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Результаты 2931-2940 из 6,558
Formation of Disinfection Byproducts from Algal Organic Matter Exposed to Monochloramine: Effects of Monochloramine Dosages, pH, and Bromide Concentrations Полный текст
2020
Gu, Xin | Zhai, Hongyan | Zhou, Yanan
The formation of volatile DBPs and haloacetic acids (HAAs) from algal organic matter (AOM) in different chloramination conditions (i.e., different monochloramine (NH₂Cl) dosages, pH values, and bromide concentrations) was studied. In chloramination of AOM, HAAs were the major DBP species, followed by trihalomethanes (THMs), haloacetonitriles (HANs), and haloketones (HKs). The levels of THMs, HAAs, HKs, and HANs generated in chloramination were 75%, 69%, 68%, and 122% of those in chlorination, respectively. The concentrations of THMs and HAAs both doubled as the NH₂Cl dosage doubled. The proportions of bromodichloromethane and dibromochloromethane in THMs and the proportions of dichloroacetic acid and trichloroacetic acid in HAAs increased with the NH₂Cl dosage. Accelerating the pH value enhanced the formation of THMs, HAAs, and HANs, respectively, and favored the formation of brominated THMs. The HAN species distribution was unaffected by the NH₂Cl dosage and pH. Increasing bromide levels slightly increased the yield of THMs and slightly decreased the yields of HAAs and HKs. The species shift from the chlorinated to the brominated was more significant for THMs and HANs than for HAAs. The THM-BSF and dichloroacetonitrile-BSF values were lower in chloramination than in chlorination. The high pH value and bromide level significantly accelerated the THM-BSFs. The maximum values of THM-BSFs and dichloroacetonitrile-BSF were 0.6 and 0.5.
Показать больше [+] Меньше [-]Assessment of the effect of sodium hydrogen sulfide (hydrogen sulfide donor) on cisplatin-induced testicular toxicity in rats Полный текст
2020
Azarbarz, Nastaran | Shafiei Seifabadi, Zeinab | Moaiedi, Maasoumeh Zare | Mansouri, Esrafil
Cisplatin (CIS) is an antineoplastic drug able to produce free radicals that are capable to induce various side effects in different tissues. Hydrogen sulfide (H₂S) has notable antioxidant, anti-apoptotic, and anti-inflammatory effects in different systems but its role in male reproductive system is not fully understood. In the present research, the effect of sodium hydrosulfide (NaHS) on cisplatin-induced testicular toxicity in male rats was studied. Thirty-two Sprague–Dawley rats were equally divided into 4 groups. The control group was treated with normal saline by intraperitoneal injection. The NaHS group received NaHS (200 μg/kg/day) intraperitoneally for 15 days. The CIS group received single dose of cisplatin (5 mg/kg) intraperitoneally, while the combination of CIS and NaHS was given to the CIS+ NaHS group. At the end of the study, body and testicular weights, plasma testosterone level, histological and morphometrical alterations, inflammation via IL-1β protein, lipid peroxidation, and activity of antioxidant enzymes (including glutathione peroxidase, superoxide dismutase, and catalase) of testicular tissue were evaluated. CIS injection revealed a significant decrease (p < 0.01) in body and testis weights, plasma testosterone concentration, diameter of seminiferous tubules, germinal epithelium thickness, the number of Sertoli cells, spermatogonia and spermatocyte, Johnsen’s testicular score, and testicular antioxidant enzymes, whereas it caused a significant increase (p < 0.01) in lumen diameter of the seminiferous tubules, level of lipid peroxidation, and IL-1β protein expression when compared with the control group. NaHS administration to CIS-treated rats provided marked improvement (p < 0.05) in all biochemical, histological, and morphometrical changes induced by CIS. The beneficial effects of NaHS were mediated, at least partly, by its antioxidant and anti-inflammatory properties.
