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In-situ degradation of soil-sorbed 17β-estradiol using carboxymethyl cellulose stabilized manganese oxide nanoparticles: Column studies
2017
Han, Bing | Zhang, Man | Zhao, Dongye
This work tested a new remediation technology for in-situ degradation of estrogens by delivering a new class of stabilized manganese oxide (MnO2) nanoparticles in contaminated soils. The nanoparticles were prepared using a food-grade carboxymethyl cellulose (CMC) as a stabilizer, which was able to facilitate particle delivery into soil. The effectiveness of the technology was tested using 17β-estradiol (E2) as a model estrogen and three sandy loams (SL1, SL2, and SL3) as model soils. Column transport tests showed that the nanoparticles can be delivered in the three soils, though retention of the nanoparticles varied. The nanoparticle retention is strongly dependent on the injection pore velocity. The treatment effectiveness is highly dependent upon the mass transfer rates of both the nanoparticles and contaminants. When the E2-laden soils were treated with 22–130 pore volumes of a 0.174 g/L MnO(2) nanoparticle suspension, up to 88% of water leachable E2 was degraded. The nanoparticles were more effective for soils that offer moderate desorption rates of E2. Decreasing injection velocity or increasing MnO(2) concentration facilitate E2 degradation. The nanoparticles-based technology appears promising for in-situ oxidation of endocrine disruptors in groundwater.
Show more [+] Less [-]Mild acid and alkali treated clay minerals enhance bioremediation of polycyclic aromatic hydrocarbons in long-term contaminated soil: A 14C-tracer study
2017
Biswas, Bhabananda | Sarkar, Binoy | Rusmin, Ruhaida | Naidu, R.
Bioremediation of polycyclic aromatic hydrocarbon (PAH)-contaminated soils requires a higher microbial viability and an increased PAH bioavailability. The clay/modified clay-modulated bacterial degradation could deliver a more efficient removal of PAHs in soils depending on the bioavailability of the compounds. In this study, we modified clay minerals (smectite and palygorskite) with mild acid (HCl) and alkali (NaOH) treatments (0.5–3 M), which increased the surface area and pore volume of the products, and removed the impurities without collapsing the crystalline structure of clay minerals. In soil incubation studies, supplements with the clay products increased bacterial growth in the order: 0.5 M HCl ≥ unmodified ≥0.5 M NaOH ≥3 M NaOH ≥3 M HCl for smectite, and 0.5 M HCl ≥3 M NaOH ≥0.5 M NaOH ≥3 M HCl ≥ unmodified for palygorskite. A14C-tracing study showed that the mild acid/alkali-treated clay products increased the PAH biodegradation (5–8%) in the order of 0.5 M HCl ≥ unmodified > 3 M NaOH ≥ 0.5 M NaOH for smectite, and 0.5 M HCl > 0.5 M NaOH ≥ unmodified ≥ 3 M NaOH for palygorskite. The biodegradation was correlated (r = 0.81) with the bioavailable fraction of PAHs and microbial growth as affected particularly by the 0.5 M HCl and 0.5 M NaOH-treated clay minerals. These results could be pivotal in developing a clay-modulated bioremediation technology for cleaning up PAH-contaminated soils and sediments in the field.
Show more [+] Less [-]Antibiotics degradation in soil: A case of clindamycin, trimethoprim, sulfamethoxazole and their transformation products
2017
Koba, Olga | Golovko, Oksana | Kodešová, Radka | Fér, Miroslav | Grabic, Roman
Twelve different soil types that represent the soil compartments of the Czech Republic were fortified with three antibiotics (clindamycin (CLI), sulfamethoxazole (SUL), and trimethoprim (TRI)) to investigate their fate. Five metabolites (clindamycin sulfoxide (CSO), hydroxy clindamycin sulfoxide (HCSO), S-(SDC) and N-demethyl clindamycin (NDC), N4-acetyl sulfamethoxazole (N4AS), and hydroxy trimethoprim (HTR)) were detected and identified using HPLC/HRMS and HRPS in the soil matrix in this study. The identities of CSO and N4AS were confirmed using commercially available reference standards.The parent compounds degraded in all soils. Almost all of the metabolites have been shown to be persistent in soils, with the exception of N4AS, which was formed and degraded completely within 23 days of exposure. The rate of degradation mainly depended on the soil properties.The PCA results showed a high dependence between the soil type and behaviour of the pharmaceutical metabolites.The mentioned metabolites can be formed in soils, and the most persistent ones may be transported to the ground water and environmental water bodies. Because no information on the effects of those metabolites on living organism are available, more studies should be performed in the future to predict the risk to the environment.
