2021 |
Zhang J, Hu H, Wang M, Li Y, Wu S, Cao Y, et al., 'Land application of sewage sludge biochar: Assessments of soil-plant-human health risks from potentially toxic metals', SCIENCE OF THE TOTAL ENVIRONMENT, 756 (2021)
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2021 |
Long Y, Yang X, Cao Y, Lv G, Li Y, Pan Y, et al., 'Relationship between soil fungi and seedling density in the vicinity of adult conspecifics in an arid desert forest', Forests, 12 1-16 (2021)
© 2021 by the authors. Licensee MDPI, Basel, Switzerland. Research Highlights: 1. Soil fungi have a higher influence on seedling density compared to soil environmental factors; 2.... [more]
© 2021 by the authors. Licensee MDPI, Basel, Switzerland. Research Highlights: 1. Soil fungi have a higher influence on seedling density compared to soil environmental factors; 2. Host-specific pathogens and beneficial fungi affect seeding density via different influencing mechanisms. Background and Objectives: The growth and development of seedlings are the key processes that affect forest regeneration and maintain community dynamics. However, the influencing factors of seedling growth around their adult conspecifics are not clear in arid desert forests. Probing the intrinsic relations among soil fungi, soil environmental factors (pH, water content, salinity, and nutrition), and seedling density will improve our understanding of forest development and provide a theoretical basis for forest management and protection. Materials and Methods: Four experimental plot types, depending on the distance to adult conspecifics, were set in an arid desert forest. Soil environmental factors, the diversity and composition of the soil fungal community, and the seedlings¿ density and height were measured in the four experimental plot types, and their mutual relations were analyzed. Results: Seedling density as well as the diversity and composition of the soil fungal community varied significantly among the four plot types (p < 0.05). Soil environmental factors, especially soil salinity, pH, and soil water content, had significant influences on the seedling density and diversity and composition of the soil fungal community. The contribution of soil fungi (72.61%) to the variation in seedling density was much higher than the soil environmental factors (27.39%). The contribution of detrimental fungi to the variation in seedling density was higher than the beneficial fungi. Conclusions: Soil fungi mostly affected the distribution of seedling density in the vicinity of adult conspecifics in an arid desert forest. The distribution of seedling density in the vicinity of adults was mainly influenced by the detrimental fungi, while the adults in the periphery area was mainly influenced by the beneficial fungi.
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2021 |
Liu W, Yang X, Duan L, Naidu R, Yan K, Liu Y, et al., 'Variability in plant trace element uptake across different crops, soil contamination levels and soil properties in the Xinjiang Uygur Autonomous Region of northwest China', Scientific Reports, 11 (2021)
© 2021, The Author(s). This study investigated contamination status of eight trace elements (As, Cd, Cr, Hg, Pb, Cu, Zn and Ni) in farmland soils and crops at 535 sites across the... [more]
© 2021, The Author(s). This study investigated contamination status of eight trace elements (As, Cd, Cr, Hg, Pb, Cu, Zn and Ni) in farmland soils and crops at 535 sites across the Xinjiang Uygur Autonomous Region, Northwest China. Land use types of the sampling sites included vegetable patch, grain field and orchard. Our experimental results indicated all farmland soils were considered as trace element contamination based on the Nemerow comprehensive pollution index (NCPI > 1). However, 91.97% of the crop samples were uncontaminated according to the Chinese Risk Control Standard. Soils from the vegetable patch showed higher pollution level comparison with that from grain field and orchard. Health risks for both non-carcinogenic and carcinogenic risks were calculated through crop ingestion exposure pathway. Grain samples showed highest health risks, followed by melon and fruit, and vegetables. The health risks of crops were mainly driven by Cr and Cd. Crop consumption may pose risks for children but not adults. The source of trace element contamination in the different farmland soils varied and may be attributed to the different agricultural activities. Plant type had a greater influence on the trace element accumulation in crops compared with soil trace element contents and physicochemical properties.
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2021 |
Gao Y, Du J, Bahar MM, Wang H, Subashchandrabose S, Duan L, et al., 'Metagenomics analysis identifies nitrogen metabolic pathway in bioremediation of diesel contaminated soil', Chemosphere, 271 (2021)
© 2021 Elsevier Ltd Nitrogen amendment is known to effectively enhance the bioremediation of hydrocarbon-contaminated soil, but the nitrogen metabolism in this process is not well... [more]
© 2021 Elsevier Ltd Nitrogen amendment is known to effectively enhance the bioremediation of hydrocarbon-contaminated soil, but the nitrogen metabolism in this process is not well understood. To unravel the nitrogen metabolic pathway(s) of diesel contaminated soil, six types of nitrogen sources were added to the diesel contaminated soil. Changes in microbial community and soil enzyme genes were investigated by metagenomics analysis and chemical analysis through a 30-day incubation study. The results showed that ammonium based nitrogen sources significantly accelerated the degradation of total petroleum hydrocarbon (TPH) (79¿81%) compared to the control treatment (38%) and other non-ammonium based nitrogen amendments (43¿57%). Different types of nitrogen sources could dramatically change the microbial community structure and soil enzyme gene abundance. Proteobacteria and Actinobacteria were identified as the two dominant phyla in the remediation of diesel contaminated soil. Metagenomics analysis revealed that the preferred metabolic pathway of nitrogen was from ammonium to glutamate via glutamine, and the enzymes governing this transformation were glutamine synthetase and glutamate synthetase; while in nitrate based amendment, the conversion from nitrite to ammonium was restrained by the low abundance of nitrite reductase enzyme and therefore retarded the TPH degradation rate. It is concluded that during the process of nitrogen enhanced bioremediation, the most efficient nitrogen cycling direction was from ammonium to glutamine, then to glutamate, and finally joined with carbon metabolism after transforming to 2-oxoglutarate.
