Rai Kookana - Academia.edu (original) (raw)

Papers by Rai Kookana

In recognition of the potential role that “Biochar or Black Carbon” can play in sequestration of ... more In recognition of the potential role that “Biochar or Black Carbon” can play in sequestration of carbon, reducing the emission of greenhouse gases and improving the soil fertility, phrases such as “Black is the New Green” have been coined (Marris 2006) and the International Biochar Initiative (www.biocharinternational.org) has been started. While the benefits of biochar applications to soil fertility have been well recognised, the potential negative implications of biochar amendment to soils, especially the impact on contaminant fate, dispersal and build-up is thus far not fully appreciated. This paper presents research that shows that biochar addition to soil can potentially lead to accumulation of contaminants residues in soil. The highly reactive biochar can render applied pesticide ineffective and consequently much higher application rates may be needed for the desired pest and disease control. Biochar itself can potentially serve as a source of combustion related toxicants such...

Modeling nonequilibrium overland flow and transport processes using HYDRUS-1D. (USA)

Science of The Total Environment

Environmental Science: Nano

A better recognition of the agronomic context and geographical differences, including economic, p... more A better recognition of the agronomic context and geographical differences, including economic, political and social constrains, are needed to support the development of viable and sustainable nano-innovations in agriculture.

Environmental Pollution

Sustainable alternatives to landfill disposal for municipal mixed wastes represents a major chall... more Sustainable alternatives to landfill disposal for municipal mixed wastes represents a major challenge to governments and waste management industries. In the state of New South Wales (NSW) Australia, mechanical biological treatment (MBT) is being used to reduce the volume and pathogen content of organic matter isolated from municipal waste. The product of this treatment, a compost-like output (CLO) referred to as mixed waste organic output (MWOO), is being recycled and applied as a soil amendment. However, the presence of contaminants in MWOO including trace organics, trace metals and physical contaminants such as microplastic fragments has raised concerns about potential negative effects on soil health and agriculture following land application. Here, we used multiple lines of evidence to examine the effects of land application of MWOO containing microplastics in three soils to a variety of terrestrial biota. Treatments included unamended soil, MWOO-amended soil and MWOO-amended soil into which additional high-density polyethylene (HDPE), polyethylene terephthalate (PET), or polyvinyl chloride (PVC) microplastics were added. Tests were conducted in soil media that had been incubated for 0, 3 or 9 months. Addition of microplastics had no significant negative effect on wheat seedling emergence, wheat biomass production, earthworm growth, mortality or avoidance behaviour and nematode mortality or reproduction compared to controls. There was also little evidence the microplastics affected microbial community diversity, although measurements of microbial community structure were highly variable with no clear trends.

Science of The Total Environment

Research over the last decade on emerging trace organic contaminants in aquatic systems has large... more Research over the last decade on emerging trace organic contaminants in aquatic systems has largely focused on sources such as treated wastewaters in high income countries, with relatively few studies relating to wastewater sources of these contaminants in low and middle income countries. We undertook a longitudinal survey of the Ahar River for a number of emerging organic contaminants (including pharmaceuticals, hormones, personal care products and industrial chemicals) which flows through the city of Udaipur, India. Udaipur is a city of approximately 450,000 people with no wastewater treatment occurring at the time of this survey. We found the concentrations of many of the contaminants within the river water were similar to those commonly reported in untreated wastewater in high income countries. For example, concentrations of pharmaceuticals, such as carbamazepine, antibiotics and non-steroidal anti-inflammatory drugs, ranged up to 1900 ng/L. Other organic contaminants, such as steroid estrogens (up to 124 ng/L), steroid androgens (up to 1560 ng/L), benzotriazoles (up to 11 μg/L), DEET (up to 390 ng/L), BPA (up to 300 ng/L) and caffeine (up to 37.5 μg/L), were all similar to previously reported concentrations in wastewaters in high income countries. An assessment of the population densities in the watersheds feeding into the river showed increasing population density of a watershed led to a corresponding downstream increase in the concentrations of the organic contaminants, with quantifiable concentrations still present up to 10 km downstream of the areas directly adjacent to the highest population densities. Overall, this study highlights how a relatively clean river can be contaminated by untreated wastewater released from an urban centre.

Marine pollution bulletin, 2018

Submarine sewage outfalls (SSOs) are considered the main input source of contaminants of emerging... more Submarine sewage outfalls (SSOs) are considered the main input source of contaminants of emerging concern continuously released in coastal areas, with the potential to cause adverse effects for aquatic organisms. This work presents the investigation of nine endocrine disrupting chemicals (EDCs) and 26 pharmaceutically active chemicals (PhACs) in marine sediments within the vicinities of 7 SSOs along the São Paulo State Coast (Brazil). Method optimization for the multi-residue determination by GC-MS/MS and LC-MS/MS using QuEChERS extraction/clean-up are discussed. Results demonstrate the occurrence of EDCs in concentrations ranging from less than method quantification limits (MQL) to 72.5 ng g in sediments. All PhACs were <MQLs. Nonylphenol was the most ubiquitous compound and the diversity of EDCs increased with an increase in populations serviced by SSOs. The predicted environmental risk assessment considering measured environmental concentrations and ecotoxicity endpoints from ...

