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Should oral exposure in Hypoaspis aculeifer tests be considered in order to keep them in Tier I test battery for ecological risk assessment of PPPs?
2019
Natal-da-Luz, Tiago | Gevaert, Tom | Pereira, Carla | Alves, Daniela | Arena, Maria | Sousa, José Paulo
The laboratory reproduction test with the predatory mite Hypoaspis aculeifer is currently a mandatory test in the new EU data requirements for prospective environmental risk assessment of Plant Protection Products (PPPs). However, the low sensitivity often shown by this mite towards PPPs, when compared to other invertebrates (namely Folsomia candida and Eisenia fetida), makes the test with this species not very useful in the lower tier test battery. However, the current test protocol only considers exposure to contaminants via contaminated soil, disregarding exposure via contaminated food and does not take into account the fact that H. aculeifer is a predatory species. Therefore, through this protocol, the toxicity of contaminants to soil mites might be underestimated and, thus, an adaptation of the test performance, by including exposure via contaminated food, may be necessary. With this aim, two reproduction tests with H. aculeifer were performed using copper chloride as model substance, artificial soil as test substrate and cheese mites as food. The OECD guideline was followed but, while in one test cheese mites from normal laboratory breeding cultures (clean prey mites) were provided, in the other test, cheese mites previously exposed to copper (Cu pre-exposed prey mites) were provided. Predatory mites were affected at lower concentrations in tests using Cu pre-exposed prey compared to test with clean-prey (NOEC = 1225 and 1508 mg kg⁻¹ and EC₁₀ = 1204 and 1903 mg kg⁻¹ using Cu pre-exposed and clean prey, respectively). However, this higher sensitivity was not detected by EC₅₀ values (EC₅₀ = 2634 and 2814 mg kg⁻¹ using Cu pre-exposed and clean prey, respectively). Further tests are needed in order to (i) investigate the relevance of oral exposure to different PPPs, (ii) optimize the contamination of prey mites according to the chemical properties of each substance and (iii) substantiate a proposal to adapt the standard protocol.
Show more [+] Less [-]High selective reduction of nitrate into nitrogen by novel Fe-Cu/D407 composite with excellent stability and activity
2019
Tang, Ting-Ting | Xing, Qiu-Ju | Zhang, Si-Hai | Mu, Yi | Jiang, Xun-Heng | Zhou, Zhi-Gang | Xiao, Xiao | Zou, Jian-Ping
In this study, we develop a new composite material of Fe-Cu/D407 composite via using nanoscale zero-valent iron (nZVI) with copper deposited on chelating resin (D407) to remove nitrate from the water. The experimental results show that a remarkable nitrate removal and the selectivity of N₂ are 99.9% and 89.7%, respectively, under the anaerobic conditions of Cu/Fe molar ratio of 1:2, pH = 3.0. Even without of inert gas and adjusting the initial pH of the solution, the removal rate of nitrate by Fe-Cu/D407 reached to 85% and the selectivity of nitrogen reached to 55%. Meanwhile, the Fe-Cu/D407 maintained preferable removal efficiency of nitrate (100% - 92%) over a wide pH range of 3–11. In addition, the removal rate of the drinking water, lake water and wastewater from the Fe-Cu/D407 is still very high and the reactivity of Fe-Cu/D407 was relatively unaffected by the presence of dissolved ions in the waters tested. Moreover, the synergetic effect of Fe, Cu and D407 in the composite Fe-Cu/D407 were well investigated for the first time according to the analyses of TPR, XPS and EIS. The catalytic mechanism and denitrification routes were also proposed.