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2021 |
Zhang J, Wu S, Xu J, Liang P, Wang M, Naidu R, et al., 'Comparison of ashing and pyrolysis treatment on cadmium/zinc hyperaccumulator plant: Effects on bioavailability and metal speciation in solid residues and risk assessment', Environmental Pollution, 272 (2021)
© 2020 Elsevier Ltd Phytoremediation of metal(loid)s contaminated sites is widely used, while there is scarce of investigation on the metal-enriched biomass waste safely disposal ... [more]
© 2020 Elsevier Ltd Phytoremediation of metal(loid)s contaminated sites is widely used, while there is scarce of investigation on the metal-enriched biomass waste safely disposal which resulted in risks of causing secondary pollution to the soil and water bodies and even to human health. Thus, this study compared the effects of ashing and pyrolysis treatments on cadmium (Cd) and zinc (Zn) hyperaccumulation plant Sedum plumbizincicola. Chemical speciation, the Toxicity Characteristic Leaching Procedure (TCLP), and diethylenetriamine pentaacetic acid (DTPA) extraction were employed to characterize the bioavailability and leachability of Cd and Zn in the solid residues after pyrolysis and ashing. The risk assessment code (RAC) and potential ecological risk index (RI) were subsequently used to evaluate the risk of the solid residues to the environment. The results showed that both ashing and pyrolysis treatments could transform the bioavailable Cd and Zn in S. plumbizincicola into a more stable form, and the higher the temperature the greater the stablility. Pyrolysis converted a maximum of 80.0% of Cd and 70.3% of Zn in S. plumbizincicola to the oxidisable and residual fractions, compared with ashing which achieved only a ~42% reduction. The pyrolysis process minimised the risk level of Cd and Zn to the environment based on the RAC and RI assessments. The results of the TCLP test, and DTPA extraction confirmed that the leaching rate and the bioavailable portion of Cd and Zn in the biochars produced by pyrolysis were invariably significantly (p < 0.05) lower than the solid residues produced by ashing, and reached the lowest at 650 °C. In other words, pyrolysis was better than ashing for thermal treatment of the metal-enriched hyperaccumulator plant, in view of minimising the bioavailability and leachability of Cd and Zn from the solid residues to the environment. This study provides fundamental data on the choice of treatments for the disposal of metal-enriched plant biomass.
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2020 |
Besha AT, Liu Y, Fang C, Bekele DN, Naidu R, 'Assessing the interactions between micropollutants and nanoparticles in engineered and natural aquatic environments', Critical Reviews in Environmental Science and Technology, 50 135-215 (2020) [C1]
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2020 |
Naidu R, Nadebaum P, Fang C, Cousins I, Pennell K, Conder J, et al., 'Per- and poly-fluoroalkyl substances (PFAS): Current status and research needs', Environmental Technology and Innovation, 19 (2020) [C1]
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2020 |
Nuruzzaman M, Ren J, Liu Y, Rahman MM, Shon HK, Naidu R, 'Hollow Porous Silica Nanosphere with Single Large Pore Opening for Pesticide Loading and Delivery', ACS Applied Nano Materials, 3 105-113 (2020) [C1]
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2020 |
Hassan M, Liu Y, Naidu R, Du J, Qi F, 'Adsorption of Perfluorooctane sulfonate (PFOS) onto metal oxides modified biochar', Environmental Technology and Innovation, 19 (2020) [C1]
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2020 |
Wang X, Luo X, Wang Q, Liu Y, Naidu R, 'Predicting the combined toxicity of binary metal mixtures (Cu-Ni and Zn-Ni) to wheat.', Ecotoxicology and Environmental Safety, 205 (2020) [C1]
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2020 |
Liu Y, Qi F, Fang C, Naidu R, Duan L, Dharmarajan R, Annamalai P, 'The effects of soil properties and co-contaminants on sorption of perfluorooctane sulfonate (PFOS) in contrasting soils', Environmental Technology and Innovation, 19 (2020) [C1]
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2020 |
Al Amin M, Sobhani Z, Liu Y, Dharmaraja R, Chadalavada S, Naidu R, et al., 'Recent advances in the analysis of per- and polyfluoroalkyl substances (PFAS) A review', Environmental Technology and Innovation, 19 (2020) [C1]
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2020 |
Duan Q, Duan L, Liu Y, Naidu R, Zhang H, Lei Y, 'A novel in-situ passive sampling technique in the application of monitoring diuron in the aquatic environment', Environmental Technology and Innovation, 20 (2020) [C1]
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2020 |
Yan K, Dong Z, Naidu R, Liu Y, Li Y, Wijayawardena A, et al., 'Comparison of in vitro models in a mice model and investigation of the changes in Pb speciation during Pb bioavailability assessments', Journal of Hazardous Materials, 388 (2020) [C1]
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2020 |
Hassan M, Naidu R, Du J, Liu Y, Qi F, 'Critical review of magnetic biosorbents: Their preparation, application, and regeneration for wastewater treatment', SCIENCE OF THE TOTAL ENVIRONMENT, 702 (2020) [C1]
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2020 |