Ecotoxicology and environmental safety, 2018

The use of pyrethroid and neonicotinoid insecticides has increased in Australia over the last dec... more The use of pyrethroid and neonicotinoid insecticides has increased in Australia over the last decade, and as a consequence, increased concentrations of the neonicotinoid insecticide imidacloprid have been measured in Australian rivers. Previous studies have shown that non-target crustaceans, including commercially important species, can be extremely sensitive to these pesticides. Most shrimp farms in Australia are predominantly located adjacent to estuaries so they can obtain their required saline water, which support multiple land uses upstream (e.g. sugar-cane farming, banana farming, beef cattle and urbanisation). Larval and post-larval shrimp may be most susceptible to the impacts of these pesticides because of their high surface area to volume ratio and rapid growth requirements. However, given the uncertainties in the levels of insecticides in farm intake water and regarding the impacts of insecticide exposure on shrimp larvae, the risks that the increased use of new classes o...

The Science of the total environment, Jan 8, 2018

Reuse of treated wastewater for irrigation of crops is growing in arid and semi-arid regions, whi... more Reuse of treated wastewater for irrigation of crops is growing in arid and semi-arid regions, whilst increasing amounts of biosolids are being applied to fields to improve agricultural outputs. Due to incomplete removal in the wastewater treatment processes, pharmaceuticals present in treated wastewater and biosolids can contaminate soil systems. Benzodiazepines are a widely used class of pharmaceuticals that are released following wastewater treatment. Benzodiazepines are represented by a class of compounds with a range of physicochemical properties and this study was therefore designed to evaluate the influence of soil properties on the sorption behaviour and subsequent uptake of seven benzodiazepines (chlordiazepoxide, clonazepam, diazepam, flurazepam, oxazepam, temazepam and triazolam) in two plant species. The sorption and desorption behaviour of benzodiazepines was strongly influenced by soil type and hydrophobicity of the chemical. The partitioning behaviour of these chemical...

Journal of Agricultural and Food Chemistry

Plant protection products containing nanomaterials that alter the functionality or risk profile o... more Plant protection products containing nanomaterials that alter the functionality or risk profile of active ingredients (nano-enabled pesticides) promise many benefits over conventional pesticide products. These benefits may include improved formulation characteristics, easier application, better targeting of pest species, increased efficacy, lower application rates, and enhanced environmental safety. After many years of research and development, nano-enabled pesticides are starting to make their way into the market. The introduction of this technology raises a number of issues for regulators, including how does the ecological risk assessment of nano-enabled pesticide products differ from that of conventional plant protection products? In this paper, a group drawn from regulatory agencies, academia, research, and the agrochemicals industry offers a perspective on relevant considerations pertaining to the problem formulation phase of the ecological risk assessment of nano-enabled pesticides.

Environmental pollution (Barking, Essex : 1987), 2017

Fullerenes (e.g. C60, C70, etc.) present in soil may undergo changes in its retention with aging.... more Fullerenes (e.g. C60, C70, etc.) present in soil may undergo changes in its retention with aging. In this study, the partitioning behavior of ((14)C)-C60 aged up to 12 weeks was investigated in biosolids-amended soil. Spiked samples were subjected to sequential partitioning using water, methanol, and toluene followed by total combustion of solids; the distribution of (14)C across solvents and matrices were used to provide insights on C60 behavior. In most samples, (14)C only partitioned in toluene with the remaining (non-extractable) activity detected in the solid phase. In all biosolids-amended soil samples, an increase in non-extractable (14)C were observed for those exposed to light (vs dark) with the greatest difference observed in biosolids + sand samples. Possible processes that contribute to the observed (14)C distribution, i.e. retention and potential transformation of C60, were discussed. Over-all, results suggest that environmental exposure to C60 and potentially transform...

Environmental Pollution, 2016

Char as a carbon-rich material, can be produced under pyrolytic conditions, wildfires or prescrib... more Char as a carbon-rich material, can be produced under pyrolytic conditions, wildfires or prescribed burn offs for fire management. The objective of this study was to elucidate mechanistic interactions of copper (Cu(2+)) and nickel (Ni(2+)) with different chars produced by pyrolysis (green waste, GW; blue-Mallee, BM) and forest fires (fresh-burnt by prescribed fire, FC; aged char produced by wild fire, AC). The pyrolytic chars were more effective sorbents of Cu(2+) (∼11 times) and Ni(2+) (∼5 times) compared with the forest fire chars. Both cross-polarization (CPMAS-NMR) and Bloch decay (BDMAS-NMR) (13)C NMR spectroscopies showed that forest fire chars have higher woody components (aromatic functional groups) and lower polar groups (e.g. O-alkyl C) compared with the pyrolytic chars. The polarity index was greater in the pyrolytic chars (0.99-1.34) than in the fire-generated chars (0.98-1.15), while aromaticity was lower in the former than in the latter. Fourier transform infrared (FTIR) and Raman spectroscopies indicated the binding of carbonate and phosphate with both Cu(2+) and Ni(2+) in all chars, but with a greater extent in pyrolytic than forest fire-generated chars. These findings have demonstrated the key role of char&amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;#39;s oxygen-containing functional groups in determining their sorption capacity for the Cu(2+) and Ni(2+) in contaminated lands.

