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High throughput and miniaturised systems for biodegradability assessments
2014
Cregut, Mickael | Jouanneau, Sulivan | Brillet, François | Durand, Marie-José | Sweetlove, Cyril | Chenèble, Jean-Charles | L’Haridon, Jacques | Thouand, Gérald
The society demands safer products with a better ecological profile. Regulatory criteria have been developed to prevent risks for human health and the environment, for example, within the framework of the European regulation REACH (Regulation (EC) No 1907, 2006). This has driven industry to consider the development of high throughput screening methodologies for assessing chemical biodegradability. These new screening methodologies must be scalable for miniaturisation, reproducible and as reliable as existing procedures for enhanced biodegradability assessment. Here, we evaluate two alternative systems that can be scaled for high throughput screening and conveniently miniaturised to limit costs in comparison with traditional testing. These systems are based on two dyes as follows: an invasive fluorescent dyes that serves as a cellular activity marker (a resazurin-like dye reagent) and a noninvasive fluorescent oxygen optosensor dye (an optical sensor). The advantages and limitations of these platforms for biodegradability assessment are presented. Our results confirm the feasibility of these systems for evaluating and screening chemicals for ready biodegradability. The optosensor is a miniaturised version of a component already used in traditional ready biodegradability testing, whereas the resazurin dye offers an interesting new screening mechanism for chemical concentrations greater than 10 mg/l that are not amenable to traditional closed bottle tests. The use of these approaches allows generalisation of high throughput screening methodologies to meet the need of developing new compounds with a favourable ecological profile and also assessment for regulatory purpose.
显示更多 [+] 显示较少 [-]Elucidation of the upper pathway of alicyclic musk Romandolide® degradation in OECD screening tests with activated sludge
2014
Seyfried, M. | Boschung, A. | Miffon, F. | Ohleyer, E. | Chaintreau, A.
The degradation of Romandolide® ([1-(3′,3′-dimethyl-1′-cyclohexyl)ethoxycarbonyl] methyl propanoate), a synthetic alicyclic musk, by activated sludge inocula was investigated using both the manometric respirometry test OECD 301F and the CO₂evolution test. In addition to measuring its biodegradability, key steps of the upper part of the metabolic pathway responsible for Romandolide® degradation were identified using extracts at different time points of incubation. Early metabolism of Romandolide® yielded ester hydrolysis products, including Cyclademol® (1-(3,3-dimethylcyclohexyl)ethanol). The principal metabolites after 31 days were identified as 3,3-dimethyl cyclohexanone and 3,3-dimethyl cyclohexyl acetate. Formation of 3,3-dimethyl cyclohexanone from Cyclademol® by sludge was confirmed in subsequent experiments using Cyclademol® as a substrate, indicating the involvement of an oxygen insertion reminiscent of a Baeyer–Villiger oxidation. Further mineralization of 3,3-dimethyl cyclohexanone was also confirmed in subsequent studies. Three steps were thus required for complete biodegradation of the alicyclic musk: (1) successive ester hydrolyses leading to the formation of Cyclademol® with concomitant degradation of the resulting acids, (2) conversion of Cyclademol® into 3,3-dimethyl cyclohexanone, and (3) further mineralization via ring cleavage.
显示更多 [+] 显示较少 [-]Evaluation of spatial distribution and accumulation of novel brominated flame retardants, HBCD and PBDEs in an Italian subalpine lake using zebra mussel (Dreissena polymorpha)
2014
Poma, Giulia | Binelli, Andrea | Volta, Pietro | Roscioli, Claudio | Guzzella, Licia
Because of the reduction in the use of polybrominated diphenyl ethers (PBDEs) and hexabromocyclododecane (HBCD), novel brominated flame retardants (NBFRs), including 1,2-bis(2,4,6-tribromophenoxy) ethane (BTBPE), decabromodiphenyl ethane (DBDPE), hexabromobenzene (HBB), and pentabromoethylbenzene (PBEB), started to be marketed as alternatives to the banned formulations. In this study, the spatial distribution and accumulation of NBFRs, PBDEs, and HBCD in the biota have been investigated in the littoral compartment of a large and deep subalpine lake (Lake Maggiore, Northern Italy), using zebra mussel Dreissena polymorpha and roach (Rutilus rutilus) as bioindicators. To our knowledge, this is the first study reporting the contamination of NBFRs in the freshwater invertebrate D. polymorpha. Contamination of zebra mussel due to PBEB, HBB, and BTBPE was low, ranging from 0.9 to 2.9 ng/g lipid weight, from 1.1 to 2.9 ng/g l.w., and from 3.5 to 9.5 ng/g l.w., respectively. PBEB and BTBPE in roach were always below the detection limit, while the contamination of HBB ranged from < limits of detection (LOD) to 1.74 ng/g l.w., indicating a weak contamination. DBDPE was < LOD in all the considered biological samples. Finally, HBCD was detected in all organic tissues with mean concentrations up to 74.4 ng/g l.w. PBDE results, supported by principal component analysis elaboration, suggested a possible contamination due to the congeners composing the penta- and deca-BDE technical formulations, which are present in the Lake Maggiore basin. The biomagnification factor values showed that tetra- and penta-BDE biomagnified, while octa-, nona-, and deca-BDE were still bioavailable and detectable in the fish muscles, but they do not biomagnified. Considering the other BFRs, only HBCD showed a moderate biomagnification potential.