Besha AT, Liu Y, Bekele DN, Dong Z, Naidu R, Gebremariam GN, 'Sustainability and environmental ethics for the application of engineered nanoparticles', ENVIRONMENTAL SCIENCE & POLICY, 103 85-98 (2020) [C1]
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2020 |
Hassan M, Liu Y, Naidu R, Parikh SJ, Du J, Qi F, Willett IR, 'Influences of feedstock sources and pyrolysis temperature on the properties of biochar and functionality as adsorbents: A meta-analysis', Science of the Total Environment, 744 (2020) [C1]
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2020 |
Zhang J, Jin J, Wang M, Naidu R, Liu Y, Man YB, et al., 'Co-pyrolysis of sewage sludge and rice husk/ bamboo sawdust for biochar with high aromaticity and low metal mobility.', Environmental Research, 191 (2020) [C1]
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2019 |
Yan K, Dong Z, Wijayawardena MAA, Liu Y, Li Y, Naidu R, 'The source of lead determines the relationship between soil properties and lead bioaccessibility', Environmental Pollution, 246 53-59 (2019) [C1]
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2019 |
Tang WC, Wang Z, Donne SW, Forghani M, Liu Y, 'Influence of red mud on mechanical and durability performance of self-compacting concrete', Journal of Hazardous Materials, 379 (2019) [C1]
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2019 |
Dong Z, Wang H, Yu YY, Li YB, Naidu R, Liu Y, 'Using 2003 2014 U.S. NHANES data to determine the associations between per- and polyfluoroalkyl substances and cholesterol: Trend and implications', Ecotoxicology and Environmental Safety, 173 461-468 (2019) [C1]
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2019 |
Liu Y, Du J, Dong Z, Rahman MM, Gao Y, Yan K, Naidu R, 'Bioavailability and risk estimation of heavy metal(loid)s in chromated copper arsenate treated timber after remediation for utilisation as garden materials.', Chemosphere, 216 757-765 (2019) [C1]
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2018 |
Han F, Kambala VSR, Dharmarajan R, Liu Y, Naidu R, 'Photocatalytic degradation of azo dye acid orange 7 using
different light sources over Fe3+-doped TiO2 nanocatalysts', Environmental Technology and Innovation, 12 27-42 (2018) [C1]
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2018 |
Yan K, Naidu R, Liu Y, Wijayawardena A, Duan L, Dong Z, 'A Pooled Data Analysis to Determine the Relationship between Selected Metals and Arsenic Bioavailability in Soil', International Journal of Environmental Research and Public Health, 15 (2018) [C1]
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2018 |
Gao YC, Guo SH, Wang JN, Zhang W, Chen GH, Wang H, et al., 'Novel Bacillus cereus strain from electrokinetically remediated saline soil towards the remediation of crude oil', Environmental Science and Pollution Research, 25 26351-26360 (2018) [C1]
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2018 |
Li Y, Li W, Xiao Q, Song S, Liu Y, Naidu R, 'Acid mine drainage remediation strategies: A review on migration and source controls', Minerals and Metallurgical Processing, 35 148-158 (2018) [C1]
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2018 |
Tang WC, Wang Z, Liu Y, Cui HZ, 'Influence of red mud on fresh and hardened properties of self-compacting concrete', Construction and Building Materials, 178 288-300 (2018) [C1]
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2018 |
Nuruzzaman M, Liu Y, Rahman MM, Naidu R, Dharmarajan R, Shon HK, Woo YC, 'Core-Shell Interface-Oriented Synthesis of Bowl-Structured Hollow Silica Nanospheres Using Self-Assembled ABC Triblock Copolymeric Micelles.', Langmuir : the ACS journal of surfaces and colloids, 34 13584-13596 (2018) [C1]
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2018 |
Wang F, Xu Y, Yang X, Liu Y, Lv GH, Yang S, 'Soil water potential determines the presence of hydraulic lift of populus euphratica olivier across growing seasons in an arid desert region', Journal of Forest Science, 64 319-329 (2018) [C1]
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2018 |
Wang Z, Tan X, Lu G, Liu Y, Naidu R, He W, 'Soil properties influence kinetics of soil acid phosphatase in response to arsenic toxicity', ECOTOXICOLOGY AND ENVIRONMENTAL SAFETY, 147 266-274 (2018) [C1]
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2018 |
Lu G, Tian H, Liu Y, Naidu R, Wang Z, He W, 'Using Qmsax* to evaluate the reasonable As(V) adsorption on soils with different pH', Ecotoxicology and Environmental Safety, 160 308-315 (2018) [C1]
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2017 |
Qi F, Yan Y, Lamb D, Naidu R, Bolan NS, Liu Y, et al., 'Thermal stability of biochar and its effects on cadmium sorption capacity', BIORESOURCE TECHNOLOGY, 246 48-56 (2017) [C1]
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2017 |
Tan X, Liu Y, Yan K, Wang Z, Lu G, He Y, He W, 'Differences in the response of soil dehydrogenase activity to Cd contamination are determined by the different substrates used for its determination', CHEMOSPHERE, 169 324-332 (2017) [C1]
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2017 |
Yan K, Dong Z, Wijayawardena MAA, Liu Y, Naidu R, Semple K, 'Measurement of soil lead bioavailability and influence of soil types and properties: A review', CHEMOSPHERE, 184 27-42 (2017) [C1]
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2017 |