Journal of hazardous materials, Jan 16, 2016

Ferrate(VI) (Fe(VI)) has been known to react with emerging organic contaminants containing electr... more Ferrate(VI) (Fe(VI)) has been known to react with emerging organic contaminants containing electron-rich organic moieties, such as phenols, anilines, olefins, reduced sulfur and deprotonated amines. Oxidation of fluoroquinolone antibiotics, ciprofloxacin (CIP) and enrofloxacin (ENR), by Fe(VI) were investigated for their reaction products and toxicity changes as well as biodegradability of these products. Ten products were identified for both CIP and ENR reactions with Fe(VI) using a high-resolution accurate-mass Orbitrap mass analyzer. Structural changes to the CIP and ENR molecule included dealkylation, formation of alcohols and amides in piperazine ring and oxygen transfer to the double bond in quinolone structure. An enamine formation mechanism was tentatively proposed to facilitate the interpretation of CIP and ENR oxidation pathways. Toxicity evaluation using Microbial Assay for toxicity Risk Assessment (MARA) bioassay indicated that Fe(VI) oxidation products of CIP and ENR co...

Journal of environmental management, 2016

The application of fixed bed high rate nitrifying trickling filters (NTFs) for the removal of tra... more The application of fixed bed high rate nitrifying trickling filters (NTFs) for the removal of track organic chemicals of concern (CoC) is less well known than their application to nutrient removal in water treatment. Particularly, the effect of exogenous organic carbon substrate (sucrose) loading on the performance of NTFs is not well understood. A laboratory-scale NTF system was operated in recirculation mode, with the objective of removing ammonia and CoC simultaneously. The efficiency of a high rate NTF for removal both of low concentration of ammonia (5 mg NH4-N L(-1)) and different concentrations of CoC in the presence of an exogenous organic carbon substrate (30 mg total organic carbon (TOC) L(-1)) was investigated. In the presence of exogenous organic carbon, the results demonstrated that the high rate NTF was able to successfully remove most of the CoCs investigated, with the removal ranging from 20.2% to 87.54%. High removal efficiencies were observed for acetaminophen (87....

Http Dx Doi Org 10 1081 Pfc 100106184, Feb 6, 2007

This paper reports on the sorption of fipronil [(+/-)-5-amino-1-(2,6-dichloro-alpha,alpha,alpha-t... more This paper reports on the sorption of fipronil [(+/-)-5-amino-1-(2,6-dichloro-alpha,alpha,alpha-trifluoro-p-tolyl)-4-trifluoromethyl-sulfinylpyrazole-3-carbonitrile] and its two main metabolites, desulfynil and sulfide derivatives on a range of soils from South Australia. The Freundlich sorption coefficient (Kf) values for fipronil on the soils ranged from 1.94 to 4.84 using a 5% acetonitrile/water mixture as the soil solution. Its two metabolites had a higher sorption affinity for soils, with Kf values ranging from 11.09 to 23.49 for the sulfide derivative and from 4.70 to 11.77 for the desulfynil derivative. Their sorption coefficients were found to be better related to the soil organic carbon than clay content. The presence of cosolvents in soil solutions had a significant influence on the sorption of fipronil. The Freundlich sorption coefficients showed a log linear relationship with the fractions of both acetonitrile and methanol in solutions. The sorption coefficient of fipronil on Turretfield soil in the aqueous solution was estimated to be from 13.80 to 19.19. Methanol had less effect on the sorption of fipronil than acetonitrile. The Kd values for fipronil on the eight soils using a 5% methanol/water mixture were from 5.34 to 13.85, which reflect more closely the sorption in the aqueous solution. The average Koc value for fipronil on the eight South Australian soils was calculated to be 825+/-214.

Soils are highly heterogeneous in physical, chemical and biological properties; which determine t... more Soils are highly heterogeneous in physical, chemical and biological properties; which determine the behaviour of a pollutant in the soil profile. To describe pollutant behaviour in soils, a variety of solute transport models have been proposed in recent years. These models vary in conceptual approach and degree of complexity, however, rarely include the scale of heterogeneity of soil properties encountered in the field. During simulation of solute transport whilst some processes are usually considered in a greater detail, the soil profile is generally taken as uniform in terms of flow and other soil physical and chemical properties. Behaviour of numerous chemicals is governed by soil properties such as soil organic matter, pH clay content, permeability, etc. which vary markedly with depth in soils. Therefore, it is important to establish both the depth-wise distribution of these properties within a soil profile and the functional description of the behavioural dependence of the pollutants on these properties. Most such relationships are either not available or not have not yet built into the models. This paper discusses the distribution of soil properties, that vary markedly with depth within a soil profile, and their importance in affecting the pollutant behaviour with field examples of heterogeneities.

Environmental Toxicology and Chemistry, Aug 1, 2006

To have an effective barrier against invading termites around building structures and to assess t... more To have an effective barrier against invading termites around building structures and to assess the potential risks to the urban environment and human beings, we need to understand the fate of termiticides applied in urban soil. The movement and degradation of a new termiticide, fipronil, were investigated in Australian soils following standard termiticide treatment methods (surface application under slab and trenching treatments along walls). Surface application studies in three field sites showed slow dissipation and little movement for fipronil in all three soils under the simulated slab during a three-year period. The greatest mass of the chemical residues remained in the quartzite sand layer (thickness, 5 cm), and only small amounts of these were found to have migrated into the soil layers (depth, 0-15 cm) underneath the quartzite sand layer. Of the three metabolites (desulfinyl, sulfide, and sulfone) found in the soils, the sulfone derivative had the highest concentration. Persistence of fipronil was affected by application rate. The time for 50% loss of the total toxic components (fipronil plus its metabolites) in the quartzite sand layer (thickness, 5 cm) ranged from 200 to 326 d for the low rate (0.15 g active ingredient/m 2) and from 633 to 674 d for the high application rate (3 g active ingredient/m 2). One-year trenching studies at two sites in Adelaide (Roseworthy Farm [RF] and Terretfield [TF]; South Australia, Australia) showed that vertical movement and dissipation of fipronil occurred in the soils. The average concentration of fipronil in the trenches (depth, 0-30 cm) decreased from 33.7 to 14.9 mg/kg in the loam soil at the RF site and from 39.4 to 14.6 mg/kg in the clay soil at the TF site over the year. With time under the natural weather condition, fipronil and its derivatives were found in the deeper soil sections without treatment (depth, 20-30 cm). However, laboratory studies using repacked soil columns showed low mobility in the loam soil from the RF site and a variably charged clay soil from Malanda (Queensland, Australia) under intermittent wetting and drying conditions.

