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Результаты 1811-1820 из 4,029
Metal concentrations in water, sediment and three fish species from the Danube River, Serbia: a cause for environmental concern
2016
Ivanović, Jelena | Janjić, Jelena | Baltić, Milan | Milanov, Raša | Bošković, Marija | Marković, Radmila V. | Glamočlija, Nataša
The aim of this study was to investigate the presence of metal contamination in water, sediments and three different fish species. All samples were taken from the Danube River in Belgrade Region, a location upstream from Grocka. Concentrations of Cd, Hg and Pb in water samples were not detected, while concentrations of Zn, Fe, Cu and As were in the range of 0.004–0.41 mg L⁻¹. Iron was the most deposited metal in sediment samples (17,530.00 mg kg⁻¹). For the purpose of heavy metal determination in fish tissue, silver carp, common carp and wels catfish were collected. Concentrations of Pb, Cd and As were determined in muscle, digestive tract and liver by inductively coupled plasma-optical emission spectrophotometry (IPC-OES). The highest concentration of Pb was in the digestive tract of all three fish species, while Cd was mostly deposited in the liver. The highest concentration of Hg was in the muscle tissue of wels catfish, and these values are above the maximum residual levels prescribed by the European Union and the maximum allowed concentrations (MACs) for Serbia. Concentration of As was mostly deposited in the liver, but under the MAC.
Показать больше [+] Меньше [-]Influence of suspended particles on the emission of organophosphate flame retardant from insulation boards
2016
Lazarov, Borislav | Swinnen, Rudi | Poelmans, David | Spruyt, Maarten | Goelen, Eddy | Covaci, Adrian | Stranger, Marianne
The influence of the presence of the so-called seed particles on the emission rate of Tris (1-chloroisopropyl) phosphate (TCIPP) from polyisocyanurate (PIR) insulation boards was investigated in this study. Two Field and Laboratory Emission Test cells (FLEC) were placed on the surface of the same PIR board and respectively supplied with clean air (reference FLEC) and air containing laboratory-generated soot particles (test FLEC). The behavior of the area-specific emission rates (SER A) over a time period of 10 days was studied by measuring the total (gas + particles) concentrations of TCIPP at the exhaust of each FLEC. The estimated SER A of TCIPP from the PIR board at the quasi-static equilibrium were found to be 0.82 μg m⁻² h⁻¹ in the absence of seed particles, while the addition of soot particles led to SER A of 2.16 μg m⁻² h⁻¹. This indicates an increase of the SER A of TCIPP from the PIR board with a factor of 3 in the presence of soot particles. The TCIPP partition coefficient to soot particles at the quasi-static equilibrium was 0.022 ± 0.012 m³ μg⁻¹. In the next step, the influence of real-life particles on TCIPP emission rates was investigated by supplying the test FLEC with air from a professional kitchen where mainly frying and baking activities took place. Similar to the reference FLEC outcomes, SER A was also found to increase in this real-life experiment over a time period of 20 days by a factor 3 in the presence of particles generated during cooking activities. The median value of estimated particle–gas coefficient for this test was 0.062 ± 0.037 m³ μg⁻¹.
Показать больше [+] Меньше [-]Beneficial role of ascorbic and folic acids antioxidants against thyroxin-induced testicular dysfunction in hyperthyroid rats
2016
Beltagy, Doha M. | Mohamed, Tarek M | El Said, Ahmed S. | Tousson, Ehab
Thyroid hormones play a fundamental role in the regulation of metabolism of almost all mammalian tissue including the reproductive system. Hyperthyroidism in early life may cause delayed sexual maturation, although physical development is normal and skeletal growth may be accelerated. Hyperthyroidism after puberty influences reproductive functions and increases testosterone level. The aim of this work is to study the effect of induced hyperthyroidism by L-thyroxine sodium administration on the testis of rats and to evaluate the ameliorating role of different antioxidants as ascorbic acid and folic acid on the hyperthyroid state via the assessment of different biochemical markers, histopathological and immunochemical sections. DNA analysis of the D1 deiodinase was performed to determine genetic mutation due to hyperthyroidism. The results showed partially disrupted in the measured biochemical parameters and spermatogenesis in hyperthyroid rats. Post-administration of both folic and ascorbic acids together in hyperthyroid rats showed the best ameliorating effects on the thyroid hormones, testosterone, testicular GGT and ALP, and all oxidative stress markers. There is no genetic mutations that occurred in D1 deiodinase due to hyperthyroidism. These findings were indicated by the proliferating cell nuclear antigen (PCNA) studies of testes.