Dong Z, Bahar MM, Jit J, Kennedy B, Priestly B, Ng J, et al., 'Issues raised by the reference doses for perfluorooctane sulfonate and perfluorooctanoic acid', ENVIRONMENT INTERNATIONAL, 105 86-94 (2017) [C1]
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2017 |
Liu Y, Bello O, Rahman MM, Dong Z, Islam S, Naidu R, 'Investigating the relationship between lead speciation and bioaccessibility of mining impacted soils and dusts', ENVIRONMENTAL SCIENCE AND POLLUTION RESEARCH, 24 17056-17067 (2017) [C1]
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2016 |
Naidu R, Arias V, Liu Y, Jit J, 'Emerging contaminants in the environment: Risk-based analysis for better management', Chemosphere, 154 350-357 (2016) [C1]
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2016 |
Dong Z, Yan K, Liu Y, Naidu R, Duan L, Wijayawardena A, et al., 'A meta-analysis to correlate lead bioavailability and bioaccessibility and predict lead bioavailability', Environment International, 92-93 139-145 (2016) [C1]
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2016 |
Dong Z, Liu CX, Liu Y, Yan K, Semple KT, Naidu R, 'Using publicly available data, a physiologically-based pharmacokinetic model and Bayesian simulation to improve arsenic non-cancer dose-response', Environment International, 92-93 239-246 (2016) [C1]
© 2016 Elsevier Ltd. Publicly available data can potentially examine the relationship between environmental exposure and public health, however, it has not yet been widely applied... [more]
© 2016 Elsevier Ltd. Publicly available data can potentially examine the relationship between environmental exposure and public health, however, it has not yet been widely applied. Arsenic is of environmental concern, and previous studies mathematically parameterized exposure duration to create a link between duration of exposure and increase in risk. However, since the dose metric emerging from exposure duration is not a linear or explicit variable, it is difficult to address the effects of exposure duration simply by using mathematical functions. To relate cumulative dose metric to public health requires a lifetime physiologically-based pharmacokinetic (PBPK) model, yet this model is not available at a population level. In this study, the data from the U.S. total diet study (TDS, 2006-2011) was employed to assess exposure: daily dietary intakes for total arsenic (tAs) and inorganic arsenic (iAs) were estimated to be 0.15 and 0.028 µg/kg/day, respectively. Meanwhile, using National Health and Nutrition Examination Survey (NHANES, 2011-2012) data, the fraction of urinary As(III) levels (geometric mean: 0.31 µg/L) in tAs (geometric mean: 7.75 µg/L) was firstly reported to be approximately 4%. Together with Bayesian technique, the assessed exposure and urinary As(III) concentration were input to successfully optimize a lifetime population PBPK model. Finally, this optimized PBPK model was used to derive an oral reference dose (Rfd) of 0.8 µg/kg/day for iAs exposure. Our study also suggests the previous approach (by using mathematical functions to account for exposure duration) may result in a conservative Rfd estimation.
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2016 |
Bello O, Naidu R, Rahman MM, Liu Y, Dong Z, 'Lead concentration in the blood of the general population living near a lead-zinc mine site, Nigeria: Exposure pathways', Science of the Total Environment, 542 908-914 (2016) [C1]
© 2015. Lead (Pb) poisoning in children is a major public health catastrophe worldwide. This report summarises both exposure pathways and blood Pb levels in children below 7. year... [more]
© 2015. Lead (Pb) poisoning in children is a major public health catastrophe worldwide. This report summarises both exposure pathways and blood Pb levels in children below 7. years of age and adults (above 18. years) from the Adudu community living near a lead-zinc mine in Nasawara, Nigeria. The average and median blood Pb levels in children and adults were 2.1 and 1.3 µg/dL, 3.1 and 1.8 µg/dL, respectively. However, Pb in 14% of adults' blood exceeded 5. µg/dL, which is the recommended threshold blood Pb concentration in adults as established by the Centers for Disease Control and Prevention (CDC). Furthermore 68% of adults' blood exceeded blood Pb action level of 2 µg/dL. For children, 11.4% and 31% of the blood samples exceeded 5 µg/dL and 2 µg/dL, respectively, while no safe blood Pb level in children has been recommended. In Nasawara, a significant difference (p< 0.05) was observed between the various age groups in children with 2-4 years old having the highest levels and 6. year old children having the lowest Pb levels. Although this study did not detect elevated levels of Pb in children's blood in regions such as Zamfara, Nigeria and Kabwe, Zambia, a high percentage of samples exceeded 2 µg/dL. Soils, floor dusts, water and crops also reveal that Pb contamination in the study area could potentially be the major cause of blood Pb in the community exposed to mining. This study also observed a significant correlation between water Pb levels of adults and blood Pb levels, suggesting that water is the major exposure pathway. This analysis highlights the need to properly manage mining activities so that the health of communities living in the vicinity of a Pb-Zn mine is not compromised.