Definitions are taken or adapted from van Leeuwen and Vermeire, 2007 except where denoted by an '... more Definitions are taken or adapted from van Leeuwen and Vermeire, 2007 except where denoted by an '*' which are definitions of the authors. Adsorption: The adhesion of molecules to surfaces of solids. Adaptation: (1) Change in an organism, in response to changing conditions of the environment (specifically chemical), which occurs without any irreversible disruption of the given biological system and without exceeding the normal (homeostatic) capacities of its response and (2) a process by which an organism stabilizes its physiological condition after an environmental change. Added contaminant limit (ACL)*: An ACL is the added concentration of a contaminant above which further appropriate investigation and evaluation of the impact on ecological values will be required. ACL values are generated in the process of deriving ecological investigation levels (EILs, see glossary). ACL(NOEC & EC10)*: Added contaminant limit calculated using no observed effect concentration (NOEC) and 10% effect concentration (EC10) toxicity data. ACL(LOEC & EC30)*: Added contaminant limit calculated using lowest observed effect concentration (LOEC) and 30% effect concentration (EC30) toxicity data. ACL(EC50)*: Added contaminant limit calculated using 50% effect concentration (EC50) toxicity data. Ambient background concentration*: (ABC)-The background concentration of chemicals which is the sum of naturally derived concentrations and those due to long-distance atmospheric transport. Using the ABC rather than the background concentration is an acknowledgement that long distance transport has effectively increased the natural background concentrations. Bioaccumulation: The net result of the uptake, distribution and elimination of a substance due to all routes of exposure, i.e. exposure to air, water, soil/sediment and food. Bioaccumulation factor: A partition coefficient for the distribution of a chemical between an organism exposed through all possible routes and an environmental compartment or food. Bioavailability: The ability of substances to interact with the biological system of an organism. Systemic bioavailability will depend on the chemical or physical reactivity of the substance and its ability to be absorbed through the gastrointestinal tract, respiratory tract or skin. It may be locally bioavailable at all these sites. Bioconcentration: The net results of the uptake, distribution and elimination of a substance due to exposure in the ambient environment (e.g., water for aquatic organisms and soil or soil pore water for soil organisms). Bioconcentration factor (BCF)*: A quantitative measure of a chemical's tendency to be taken up from the ambient environment (e.g., water for aquatic organisms and soil or soil Proposed Australian Methodology to Derive Ecological Investigation Levels x pore water for soil organisms). The BCF is the ratio of the concentration of the chemical in tissue (or a specific organ) and the concentration in the ambient environment. Biological half life: The time needed to reduce the concentration of a test chemical in the environmental compartment or organisms to half the initial concentration, by transport processes, (e.g. diffusive elimination), transformation processes (e.g. biodegradation or metabolism) or growth. Biomagnification: The accumulation and transfer of chemicals via the food web due to ingestion, resulting in an increase of the internal concentration in organisms at the succeeding trophic levels. Biomagnification factor: Quantitative measure of a chemical's tendency to be taken up through the food. Chronic: Extended or long-term exposure to a stressor, conventionally taken to include at lest a tenth of the lifespan of a species. Concentration-response curve: A curve describing the relationship between response in the test population and exposure concentration. Contaminant: Any chemical present in an environmental medium at concentrations exceeding natural background concentrations. Contaminated site: A site where a chemical or multiple chemicals have exceeded the natural background concentrations. Control: A treatment in a trial that duplicates all the conditions of the exposure treatments but contains no test material.

Water research, Sep 1, 2016

Removal of a persistent antiepileptic drug carbamazepine (CBZ) in aqueous solutions was investiga... more Removal of a persistent antiepileptic drug carbamazepine (CBZ) in aqueous solutions was investigated by using solar photolysis combined with free available chlorine (FAC). The combination of chlorination with simulated or natural sunlight markedly enhanced removal of CBZ in 10 mM phosphate buffer solution (pH 7.0) and river water (pH 7.0) compared with sunlight or FAC alone. Further analysis indicated that the observed enhancements in CBZ removal can be attributed to the in situ hydroxyl radical (HO) and ozone (O3) production during FAC photolysis. During 70 min simulated sunlight photolysis combined with FAC treatment, HO reaction contributed to 35.8% removal of CBZ and O3 reaction contributed to 40.6% removal, while only 5.3% of CBZ was removed by HOCl reaction. The oxidation products of CBZ, epoxide CBZ, 10,11-dihydro-10,11-dihydroxy CBZ, 1-(2-benzaldehyde)-4-hydro-(1H,3H)-quinazoline-2-one (BQM), 1-(2-benzaldehyde)-(1H,3H)-quinazoline-2,4-dione (BQD) and 4-aldehyde-9-acridone, w...