Показать больше [+] Меньше [-]Individual and Combined Effects of Freeze-Thaw and Ferrate(VI) Oxidation for the Treatment and Dewatering of Wastewater Sludges
2016
Diak, James | Örmeci, Banu
The study examined the individual and combined effects of potassium ferrate(VI) additions and freeze-thaw conditioning for the treatment and dewatering of sludge samples. The first part of the experiments, using primary sludge, compared potassium ferrate(VI) additions prior to freeze-thaw treatment (pretreatment) versus potassium ferrate(VI) additions following freeze-thaw treatment (posttreatment). A low dose (LD) of 1.0 g/L and a high dose (HD) of 10.0 g/L of potassium ferrate(VI) were evaluated along with a freezing temperature of −20 °C and freezing periods of 1, 8 and 15 days. Following the designated freezing period, the samples were removed from the freezer and thawed at room temperature for 12 h. The second part of the study, using anaerobically digested sludge, evaluated the effects of potassium ferrate(VI) pretreatment, using LD = 0.5 g/L and HD = 5.0 g/L, and used simulated drainage beds to separate meltwater from the sludge cake during the thawing period. The study demonstrated that stand-alone freeze-thaw can reduce faecal coliform by >3-log after being frozen for only 1 day, and pretreatment with potassium ferrate(VI) can be used to improve the effects of freeze-thaw on faecal coliform inactivation in sludge. Furthermore, the drainability of the sludge following freeze-thaw was not significantly deteriorated when potassium ferrate(VI) was added to the sludge prior to freezing, despite greater than fourfold increases in the concentrations of soluble proteins and soluble carbohydrates. The meltwater collected during the sludge thawing was approximately 85 % of the initial sludge volume. When 5 g/L of potassium ferrate(VI) was added to the sludge prior to freezing, the meltwater collected had <0.28 MPN/mL faecal coliform, the turbidity was <10 NTU and the pH was 9.1. Pretreatment with potassium ferrate(VI) also reduced the concentration of faecal coliform in the sludge cake, suggesting that freeze-thaw coupled with potassium ferrate(VI) additions can be used to stabilise sludge and reduce sludge volume.
Показать больше [+] Меньше [-]Characterization of Cd translocation and accumulation in 19 maize cultivars grown on Cd-contaminated soil: implication of maize cultivar selection for minimal risk to human health and for phytoremediation
2016
Wang, Aiyun | Wang, Minyan | Liao, Qi | He, Xiquan
Maize (Zea mays) has low Cd accumulation in grains and a high biomass compared to other crops. The capacities for Cd accumulation in different maize cultivars are, however, not fully understood. To reduce human health risk from maize grown in Cd-contaminated soil and to provide promising maize cultivars for the phytoremediation of Cd-polluted soil, a field experiment was conducted to screen low-Cd- and high-Cd-accumulation maize cultivars by evaluating the yield, Cd uptake, translocation, and accumulation differences among 19 maize cultivars. There were differences in straw dry weight (DW), root DW, and yield among the 19 cultivars. The cultivars Yudan19, Zhengda999, and Xianyu508 had a higher production compared to that of the other cultivars. The Cd concentrations in the roots were much higher than those in the straws and grains in all cultivars. The Cd accumulation factors (AFS) decreased in the order of accumulation factors in root (AFᵣₛ) > accumulation factors in straw (AFₛₛ) > accumulation factors in grain (AFgₛ). The Cd translocation factors (TFs) from root to straw (TFᵣₛ) were significantly (p < 0.05) larger than those from straw to grain (TFₛg) among all of the cultivars. The TFₛ for all of the cultivars was less than 1, and the lowest TFₛg (0.23) was found in cultivar Xiangyongdan3. The correlation analysis indicated that Cd concentrations in straws showed a significant (p < 0.01) as well as positive correlation with TFᵣₛ while a negative correlation with TFₛg (p < 0.01). Moreover, Cd accumulation in different tissues decreased in the order straw > grain > root. Among the 19 maize cultivars, Jixiang2118 and Kangnong18 accumulated the highest Cd amount in the aboveground tissues, and the corresponding values were 7,206.51 and 6,598.68 mg hm⁻², respectively. A hierarchical cluster analysis based on the Cd concentrations in grains and straws classified the 19 maize cultivars into four and two groups for a 0.4 minimum distance between clusters, respectively. Yudan19, Zhengda999, and Xianyu508 can be classified into one group in which low Cd in grains meeting the Cd tolerance limit in foods set by China National Standard, suggesting that those cultivars are safety for food and human health. However, Jixiang2118 and Kangnong18 can be classified as another group with potential application for phytoremediation in slightly or moderately Cd-polluted soil because of the high Cd accumulation in the aboveground tissues.