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2016 |
Rusmin R, Sarkar B, Biswas B, Churchman J, Liu Y, Naidu R, 'Structural, electrokinetic and surface properties of activated palygorskite for environmental application', Applied Clay Science, 134 95-102 (2016) [C1]
© 2016 Elsevier B.V. Unlike smectite, the surface characteristics of palygorskite remain underexplored for its potential application in environmental remediation. In this study, p... [more]
© 2016 Elsevier B.V. Unlike smectite, the surface characteristics of palygorskite remain underexplored for its potential application in environmental remediation. In this study, palygorskite from Western Australia was activated through thermal (300 °C for 4 h), acid (4 M HCl for 2 h at 70 °C) and acid-thermal (acid treatment followed by heating at 300 °C for 4 h) treatments, and the structural and physico-chemical characteristics were examined against the raw clay mineral. The influence of activation was systematically investigated using X-ray Diffraction (XRD), Fourier Transform Infra-Red (FTIR) spectroscopy, N2 adsorption-desorption measurements and solid state 27Al Magic Angle Spinning Nuclear Magnetic Resonance (MAS NMR) spectroscopy. The XRD patterns indicated preservation of the crystalline structure of palygorskite following all the treatments. These findings were supported by the Al (IV) and Al (VI) coordination peaks (chemical shift ~ 55 and 2.9 ppm, respectively) which were unaltered in the 27Al MAS NMR spectra of the samples. The acid-thermal activated palygorskite exhibited the highest specific surface area (152.7 m2 g- 1) and pore volume (0.2137 cm3 g- 1) which respectively were 3-fold and 69% greater than the raw palygorskite. The potentiometric titration analyses highlighted the possible role of Al derivatives towards development of the surface charge of the activated palygorskites. Electrokinetic studies described the stability of the activated products (zeta potential values ranging from - 5 mV to - 32 mV) at different electrolyte (NaNO3) concentrations. Combined acid-thermal activated palygorskite displayed a stronger specific adsorption of multivalent cations, and held a direct relevance to environmental remediation. Findings of this study will assist in the development of palygorskite-based adsorbents for heavy metal contaminants remediation.
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2016 |
Nuruzzaman M, Rahman MM, Liu Y, Naidu R, 'Nanoencapsulation, Nano-guard for Pesticides: A New Window for Safe Application', JOURNAL OF AGRICULTURAL AND FOOD CHEMISTRY, 64 1447-1483 (2016) [C1]
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2016 |
Liu Y, Naidu R, Ming H, Dharmarajan R, Du J, 'Effects of thermal treatments on the characterisation and utilisation of red mud with sawdust additive', Waste Management and Research, 34 518-526 (2016) [C1]
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2016 |
Yan K, Dong Z, Liu Y, Naidu R, 'Quantifying statistical relationships between commonly used in vitro models for estimating lead bioaccessibility', Environmental Science and Pollution Research, 23 6873-6882 (2016) [C1]
© 2015, Springer-Verlag Berlin Heidelberg. Bioaccessibility to assess potential risks resulting from exposure to Pb-contaminated soils is commonly estimated using various in vitro... [more]
© 2015, Springer-Verlag Berlin Heidelberg. Bioaccessibility to assess potential risks resulting from exposure to Pb-contaminated soils is commonly estimated using various in vitro methods. However, existing in vitro methods yield different results depending on the composition of the extractant as well as the contaminated soils. For this reason, the relationships between the five commonly used in vitro methods, the Relative Bioavailability Leaching Procedure (RBALP), the unified BioAccessibility Research Group Europe (BARGE) method (UBM), the Solubility Bioaccessibility Research Consortium assay (SBRC), a Physiologically Based Extraction Test (PBET), and the in vitro Digestion Model (RIVM) were quantified statistically using 10 soils from long-term Pb-contaminated mining and smelter sites located in Western Australia and South Australia. For all 10 soils, the measured Pb bioaccessibility regarding all in vitro methods varied from 1.9 to 106¿% for gastric phase, which is higher than that for intestinal phase: 0.2 ~ 78.6¿%. The variations in Pb bioaccessibility depend on the in vitro models being used, suggesting that the method chosen for bioaccessibility assessment must be validated against in vivo studies prior to use for predicting risk. Regression studies between RBALP and SRBC, RBALP and RIVM (0.06) (0.06¿g of soil in each tube, S:L ratios for gastric phase and intestinal phase are 1:375 and 1:958, respectively) showed that Pb bioaccessibility based on the three methods were comparable. Meanwhile, the slopes between RBALP and UBM, RBALP and RIVM (0.6) (0.6¿g soil in each tube, S:L ratios for gastric phase and intestinal phase are 1:37.5 and 1:96, respectively) were 1.21 and 1.02, respectively. The findings presented in this study could help standardize in vitro bioaccessibility measurements and provide a scientific basis for further relating Pb bioavailability and soil properties.