In recognition of the potential role that “Biochar or Black Carbon” can play in sequestration of ... more In recognition of the potential role that “Biochar or Black Carbon” can play in sequestration of carbon, reducing the emission of greenhouse gases and improving the soil fertility, phrases such as “Black is the New Green” have been coined (Marris 2006) and the International Biochar Initiative (www.biocharinternational.org) has been started. While the benefits of biochar applications to soil fertility have been well recognised, the potential negative implications of biochar amendment to soils, especially the impact on contaminant fate, dispersal and build-up is thus far not fully appreciated. This paper presents research that shows that biochar addition to soil can potentially lead to accumulation of contaminants residues in soil. The highly reactive biochar can render applied pesticide ineffective and consequently much higher application rates may be needed for the desired pest and disease control. Biochar itself can potentially serve as a source of combustion related toxicants such...

Modeling nonequilibrium overland flow and transport processes using HYDRUS-1D. (USA)

Science of The Total Environment

Environmental Science: Nano

A better recognition of the agronomic context and geographical differences, including economic, p... more A better recognition of the agronomic context and geographical differences, including economic, political and social constrains, are needed to support the development of viable and sustainable nano-innovations in agriculture.

Environmental Pollution

Sustainable alternatives to landfill disposal for municipal mixed wastes represents a major chall... more Sustainable alternatives to landfill disposal for municipal mixed wastes represents a major challenge to governments and waste management industries. In the state of New South Wales (NSW) Australia, mechanical biological treatment (MBT) is being used to reduce the volume and pathogen content of organic matter isolated from municipal waste. The product of this treatment, a compost-like output (CLO) referred to as mixed waste organic output (MWOO), is being recycled and applied as a soil amendment. However, the presence of contaminants in MWOO including trace organics, trace metals and physical contaminants such as microplastic fragments has raised concerns about potential negative effects on soil health and agriculture following land application. Here, we used multiple lines of evidence to examine the effects of land application of MWOO containing microplastics in three soils to a variety of terrestrial biota. Treatments included unamended soil, MWOO-amended soil and MWOO-amended soil into which additional high-density polyethylene (HDPE), polyethylene terephthalate (PET), or polyvinyl chloride (PVC) microplastics were added. Tests were conducted in soil media that had been incubated for 0, 3 or 9 months. Addition of microplastics had no significant negative effect on wheat seedling emergence, wheat biomass production, earthworm growth, mortality or avoidance behaviour and nematode mortality or reproduction compared to controls. There was also little evidence the microplastics affected microbial community diversity, although measurements of microbial community structure were highly variable with no clear trends.

Science of The Total Environment

Research over the last decade on emerging trace organic contaminants in aquatic systems has large... more Research over the last decade on emerging trace organic contaminants in aquatic systems has largely focused on sources such as treated wastewaters in high income countries, with relatively few studies relating to wastewater sources of these contaminants in low and middle income countries. We undertook a longitudinal survey of the Ahar River for a number of emerging organic contaminants (including pharmaceuticals, hormones, personal care products and industrial chemicals) which flows through the city of Udaipur, India. Udaipur is a city of approximately 450,000 people with no wastewater treatment occurring at the time of this survey. We found the concentrations of many of the contaminants within the river water were similar to those commonly reported in untreated wastewater in high income countries. For example, concentrations of pharmaceuticals, such as carbamazepine, antibiotics and non-steroidal anti-inflammatory drugs, ranged up to 1900 ng/L. Other organic contaminants, such as steroid estrogens (up to 124 ng/L), steroid androgens (up to 1560 ng/L), benzotriazoles (up to 11 μg/L), DEET (up to 390 ng/L), BPA (up to 300 ng/L) and caffeine (up to 37.5 μg/L), were all similar to previously reported concentrations in wastewaters in high income countries. An assessment of the population densities in the watersheds feeding into the river showed increasing population density of a watershed led to a corresponding downstream increase in the concentrations of the organic contaminants, with quantifiable concentrations still present up to 10 km downstream of the areas directly adjacent to the highest population densities. Overall, this study highlights how a relatively clean river can be contaminated by untreated wastewater released from an urban centre.

Marine pollution bulletin, 2018

Submarine sewage outfalls (SSOs) are considered the main input source of contaminants of emerging... more Submarine sewage outfalls (SSOs) are considered the main input source of contaminants of emerging concern continuously released in coastal areas, with the potential to cause adverse effects for aquatic organisms. This work presents the investigation of nine endocrine disrupting chemicals (EDCs) and 26 pharmaceutically active chemicals (PhACs) in marine sediments within the vicinities of 7 SSOs along the São Paulo State Coast (Brazil). Method optimization for the multi-residue determination by GC-MS/MS and LC-MS/MS using QuEChERS extraction/clean-up are discussed. Results demonstrate the occurrence of EDCs in concentrations ranging from less than method quantification limits (MQL) to 72.5 ng g in sediments. All PhACs were <MQLs. Nonylphenol was the most ubiquitous compound and the diversity of EDCs increased with an increase in populations serviced by SSOs. The predicted environmental risk assessment considering measured environmental concentrations and ecotoxicity endpoints from ...