Show more [+] Less [-]Polybrominated diphenyl ethers (PBDES) and hexa-brominated biphenyls (Hexa-BBs) in fresh foods ingested in Taiwan
2017
Chang, Jung-Wei | Hung, Chung-Feng | Hsu, Ya-Chen | Kao, Yi-Ting | Lee, Ching-Chang
Polybrominated diphenyl ethers (PBDEs) and hexa-brominated biphenyls (Hexa-BBs) are bioaccumulative and aggregate in the food chain. Therefore, background monitoring and risk assessment for dietary intake are necessary. In present study, a systematic sampling method was first used to collect the high fat content foodstuff such as poultry, livestock, eggs, fish, other seafood, dairy products, and the infant foods and then foodstuff with high consumption in seven categories of 600 food samples. After integrating four years of background surveys of PBDE levels (2010–2013) and one year of that of Hexa-BBs (2013), the highest estimated daily intake (EDI) of PBDEs for Taiwanese food consumption was found in 0- to 3-year-olds (mean = 9.38 ng kg−1 bw d−1, the 95% upper limit of Monte Carlo Simulation (MCS P95) was 21.52 ng kg−1 bw d−1), and the lowest in 16- to 18-year-old girls (mean = 3.35 ng kg−1 bw d−1, MCS P95 was 6.53 ng kg−1 bw d−1). Moreover, the highest of EDI of Hexa-BBs was found in 0–3 years old (mean = 0.007 ng kg−1 bw d−1, MCS P95 = 0.019 ng kg−1 bw d−1), and lowest in 17–18 years old female (mean = 0.002 ng/kg/day, MCS P95 = 0.005 ng kg−1 bw d−1). This study suggests that the large MOEs (>2.5) for the four important congeners BDE-47, -99, −153, and −209, indicate that the dietary exposures are not probably a significant health concern for Taiwanese.
Show more [+] Less [-]Seasonal variation in the nature of DOM in a river and drinking water reservoir of a closed catchment
2017
Awad, John | Leeuwen, John van | Chow, Christopher W.K. | Smernik, Ronald J. | Anderson, Sharolyn J. | Cox, Jim W.
Dissolved organic matter (DOM) in surface waters used for drinking purposes can vary markedly in character depending on its source within catchments and the timing and intensity of rainfall events. Here we report the findings of a study on the character and concentration of DOM in waters collected during different seasons from Myponga River and Reservoir, South Australia. The character of DOM was assessed in terms of its treatability by enhanced coagulation and potential for disinfection by-product i.e. trihalomethane (THM) formation. During the wet seasons (winter and spring), water samples from the river had higher DOC concentrations (X¯: 21 mg/L) and DOM of higher average molecular weight (AMW: 1526 Da) than waters collected during the dry seasons (summer and autumn: DOC: 13 mg/L; AMW: 1385 Da). Even though these features led to an increase in the percentage removal of organics by coagulation with alum (64% for wet compared with 53% for dry season samples) and a lower alum dose rate (10 versus 15 mg alum/mg DOC removal), there was a higher THM formation potential (THMFP) from wet season waters (treated waters: 217 μg/L vs 172 μg/L). For reservoir waters, samples collected during the wet seasons had an average DOC concentration (X¯: 15 mg/L), percentage removal of organics by alum (54%), alum dose rates (13 mg/mg DOC) and THMFP (treated waters: 207 μg/L) that were similar to samples collected during the dry seasons (mean DOC: 15 mg/L; removal of organics: 52%; alum dose rate: 13 mg/mg DOC; THMFP: 212 μg/L for treated waters). These results show that DOM present in river waters and treatability by alum are highly impacted by seasonal environmental variations. However these in reservoir waters exhibit less seasonal variability. Storage of large volumes of water in the reservoir enables mixing of influent waters and stabilization of water quality.