Показать больше [+] Меньше [-]Inhibition effects of some pesticides and heavy metals on carbonic anhydrase enzyme activity purified from horse mackerel (Trachurus trachurus) gill tissues Полный текст
2020
Caglayan, Cuneyt | Taslimi, Parham | Türk, Cebrahil | Gulcin, İlhami | Kandemir, Fatih Mehmet | Demir, Yeliz | Beydemir, Şükrü
The gill tissue is the main site of metabolic enzymes or compensation, with the kidney tissue playing a supporting role. At the gill tissue, carbonic anhydrase enzymes (CAs) catalyze the hydration of CO₂ to HCO₃⁻ and H⁺ for production to the H₂O. In this work, the CA enzyme was purified from horse mackerel (Trachurus trachurus) gill with a specific activity of 21,381.42 EU/mg, purification fold of 150.61, total activity of 2347.68 EU/mL, and a yield of 16.13% using sepharose 4B-L-tyrosine-sulfanilamide affinity gel chromatography. For recording the enzyme purity, gel electrophoresis was performed, and single band was seen. The molecular weight of this enzyme was found approximately 35 kDa. Also, the inhibitory effects of different pesticides such as thiram, clofentezine, propineb, deltamethrin, azoxystrobin, and thiophanate and heavy metal ions such as Fe²⁺, Cu²⁺, Co²⁺, Pb²⁺ Hg²⁺, and As³⁺ on horse mackerel gill tissue CA enzyme activities were investigated. Our results indicated that these pesticides and metal ions showed inhibitory effects at low nanomolar and millimolar concentrations for fish gill CA enzymes, respectively.
Показать больше [+] Меньше [-]Dietary intake assessment of pyrethroid residues from okra and eggplant grown in peri-urban areas of Punjab, Pakistan Полный текст
2020
Amjad, Adnan | Randhawa, Muhammad Atif | Javed, Muhammad Sameem | Muhammad, Zafarullah | Ashraf, Mussawar | Ahmad, Zulfiqar | Murtaza, Shamas
This study was designed to assess the gradual increase in the use of insecticides on vegetables and to familiarize the consumers regarding the insecticide residues. The purpose of this research work was to highlight the detrimental effects of pyrethroids (bifenthrin, cyfluthrin, cypermethrin, deltamethrin, fenvalerate, lambda-cyhalothrin, and permethrin) compare with dietary intake assessment of eggplant and okra grown in peri-urban environment. In this manner, a total of 180 (n = 60 × 3) samples of eggplant (Solanum melongena) and okra (Abelmoschus esculentus) were procured from the peri-urban farming system of Faisalabad, Multan, and Gujranwala to assess the pyrethroid residues along with their dietary intake assessment. The procured vegetables were quantified for pyrethroid residues by using gas chromatography (GC) equipped with an electron capture detector (ECD). Outcomes of this study revealed that for okra samples, the highest residues of bifenthrin (1.25 mg kg⁻¹) were found in Gujranwala then Multan (1.5 mg kg⁻¹) and Faisalabad (1.04 mg kg⁻¹), whereas in eggplant, the highest residues were recorded for bifenthrin from Faisalabad (1.33 mg kg⁻¹) and Gujranwala (0.78 mg kg⁻¹). In Multan, the highest residues for cyfluthrin (1.18 mg kg⁻¹) were reported in eggplant. Out of all analyzed samples for pyrethroid residues, 32% samples contained detectable residues and 6% samples exceeded their maximum residual limits (MRLs) established by the European Union (EU). Dietary intake assessment (mg kg⁻¹ day⁻¹) was calculated as per their maximum permissible intake (MPI) values, i.e., bifenthrin (1.28), cyfluthrin (1.28), cypermethrin (3.20), deltamethrin (0.64), fenvalerate (1.28), lambda-cyhalothrin (0.064), and permethrin (3.20) respectively. Conclusively, residues from the Multan region were greater than those from Gujranwala and Faisalabad showing excessive application of pyrethroids. Overall results revealed that although some samples exceeded MRLs in selected areas, their safe consumption limit was found.
Показать больше [+] Меньше [-]Beta radioactivity of urban surface–deposited sediment in three Russian cities Полный текст
2020
Hanfi, Mohamed Y. | Yarmoshenko, Ilia V. | Seleznev, Andrian A. | Malinovsky, Georgy | Ilgasheva, Ekaterina | Zhukovsky, Michael V.