Показать больше [+] Меньше [-]Depth profile of persistent and emerging organic pollutants upstream of the Three Gorges Dam gathered in 2012/2013
2016
Deyerling, Dominik | Wang, Jingxian | Bi, Yonghong | Peng, Chengrong | Pfister, Gerd | Henkelmann, Bernhard | Schramm, Karl–Werner
Persistent and emerging organic pollutants were sampled in September 2012 and 2013 at a sampling site in front of the Three Gorges Dam near Maoping (China) in a water depth between 11 and 61 m to generate a depth profile of analytes. A novel compact water sampling system with self-packed glass cartridges was employed for the on-site enrichment of approximately 300 L of water per sample to enable the detection of low analytes levels in the picogram per liter-scale in the large water body. The overall performance of the sampling system was acceptable for the qualitative detection of polycyclic aromatic hydrocarbons (PAHs), polychlorinated biphenyls (PCBs), organochlorine pesticides (OCPs), perfluoroalkylic acids (PFAAs), pharmaceutical residues and polar pesticides. Strongly particle-associated analytes like PAHs and PCBs resided mainly in the glass wool filter of the sampling system, whereas all other compounds have mainly been enriched on the XAD-resin of the self-packed glass cartridges. The sampling results revealed qualitative information on the presence, depth distribution and origin of the investigated compounds. Although the depth profile of PAHs, PCBs, OCPs, and PFAAs appeared to be homogeneous, pharmaceuticals and polar pesticides were detected in distinct different patterns with water depth. Source analysis with diagnostic ratios for PAHs revealed their origin to be pyrogenic (burning of coal, wood and grass). In contrast, most PCBs and OCPs had to be regarded as legacy pollutants which have been released into the environment in former times and still remain present due to their persistence. The abundance of emerging organic pollutants could be confirmed, and their most abundant compounds could be identified as perfluorooctanoic acid, diclofenac and atrazine among investigated PFAAs, pharmaceuticals and polar pesticides, respectively.
Показать больше [+] Меньше [-]Global gene expression profiling using heterologous DNA microarrays to analyze alterations in the transcriptome of Mus spretus mice living in a heavily polluted environment
2016
Ruiz-Laguna, Julia | Vélez, José M. | Pueyo, Carmen | Abril, Nieves
Microarray platforms are a good approach for assessing biological responses to pollution as they enable the simultaneous analyses of changes in the expression of thousands of genes. As an omic and non-targeted methodology, this technique is open to unforeseen responses under particular environmental conditions. In this study, we successfully apply a commercial oligonucleotide microarray containing Mus musculus whole-genome probes to compare and assess the biological effects of living in a heavily polluted settlement, the Domingo Rubio stream (DRS), at the Huelva Estuary (SW Spain), on inhabitant free-living Mus spretus mice. Our microarray results show that mice living in DRS suffer dramatic changes in gene and protein expression compared with reference specimens. DRS mice showed alteration in the oxidative status of hepatocytes, with activation of both the innate and the acquired immune responses and the induction of chronic inflammation, accompanied by metabolic alterations that imply the accumulation of lipids in the liver (hepatic steatosis). The identified deregulated genes may be useful as biomarkers of environmental pollution.