Show more [+] Less [-]Using machine learning to identify air pollution exposure profiles associated with early cognitive skills among U.S. children
2017
Stingone, Jeanette A. | Pandey, Om P. | Claudio, Luz | Pandey, Gaurav
Data-driven machine learning methods present an opportunity to simultaneously assess the impact of multiple air pollutants on health outcomes. The goal of this study was to apply a two-stage, data-driven approach to identify associations between air pollutant exposure profiles and children's cognitive skills. Data from 6900 children enrolled in the Early Childhood Longitudinal Study, Birth Cohort, a national study of children born in 2001 and followed through kindergarten, were linked to estimated concentrations of 104 ambient air toxics in the 2002 National Air Toxics Assessment using ZIP code of residence at age 9 months. In the first-stage, 100 regression trees were learned to identify ambient air pollutant exposure profiles most closely associated with scores on a standardized mathematics test administered to children in kindergarten. In the second-stage, the exposure profiles frequently predicting lower math scores were included within linear regression models and adjusted for confounders in order to estimate the magnitude of their effect on math scores. This approach was applied to the full population, and then to the populations living in urban and highly-populated urban areas. Our first-stage results in the full population suggested children with low trichloroethylene exposure had significantly lower math scores. This association was not observed for children living in urban communities, suggesting that confounding related to urbanicity needs to be considered within the first-stage. When restricting our analysis to populations living in urban and highly-populated urban areas, high isophorone levels were found to predict lower math scores. Within adjusted regression models of children in highly-populated urban areas, the estimated effect of higher isophorone exposure on math scores was −1.19 points (95% CI −1.94, −0.44). Similar results were observed for the overall population of urban children. This data-driven, two-stage approach can be applied to other populations, exposures and outcomes to generate hypotheses within high-dimensional exposure data.
Show more [+] Less [-]Multigenerational effects of gold nanoparticles in Caenorhabditis elegans: Continuous versus intermittent exposures
2017
Moon, Jongmin | Kwak, Jin Il | Kim, Shin Woong | An, Youn-Joo
Nanomaterials can become disseminated directly or indirectly into the soil ecosystem through various exposure routes. Thus, it is important to study various deposition routes of nanomaterials into the soil, as well as their toxicities. Here, we investigated the multigenerational effects of gold nanoparticles (AuNPs) on C. elegans after continuous or intermittent food intake. Following continuous exposure, significant differences were observed in the reproduction rate of C. elegans in the F2–F4 generations, which were associated with reproductive system abnormalities. However, following intermittent AuNP exposure in P0 and F3, reproductive system abnormalities and inhibited reproduction rates were observed in F2 and F3. While continuous AuNP exposure impaired reproduction from F2 to F4, intermittent exposure caused more pronounced effects on F3 worms, which may have resulted from damage during the convalescence period up through F2. These data showed the occurrence of multigenerational effects following different exposure patterns, exposure levels, and recovery periods. To our knowledge, this is the first study to demonstrate that multigenerational nano-toxicity is caused by different exposure patterns and provides insights into the unpredictable exposure scenarios of AuNPs and their adverse effects.
Show more [+] Less [-]Electrochemical oxidation of the polycyclic aromatic hydrocarbons in polluted concrete of the residential buildings
2017
Aćimović, Danka D. | Karić, Slavko D. | Nikolić, Željka M. | Brdarić, Tanja P. | Tasić, Gvozden S. | Marčeta Kaninski, Milica P. | Nikolić, Vladimir M.
Polycyclic aromatic hydrocarbons (PAH) have been listed by the United States Environmental Protection Agency (US EPA) and by the European Community as priority environmental pollutants. The removal of PAHs from soils, sediments and waste water has attracted attention of scientists and engineers for several decades. Electrochemical oxidation of PAH compounds in water, is receiving increasing attention, due to its convenience and simplicity. In this study we performed electrochemical oxidation of 16 EPA PAHs mixture in 10% NaCl aqueous solution in potentiostatic conditions, at voltage 1 V. Decrease of concentration of some individual PAHs, up to 70% referred to their starting concentration, after 60 min of electrolysis, was confirmed by UPLC/PDA analysis. In further work investigation was extrapolated to in situ removal of PAHs from concrete, as the medium where, to our knowledge, such way of PAH removal has not been investigated before.High concentrations of PAH contamination occurred in the concrete structure of the residential buildings in Belgrade in 2014. Application of DC voltage of 50 V between nickel and stainless steel electrodes packed in the concrete wall, moisturized with the 10% NaCl solution, led to considerable removal of the pollutants by oxidation process throughout the concrete.