显示更多 [+] 显示较少 [-]Application of the triolein-embedded cellulose acetate membrane passive sampler for monitoring of polycyclic aromatic hydrocarbons in water
2014
Tang, Jianfeng | He, Guiying | Li, Gang
Triolein-embedded cellulose acetate membrane (TECAM) can be used as a passive sampler to measure hydrophobic organic contaminants in water. Uptake constant rates (k ᵤ ) for polycyclic aromatic hydrocarbons (PAHs) by TECAM sampling were measured under different hydrodynamic conditions. The measured k ᵤ values were modeled to enable the quantification of time weighed average (TWA) concentrations of PAHs in the field. An empirical relationship that enables the calculation of in situ k ᵤ values of chemicals using performance reference compounds (PRCs) was derived and its application was demonstrated in a field study. The results showed that freely dissolved concentrations of hydrophobic organic compounds (HOCs) can be accurately measured in the field using TECAM method based on empirical uptake models calibrated with PRCs.
显示更多 [+] 显示较少 [-]Weighted species sensitivity distribution method to derive site-specific quality criteria for copper in Tai Lake, China
2014
Shi, Rui | Yang, Chunhui | Su, Runhua | Jin, Jiarui | Chen, Yi | Liu, Hongling | Giesy, John P. | Yu, Hongxia
Tai Lake (Ch: Taihu), which is the largest lake in Jiangsu province, China, has been affected by human activities. As part of a concerted effort to improve water quality to protect the integrity of the Tai Lake ecosystem, a water quality criterion (WQC) was developed for copper (Cu) II. The acute WQC was based on 440 values for acute toxicity of Cu to 24 species from 6 phyla, 16 families, and 20 genera. In addition, 255 values for chronic toxicity of Cu to 10 species from 5 phyla, 8 families, and 9 genera were used to derive chronic WQC. Instead of using a traditional approach based species sensitivity distributions (SSD), a weighted species sensitivity distribution (WSSD) approach was used to calculate the cumulative probability based on endemic species to Tai Lake. Acute and chronic WQC developed by use of the WSSD were 5.3 and 3.7 μg Cu/L, respectively. While the WQC values were comparable to those of other countries, there were slight differences due to variability in species composition of different regions. The site-specific criteria indicated that the current standard set for surface water by the Chinese government might not be protective of aquatic organisms in Tai Lake.
显示更多 [+] 显示较少 [-]Effects of hydraulic retention time and nitrobenzene concentration on the performance of sequential upflow anaerobic filter and air lift reactors in treating nitrobenzene-containing wastewater
2014
Wu, Jinhua | Chen, Guocai | Gu, Jingjing | Yin, Weizhao | Lu, Mengxiong | Li, Ping | Yang, Bo
Sequential upflow anaerobic filter (UAF)/air lift (ALR) reactors were employed to investigate the effects of hydraulic retention time (HRT) and nitrobenzene (NB) concentration on treatment of NB-containing wastewater. The results showed that NB was effectively reduced to aniline (AN) with glucose as co-substrate in the UAF reactor. The AN and the remaining intermediates after the UAF reactor were then efficiently degraded in the ALR reactor. A removal efficiency of 100% and 96% was obtained for NB and chemical oxygen demand (COD), respectively, using sequential UAF/ALR reactors with an HRT of 8–72 h in the UAF reactor and 2–18 h in the ALR reactor. The corresponding optimal influent NB concentration varied between 100 and 400 mg l⁻¹to achieve the optimal NB and COD removal. The NB removal efficiency decreased to 90% and to 97% if the HRT in the UAF reactor decreased from 8 to 2 h and the influent NB concentration increased from 400 to 800 mg l⁻¹, respectively. The results showed that sequential UAF/ALR system can be operated at low HRTs and high NB concentrations without significantly affecting the removal efficiency of NB in the reactor system. The UAF/ALR system can provide an effective yet low cost method for treatment of NB-containing industrial wastewater.