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2016 |
Duan L, Naidu R, Liu Y, Dong Z, Mallavarapu M, Herde P, et al., 'Comparison of oral bioavailability of benzo[a]pyrene in soils using rat and swine and the implications for human health risk assessment', Environment International, 94 95-102 (2016) [C1]
© 2016 Elsevier Ltd. Background: There are many uncertainties concerning variations in benzo[a]pyrene (B[a]P) soil guidelines protecting human health based on carcinogenic data ob... [more]
© 2016 Elsevier Ltd. Background: There are many uncertainties concerning variations in benzo[a]pyrene (B[a]P) soil guidelines protecting human health based on carcinogenic data obtained in animal studies. Although swine is recognised as being much more representative of the human child in terms of body size, gut physiology and genetic profile the rat/mice model is commonly used in practice. Objectives: We compare B[a]P bioavailability using a rat model to that estimated in a swine model, to investigate the correlation between these two animal models. This may help reduce uncertainty in applying bioavailability to human health risk assessment. Methods: Twelve spiked soil samples and a spiked silica sand (reference material) were dosed to rats in parallel with a swine study. B[a]P bioavailability was estimated by the area under the plasma B[a]P concentration-time curve (AUC) and faecal excretion as well in the rats. Direct comparison between the two animal models was made for: firstly, relative bioavailability (RB) using AUC assay; and secondly, the two assays in the rat model. Results: Both AUC and faecal excretion assays showed linear dose-response for the reference material. However, absolute bioavailability was significantly higher when using faecal excretion assay (p < 0.001). In aged soils faecal excretion estimated based on solvent extraction was not accurate due to the form of non-extractable fraction through ageing. A significant correlation existed between the two models using RB for soil samples (RBrat = 0.26RBswine + 17.3, R2 = 0.70, p < 0.001), despite the regression slope coefficient revealing that the rat model would underestimate RB by about one quarter compared to using swine. Conclusions: In the comparison employed in this study, an interspecies difference of four in RB using AUC assay was identified between the rat and swine models regarding pharmacokinetic differences, which supported the body weight scaling method recommended by US EPA. Future research should focus on the carcinogenic competency (pharmacodynamics) used in experiment animals and humans.
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2016 |
Ming H, Naidu R, Sarkar B, Lamb DT, Liu Y, Megharaj M, Sparks D, 'Competitive sorption of cadmium and zinc in contrasting soils', Geoderma, 268 60-68 (2016) [C1]
© 2016 Elsevier B.V. The sorption behavior of cadmium (Cd(II)) and zinc (Zn(II)) on two virgin soils with different pH levels was studied using single metal and competitive dual m... [more]
© 2016 Elsevier B.V. The sorption behavior of cadmium (Cd(II)) and zinc (Zn(II)) on two virgin soils with different pH levels was studied using single metal and competitive dual metal systems. In the single metal system, Zn exhibited a greater affinity for the alkaline soil, as indicated by the Langmuir constant (KL = 8.85 L/kg) compared with Cd (KL = 1.79 L/kg). However, much less sorption of both Zn (KL = 0.19 L/kg) and Cd (KL = 0.07 L/kg) was observed in the acidic soil. The competitive sorption data were modeled using two-metal Freundlich and Langmuir functions. The competition for metal sorption occurred in the alkaline soil only at a higher concentration of the competing metals, whereas the effect was significant even at lower concentrations in the acidic soil. The cumulative amount of both metals sorbed in the soil was similar to that of single metal systems in the studied concentration range, demonstrating that the number of sites available for sorption remained constant irrespective of the competition. This study indicated that Cd might be more mobile in a mixed-metal system than in a single-metal scenario and thus poses a serious ecotoxicological threat. This study is important for assessing the risks and developing management strategies for multiple heavy metal contaminated soils.
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2015 |
Duan L, Naidu R, Liu Y, Palanisami T, Dong Z, Mallavarapu M, Semple KT, 'Effect of ageing on benzo[a]pyrene extractability in contrasting soils', Journal of Hazardous Materials, 296 175-184 (2015) [C1]
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2015 |
Rusmin R, Sarkar B, Liu Y, McClure S, Naidu R, 'Structural evolution of chitosan-palygorskite composites and removal of aqueous lead by composite beads', Applied Surface Science, 353 363-375 (2015)
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2015 |
Dong Z, Liu Y, Duan L, Bekele D, Naidu R, 'Uncertainties in human health risk assessment of environmental contaminants: A review and perspective', Environment International, 85 120-132 (2015) [C1]
© 2015 Elsevier Ltd. Addressing uncertainties in human health risk assessment is a critical issue when evaluating the effects of contaminants on public health. A range of uncertai... [more]
© 2015 Elsevier Ltd. Addressing uncertainties in human health risk assessment is a critical issue when evaluating the effects of contaminants on public health. A range of uncertainties exist through the source-to-outcome continuum, including exposure assessment, hazard and risk characterisation. While various strategies have been applied to characterising uncertainty, classical approaches largely rely on how to maximise the available resources. Expert judgement, defaults and tools for characterising quantitative uncertainty attempt to fill the gap between data and regulation requirements. The experiences of researching 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD) illustrated uncertainty sources and how to maximise available information to determine uncertainties, and thereby provide an 'adequate' protection to contaminant exposure. As regulatory requirements and recurring issues increase, the assessment of complex scenarios involving a large number of chemicals requires more sophisticated tools. Recent advances in exposure and toxicology science provide a large data set for environmental contaminants and public health. In particular, biomonitoring information, in vitro data streams and computational toxicology are the crucial factors in the NexGen risk assessment, as well as uncertainties minimisation. Although in this review we cannot yet predict how the exposure science and modern toxicology will develop in the long-term, current techniques from emerging science can be integrated to improve decision-making.
