal of copper, chromium and arsenic from the tannery and timber treatment effluents and remediation of chromium of contaminated soil : a thesis presented in partial fulfillment of the requirements for the degree of Master of Applied Science at Massey University(Massey University, 1997) Thiagarajan, SubramaniTannery and timber treatment effluents are considered to be the major source of Copper (Cu), Chromium (Cr) and Arsenic (As) heavy metal contamination into the environment. Chromium is used in tanneries for the treatment of hides and skins whereas, copper, chromium, and arsenic (CCA) solution is used as the timber treatment chemical. Chromium is used as Cr (III) in tannery industry and as Cr (VI) in timber treatment industry. Arsenic and Cr (VI) which are present in the timber treatment effluent are highly toxic and carcinogenic. An initial survey has indicated that some tannery industries in New Zealand have not developed pre-treatment practices to reduce the heavy metal concentration before discharging the effluent into soil or waterways. The heavy metal pollution due to timber treatment industries may occur from the drips, leaks and spills due to poor handling of CCA solution while treating timber. In this project, the potential value of industrial waste materials, such as Pinus radiata bark, fluidised bed boiler ash (FBA), flue gas desulphurisation gypsum (FGDG) and natural resources, such as zeolite, peat soil, and two soils (Tokomaru and Egmont soils) to reduce heavy metal concentration in tannery and timber treatment effluents was examined. The value of these materials in the remediation of soil contaminated with Cr was examined using a growth experiment. The effect of pre-treatment of Pinus bark with acid, alkali of formaldehyde/acid on the retention of Cr was examined. Pre-treatment of Pinus bark increased the heavy metal retention only at low heavy metal concentration and did not significantly improve the heavy metal retention at high concentration. The extent of adsorption increased with an increase in surface area of Pinus bark material. Speciation of Cr indicated that Cr (VI) is reduced to Cr (III) and adsorbed onto the Pinus bark. FBA was found to be most efficient in reducing the Cr (III) concentration from tannery effluent and As and Cu concentrations in the timber treatment effluent. In the case of Cr (VI), the highest retention was shown by the Pinus bark and the peat soil. The increased retention of Cr (III), Cu and As by FBA was due to the precipitation of Cr (III) as chromium hydroxide, Cu as cupric hydroxide and As as calcium arsenate. A combination of FBA + Pinus bark or FBA + peat soil was efficient in reducing all the three heavy metal (Cu, Cr (VI) and As) concentration from the timber treatment effluent. The effluents contaminated with Cu, Cr and As can be passed through a column containing FBA and Pinus bark or peat soil. A growth experiment using sun flower (Helianthus annus) was set-up to examine the effectiveness of FBA, lime and Pinus bark to immobilise Cr in contaminated soil. FBA and lime amended soils were effective in establishing a normal plant growth of sun flower in Cr (III) contaminated soil even at high Cr (III) levels (3200 mg/kg soil). Incorporation of lime or FBA in Cr (III) contaminated soils causes precipitation of Cr (III) and thereby reduces the bioavailabilty of Cr for plants uptake. Only Pinus bark amended soil was found to be effective in remediating Cr (VI) contaminated soil even at 3200 mg/kg soil. Pinus bark material effectively retained the Cr (VI) present in the soil solution and thus reducing the toxicity and bioavailability of Cr (VI) to plants.Item Remediation of New Zealand sheep dip sites using biochar and phytoextraction technologies : a thesis presented in partial fulfilment of the requirements for the degree of Doctor of Philosophy in Soil Science, Institute of Agriculture and Environment, College of Sciences, Massey University, Palmerston North, New Zealand(Massey University, 2013) Gregory, SamuelThe practice of sheep dipping, which subjected livestock to inorganic and organic agricultural pesticides to eradicate pests such as lice and keds, is a historic practice; sheep dipping is no longer practiced in New Zealand today. Animals would be submerged in solid structures known as dips containing chemicals such as arsenicals and organochlorines with the leftover solution pumped onto surrounding soil. The use of pesticides such as these is now banned by law due to their persistence in the environment. Today an estimated 50,000 contaminated