显示更多 [+] 显示较少 [-]Impact of dispersed fuel oil on cardiac mitochondrial function in polar cod Boreogadus saida
2014
Dussauze, Matthieu | Camus, Lionel | Le Floch, Stéphane | Pichavant-Rafini, Karine | Geraudie, Perrine | Coquillé, Nathalie | Amérand, Aline | Lemaire, Philippe | Theron, Michael
In this study, impact of dispersed oil on cardiac mitochondrial function was assessed in a key species of Arctic marine ecosystem, the polar cod Boreogadus saida. Mature polar cod were exposed during 48 h to dispersed oil (mechanically and chemically) and dispersants alone. The increase observed in ethoxyresorufin-O-deethylase activity and polycyclic aromatic hydrocarbon metabolites in bile indicated no difference in contamination level between fish exposed to chemical or mechanical dispersion of oil. Oil induced alterations of O₂consumption of permeabilised cardiac fibres showing inhibitions of complexes I and IV of the respiratory chain. Oil did not induce any modification of mitochondrial proton leak. Dispersants did not induce alteration of mitochondrial activity and did not increase oil toxicity. These data suggest that oil exposure may limit the fitness of polar cod and consequently could lead to major disruption in the energy flow of polar ecosystem.
显示更多 [+] 显示较少 [-]Spatial variability of sediment ecotoxicity in a large storm water detention basin
2014
Merchan, Carolina Gonzalez | Perrodin, Yves | Barraud, Sylvie | Sébastian, Christel | Becouze-Lareure, Céline | Bazin, Christine | Kouyi, Gislain Lipeme
Detention basins are valuable facilities for urban storm water management, from both the standpoint of flood control and the trapping of pollutants. Studies performed on storm water have shown that suspended solids often constitute the main vector of pollutants (heavy metals, polycyclic aromatic hydrocarbon (PAH), etc.). In order to characterise the ecotoxicity of urban sediments from storm water detention basins, the sediments accumulated over a 6-year period were sampled at five different points through the surface of a large detention basin localised in the east of Lyon, France. A specific ecotoxicological test battery was implemented on the solid phase (raw sediment) and the liquid phase (interstitial water of sediments). The results of the study validated the method formulated for the ecotoxicological characterization of urban sediments. They show that the ecotoxicological effect of the sediments over the basin is heterogeneous and greater in areas often flooded. They also show the relationship between, on one hand, the physical and chemical characteristics of the sediments and, on the other hand, their ecotoxicity. Lastly, they contribute to a better understanding of the dynamics of the pollution close to the bottom of detention basins, which can be useful for improving their design. The results of this research raise particularly the issue of using oil separators on the surface of detention basins.
显示更多 [+] 显示较少 [-]A scale-up field experiment for the monitoring of a burning process using chemical, audio, and video sensors
2014
Stavrakakis, P. | Agapiou, A. | Mikedi, K. | Karma, S. | Statheropoulos, M. | Pallis, G. C. | Pāppā, Ā.
Fires are becoming more violent and frequent resulting in major economic losses and long-lasting effects on communities and ecosystems; thus, efficient fire monitoring is becoming a necessity. A novel triple multi-sensor approach was developed for monitoring and studying the burning of dry forest fuel in an open field scheduled experiment; chemical, optical, and acoustical sensors were combined to record the fire spread. The results of this integrated field campaign for real-time monitoring of the fire event are presented and discussed. Chemical analysis, despite its limitations, corresponded to the burning process with a minor time delay. Nevertheless, the evolution profile of CO₂, CO, NO, and O₂ were detected and monitored. The chemical monitoring of smoke components enabled the observing of the different fire phases (flaming, smoldering) based on the emissions identified in each phase. The analysis of fire acoustical signals presented accurate and timely response to the fire event. In the same content, the use of a thermographic camera, for monitoring the biomass burning, was also considerable (both profiles of the intensities of average gray and red component greater than 230) and presented similar promising potentials to audio results. Further work is needed towards integrating sensors signals for automation purposes leading to potential applications in real situations.
显示更多 [+] 显示较少 [-]Revisions to the derivation of the Australian and New Zealand guidelines for toxicants in fresh and marine waters
2014
Warne, M. St. J. | Batley, G. E. | Braga, O. | Chapman, J. C. | Fox, D. R. | Hickey, C. W. | Stauber, J. L. | Van Dam, R.
The Australian and New Zealand Guidelines for Fresh and Marine Water Quality are a key document in the Australian National Water Quality Management Strategy. These guidelines released in 2000 are currently being reviewed and updated. The revision is being co-ordinated by the Australian Department of Sustainability, Environment, Water, Population and Communities, while technical matters are dealt with by a series of Working Groups. The revision will be evolutionary in nature reflecting the latest scientific developments and a range of stakeholder desires. Key changes will be: increasing the types and sources of data that can be used; working collaboratively with industry to permit the use of commercial-in-confidence data; increasing the minimum data requirements; including a measure of the uncertainty of the trigger value; improving the software used to calculate trigger values; increasing the rigour of site-specific trigger values; improving the method for assessing the reliability of the trigger values; and providing guidance of measures of toxicity and toxicological endpoints that may, in the near future, be appropriate for trigger value derivation. These changes will markedly improve the number and quality of the trigger values that can be derived and will increase end-users’ ability to understand and implement the guidelines in a scientifically rigorous manner.
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