Show more [+] Less [-]More obvious air pollution impacts on variations in bacteria than fungi and their co-occurrences with ammonia-oxidizing microorganisms in PM2.5
2019
Fan, Xiao-Yan | Gao, Jing-Feng | Pan, Kai-Ling | Li, Ding-Chang | Dai, Hui-Hui | Li, Xing
Based on long-term systematic sampling, information is currently limited regarding the impacts of different air pollution levels on variations of bacteria, fungi and ammonia-oxidizing microorganisms (AOMs) in fine particulate matter (PM₂.₅), especially their interactions. Here, PM₂.₅ samples were weekly collected at different air pollution levels in Beijing, China during one-year period. Microbial composition was profiled using Illumina sequencing, and their interactions were further investigated to reveal the hub genera with network analysis. Diversity of bacteria and fungi showed obvious seasonal variations, and the heavy- or severe-pollution levels mainly affected the diversity and composition of bacteria, but not fungi. While, the community structure of both bacteria and fungi was influenced by the combination of air pollution levels and seasons. The most abundant bacterial genera and some genera with highest abundance in heavy- or severe-pollution days were the hub bacteria in PM₂.₅. Whereas, only the dominant fungi in light-pollution days in winter were the hub fungi in PM₂.₅. The complex positive correlations of bacterial or fungal pathogens would aggravate the air pollution effects on human health, despite of their low relative abundances. Moreover, the strong co-occurrence and co-exclusion patterns of bacteria and fungi in PM₂.₅ were identified. Furthermore, the hub environmental factors (e.g., relative humidity and atmospheric pressure) may play central roles in the distributions of bacteria and fungi, including pathogens. Importantly, AOMs showed significant co-occurrence patterns with the main bacterial and fungal genera and potential pathogens, providing possible microbiological evidences for controlling ammonia emissions to effectively reduce PM₂.₅ pollution. These results highlighted the more obvious air pollution impacts on bacteria than fungi, and the complex bacterial-fungal interactions, as well as the important roles of AOMs in airborne microbial interactions webs, improving our understanding of bioaerosols in PM₂.₅.
Show more [+] Less [-]Prenatal aluminum exposure is associated with increased newborn mitochondrial DNA copy number
2019
Liu, Bingqing | Song, Lulu | Zhang, Lina | Wu, Mingyang | Wang, Lulin | Cao, Zhongqiang | Zhang, Bin | Xu, Shunqing | Wang, Youjie
Aluminum is a widely distributed metal that has been reported to have embryotoxicity and fetotoxicity in animal studies. However, there has been no study of the association between prenatal aluminum exposure and newborn mitochondrial DNA copy number (mtDNAcn). We aimed to investigate the effect of prenatal aluminum exposure on newborn mtDNAcn. A total of 762 mother-newborn pairs were recruited between November 2013 and March 2015 in Wuhan city, China. We measured maternal urinary aluminum concentrations at three trimesters of pregnancy. Relative mtDNAcn was measured in DNA extracted from umbilical cord blood samples. We used generalized estimating equations to assess the relationship between prenatal aluminum exposure and newborn mtDNAcn. The geometric means of creatinine corrected aluminum concentrations were 31.0 μg/g Cr (95% CI: 27.6, 34.7), 40.9 μg/g Cr (95% CI: 35.7, 46.8) and 58.4 μg/g Cr (95% CI: 51.2, 67.4) for the first, second and third trimesters, respectively. After adjustment for potential confounding factors, a doubling of maternal urinary aluminum concentrations during the second and third trimesters was related to 3.16% (95% CI: 0.88, 5.49) and 4.20% (95% CI: 1.64, 6.81) increases in newborn mtDNAcn, respectively, while the association between maternal urinary aluminum concentration during the first trimester and newborn mtDNAcn was not significant (percent difference: 0.70%, 95% CI: −2.25, 3.73). Prenatal aluminum exposure during the second and third trimesters was positively associated with newborn mtDNAcn. Further studies are essential to elucidate on the potential health consequences of newborn mtDNAcn.
Show more [+] Less [-]Cyanobacterial blooms act as sink and source of endocrine disruptors in the third largest freshwater lake in China
2019
Jia, Yunlu | Chen, Qiqing | Crawford, Sarah E. | Song, Lirong | Chen, Wei | Hammers-Wirtz, Monika | Strauss, Tido | Seiler, Thomas-Benjamin | Schäffer, Andreas | Hollert, Henner
Cyanobacterial blooms are of global concern due to the multiple harmful risks they pose towards aquatic ecosystem and human health. However, information on the fate of organic pollutants mediated by cyanobacterial blooms in eutrophic water remains elusive. In the present study, endocrine disruptive potentials of phytoplankton samples were evaluated throughout a year-long surveillance in a large and eutrophic freshwater lake. Severe cyanobacterial blooms persisted during our sampling campaigns. Estrogenic agonistic, anti-estrogenic, anti-androgenic, and anti-glucocorticogenic effects were observed in the phytoplankton samples using in vitro reporter gene bioassays. 27 endocrine disrupting chemicals (EDCs) of different modes of action were detected in the samples via UPLC-MS/MS system. Results from mass balance analysis indicated that the measured estrogenic activities were greater than the predicted estrogenic potencies from chemical analysis, demonstrating that chemical analysis of targeted EDCs is unable to fully explain the compounds responsible for the observed estrogenicities. Results from Spearman's correlation analysis concluded that the concentrations of ten EDCs in phytoplankton samples were negatively correlated with cyanobacterial biomass, suggesting the potential occurrence of biomass bio-dilution effects of EDCs due to the huge biomass of cyanobacteria during bloom seasons. The present study provided complementary information about the potential endocrine disruptive risks of cyanobacterial blooms, which is important for understanding and regulating EDCs in eutrophic lakes.