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2014 |
Duan L, Palanisami T, Liu Y, Dong Z, Mallavarapu M, Kuchel T, et al., 'Effects of ageing and soil properties on the oral bioavailability of benzo[a]pyrene using a swine model', Environment International, 70 192-202 (2014) [C1]
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2014 |
Liu Y, Naidu R, 'Hidden values in bauxite residue (red mud): Recovery of metals', WASTE MANAGEMENT, 34 2662-2673 (2014)
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2013 |
Liu Y, Naidu R, Ming H, 'Surface electrochemical properties of red mud (bauxite residue): Zeta potential and surface charge density', JOURNAL OF COLLOID AND INTERFACE SCIENCE, 394 451-457 (2013) [C1]
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2011 |
Liu Y, Naidu R, Ming H, 'Red mud as an amendment for pollutants in solid and liquid phases', GEODERMA, 163 1-12 (2011)
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2010 |
Liu YJ, Gong WQ, Zeng SJ, Liu J, Pi KW, Li YB, Hu F, 'Study of domestication of acidithiobacillus and effects on leaching of low grade phosphate ore', Wuhan Ligong Daxue Xuebao/Journal of Wuhan University of Technology, 32 5-8 (2010)
Strains of Acidithiobacillus ferrooxidans (Atf) and Acidithiobacillus thiooxidans (Att) were isolated and purified from water samples collected from a hot spring in Guangxi provin... [more]
Strains of Acidithiobacillus ferrooxidans (Atf) and Acidithiobacillus thiooxidans (Att) were isolated and purified from water samples collected from a hot spring in Guangxi province. The purified Atf and Att were used in the leaching of a low grade phosphate ore. The results were compared with those obtained with Atf and Att after domestication. The results indicated that: 1) The activity of those domesticated Acidithiobacillus was enhanced, as the average pH value of Att was lower than the original ones and an obvious reduction of pH of the Atf which was domesticated by low grade phosphate ore with the concentration of 5~10 g/L was observed; 2) The domesticated Acidithiobacillus were easily adapted to the lixivium of phosphate ore with rapid decrease of pH value and high leaching rate at the 30th day of bioleaching. Particularly, the leaching rate was enhanced by up to 11%, with Att domesticated with both culture media with or without phosphate. The Atf domesticated with 2~8 g/L phosphate ore in culture media with phosphate increased the leaching rate by 28% at most. Meanwhile, the leaching rate of Atf domesticated with 10~15 g/L phosphate ore in culture media without phosphate was amolst 2 times of the original ones.
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2009 |
Zeng SJ, Gong WQ, Liu YJ, Liu J, Pi KW, Li YB, Hu F, 'Research on effects of ways of stirring on bacterial leaching of phosphate', Wuhan Ligong Daxue Xuebao/Journal of Wuhan University of Technology, 31 (2009)
Difference ways of stirring, i.e. no-stirring, shaking, magnetic stirring and mechanical stirring, were employed in the bioleaching of phosphate in the ore. The leaching effects w... [more]
Difference ways of stirring, i.e. no-stirring, shaking, magnetic stirring and mechanical stirring, were employed in the bioleaching of phosphate in the ore. The leaching effects with different ways of stirring were analyzed and compared, revealing the factors responsible for the leaching of phosphorus element. The experimental results indicated that the leaching effects with magnetic stirring and mechanical stirring were obviously better than those with no-stirring and shaking and the leaching time was reduced significantly. The qualitative analysis using scanning electron microscope and energy dispersive spectroscopy showed that jarosite was one of the products of bacterial leaching and the major factor influencing the leaching effects.
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2009 |
Liu YJ, Gong WQ, Zeng SJ, Liu J, Pi KW, Li YB, et al., 'Research on cultivation of acidithiobacillus strains by microwave mutagenesis for bioleaching of low-grade phosphate ore', Wuhan Ligong Daxue Xuebao/Journal of Wuhan University of Technology, 31 16-19 (2009)
Microwave mutagenesis is an effective physical method to cultivate high quality microbial strains. In this article, continuous and discontinuous microwave mutagenesis methods are ... [more]
Microwave mutagenesis is an effective physical method to cultivate high quality microbial strains. In this article, continuous and discontinuous microwave mutagenesis methods are used to cultivate acidithiobacillus (At t and At f) strains. As a result, the optimized mutagenesis conditions for different acidithiobacillus strains are worked out. The effects of recycling the bacteria after bioleaching upon the activity of the bacteria and bioleaching rate of phosphate ore are investigated. The results indicate that both the bacteria activity and bioleaching rate of phosphate ore are enhanced significantly.
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2008 |
Wang EW, Gong WQ, Shen QS, Liu J, Liu YJ, Zeng SJ, 'Effects of physical mutagenesis on leaching phosphorus with acidithiobacillus ferrooxidans', Wuhan Ligong Daxue Xuebao/Journal of Wuhan University of Technology, 30 44-47 (2008)
Strains of acidithiobacillus ferrooxidans were separated and purified from water samples collected from a hot spring in Guangxi province. The purified At f was used in the leachin... [more]
Strains of acidithiobacillus ferrooxidans were separated and purified from water samples collected from a hot spring in Guangxi province. The purified At f was used in the leaching of a low grade phosphate ore. The results were compared with those obtained with At f after physical mutagenesis. The results indicated that: 1) the rate of phosphorus leached with purified At f was higher than that with unpurified At f, with the fifth purification being the best. 2) The oxidation activity and rate of phosphorus leached with At f after UV mutagenesis increased initially and then decreased as a function of mutagenesis time with an optimum occurred at 5 min. 3) The time for complete oxidation of Fe2+ with At f, after ultrasonic mutagenesis was at lease 65 h shorter than that with At f, before ultrasonic mutagenesis and the rate of phosphorus leached increased by up to about 35%. 4) With low temperature mutagenesis the optimal results were obtained with At f after 1 h low temperature mutagenesis.
