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Where are we? Towards an understanding of the selective accumulation of microplastics in mussels 全文
2021
Li, Jiana | Wang, Zhenglu | Rotchell, Jeanette M. | Shen, Xiaoteng | Li, Qipei | Zhu, Jingmin
Mussels are suggested as bioindicators of marine microplastic pollution. However, they are selective in regards to accumulation of microplastics. To make studies more targeted and comparable, ultimately helping to determine the suitability of the mussel as a bioindicator species for microplastic exposure, we review the published literature that has directly or indirectly demonstrated particle selection in mussels. The reported difference between microplastic levels in mussel tissues and environmental matrices provides evidence for their selective uptake characteristics. Both the organ-specific fate characteristics of microplastics, and the different movement patterns of microplastics in the same organ, show that selective translocation processes take place. The selective elimination is reflected in multiple aspects which include (1) the different characteristics of microplastics in excretion and mussel body; (2) the different retention time of various microplastics in mussels; and (3) the tissue-specific change in the numbers of microplastics during the depuration process. This selectivity is affected by the characteristics of the microplastics, the environmental, or laboratory exposure concentrations, feeding status, and other factors. There are still many research gaps and contradictory viewpoints in this field due to this complexity. The current methodology needs improvement and a breakthrough in standardization.
显示更多 [+] 显示较少 [-]Evaluating the effectiveness of green marketing of socio-economic organizations in reducing environmental pollution 全文
2021
Hojjat Nazari | Sadegh Zibakalam | Mohammad Reza Parvin
The purpose of this study is to measure and evaluate the effectiveness of environmental advertising related to green marketing by organization. In other words, the researcher seeks to find the success rate of environmental advertising in reducing environmental pollution. The type of goal is an application that has been done by descriptive-survey method. A researcher-made questionnaire was used to collect data. The statistical populations of the study were consumers of environmental friendly goods in Tehran. Confirmatory factor analysis method and SPSS, Version21 and AMOS (2016) software were used for data analysis. The results showed that the models for measuring the research variables are appropriate models. Because the value of Ï2 and the value of RMSEA are low and also the values of AGFI, GFI and NFI are greater than 0.9 and the significance level of factor loads is less than 5%, which indicates the significance of the relationship defined in the measurement models. Also, the effect of communication stimuli on the cognitive and emotional response of consumers and then the effect of content stimuli on the cognitive and emotional response of users in this study has the highest influence. However, neither content nor communication stimuli have influenced consumer attitudes.
显示更多 [+] 显示较少 [-]Investigation of physicochemical properties of water in downstream areas of selected dams in Aras catchment and water quality assessment (Case study: Aras catchment in the border area of Iran and Armenia) 全文
2021
Ebrahim Safizadeh | Dariush Karimi | Hamid Reza Gahfarzadeh | Seyed Abbas Pourhashemi
The aim of this study was to evaluate the physicochemical properties of downstream water of Aras river dams. Sampling was performed from early 2018-2019 in selected stations. Heavy metals were measured by atomic absorption spectrometry. Nitrate, nitrite and total dissolved solids concentrations were also measured by spectrophotometer. Concentrations of Ca, Na and K were measured with a Flame Photometer and the rest were measured with specialized devices. The results showed that the lowest electrical conductivity in the measured samples was 0.789 and the highest was 4.346 µs/cm, which basically indicates the high limit of soil and water for irrigation of plants. On the other hand, total solids with 1211 ppm indicate a moderate limit for salinity. Also; regarding pH, the average recorded for the study area is 8.17, which is within the national permissible and standard range of the world health organization. Nitrate and nitrite are both above the permissible and standard range. Potassium is within the permitted and standard range. Calcium, according to the average obtained in the study area (64 ppm) can be said that this parameter is within the allowable and standard range. In the case of lead (0.09 ppb), it can be said that this parameter is within the allowable and standard range. In the case of cadmium (0.8 ppb), it can be said that this parameter is within the allowable and standard range, 3 parameters nitrate, nitrite and TDS have an average higher than the national standard.