Ecotoxicology and environmental safety, 2018

The use of pyrethroid and neonicotinoid insecticides has increased in Australia over the last dec... more The use of pyrethroid and neonicotinoid insecticides has increased in Australia over the last decade, and as a consequence, increased concentrations of the neonicotinoid insecticide imidacloprid have been measured in Australian rivers. Previous studies have shown that non-target crustaceans, including commercially important species, can be extremely sensitive to these pesticides. Most shrimp farms in Australia are predominantly located adjacent to estuaries so they can obtain their required saline water, which support multiple land uses upstream (e.g. sugar-cane farming, banana farming, beef cattle and urbanisation). Larval and post-larval shrimp may be most susceptible to the impacts of these pesticides because of their high surface area to volume ratio and rapid growth requirements. However, given the uncertainties in the levels of insecticides in farm intake water and regarding the impacts of insecticide exposure on shrimp larvae, the risks that the increased use of new classes o...

The Science of the total environment, Jan 8, 2018

Reuse of treated wastewater for irrigation of crops is growing in arid and semi-arid regions, whi... more Reuse of treated wastewater for irrigation of crops is growing in arid and semi-arid regions, whilst increasing amounts of biosolids are being applied to fields to improve agricultural outputs. Due to incomplete removal in the wastewater treatment processes, pharmaceuticals present in treated wastewater and biosolids can contaminate soil systems. Benzodiazepines are a widely used class of pharmaceuticals that are released following wastewater treatment. Benzodiazepines are represented by a class of compounds with a range of physicochemical properties and this study was therefore designed to evaluate the influence of soil properties on the sorption behaviour and subsequent uptake of seven benzodiazepines (chlordiazepoxide, clonazepam, diazepam, flurazepam, oxazepam, temazepam and triazolam) in two plant species. The sorption and desorption behaviour of benzodiazepines was strongly influenced by soil type and hydrophobicity of the chemical. The partitioning behaviour of these chemical...

Journal of Agricultural and Food Chemistry

Plant protection products containing nanomaterials that alter the functionality or risk profile o... more Plant protection products containing nanomaterials that alter the functionality or risk profile of active ingredients (nano-enabled pesticides) promise many benefits over conventional pesticide products. These benefits may include improved formulation characteristics, easier application, better targeting of pest species, increased efficacy, lower application rates, and enhanced environmental safety. After many years of research and development, nano-enabled pesticides are starting to make their way into the market. The introduction of this technology raises a number of issues for regulators, including how does the ecological risk assessment of nano-enabled pesticide products differ from that of conventional plant protection products? In this paper, a group drawn from regulatory agencies, academia, research, and the agrochemicals industry offers a perspective on relevant considerations pertaining to the problem formulation phase of the ecological risk assessment of nano-enabled pesticides.

Environmental pollution (Barking, Essex : 1987), 2017

Fullerenes (e.g. C60, C70, etc.) present in soil may undergo changes in its retention with aging.... more Fullerenes (e.g. C60, C70, etc.) present in soil may undergo changes in its retention with aging. In this study, the partitioning behavior of ((14)C)-C60 aged up to 12 weeks was investigated in biosolids-amended soil. Spiked samples were subjected to sequential partitioning using water, methanol, and toluene followed by total combustion of solids; the distribution of (14)C across solvents and matrices were used to provide insights on C60 behavior. In most samples, (14)C only partitioned in toluene with the remaining (non-extractable) activity detected in the solid phase. In all biosolids-amended soil samples, an increase in non-extractable (14)C were observed for those exposed to light (vs dark) with the greatest difference observed in biosolids + sand samples. Possible processes that contribute to the observed (14)C distribution, i.e. retention and potential transformation of C60, were discussed. Over-all, results suggest that environmental exposure to C60 and potentially transform...

Environmental Pollution, 2016

Char as a carbon-rich material, can be produced under pyrolytic conditions, wildfires or prescrib... more Char as a carbon-rich material, can be produced under pyrolytic conditions, wildfires or prescribed burn offs for fire management. The objective of this study was to elucidate mechanistic interactions of copper (Cu(2+)) and nickel (Ni(2+)) with different chars produced by pyrolysis (green waste, GW; blue-Mallee, BM) and forest fires (fresh-burnt by prescribed fire, FC; aged char produced by wild fire, AC). The pyrolytic chars were more effective sorbents of Cu(2+) (∼11 times) and Ni(2+) (∼5 times) compared with the forest fire chars. Both cross-polarization (CPMAS-NMR) and Bloch decay (BDMAS-NMR) (13)C NMR spectroscopies showed that forest fire chars have higher woody components (aromatic functional groups) and lower polar groups (e.g. O-alkyl C) compared with the pyrolytic chars. The polarity index was greater in the pyrolytic chars (0.99-1.34) than in the fire-generated chars (0.98-1.15), while aromaticity was lower in the former than in the latter. Fourier transform infrared (FTIR) and Raman spectroscopies indicated the binding of carbonate and phosphate with both Cu(2+) and Ni(2+) in all chars, but with a greater extent in pyrolytic than forest fire-generated chars. These findings have demonstrated the key role of char&amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;#39;s oxygen-containing functional groups in determining their sorption capacity for the Cu(2+) and Ni(2+) in contaminated lands.