Study of gross beta activity was conducted in Russian cities Ekaterinburg, Rostov-on-Don, and Nizhny Novgorod. The cities were characterized by continental climate, although they are located in different geographical zones. The bulk urban samples were fractionated with three size fractions: dust (0.002–0.1 mm), fine sand (0.1–1 mm), and coarse sand (> 1 mm). Measurement setup equipped with beta radiometer BDPB-01 was designed to measure the low levels of gross beta-activity in a small amount of the obtained size-fractionated samples. According to the results of the study, the gross beta activity depends on the size fraction and the city. The highest beta activity concentration was found in the dust fraction which is about the same in all cities 0.8–0.9 Bq g⁻¹. In size fractions of fine sand and coarse sand, the beta activity depends on the city. Among other cities, the highest average beta concentration was found in Ekaterinburg (0.8 and 0.6 Bq g⁻¹ in fine and coarse sand fractions, respectively), while the lowest is 0.28 and 0.44 Bq g⁻¹, respectively. The relationship of beta activity concentration with mineral and chemical composition is studied. Average beta activity in the different fractions of the surface–deposited sediment correlates with uranium, thorium, and organic matter concentration. The gross beta activity may be considered an indicator of high contribution of dust and high pollution with Pb, Cu, and Zn in the urban environment.
Показать больше [+] Меньше [-]The Different Biomarkers in the Assessment of the Marine Environmental Quality Using the Representative Species Mytilus trossulus Полный текст
2020
Istomina, Aleksandra | Mazur, Andrey | Chelomin, Viktor | Kukla, Sergey | Slobodskova, Valentina | Zvyagintsev, Aleksandr | Kolosova, Lyudmila | Zhukovskaya, Avianna | Fedorets, Yuliya
The mussel Mytilus trossulus was used to assess the relationship between the reactions of biomarkers and the degree of environmental pollution, as well as their potential use in biomonitoring. Metal bioaccumulation and a battery of biomarkers were measured in the mussels from the Zolotoy Rog Bay and Vostok Bay (Peter the Great Bay, the Sea of Japan) that display substantial differences in the levels of pollution. The biomarkers included lysosomal membrane stability (LMS); condition indices (CI and CIL); the activities of catalase (CAT), glutathione-S-transferase (GST) and acetylcholinesterase (AChE); and the levels of lipid peroxidation (thiobarbituric acid reactive substances, TBARS), protein oxidation (protein carbonyls, PC), and DNA damage. At the molecular level for M. trossulus, the biomarkers of oxidative stress (CAT, TBARS, and PC) and AChE do not show a known degree of environmental pollution. At the same time, the biomarkers LMS and condition indices, as well as the biomarkers GST and DNA damage, are sensitive to complex chronic environmental pollution.
Показать больше [+] Меньше [-]China’s regional environmental efficiency evaluation: a dynamic analysis with biennial Malmquist productivity index based on common weights Полный текст
2020
Zhu, Weiwei | Zhu, Yaqin | Yu, Yu
China’s economy in the past 10 years has developed rapidly and achieved great success, but at the same time, environmental problems have been deteriorating, seriously hindering the country’s regional sustainable development. This paper proposes a common-weights DEA model based on “the priority of choosing common weights” to assess the environmental performance of 30 provinces from 2006 to 2015 and analyzes regional development in combination with China’s economic division. This paper also introduces the biennial Malmquist Productivity Index (BMPI) to study environmental productivity levels during the 11th and 12th Five Year Plans (FYP) from a time series perspective. The results present a large gap in regional environmental efficiency, mainly manifested by the fact that the eastern and northeastern regions’ environmental condition is obviously better than that of the central and western regions. BMPI analysis indicates that the overall environmental performances during the 11th and 12th FYPs did not improve significantly, with a clear imbalance in the western region, implying that its development potential is huge. On this basis, we offer some suggestions for improving the environmental performance of different regions.