Show more [+] Less [-]Benefits of current and future policies on emissions of China's coal-fired power sector indicated by continuous emission monitoring
2019
Zhang, Yan | Bo, Xin | Zhao, Yu | Nielsen, Chris P.
Emission inventories are critical to understanding the sources of air pollutants, but have high uncertainties in China due in part to insufficient on-site measurements. In this study, we developed a method of examining, screening and applying online data from the country's improving continuous emission monitoring systems (CEMS) to reevaluate a “bottom-up” emission inventory of China's coal-fired power sector. The benefits of China's current national emission standards and ultra-low emission policy for the sector were quantified assuming their full implementation. The derived national average emission factors of SO₂, NOₓ and particulate matter (PM) were 1.00, 1.00 and 0.25 kg/t-coal respectively for 2015 based on CEMS data, smaller than those of previous studies that may not fully recognize improved emission controls in recent years. The annual emissions of SO₂, NOₓ and PM from the sector were recalculated at 1321, 1430 and 334 Gg respectively, 75%, 63% and 76% smaller than our estimates based on a previous approach without the benefit of CEMS data. The results imply that online measurement with proper data screening can better track the recent progress of emission controls. The emission intensity (the ratio of emissions to economic output) of Northwest China was larger than that of other regions, attributed mainly to its less intensive economy and industry. Transmission of electricity to more-developed eastern provinces raised the energy consumption and emissions of less-developed regions. Judged by 95 percentiles of flue-gas concentrations measured by CEMS, most power plants met the current national emission standards in 2015 except for those in Northwest and Northeast China, while plants that met the ultra-low emission policy were much scarcer. National SO₂, NOₓ and PM emissions would further decline by 68%, 55% and 81% respectively if the ultra-low emission policy can be strictly implemented, implying the great potential of the policy for emission abatement.
Show more [+] Less [-]Plastic film mulching increased the accumulation and human health risks of phthalate esters in wheat grains
2019
Shi, Mei | Sun, Yingying | Wang, Zhaohui | He, Gang | Quan, Hanxiang | He, Hongxia
Plastic film mulching is a common practice to increase crop yield in dryland, while the wide use of plastic film has resulted in ubiquitous phthalate esters (PAEs) releasing into the soil. PAEs in soil could be taken up and accumulated by dietary intake of food crops such as wheat, thus imposing health risks to residents. In the present study, samples from a long-term location-fixed field experiment were examined to clarify the accumulation of PAEs in soil and wheat, and to assess the human health risks from PAEs via dietary intake of wheat grain under plastic film mulching cultivation in dryland. Results showed that concentrations of PAEs in grains from mulching plots ranged from 4.1 to 12.6 mg kg−1, which were significantly higher than those in the control group. There was a positive correlation for the PAE concentrations between wheat grains and field soils. Concentrations of PAEs in the soil were in the range of 1.8–3.5 mg kg−1 for the mulching treatment, and 0.9–2.7 mg kg−1 for the control group. Di-n-butyl phthalate (DBP) and di-(2-ethylhexyl) phthalate (DEHP) were detected in all soil and grain samples, and DEHP was found to be the dominant PAE compound in grains. Based on DEHP concentrations in wheat grains, the values of carcinogenic risk for adults were higher than the recommended value 10−4. Results indicated that wheat grains from film mulching plots posed a considerable non-carcinogenic risk to residents, with children being the most sensitive resident group. Findings of this work call the attention to the potential pollution of grain crops growing in the plastic film mulching crop production systems.