Journal of hazardous materials, Jan 16, 2016

Ferrate(VI) (Fe(VI)) has been known to react with emerging organic contaminants containing electr... more Ferrate(VI) (Fe(VI)) has been known to react with emerging organic contaminants containing electron-rich organic moieties, such as phenols, anilines, olefins, reduced sulfur and deprotonated amines. Oxidation of fluoroquinolone antibiotics, ciprofloxacin (CIP) and enrofloxacin (ENR), by Fe(VI) were investigated for their reaction products and toxicity changes as well as biodegradability of these products. Ten products were identified for both CIP and ENR reactions with Fe(VI) using a high-resolution accurate-mass Orbitrap mass analyzer. Structural changes to the CIP and ENR molecule included dealkylation, formation of alcohols and amides in piperazine ring and oxygen transfer to the double bond in quinolone structure. An enamine formation mechanism was tentatively proposed to facilitate the interpretation of CIP and ENR oxidation pathways. Toxicity evaluation using Microbial Assay for toxicity Risk Assessment (MARA) bioassay indicated that Fe(VI) oxidation products of CIP and ENR co...

Journal of environmental management, 2016

The application of fixed bed high rate nitrifying trickling filters (NTFs) for the removal of tra... more The application of fixed bed high rate nitrifying trickling filters (NTFs) for the removal of track organic chemicals of concern (CoC) is less well known than their application to nutrient removal in water treatment. Particularly, the effect of exogenous organic carbon substrate (sucrose) loading on the performance of NTFs is not well understood. A laboratory-scale NTF system was operated in recirculation mode, with the objective of removing ammonia and CoC simultaneously. The efficiency of a high rate NTF for removal both of low concentration of ammonia (5 mg NH4-N L(-1)) and different concentrations of CoC in the presence of an exogenous organic carbon substrate (30 mg total organic carbon (TOC) L(-1)) was investigated. In the presence of exogenous organic carbon, the results demonstrated that the high rate NTF was able to successfully remove most of the CoCs investigated, with the removal ranging from 20.2% to 87.54%. High removal efficiencies were observed for acetaminophen (87....

Http Dx Doi Org 10 1081 Pfc 100106184, Feb 6, 2007

This paper reports on the sorption of fipronil [(+/-)-5-amino-1-(2,6-dichloro-alpha,alpha,alpha-t... more This paper reports on the sorption of fipronil [(+/-)-5-amino-1-(2,6-dichloro-alpha,alpha,alpha-trifluoro-p-tolyl)-4-trifluoromethyl-sulfinylpyrazole-3-carbonitrile] and its two main metabolites, desulfynil and sulfide derivatives on a range of soils from South Australia. The Freundlich sorption coefficient (Kf) values for fipronil on the soils ranged from 1.94 to 4.84 using a 5% acetonitrile/water mixture as the soil solution. Its two metabolites had a higher sorption affinity for soils, with Kf values ranging from 11.09 to 23.49 for the sulfide derivative and from 4.70 to 11.77 for the desulfynil derivative. Their sorption coefficients were found to be better related to the soil organic carbon than clay content. The presence of cosolvents in soil solutions had a significant influence on the sorption of fipronil. The Freundlich sorption coefficients showed a log linear relationship with the fractions of both acetonitrile and methanol in solutions. The sorption coefficient of fipronil on Turretfield soil in the aqueous solution was estimated to be from 13.80 to 19.19. Methanol had less effect on the sorption of fipronil than acetonitrile. The Kd values for fipronil on the eight soils using a 5% methanol/water mixture were from 5.34 to 13.85, which reflect more closely the sorption in the aqueous solution. The average Koc value for fipronil on the eight South Australian soils was calculated to be 825+/-214.

Soils are highly heterogeneous in physical, chemical and biological properties; which determine t... more Soils are highly heterogeneous in physical, chemical and biological properties; which determine the behaviour of a pollutant in the soil profile. To describe pollutant behaviour in soils, a variety of solute transport models have been proposed in recent years. These models vary in conceptual approach and degree of complexity, however, rarely include the scale of heterogeneity of soil properties encountered in the field. During simulation of solute transport whilst some processes are usually considered in a greater detail, the soil profile is generally taken as uniform in terms of flow and other soil physical and chemical properties. Behaviour of numerous chemicals is governed by soil properties such as soil organic matter, pH clay content, permeability, etc. which vary markedly with depth in soils. Therefore, it is important to establish both the depth-wise distribution of these properties within a soil profile and the functional description of the behavioural dependence of the pollutants on these properties. Most such relationships are either not available or not have not yet built into the models. This paper discusses the distribution of soil properties, that vary markedly with depth within a soil profile, and their importance in affecting the pollutant behaviour with field examples of heterogeneities.

Environmental Toxicology and Chemistry, Aug 1, 2006

To have an effective barrier against invading termites around building structures and to assess t... more To have an effective barrier against invading termites around building structures and to assess the potential risks to the urban environment and human beings, we need to understand the fate of termiticides applied in urban soil. The movement and degradation of a new termiticide, fipronil, were investigated in Australian soils following standard termiticide treatment methods (surface application under slab and trenching treatments along walls). Surface application studies in three field sites showed slow dissipation and little movement for fipronil in all three soils under the simulated slab during a three-year period. The greatest mass of the chemical residues remained in the quartzite sand layer (thickness, 5 cm), and only small amounts of these were found to have migrated into the soil layers (depth, 0-15 cm) underneath the quartzite sand layer. Of the three metabolites (desulfinyl, sulfide, and sulfone) found in the soils, the sulfone derivative had the highest concentration. Persistence of fipronil was affected by application rate. The time for 50% loss of the total toxic components (fipronil plus its metabolites) in the quartzite sand layer (thickness, 5 cm) ranged from 200 to 326 d for the low rate (0.15 g active ingredient/m 2) and from 633 to 674 d for the high application rate (3 g active ingredient/m 2). One-year trenching studies at two sites in Adelaide (Roseworthy Farm [RF] and Terretfield [TF]; South Australia, Australia) showed that vertical movement and dissipation of fipronil occurred in the soils. The average concentration of fipronil in the trenches (depth, 0-30 cm) decreased from 33.7 to 14.9 mg/kg in the loam soil at the RF site and from 39.4 to 14.6 mg/kg in the clay soil at the TF site over the year. With time under the natural weather condition, fipronil and its derivatives were found in the deeper soil sections without treatment (depth, 20-30 cm). However, laboratory studies using repacked soil columns showed low mobility in the loam soil from the RF site and a variably charged clay soil from Malanda (Queensland, Australia) under intermittent wetting and drying conditions.