Show more [+] Less [-]Uptake and subcellular distribution of triclosan in typical hydrophytes under hydroponic conditions
2017
He, Yupeng | Nie, Enguang | Li, Chengming | Ye, Qingfu | Wang, Haiyan
The increasing discharge of pharmaceuticals and personal care products (PPCPs) into the environment has generated serious public concern. The recent awareness of the environmental impact of this emerging class of pollutants and their potential adverse effects on human health have been documented in many reports. However, information regarding uptake and intracellular distribution of PPCPs in hydrophytes under hydroponic conditions, and potential human exposure is very limited. A laboratory experiment was conducted using ¹⁴C-labeled triclosan (TCS) to investigate uptake and distribution of TCS in six aquatic plants (water spinach, purple perilla, cress, penny grass, cane shoot, and rice), and the subcellular distribution of ¹⁴C-TCS was determined in these plants. The results showed that the uptake and removal rate of TCS from nutrient solution by hydrophytes followed the order of cress (96%) > water spinach (94%) > penny grass (87%) > cane shoot (84%) > purple perilla (78%) > rice (63%) at the end of incubation period (192 h). The range of ¹⁴C-TCS content in the roots was 94.3%–99.0% of the added ¹⁴C-TCS, and the concentrations in roots were 2–3 orders of magnitude greater than those in shoots. Furthermore, the subcellular fraction-concentration factor (3.6 × 10²–2.6 × 10³ mL g⁻¹), concentration (0.58–4.47 μg g⁻¹), and percentage (30%–61%) of ¹⁴C-TCS in organelles were found predominantly greater than those in cell walls and/or cytoplasm. These results indicate that for these plants, the roots are the primary storage for TCS, and within plant cells organelles are the major domains for TCS accumulation. These findings provide a better understanding of translocation and accumulation of TCS in aquatic plants at the cellular level, which is valuable for environmental and human health assessments of TCS.
Show more [+] Less [-]Using new hetero-spectral two-dimensional correlation analyses and synchrotron-radiation-based spectromicroscopy to characterize binding of Cu to soil dissolved organic matter
2017
Sun, Fusheng | Li, Yaqing | Wang, Xiang | Chi, Zhilai | Yu, Guanghui
Understanding the binding characteristics of copper (Cu) to different functional groups in soil dissolved organic matter (DOM) is important to explore Cu toxicity, bioavailability and ultimate fate in the environment. However, the methods used to explore such binding characteristics are still limited. Here, two-dimensional correlation spectroscopy (2DCOS) integrated with Fourier transform infrared (FTIR), 29Si nuclear magnetic resonance (NMR), 27Al NMR, and synchrotron-radiation-based FTIR spectromicroscopy were used to explore the binding characteristics of Cu to soil DOM as part of a long-term (23 years) fertilization experiment. Compared with no fertilization and inorganic fertilization (NPK), long-term pig manure fertilization (M) treatment significantly increased the concentration of total and bioavailable Cu in soils. Furthermore, hetero-spectral 2DCOS analyses demonstrated that the binding characteristics of Cu onto functional groups in soil DOM were modified by fertilization regimes. In the NPK treatment, Cu was bound to aliphatic C, whereas in the manure treatment SiO groups had higher affinity toward Cu than aliphatic C. Also, the sequence of binding of functional groups to Cu was modified by the fertilization treatments. Moreover, synchrotron-radiation-based FTIR spectromicroscopy showed that Cu, clay minerals and sesquioxides, and C functional groups were heterogeneously distributed at the micro-scale. Specifically, clay-OH as well as mineral elements had a distribution pattern similar to Cu, but certain (but not all) C forms showed a distribution pattern inconsistent with that of Cu. The combination of synchrotron radiation spectromicroscopy and 2DCOS is a useful tool in exploring the interactions among heavy metals, minerals and organic components in soils.
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