sheep dip sites exist in New Zealand representing perhaps the countries’ most significant, but understated, environmental challenge. To determine whether this historic agricultural practice had led to contamination of the environment, an investigation into the extent of contamination resulting from sheep dipping at a known historic dip site in Te Mahia, New Zealand was carried out. Characterisation of the site by arsenic soil concentration mapping revealed that 500 m2 of agricultural land has been contaminated with this metalloid and that arsenic exists at varying high concentrations through the soil profile. Environmental risk from these historic pesticides was established by analysing plant and water samples below the dip site. Staple Maori food varieties such as watercress were significantly contaminated with arsenic while water samples taken from the stream below the dip returned spiked arsenic concentrations. Based on this, it was justified that arsenic/organochlorine contamination would need to be managed to reduce their effect on these food sources. The design of a coupled remediation strategy using phytoextraction and biochar was utilized to reduce remediation times and is the basis of this thesis. Contaminated soil from the site was removed and amended with two types of biochar produced from willow feedstock. These biochars, known as 350°C and 550°C biochar were added into the soil at application rates of 30 t ha-1 and 60 t ha-1. During a series of 180 d glasshouse trials, the phytoextraction of arsenic into Lolium perenne (ryegrass) shoot tissue was analysed along with growth parameters of shoot and root biomass and corresponding response to arsenic at the molecular level. In soil; microbial activity, soil bacterial community, organochlorine concentration, and element dynamics were analysed as a function of biochar amendment. Soil microbial activity, analysed using the dehydrogenase assay (DHA), was significantly increased (P<0.01) under all biochar treatments compared to the control after 180 d during two glasshouse trials. Metagenomic analysis of the soil bacterial community revealed that biochar amended soils were selecting for bacterial species such as Chryseobacterium, Flavobacterium and Dyadobacter and the family Pseudomonadaceae which are known bioremediators of hydrocarbons. This resulted in isomers of the organochlorine hexachlorocyclohexane (HCH), particularly alpha-HCH and gamma-HCH (lindane), undergoing 10-fold and 4-fold reductions in soil concentrations respectively (2.2 mg kg-1 and 0.4mg kg-1) compared to the control (25 mg kg-1 and 1.6 mg kg-1 respectively). Amendment of soil with both biochars also caused a significant reduction (P<0.01) in soil DDT levels. Biochar promoted a 2-fold increase in shoot dry weight (DW) and a 3-fold increase in root DW after 180 d during one glasshouse trial while during the second trial only ryegrass root biomass was significantly increased as a function of biochar amendment. This increase was attributed, at least in part, to the fertility value of biochar. No negative effect of biochar amendments on ryegrass germination was observed. All biochar amendments resulted in significant increases in arsenic concentrations within ryegrass shoot material. Through extrapolation, 350°C biochar amended soils was estimated to have the potential to increase ryegrass sward DW growth by 0.68 t ha-1 compared to ryegrass grown on unamended soils and would correspond to an increase in the extraction of total arsenic by 14,000 mg ha-1 compared to unamended soils and in doing so decrease soil remediation times by over 50 %. Increased arsenic uptake as a function of biochar amendment resulted in increased enzymic activity of components of the antioxidant pathway including SOD and APX in most biochar treatments but across all treatments a reduction in GPX activity was observed. Analysis of specific metabolites utilizing metabolomics also suggest a definitive metabolite profile under biochar amendment compared to contaminated control ryegrass samples. However, there was no significant difference (P<0.05) in chlorophyll content in response to the total arsenic concentration in ryegrass shoot tissue grown on contaminated soil. The observed increases in activity of SOD, APX and steady CAT activity is suggested to be efficiently catalysing the production of harmful ROS in this soil. A 6-month field investigation into the effect of biochar amendment on the extraction of arsenic into a high biomass crop (Salix sp) resulted in significant increases of arsenic in