显示更多 [+] 显示较少 [-]Removal of Malathion on Carbon using Iron Oxide Nanoparticles (Fe3O4) in Aquatic Environments 全文
2021
Malektaj Eskandari Makvand | Sima Sabzalipour | Mahboobeh Cheraghi | Neda Orak
The development of nanotechnology and the possible entry of nanoparticles into aquatic environments have raised environmental concerns. The present study aimed to investigate the effect of iron oxide nanoparticles (Fe3O4) loaded on carbon to remove malathion in order to evaluate the toxicity potential of nanoparticles in aqueous environments. We examined the characteristics of iron oxide nanoparticles (Fe3O4) using XRD refraction, Fourier irradiated spectroscopy (FTIR), the catalytic activity of iron nanoparticles for activation of persulfate, and malathion decomposition. Moreover, we assessed the influence of effective parameters on this process, such as pH, persulfate concentration, and the number of iron oxide nanoparticles (Fe3O4). The results showed that 82% of malathion was decomposed by the combined process of iron oxide nanoparticles loaded on carbon at pH=5 and 0.4 g of iron nanoparticles in 60 minutes. Additionally, according to the results obtained from the advanced oxidation processes, it was able to optimally remove malathion from the aquatic environment. This study revealed that nanoparticle stabilization technology on activated carbon could be used as an effective, efficient, and fast adsorbent to remove certain contaminants, such as malathion, from aqueous solutions. Although the combination of processes may complicate their analysis and mechanism, the study of this process could be a promising emergence of hybrid processes in water and wastewater treatment. In general, the results of this study relatively indicated that the physicochemical properties of nanoparticles, such as size, shape, surface, general morphology, and chemical composition, in different environmental conditions can significantly affect carbon in removing the malathion
显示更多 [+] 显示较少 [-]Application of Steam Enhanced Extraction method on BTEX contaminated soil in a Nigerian petroleum depot and Automobile workshop sites in Ilorin metropolis, Nigeria. 全文
2021
Ismail Muhibbu-din | Isaac Ayodele
. Benzene, toluene, ethyl benzene and xylene (BTEX) are major causes of contaminated soil. This is due to fuel leakages or spillages, various forms hydrocarbon burning/combustion and land disposal petroleum base oil. Contaminated soil samples were excavated from two different locations within Ilorin metropolis; pipelines and products marketing company, a Nigerian petroleum depot, Ilorin depot and auto mechanic workshop of over ten years. Steam enhanced extraction method was employed through injection of steam to contaminated soil from steam generator into soil pot where contaminated soil was placed. After the remediation process the steam soil samples were taken to the laboratory where the sonication extraction technique was used to extract the contaminants (BTEX) from the steamed soil samples of 30, 60 and 90 minutes respectively. The extract from the steamed soil samples of 30, 60 and 90 minutes were subjected Gas Chromatography fitted with flame ionization detector analysis to determine the exact amount of BTEX removed after remediation process. Pre-treated soil sample of auto mechanics workshop was found to be 4.5004 x 10-1 mg/kg and post-treated soil samples were found to be 1.8164 x10-1 mg/kg, 8.7519 x10-1 mg/kg and 5.7006 x10-2 mg/kg for 30, 60 and 90 minutes respectively after remediation process while Pre-treated soil sample of a Nigerian petroleum depot was found to be 6.6049 x 10-1 mg/kg and post-treated soil samples were found to be 2.9320 x10-1 mg/kg, 1.9855 x10-1 mg/kg and 1.0237 x10-1 mg/kg for 30, 60 and 90 minutes respectively after remediation process
显示更多 [+] 显示较少 [-]Modelling fuzzy multi-criteria decision-making method to locate industrial estates based on geographic information system 全文
2021
Mohammad Reza Jangjoo
Existing conditions for locating urban equipment and facilities require a set of limiting and reinforcing factors. Interaction of environmental, industrial, social and political changes in our rapid growth adds to the complexity of regional systems. Locating takes place by various methods, in which the priority is the application of modern methods leading to reduced uncertainty. The present study aimed to select the best location using nine criteria (slope, distance from fault, distance from river, distance from road, and distance from villages, soil type, land use, average temperature, and average rainfall) in GIS software for mapping. Fuzzy logic and fuzzy-analytical hierarchy process (FAHP) model were applied to reduce location uncertainty. The accuracy of the results was checked using field data, in which six stations designated for the establishment of industrial estates in the study area were compared with the results of the FAHP model. The results of FAHP model in GIS software and their validation showed that the proposed model has excellent capabilities in locating industrial estates.