Показать больше [+] Меньше [-]Implementing the monitoring breakdown structure: native lichens as biomonitors of element deposition in the southern Patagonian forest connected with the Puyehue volcano event in 2011—a 6-year survey (2006–2012) Полный текст
2020
Conti, M. E. | Plà, Rita | Simone, Cristina | Jasan, Raquel | Finoia, Maria Grazia
This study aims to investigate the airborne elements’ deposition by using native Usnea barbata lichens as biomonitors in the forested areas of Tierra del Fuego (TdF, southern Patagonia), an apparently pristine environment. The present study is linked to the volcanic eruption of the Puyehue-Cordón Caulle which started in north Patagonia in June 2011, which gives rise to long-distance transport of pollutants through the atmosphere at 1700 km from our sampling sites. The monitoring breakdown structure (MBS) was applied to three sampling campaigns in 2006 (baseline) ➔ 2011–2012 (3 and 15 months after the volcanic event, respectively). We have on purpose enhanced the information variety endowment: (i) Seventy-one referenced sites were double sampled; (ii) up to 426 composite lichen samples were collected; (iii) twenty-six elements were measured by neutron activation analysis (As, Ba, Br, Ca, Ce, Co, Cr, Cs, Eu, Fe, Hf, K, La, Lu, Na, Rb, Sb, Sc, Se, Sm, Ta, Tb, Th, U, Yb, Zn) for samples of 2011 and 2012 campaigns; (iv) thirteen common elements (As, Ba, Ca, Co, Cr, Cs, Fe, K, Na, Sb, Se, U, Zn) were determined in 2006 for the baseline comparison. The natural contamination by tephras is reflected by lichens more clearly in the 2011 campaign, where Ba, Cr, Na, Ca, Cs, and U showed higher median levels compared with the baseline campaign (2006). Ca, K, and Na were the most accumulated elements after the volcano event and could be associated with the volcanic ashes’ deposition. Rare earth elements (REEs) showed no significant bioaccumulation levels between 2011 and 2012, indicating their association with higher lithogenic inputs than volcanic ashes. Using the Earth’s crust as reference, nine elements (As, Ba, Br, Ca, K, Na, Sb, Se, and Zn) presented moderate/significant mean enrichment factor (EF) values (> 5). The usefulness of Usnea barbata as test species for direct biomonitoring oriented kinetic studies in areas characterized by a low human impact is confirmed. Eventually, our results confirm that TdF is not an actual pristine environment as earlier supposed.
Показать больше [+] Меньше [-]Use of Magnetic Activated Carbon in a Solid Phase Extraction Procedure for Analysis of 2,4-dichlorophenol in Water Samples Полный текст
2020
Rodrigues, Samantha Christina | Silva, Maria Cristina | Torres, Juliana Arriel | Bianchi, Maria Lucia
In the present study, a composite was synthesized by the impregnation of activated carbon with magnetite (Fe₃O₄) using a simple co-precipitation method. Several characterizations were performed, such as X-ray diffraction (XRD), scanning electron microscopy (SEM), point of zero charge (PZC), specific surface area, and Fourier transform infrared spectroscopy (FTIR). The magnetic activated carbon composite (MAC) was used as a new adsorbent for magnetic solid phase extraction (MSPE) of 2,4-dichlorophenol (2,4-DCP) in water samples. The main experimental parameters, such as adsorbent mass, pH, adsorbent/adsorbent contact time, volume and type of desorbent, sample volume, and desorption time were optimized. The method showed linearity in the investigated concentration range of 1 μg mL⁻¹–6 μg mL⁻¹ (R² = 0.999). The limit of detection (LOD) and the limit of quantification (LOQ) were 0.293 μg mL⁻¹ and 0.890 μg mL⁻¹, respectively. The recoveries for the water samples ranged from 50.0% to 55.0% and the relative standard deviation (RSD) was less than 4.8%. The CAM presented application to MSPE and the magnetic properties inserted in the activated carbon (AC) contributed for the fast and easy removal of the adsorbent from the reaction medium. Thus, the proposed method proved to be easy, efficient, and environmentally friendly due to low solvent consumption.
Показать больше [+] Меньше [-]Does environmental protection promote economic development? From the perspective of coupling coordination between environmental protection and economic development Полный текст
2020
Peng, Benhong | Sheng, Xin | Wei, Guo
Environmental protection and economic development seem to be controversial, and there have been opposite views for a long time. Hence, in this article, representative indicators of economy and environment are selected to analyze the external correlation and the internal relationship between environment and economy from the perspective of coupling coordination. The results show that environmental protection may slow down economic growth in the short term. However, their correlation becomes increasingly stronger with higher degree of coupling, and as the result in the long run, environmental protection can gradually improve the infrastructure of economic development, and environmental and economic development will become more closely coordinated in promoting green economic development. It is demonstrated that an effective way to promoting economic development is to promote scientific and technological innovation and cultivate high-end talents and improve regional cooperation, which can reduce the negative effect of environmental protection on economic development. It is also necessary to enhance the positive impact of environmental protection on economic development by transforming the mode of economic development, developing the environmental protection industry, and raising people’s awareness of environmental protection. Thus, the coupling coordination between environment and economy can sustain, with both continuously bolstered.
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