stem biomass as a function of biochar amendment. When data was extrapolated to predict results of a long-term field trial and scale under willow treatment (stem) it was calculated that over 67.7 g of arsenic could be extracted in soils amended with 350°C biochar compared to 5.9 g extracted under control treatment. This could result - assuming a similar rate of extraction with time - in levels of arsenic concentration in soils reaching background concentrations in as little as 6 years, a reduction in remediation times of 92%.Item EDTA-enhanced transport of copper from contaminated soil and its implications : a thesis presented in partial fulfilment of the requirements for the degree of Doctor of Philosophy in Soil Science at Massey University(Massey University, 2002) Thayalakumaran, ThabonithyAn understanding of the interacting physical and chemical processes involved is necessary for efficient and environmentally responsible remediation of copper-contaminated soils through EDTA-enhanced mobilisation, using either ex situ or in situ methods. In order to study these processes, leaching experiments were performed on repacked columns and intact cores, with various initial and boundary conditions, in two contrasting soils containing varying amounts of copper. One soil was an alluvial Manawatu fine sandy loam, which was low in organic matter, and the other a volcanic Opotiki sandy loam with a higher organic matter content. In both soils, the EDTA moved without any observable adsorption when the soil pH was above 5.0. But, uncontaminated Opotiki soil with a pH of 4.5, did adsorb EDTA to some extent. Leaching with an excess of 0.01 M EDTA, extracted all but 40 mg kg-1 of the copper that was initially present in the repacked Manawatu soil and all but 90 mg kg-1 of the copper from the Opotiki repacked soil. In the intact Opotiki soil cores the EDTA reduced the copper concentration in the top 25 mm of the intact core from 240 to 80 mg kg-1. EDTA not only leached the copper from the soil, but also a substantial amount of iron. Opotiki soil with pulses of EDTA left in it for up to a month before leaching showed a time-dependent drop in the amount of copper leached, and a corresponding increase in the amount of iron leached. Increased EDTA residence time in the Manawatu soil prior to leaching in general also showed a time-dependent increase in iron leached. With increasing EDTA residence time in the soil, the mass of copper leached dropped markedly in the low-Cu Manawatu soil. However, the copper remained in the soil solution, and so prone to leaching, for at least a month in the medium and high-Cu Manawatu soils. These results are consistent with CuEDTA2- being gradually transformed to the more stable Fe(III)EDTA- and Cu2+ in all cases. Copper contaminated Opotiki repacked soil columns and intact cores growing the grass Agrostis tenuis on were used to investigate the relative importance of plant uptake and leaching of copper. Application of 1800 µmol of EDTA to 0.9 kg of the contaminated soil in a repacked column increased the leaf copper concentration from 30 µg g-1 to 300 µg g-1. The same amount of EDTA applied to 1.0 kg of soil in the intact cores, increased the herbage copper concentration to 60 µg g-1. Leaching the columns and cores with water about a month after the EDTA application removed 25 to 169 times more copper than was taken up by the herbage. The convection dispersion equation (CDE), coupled with a source/sink term accounting for time-dependent reactions taking chemical species into or out of solution, was used to model the EDTA-enhanced transport of copper in contaminated soils. In general, the model successfully described the copper concentration in the leachate and soil, despite the quite different amounts and concentrations of EDTA applied, and the varying lengths of time it was left in the soil before leaching. However, the values for the key parameters had to be adjusted appropriately, with faster rate constants for the Manawatu soil than the Opotiki soil. The observed differences in behavior between the repacked and intact Opotiki soil could be simulated by increasing the dispersivity from 3 to 23 mm, while leaving unchanged the parameters describing the chemistry. The results on the kinetics of the EDTA and the soil copper reaction, and for the stability of the CuEDTA2- and its interaction with physical processes, suggest that in situ remediation of copper contaminated soils is possible. However, the applied EDTA should be leached immediately or within few days. It would also require that