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Quantification of plankton-sized microplastics in a productive coastal Arctic marine ecosystem
2020
Rist, Sinja | Vianello, Alvise | Winding, Mie Hylstofte Sichlau | Nielsen, Torkel Gissel | Almeda, Rodrigo | Torres, Rocío Rodríguez | Vollertsen, Jes
Microplastics (MPs) are polluting the Arctic, but our understanding of their abundance, distribution, and sources is limited. This study quantified MPs down to 10 μm in marine waters of the most populated region in Greenland. A new plastic-free pump-filter system was used to collect MPs from surface waters in the fjord Nuup Kangerlua close to Nuuk. Additionally, we took samples by horizontal tows with a bongo net (300 μm mesh-size). The median concentrations were 142 MPs m⁻³ and 0.12 MPs m⁻³ in the pump and bongo samples, respectively. The most abundant polymer was polyester across stations and sampling types. Fibers were the dominant shape in the bongo samples, while non-fibrous particles dominated in the pump samples. MP abundance was lower in the fjord and increased close to Nuuk and towards the open ocean, indicating that Nuuk is an important point source for MPs. In both samples, concentrations of MPs increased with decreasing size, illustrating the importance of quantifying the smallest fraction of MPs. Thus, the use of methods allowing for a quantification of the smallest MPs is vital to reduce the underestimation of MP concentrations in the environment. The smallest size fraction is also most available to plankton-feeding marine invertebrates and an important entry point for MPs into marine food webs. At the found concentrations, immediate adverse effects on the pelagic food webs are unlikely. However, growing anthropogenic activities could increase the risk of MPs to affect the sensitive Arctic ecosystem.
Show more [+] Less [-]Adding a complex microbial agent twice to the composting of laying-hen manure promoted doxycycline degradation with a low risk on spreading tetracycline resistance genes
2020
Liang, Jiadi | Jin, Yiman | Wen, Xin | Mi, Jiandui | Wu, Yinbao
Poultry manure is a reservoir for antibiotics and antibiotic resistance genes and composting is an effective biological treatment for manure. This study explored the effect of using two methods of adding a complex microbial agent to the composting of laying-hen manure on doxycycline degradation and tetracycline resistance genes elimination. The results showed that incorporating a complex microbial agent at 0.8% (w/w) on the 0ᵗʰ and 11th day (group MT2) effectively degraded doxycycline with a final degradation rate of 46.83 ± 0.55%. The half-life of doxycycline in this group was 21.90 ± 0.00 days and was significantly lower than that of group MT1 (1.6% (w/w) complex microbial agent added on the 0ᵗʰ day) and group DT (compost without complex microbial agent). But there was no significant difference in the final degradation rate of doxycycline between group DT and group MT1. The addictive with the complex microbial agent changed the microbial community structure. Bacteroidetes, Firmicutes and Proteobacteria were the dominant phyla during composting. Aerococcus, Desemzia, Facklamia, Lactobacillus, Streptococcus, and Trichococcus were the bacteria related to the degradation of doxycycline. Moreover, the incorporation of a complex microbial agent could decrease the risk on spreading tetracycline resistance genes. The single addition promoted the elimination of tetM, whose possible hosts were Enterococcus, Lactobacillus, Staphylococcus, and Trichococcus. Adding the complex microbial agent twice promoted the elimination of tetX, which was related to the low abundance of Chryseobacterium, Flavobacterium and Neptunomonas in group MT2. Redundancy analysis showed that the bacterial community, residual doxycycline and physiochemical properties have a potential effect on the variation in tetracycline resistance genes levels. Overall, adding the complex microbial agent twice is an effective measure to degrade doxycycline.