显示更多 [+] 显示较少 [-]Detection of selected tire wear compounds in urban receiving waters 全文
2021
Johannessen, Cassandra | Helm, Paul | Metcalfe, Christopher D.
Road runoff is an important vector for the transport of chemicals originating from tire wear into receiving waters. In this study, samples of surface water were collected in the summer of 2020 from two rivers near high-traffic corridors in the Greater Toronto Area (GTA) in Canada. These samples were analyzed for two additives used in tire production, 1,3-diphenyl guanidine (DPG) and hexamethoxymethylmelamine (HMMM), as well 26 of the transformation compounds of HMMM. In addition, samples were analyzed for 6PPD-quinone (6PPD-q), an oxidation by-product of a tire additive that was recently identified as a candidate compound responsible for mass mortalities of Coho salmon (Oncorhynchus kisutch) in spawning streams in the USA. Grab and composite samples were collected during rain events (i.e., wet events) at both locations. Grab samples were collected from the Don River upstream, downstream and at the point of discharge from a municipal wastewater treatment plant (WWTP) during a period of dry weather. Of the target analytes, 6PPD-q, DPG and HMMM, as well as 15 of the transformation compounds of HMMM, were detected at concentrations above limits of quantitation. The concentrations of 6PPD-q in the receiving waters during wet events were within the range of the LC50 for adult Coho salmon. One of the transformation products (TPs) of HMMM, dimethoxymethylmelamine was detected in a composite sample from Highland Creek at an estimated concentration greater than 10 μg/L, indicating that more research is needed to evaluate the potential hazards to the aquatic environment from this compound. Sampling in the Don River during a dry period showed that discharges of wastewater from WWTPs are also continuous sources of the TPs of HMMM. This study contributes to the growing literature showing that chemicals derived from tire wear are ubiquitous in urban watersheds and may be a significant hazard to aquatic organisms.
显示更多 [+] 显示较少 [-]Improving pollutants environmental risk assessment using a multi model toxicity determination with in vitro, bacterial, animal and plant model systems: The case of the herbicide alachlor 全文
2021
Pereira, Susana P. | Santos, Sandra M.A. | Fernandes, Maria A.S. | Deus, Cláudia M. | Martins, João D. | Pedroso de Lima, Maria C. | Vicente, Joaquim A.F. | Videira, Romeu A. | Jurado, Amália S.
Several environmental pollutants, including pesticides, herbicides and persistent organic pollutants play an important role in the development of chronic diseases. However, most studies have examined environmental pollutants toxicity in target organisms or using a specific toxicological test, losing the real effect throughout the ecosystem. In this sense an integrative environmental risk of pollutants assessment, using different model organisms is necessary to predict the real impact in the ecosystem and implications for target and non-target organisms.The objective of this study was to use alachlor, a chloroacetanilide herbicide responsible for chronic toxicity, to understand its impact in target and non-target organisms and at different levels of biological organization by using several model organisms, including membranes of dipalmitoylphosphatidylcholine (DPPC), rat liver mitochondria, bacterial (Bacillus stearothermophilus), plant (Lemna gibba) and mammalian cell lines (HeLa and neuro2a).Our results demonstrated that alachlor strongly interacted with membranes of DPPC and interfered with mitochondrial bioenergetics by reducing the respiratory control ratio and the transmembrane potential. Moreover, alachlor also decreased the growth of B. stearothermophilus and its respiratory activity, as well as decreased the viability of both mammalian cell lines. The values of TC₅₀ increased in the following order: Lemna gibba < neuro2a < HeLa cells < Bacillus stearothermophilus. Together, the results suggest that biological membranes constitute a putative target for the toxic action of this lipophilic herbicide and point out the risks of its dissemination on environment, compromising ecosystem equilibrium and human health.