Show more [+] Less [-]Oxidative degradation of chlorophenolic compounds with pyrite-Fenton process
2019
Kantar, Cetin | Oral, Ozlem | Urken, Ozge | Oz, Nilgun Ayman | Keskin, Selda
Batch experiments, in conjunction with chromatographic and spectroscopic measurements, were performed to comparatively investigate the degradation of various chlorophenolic (CP) compounds (e.g., 2-CP, 4-CP, 2,3-DCP, 2,4-DCP, 2,4,6-TCP, 2,3,4,6-TeCP) by a modified Fenton process using pyrite as the catalyst. The batch results show that the CP removal by pyrite-Fenton process was highly dependent on chemical conditions (e.g., pH, CP and pyrite concentration), CP type, number and location of chlorine atoms on the aromatic ring. With the exception of 2,3,4,6-TeCP and 2,3-DCP, the CP removal decreased with increasing the number of chlorine constituents. While the main mechanism responsible for monochlorophenol removal (e.g., 2-CP and 4-CP) was the hydroxyl radical attack on aromatic rings, the CP removal for multichlorophenolic compounds (e.g., 2,3,4,6-TeCP) was driven by both: (1) hydroxyl radical attack on aromatic rings by both solution and surface-bound hydroxyl radicals and (2) adsorption onto pyrite surface sites. The adsorption affinity increased with increasing the number of Cl atoms on the aromatic ring due to enhanced hydrophobic effect. The TOC removal was not 100% complete for all CPs investigated due to formation of chemically less degradable chlorinated intermediate organic compounds as well as low molecular weight organic acids such as formic and acetic acid. Spectroscopic measurements with SEM-EDS, zeta potential and XPS provided evidence for the partial oxidation of pyrite surface Fe(II) and disulfide groups under acidic conditions.
Show more [+] Less [-]Railroad derived nitrogen and heavy metal pollution does not affect nitrogen fixation associated with mosses and lichens at a tundra site in Northern Sweden
2019
Goth, Astrid | Michelsen, Anders | Rousk, Kathrin
Traffic derived nitrogen (N) and heavy metal pollution is a well-known phenomenon, but little explored in otherwise pristine ecosystems such as subarctic tundra. Here, the main source of N input to the ecosystem is via N₂ fixation by moss- and lichen-associated bacteria. While inhibitory effects of N deposition on moss-associated N₂ fixation have been reported, we still lack understanding of the effects of traffic derived N and heavy metal deposition on this ecosystem function in an otherwise pristine setting. To test this, we established a distance gradient (0–1280 m) away from a metal pollution source -a railway transporting iron ore that passes through a subarctic birch forest. We assessed the effects of railway-derived pollution on N₂ fixation associated with two moss species Pleurozium schreberi, Hylocomium splendens and with the lichen Peltigera aphthosa. Deposition and availability of N and heavy metals (Fe, Cu, Zn, Pb) as well as the respective contents in moss, lichen and soil was assessed. While we found a steep gradient in metal concentration in moss, lichen and soil with distance away from the pollution source, N deposition did not change, and with that, we could not detect a distance gradient in moss- or lichen-associated N₂ fixation. Hence, our results indicate that N₂ fixing bacteria are either not inhibited by heavy metal deposition, or that they are protected within the moss carpet and lichen tissue.
Show more [+] Less [-]Environmental exposure to non-essential trace elements in two bat species from urbanised (Tadarida teniotis) and open land (Miniopterus schreibersii) areas in Italy
2019
Andreani, Giulia | Cannavacciuolo, Annunziata | Menotta, Simonetta | Spallucci, Valentina | Fedrizzi, Giorgio | Carpenè, Emilio | Isani, Gloria
Bats are particularly suited as bioindicators of trace element pollution due to their longevity and their position in the trophic chain. In this study, the concentrations of ten non-essential trace elements (Al, As, Ba, Cd, Hg, Pb, Sb, Sr, Th, Tl) were determined in the tissues (whole body, skin-fur, skinned body, liver, kidney and bone) of lactant Tadarida teniotis from a nursery colony in Rome. A large number of bats from this nursery died before fledging and had bone deformities and fractures. The concentrations of non-essential trace elements in bone and whole body were also analysed in adult specimens of Miniopterus schreibersii from a colony located in a natural park in Northern Italy. In lactant T. teniotis, the Pb concentration decreased in the following order: bone>liver>skinned body>whole body>skin-fur>kidney, and exceeded the toxic threshold associated with negative effects reported for different mammalian species. The levels of the other non-essential trace elements were within a range indicative of low environmental contamination in both species. Significant interspecies differences (P < 0.05) were observed for concentrations of Pb and Ba, higher in the bones of T. teniotis, and of Cd, Hg and Sr, higher in the bones of M. schreibersii. In lactant T. teniotis, the different sources of Pb exposure, through inhalation and/or food, may represent a potential threat to the colony of this synanthropic European bat.
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