Show more [+] Less [-]Short-term exposure to ZnO/MCB persistent free radical particles causes mouse lung lesions via inflammatory reactions and apoptosis pathways
2020
Zhang, Xing | Gu, Wenyi | Ma, Zhongliang | Liu, Yun | Ru, Hongbo | Zhou, Jizhi | Zang, Yi | Xu, Zhiping | Qian, Guangren
Environmentally persistent free radicals (EPFRs) are easily generated in the combustion processes of municipal solid waste (MSW) and can cause adverse effects on human health. This study focuses on understanding the toxicity of EPFR particles (ZnO/MCB containing EPFRs) to human bronchial epithelial cell lines BEAS-2B and 16HBE, murine macrophages Raw264.7, and the lung of BALB/c mice after a short exposure (7 days). Exposure of BEAS-2B, 16HBE, and Raw264.7 cells to ZnO/MCB particles significantly increased the reactive oxygen species (ROS) production and perturbed levels of intracellular redox conditions (decreased the intracellular GSH level and the activity of cytosolic SOD, and stimulated oxidative stress related proteins such as HO-1 and Nrf2). EPFR particles decreased the mitochondrial membrane potential (MMP) and induced cell apoptosis, including the activation of Caspase-3, Bax, and Bcl-2 apoptotic signalling pathways. A signature inflammatory condition was observed in both cell models and the mouse model for lung lesions. Our data suggest that EPFRs in particles have greater toxicity to lung cells and tissues that are potential health hazards to human lung.
Show more [+] Less [-]Usefulness of bee bread and capped brood for the assessment of monocyclic aromatic hydrocarbon levels in the environment
2020
Zięba, Katarzyna | Szostak, Elżbieta | Czekońska, Krystyna | Miśkowiec, Paweł | Moos-Matysik, Agnieszka | Nyczyk-Malinowska, Anna | Szentgyörgyi, Hajnalka
Monitoring airborne pollutants, like aromatic hydrocarbons, are raising more and more concerns recently. Various sampling techniques and methods are known to collect, measure, and analyse environmental pollution levels based on honey bee bodies or bee product samples. Although honey bees are studied in detail and sampling methods are becoming more and more sophisticated biological samples may significantly differ in pollutant accumulation, showing a wide range of pollution levels even in the same site and environment. We have compared the pollution levels of honey bee capped brood and bee bread (pollen collected by honey bees and deposited in the hive) originating from four sites during two years of study and twelve honey bee families near various pollution sources emitting monocyclic aromatic hydrocarbons (BTEX) to the environment. Our result showed, that the environmental monitoring of BTEX can be based on sampling honey bees, and bee bread in particular. However, we found a significant difference in the uptake of these pollutants regarding sample type. Pollen collected as a food source revealed consistently higher levels of BTEX than bee brood, as well as some other differences in pollution levels between samples and between seasons, as opposed to capped brood. Based on our results, we suggest that for measuring and monitoring of BTEX pollution in the environment the use of bee bread is a valuable source of information.
Show more [+] Less [-]Behavior of eukaryotic symbionts in large benthic foraminifers Calcarina gaudichaudii and Baculogypsina sphaerulata under exposure to wastewater
2020
Akther, Shumona | Suzuki, Jumpei | Pokhrel, Preeti | Okada, Teruhisa | Imamura, Masahiro | Enomoto, Tadao | Kitano, Takashi | Kuwahara, Yuji | Fujita, Masafumi
Large benthic foraminifers (LBFs) are significant contributors to coral island formation in the Pacific Ocean. In recent years, the population of LBFs has decreased because of the increase in anthropogenic influences, such as wastewater (WW) discharge. To implement efficient mitigation measures, pollution tolerance in LBFs should be understood. However, the effects of WW on LBFs and their symbionts have not yet been demonstrated. This study examined the changes in the photosynthetic efficiency (Y[II]) of Calcarina gaudichaudii and Baculogypsina sphaerulata in response to WW by using a pulse-amplitude-modulation fluorometer. These LBFs were exposed to WW with different dilution levels for 22 days. The Y(II) values of the LBFs were found to deteriorate within 1–2 days. However, the Y(II) values both deteriorated and were enhanced in the experiments, thus indicating that WW contains both harmful and beneficial components. Baculogypsina sphaerulata showed an earlier response and greater sensitivity to WW and a higher epibiont infestation than C. gaudichaudii. This result can be attributed to the differences in the physiological and morphological responses of distinct LBFs. A sequencing analysis of 18S rDNA confirmed that the dominant eukaryotic symbionts in the two LBFs studied were Ochrophyta and Labyrinthulomycetes. These eukaryotic symbionts were released and attached as epibionts onto LBFs that were exposed to WW, thus leading to an increase in inactive LBFs. The Shannon–Weaver and Simpson diversity indices revealed that eukaryotic symbiont communities decreased in biodiversity after exposure to WW because of the abundance of algal symbionts. On the basis of these results, we conclude that WW, even with 10,000 × dilution, causes a decrease in active LBF populations owing to the release of eukaryotic symbionts, the decrease in biodiversity, and the infestation of epibionts even though Y(II) is temporarily enhanced. These responses are more significant in B. sphaerulata than in C. gaudichaudii.