显示更多 [+] 显示较少 [-]Effects of algae proliferation and density current on the vertical distribution of odor compounds in drinking water reservoirs in summer 全文
2021
Wu, Tianhao | Zhu, Guangwei | Zhu, Mengyuan | Xu, Hai | Yang, Jun | Zhao, Xianfu
Reservoirs are an important type of drinking water source for megacities, while lots of reservoirs are threatened by odor problems during certain seasons. The influencing factors of odor compounds in reservoirs are still unclear. During August 2019, a nationwide survey investigating the distribution of odor compounds in reservoirs used as drinking water sources was conducted on seven reservoirs. 2-methylisoborneol (2-MIB) and geosmin were detected in almost every reservoir, and some odor compound concentrations even exceeded the odor threshold concentration. The average concentration of 2-MIB was 2.68 ng/L, and geosmin was 3.63 ng/L. The average chlorophyll a concentration was 8.25 μg/L. The dominant genera of phytoplankton in these reservoirs belonged to cyanobacteria and diatom. Statistical analysis showed that odor compound concentration was significantly related to the chlorophyll a concentration and indicated that the odor compounds mainly came from phytoplankton. The concentration of odor compounds in the euphotic zone was significantly related to phytoplankton species and biomass. Therefore, the odor compound concentrations in the subsurface chlorophyll maxima layer was generally higher than in the surface layer. However, the odor compounds in the hypolimnion layer were related to the density current. This research suggests that both phytoplankton proliferation events and heavy storm events are important risk factors increasing odor compounds in reservoirs. Control of algal bloom, in-situ profile monitoring system and depth-adjustable pumping system will greatly reduce the risk of odor problems in reservoirs using as water supplies for large cities.
显示更多 [+] 显示较少 [-]Contributions of internal emissions to peaks and incremental indoor PM2.5 in rural coal use households 全文
2021
Men, Yatai | Li, Jianpeng | Liu, Xinlei | Li, Yaojie | Jiang, Ke | Luo, Zhihan | Xiong, Rui | Cheng, Hefa | Tao, Shu | Shen, Guofeng
Indoor air quality is critically important to the human as people spend most time indoors. Indoor PM₂.₅ is related to the outdoor levels, but more directly influenced by internal sources. Severe household air pollution from solid fuel use has been recognized as one major risk for human health especailly in rural area, however, the issue is significantly overlooked in most national air quality controls and intervention policies. Here, by using low-cost sensors, indoor PM₂.₅ in rural homes burning coals was monitored for ~4 months and analyzed for its temporal dynamics, distributions, relationship with outdoor PM₂.₅, and quantitative contributions of internal sources. A bimodal distribution of indoor PM₂.₅ was identified and the bimodal characteristic was more significant at the finer time resolution. The bimodal distribution maxima were corresponding to the emissions from strong internal sources and the influence of outdoor PM₂.₅, respectively. Indoor PM₂.₅ was found to be correlated with the outdoor PM₂.₅, even though indoor coal combustion for heating was thought to be predominant source of indoor PM₂.₅. The indoor-outdoor relationship differed significantly between the heating and non-heating seasons. Impacts of typical indoor sources like cooking, heating associated with coal use, and smoking were quantitatively analyzed based on the highly time-resolved PM₂.₅. Estimated contribution of outdoor PM₂.₅ to the indoor PM₂.₅ was ~48% during the non-heating period, but decreased to about 32% during the heating period. The contribution of indoor heating burning coals comprised up to 47% of the indoor PM₂.₅ during the heating period, while the other indoor sources contributed to ~20%. The study, based on a relatively long-term timely resolved PM₂.₅ data from a large number of rural households, provided informative results on temporal dynamics of indoor PM₂.₅ and quantitative contributions of internal sources, promoting scientific understanding on sources and impacts of household air pollution.
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