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2008 |
Shen QS, Gong WQ, Wang EW, Liu J, Liu YJ, Zeng SJ, 'Bioleaching of low-grade phosphate ore with microwave-mutated acidithiobacillus thiooxidans', Wuhan Ligong Daxue Xuebao/Journal of Wuhan University of Technology, 30 29-32 (2008)
A strain of Acidithiobacillus thiooxidans (At t) isolated from a sulfur-containing hot spring in Guangxi was used to leach low-grade phosphate ore after being purified and cultiva... [more]
A strain of Acidithiobacillus thiooxidans (At t) isolated from a sulfur-containing hot spring in Guangxi was used to leach low-grade phosphate ore after being purified and cultivated. Then microwave mutagenesis study was carried out with the strain. The isolated and purified strain of At t had the capability of leaching low-grade phosphate ore, but the leaching-rate was low. Microwave could cause mutation of At t effectively and change its growth activity and acid-producing capacity. Strains treated for different mutagenesis time showed different bioleaching ability. The leaching-rate of the strain mutagenized with microwave for 10 s was the highest and reached 32.74% after bioleaching for 20 d, which increased almost 42% than that of the original At t strain.
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2007 |
Gong W, Zhang X, Yuan H, Liu Y, Bian X, Chen W, Liu J, 'Experimental Study on Bacterial Leaching of Low-Grade Phosphate Gangue', Journal of Shanghai Second Polytechnic University, 24 125-130 (2007) |
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2007 |
Gong WQ, Chen W, Zhang XZ, Bian X, Liu YJ, Liu J, et al., 'Isolation and cultivation of acidithiobacillus ferrooxidans and its effects on bioleaching of phosphate ore', Guocheng Gongcheng Xuebao/The Chinese Journal of Process Engineering, 7 584-588 (2007)
A strain of Acidithiobacillus ferrooxidans that can be used effectively in the leaching of low grade phosphate ore was isolated from acid mine drainage from a coal mine in Anhui P... [more]
A strain of Acidithiobacillus ferrooxidans that can be used effectively in the leaching of low grade phosphate ore was isolated from acid mine drainage from a coal mine in Anhui Province in China. Its characteristics of morphology and growth were studied. Through the investigation of the effects of different solid culture medium components on the isolation and purification of Acidthiobacillus ferrooxidans, the optimum isolation conditions were determined as: the concentration of Fe2+ in 9 K solid culture medium was 4.5 g/L. A double-layer plate, with heterotrophic microbe Rhodotorula sp. spreading onto the bottom layer and chemoautotrophic bacterium At.f spreading onto the upper layer, was used. The influential factors including culture media, energy source materials and the addition of surfactant on the leaching of phosphate ore with the cultivated At. f were studied. Through preliminary experiments, up to 48% of phosphate in the ore was leached out using the isolated At. f strain.
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2007 |
Gong WQ, Bian X, Chen W, Zhang XZ, Liu YJ, Liu J, et al., 'Cultivation characteristics of acidithiobacillus thiooxidans and bioleaching of low-grade phosphate ore with it', Wuhan Ligong Daxue Xuebao/Journal of Wuhan University of Technology, 29 53-57 (2007)
A strain of Acidithiobacillus thiooxidans (At. t) that can be used effectively in the leaching of low-grade phosphate ore was isolated from acid mine drainage from a coal mine in ... [more]
A strain of Acidithiobacillus thiooxidans (At. t) that can be used effectively in the leaching of low-grade phosphate ore was isolated from acid mine drainage from a coal mine in Anhui. Its characteristics of morphology and cultivation were studied. Through the investigation of the effect of different solid culture medium components on the isolation and purification of Acidthiobacillus thiooxidans, the optimum isolation conditions were determined by using a double-layer plate with chemoautotrophic bacterium At. t spread onto the upper Starkey solid culture medium layer, and heterotrophic microbe Rhodotorula sp. spread onto the bottom agar layer, resulting in significantly increased density and reduced forming time of the bacterial colony. The influence of factors including culture media and the addition of surfactant on the leaching of phosphate ore with the cultivated At. t was studied. Through preliminary experiments, up to 48.41% of phosphate in the ore was leached out by using the isolated At. t strain.
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2007 |
Gong WQ, Zhang XZ, Liu YJ, Chen W, Bian X, Liu J, et al., 'Influence of surfactants on leaching of phosphate ore with Acidithiobacillus thiooxidans', Zhongnan Daxue Xuebao (Ziran Kexue Ban)/Journal of Central South University (Science and Technology), 38 60-64 (2007)
During the leaching of phosphate ore with sulfuric acid produced by the oxidation of reductive sulfur with Acidithiobacillus, different types of Tween surfactants were used to pro... [more]
During the leaching of phosphate ore with sulfuric acid produced by the oxidation of reductive sulfur with Acidithiobacillus, different types of Tween surfactants were used to promote the interaction between the bacteria and the ore and to increase the rate of phosphate leached. The effects of the surfactants on the phosphate ore leaching with Acidithiobacillus thiooxidans were evaluated by measuring the pH value of solution, the density of bacteria cell in solution and the rate of phosphate leached. The results show that Tween 20, 60 and 80 all can improve the leaching of the ore and the optimal dosages are 10, 10 and 100 g/m3, respectively. The effect of Tween 60 is the best with about 15% increase of the rate of phosphate leached with a dosage of 10 g/cm3.
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Bekele DN, Liu Y, Donaghey M, Umeh A, Arachchige CSV, Chadalavada S, Naidu R, 'Separation and Lithological Mapping of PFAS Mixtures in the Vadose Zone at a Contaminated Site', Frontiers in Water, 2 [C1]
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