the residence time of soil water moving through the profile to the water table was in excess of a month. EDTA-enhanced phytoremediation of copper might be possible if leaching can be avoided. If drainage occurs the copper moving below the root zone is likely to be at least an order of magnitude greater than that taken up by the vegetation.Item Phytoremediation of mercury-contaminated mine wastes : a thesis presented in partial fulfilment of the requirements for the degree of Doctor of Philosophy in Soil Science, Massey University, Palmerston North(Massey University, 2004) Morena, Fábio NettoMercury (Hg) is a toxic heavy metal that is concentrated in organisms. Injudicious use of Hg and its compounds have resulted in widespread soil contamination. This study investigates the potential use of plants for the remediation of Hg-contaminated mine wastes. Plants can remove soil Hg via phytoextraction and phytovolatilisation. I investigated both of these strategies by focusing on a methodology for Hg analyses in plants and soils with a view to the determination of volatile Hg emitted from plants. Secondly, I determined the feasibility of Hg phytoextraction and phytovolatilisation from contaminated mine wastes. An accurate method for the analysis of Hg in air, plant and various soil fractions was a key component of this study. I developed a hydride-generation atomic absorption spectroscopy method for total Hg analyses in digest and liquid matrices of the aforementioned samples. Quality assurance was ensured by comparing results with those of an external certified laboratory. The maximum discrepancy was 15 %. To measure plant Hg-volatilisation, a method that captures Hg-vapour in solution for subsequent analyses was developed. Initially this system was used to trap Hg vapours released from the root system of Brassica juncea plants grown in hydroponic solutions. A subsequent study improved the Hg trapping system, allowing the capture of volatile Hg from both roots and shoots. Mercury recoveries from the whole plant system (traps + plant + solutions) averaged 90 % using this experimental apparatus. In most contaminated substrates, plant Hg uptake is insignificant, possibly due to the low bioavailability of Hg. This represents an obstacle for effective remediation using phytoextraction. Geochemical studies were carried out in Hg-contaminated substrates to examine the potential of chemical agents to induce Hg solubility and subsequent plant uptake. These studies utilised Hg-contaminated mine tailings collected from three locations: the Tui base-metal mine, in the North Island of New Zealand, the Gold Mountain mine, in North-Central China and, the Serra Pelada artisanal mine site, in Northern Brazil. The results demonstrated that Hg solubility in all tested substrates is increased in the presence of sulphur-containing chemical ligands. The effectiveness of these ligands was influenced by site-specific geochemistry. Plants species were able to accumulate up to 60 mg/kg of Hg in shoot tissues upon addition of sulphur-containing ligands to Tui and Gold Mountain substrates. The degree of plant-Hg accumulation was shown to be dependant on plant species and on the thioligand-induced soluble Hg fraction. Shoot Hg transport was inhibited for Gold Mountain substrate amended with 1.25g/kg of humic acid. The maximum Hg extraction yield for B. juncea plants growing in Tui field sites averaged 25 g per hectare following application of sodium thiosulphate. Volatilisation of Hg vapour from barren substrates occurred as a result of biotic (microorganisms) and abiotic (chemical and photochemical reduction) processes. The presence of B. juncea plants in substrates enhanced the volatilisation process up to 23 fold. Phytovolatilisation was the dominant pathway responsible for between 75 to 99.5 % of the total Hg removed from substrates. It was concluded that Hg removal from contaminated mine wastes can be accomplished by both thioligand-induced phytoextraction and phytovolatilisation. There are risks of groundwater contamination by Hg species mobilised after application of thioligands to substrates. Estimated Hg (0) emissions from plant-based operations at contaminated sites ranged between 1.5 to 3.6 kg of Hg/ha per year. Due to extensive atmospheric dilution, Hg emissions from small-scale phytoremediation operations would not cause serious harm to the local population or the regional environment. Phytoremediation combined with gold-phytoextraction can help to mitigate Hg-pollution in artisanal mine sites in the developing world.