Show more [+] Less [-]A theorem on a product of lognormal variables and hybrid models for children’s exposure to soil contaminants
2020
Li, Zijian
This study developed hybrid Bayesian models to investigate the modeling process for children’s exposure to soil contaminants, which involves the intrinsic uncertainty of the exposure model, people’s judgments regarding random variables, and limited data resources. A hybrid Bayesian p-box was constructed, which was facilitated by a multiple integral dimensionality reduction (MIDR) theorem. The results indicated that exposure frequency (EF) dominated the exposure dose. The hybrid Bayesian p-box for the Frequentist-Bayesian (F–B) model at the 95th percentile of the simulated average daily dose (ADD) values corresponded to a 4.40 order-of-magnitude difference between the upper and lower bounds of the p-box. This considerable uncertainty was magnified by the combination of the highest posterior density (HPD) regions for three groups of the distribution parameters. For the Interior-Bayesian (I–B) hybrid model, the uncertainty of the outcomes, namely, [1.75 × 10⁻⁸, 2.18 × 10⁻⁸] mg kg⁻¹d⁻¹, was limited by the HPD regions for only one parameter unless the hyperparameters for the variables’ distributions were further evaluated. It was concluded that the hybrid models could provide a novel understanding of the complexity of the exposure modeling process compared to the traditional modeling method.
Show more [+] Less [-]Association of bisphenol A and its alternatives bisphenol S and F exposure with hypertension and blood pressure: A cross-sectional study in China
2020
Jiang, Shunli | Liu, Huimin | Zhou, Shuang | Zhang, Xu | Peng, Cheng | Zhou, Hao | Tong, Yeqing | Lü, Qing
Epidemiological studies have investigated the associations of bisphenol A (BPA) exposure with hypertension risk or blood pressure levels, but findings are inconsistent. Furthermore, the association between its alternatives bisphenol S and F (BPS and BPF) and hypertension risk are not yet known. We conducted a cross-sectional study in 1437 eligible participants without hypertension-related diseases, with complete data about blood pressure levels, hypertension diagnosis, and urinary bisphenols concentrations. Multivariable logistic and linear models were respectively applied to examine the associations of urinary bisphenols concentrations with hypertension risk and blood pressure levels. The dose-response relationship was explored by the restricted cubic spline model. Compared with the reference group of BPA, individuals in the middle and high exposure group had an adjusted odds ratio (OR) of 1.30 and 1.40 for hypertension, had a 3.08 and 2.82 mm Hg higher systolic blood pressure (SBP) levels, respectively, with an inverted “U” shaped dose-response relationship. Compared with the reference group of BPS, individuals in the second and third tertile had an adjusted OR of 1.49 and 1.48 for hypertension, had a 2.61 and 3.89 mm Hg increased levels of SBP, respectively, with a monotonic curve. No significant associations of BPF exposure with hypertension risk or blood pressure levels were found. BPA and BPS exposure were suggested to be associated with increased hypertension risk and blood pressure levels, with different dose-response relationships. Our findings have important implications for public health but require confirmation in prospective studies.