Definitions are taken or adapted from van Leeuwen and Vermeire, 2007 except where denoted by an '... more Definitions are taken or adapted from van Leeuwen and Vermeire, 2007 except where denoted by an '*' which are definitions of the authors. Adsorption: The adhesion of molecules to surfaces of solids. Adaptation: (1) Change in an organism, in response to changing conditions of the environment (specifically chemical), which occurs without any irreversible disruption of the given biological system and without exceeding the normal (homeostatic) capacities of its response and (2) a process by which an organism stabilizes its physiological condition after an environmental change. Added contaminant limit (ACL)*: An ACL is the added concentration of a contaminant above which further appropriate investigation and evaluation of the impact on ecological values will be required. ACL values are generated in the process of deriving ecological investigation levels (EILs, see glossary). ACL(NOEC & EC10)*: Added contaminant limit calculated using no observed effect concentration (NOEC) and 10% effect concentration (EC10) toxicity data. ACL(LOEC & EC30)*: Added contaminant limit calculated using lowest observed effect concentration (LOEC) and 30% effect concentration (EC30) toxicity data. ACL(EC50)*: Added contaminant limit calculated using 50% effect concentration (EC50) toxicity data. Ambient background concentration*: (ABC)-The background concentration of chemicals which is the sum of naturally derived concentrations and those due to long-distance atmospheric transport. Using the ABC rather than the background concentration is an acknowledgement that long distance transport has effectively increased the natural background concentrations. Bioaccumulation: The net result of the uptake, distribution and elimination of a substance due to all routes of exposure, i.e. exposure to air, water, soil/sediment and food. Bioaccumulation factor: A partition coefficient for the distribution of a chemical between an organism exposed through all possible routes and an environmental compartment or food. Bioavailability: The ability of substances to interact with the biological system of an organism. Systemic bioavailability will depend on the chemical or physical reactivity of the substance and its ability to be absorbed through the gastrointestinal tract, respiratory tract or skin. It may be locally bioavailable at all these sites. Bioconcentration: The net results of the uptake, distribution and elimination of a substance due to exposure in the ambient environment (e.g., water for aquatic organisms and soil or soil pore water for soil organisms). Bioconcentration factor (BCF)*: A quantitative measure of a chemical's tendency to be taken up from the ambient environment (e.g., water for aquatic organisms and soil or soil Proposed Australian Methodology to Derive Ecological Investigation Levels x pore water for soil organisms). The BCF is the ratio of the concentration of the chemical in tissue (or a specific organ) and the concentration in the ambient environment. Biological half life: The time needed to reduce the concentration of a test chemical in the environmental compartment or organisms to half the initial concentration, by transport processes, (e.g. diffusive elimination), transformation processes (e.g. biodegradation or metabolism) or growth. Biomagnification: The accumulation and transfer of chemicals via the food web due to ingestion, resulting in an increase of the internal concentration in organisms at the succeeding trophic levels. Biomagnification factor: Quantitative measure of a chemical's tendency to be taken up through the food. Chronic: Extended or long-term exposure to a stressor, conventionally taken to include at lest a tenth of the lifespan of a species. Concentration-response curve: A curve describing the relationship between response in the test population and exposure concentration. Contaminant: Any chemical present in an environmental medium at concentrations exceeding natural background concentrations. Contaminated site: A site where a chemical or multiple chemicals have exceeded the natural background concentrations. Control: A treatment in a trial that duplicates all the conditions of the exposure treatments but contains no test material.

Water research, Sep 1, 2016

Removal of a persistent antiepileptic drug carbamazepine (CBZ) in aqueous solutions was investiga... more Removal of a persistent antiepileptic drug carbamazepine (CBZ) in aqueous solutions was investigated by using solar photolysis combined with free available chlorine (FAC). The combination of chlorination with simulated or natural sunlight markedly enhanced removal of CBZ in 10 mM phosphate buffer solution (pH 7.0) and river water (pH 7.0) compared with sunlight or FAC alone. Further analysis indicated that the observed enhancements in CBZ removal can be attributed to the in situ hydroxyl radical (HO) and ozone (O3) production during FAC photolysis. During 70 min simulated sunlight photolysis combined with FAC treatment, HO reaction contributed to 35.8% removal of CBZ and O3 reaction contributed to 40.6% removal, while only 5.3% of CBZ was removed by HOCl reaction. The oxidation products of CBZ, epoxide CBZ, 10,11-dihydro-10,11-dihydroxy CBZ, 1-(2-benzaldehyde)-4-hydro-(1H,3H)-quinazoline-2-one (BQM), 1-(2-benzaldehyde)-(1H,3H)-quinazoline-2,4-dione (BQD) and 4-aldehyde-9-acridone, w...