Показать больше [+] Меньше [-]Inorganic Arsenic Concentrations in Wheat Chaff Exceed Those in Wheat Grain
2016
Duncan, Elliott G. | Maher, William A. | Jagtap, Rajani | Foster, Simon D. | Krikowa, Frank | O’Sullivan, Cathryn A. | Roper, Margaret M.
Eight wheat cultivars were grown in soil amended with arsenate (Asⱽ) at a concentration of 15 mg As kg⁻¹ soil, with or without a triple super phosphate amendment of 40 mg P kg⁻¹ soil. All eight wheat cultivars accumulated higher As in stems/leaves (9–23 μg As g⁻¹) and chaff (9–22 μg As g⁻¹) compared with the grain (0.6–1.6 μg As g⁻¹). The As present in stems/leaves, grain and chaff was found as inorganic As species—Asⱽ or arsenite (Asᴵᴵᴵ). For most cultivars, increased P availability had minimal influence on As accumulation in chaff tissues. If this data is reflective of what occurs in situ, then As can accumulate in chaff at similar concentrations to stem and leaf tissues which are much higher than in grain. Further research is required to determine the risks of As accumulation in livestock products (meat and dairy) when fed with As-contaminated wheat chaff.
Показать больше [+] Меньше [-]Phosphorus Removal from Aqueous Solution by Pre- or Post-Modified Biochars Derived from Agricultural Residues
2016
Yu, Peiwen | Xue, Yingwen | Gao, Fei | Liu, Zhigang | Cheng, Xiaoru | Yang, Kai
Biochar produced from agricultural residues through pyrolysis has the characteristics of large specific surface area and porous structure and thus can be used as an adsorbent for various contaminants. In this study, five types of agricultural residues, peanut shells (PS), mung bean shells (MBS), rice husk (RH), corn cob (CC), and cotton stalks (CS), were selected as feedstocks to prepare biochars. Magnesium chloride (MgCl₂; 5 mol L⁻¹ m) solution was used as a modifier to prepare pre-modified and post-modified biochar adsorbents. The modified biochars were used in adsorption experiment to test their sorption ability to phosphate from aqueous solution. Model simulations and analysis were used to determine phosphorus removal mechanisms. Experimental results showed that the phosphate removal efficiency of the pre-modified cotton stalk paralyzed at 600 °C (Pre-CS600) was the best with adsorption capacity of 129.9 mg g⁻¹. The results also showed that the adsorption capacity of the biochar pre-modified by MgCl₂ was much better than that of unmodified and post-modified ones, suggesting the pre-modification method can be used to prepare modified biochars for the removal of phosphorus from aqueous solution.
Показать больше [+] Меньше [-]Water Quality Impact from the Discharge of Coal Mine Wastes to Receiving Streams: Comparison of Impacts from an Active Mine with a Closed Mine
2016
Price, Philip | Wright, Ian A.
This study examined two underground coal mines in the Sydney basin and investigated the water chemistry impact from their wastewater discharges to surface receiving waters. One mine closed 17 years prior to the study, and the other was still active. The geology of both mine locations shared many similarities and some important differences that influenced their wastewater chemistry and its subsequent impact on receiving waterways. Water quality of wastewater discharges from the two mines and their receiving waterways was investigated over a 6-month period. Both mine discharges caused comprehensive modification to receiving water chemistry. The closed mine increased electrical conductivity (EC) 3.3 times from upstream (33 μS/cm) compared to downstream (108 μS/cm). In comparison, the active mine increased EC by 9.4 times (173 μS/cm) upstream to 1628 μS/cm downstream. Both coal mine wastes increased the concentration of different contaminants to levels that are potentially hazardous for receiving water ecosystems. The active mine increased bicarbonate concentration in the receiving water by more than 60 times to 743 mg/L. The closed mine increased zinc and nickel concentrations in its receiving stream by 70 and 20 times to 318 and 360 μg/L. The active coal mine discharge was dominated by sodium and bicarbonate ions compared to magnesium and sulphate ions in the closed mine drainage. Although both receiving waters were sodium and chloride dominated upstream of the mine waste, their ionic composition was strongly modified due to the inflow of coal mine wastes. Results from this study are a reminder that water pollution from coal mines is important for both active mines and for closed mines decades after mining activity ceases.
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