Show more [+] Less [-]Legacy and emerging organophosphorus flame retardants and plasticizers in frogs: Sex difference and parental transfer
2020
Liu, Yin-E | Luo, Xiao-Jun | Guan, Ke-Lan | Huang, Chen-Chen | Zhu, Chun-You | Qi, Xue-Meng | Zeng, Yan-Hong | Mai, Bi-Xian
Black-spotted frogs and bullfrogs from an e-waste polluted area were collected and examined for legacy and emerging organophosphorus flame retardants (PFRs) and plasticizers. Total concentrations of PFRs and plasticizers were 0.62–15 ng/g wet weight (ww) and 316–4904 ng/g ww in muscles, 2.2–59 ng/g ww and 127–5757 ng/g ww in eggs and gonads, and 1.2–15 ng/g ww and 51–1510 ng/g ww in oviducts, respectively. For muscle tissues, concentrations of ∑PFRs, triethyl phosphate, tris-(2-chloroethyl) phosphate, and tris-(chloro-2-propyl) phosphate were significantly higher in the males than females (p < 0.05). However, for reproductive tissues, eggs exhibited higher levels of those contaminants than gonads (p < 0.05). No significant sex difference in levels of plasticizers was observed in muscles. In contrast, levels for (2-ethylhexyl) phthalate, di-n-butyl phthalate, and di-iso-butyl phthalate in gonads were significantly higher than those in eggs (p < 0.05). Significantly negative linear correlations between maternal transfer ratios and log KOW were found in female frogs. Paternal transfer potentials were first significantly and positively correlated to log KOW (<6) and then decreased afterward in the males. These results indicated that parental transfer was answer for the sex-specific accumulation of PFRs and plasticizers in frogs.
Show more [+] Less [-]Particulate air pollution in Ho Chi Minh city and risk of hospital admission for acute lower respiratory infection (ALRI) among young children
2020
Luong, Ly Thi Mai | Dang, Tran Ngoc | Thanh Huong, Nguyen Thi | Phùng, Dũng | Tran, Long K. | Van Dung, Do | Thai, Phong K.
High levels of air pollutants in Vietnam, especially particulate matters including PM₂.₅, can be important risk factors for respiratory diseases among children of the country. However, few studies on the effects of ambient air pollution on human health have been conducted in Vietnam so far. The aim of this study is to examine the association between PM₂.₅ and hospital admission due to acute lower respiratory infection (ALRI) among children aged < 5 years old in Ho Chi Minh city, the largest city of Vietnam. Data relating PM₂.₅ and hospital admission were collected from February 2016–December 2017 and a time series regression analysis was performed to examine the relationship between PM₂.₅ and hospital admission including the delayed effect up to three days prior to the admission. We found that each 10 μg/m³ increase in PM₂.₅ was associated with an increase of 3.51 (95%CI: 0.96–6.12) risk of ALRI admission among children. According to the analysis, male children are more sensitive to exposure to PM₂.₅ than females, while children exposed to PM₂.₅ are more likely to be infected with acute bronchiolitis than with pneumonia. The study demonstrated that young children in HCMC are at increased risk of ALRI admissions due to the high level of PM₂.₅ concentration in the city's ambient air.
Show more [+] Less [-]Low endogenous NO levels in roots and antioxidant systems are determinants for the resistance of Arabidopsis seedlings grown in Cd
2020
Terrón-Camero, Laura C. | del Val, Coral | Sandalio, Luisa M. | Romero-Puertas, María C.
Cadmium (Cd), which is a toxic non-essential heavy metal capable of entering plants and thus the food chain, constitutes a major environmental and health concern worldwide. An understanding of the tools used by plants to overcome Cd stress could lead to the production of food crops with lower Cd uptake capacity and of plants with greater Cd uptake potential for phytoremediation purposes in order to restore soil efficiency in self-sustaining ecosystems. The signalling molecule nitric oxide (NO), whose function remains unclear, has recently been involved in responses to Cd stress. Using different mutants, such as nia1nia2, nox1, argh1-1 and Atnoa1, which were altered in NO metabolism, we analysed various parameters related to reactive oxygen and nitrogen species (ROS/RNS) metabolism and seedling fitness following germination and growth under Cd treatment conditions for seven days. Seedling roots were the most affected, with an increase in ROS and RNS observed in wild type (WT) seedling roots, leading to increased oxidative damage and fitness loss. Mutants that showed lower NO levels in seedling roots under Cd stress were more resistant than WT seedlings due to the maintenance of antioxidant systems which protect against oxidative damage.
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