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2.
Background, aim, and scope At tropical latitudes, and especially on the semi-arid coasts of the Brazilian Northeast, the rainfall regime governs the
water quality of estuaries due to the pronounced difference between the rainy and dry seasons. These changes may be responsible
for seasonal changes in bioavailability of mercury (Hg) and other pollutants to the estuarine and coastal biota. Mercury bioaccumulates
along estuarine–marine food chains usually result in higher concentrations in tissues of top predators and posing a risk to
both marine mammals and humans alike. The Goiana River Estuary (7.5° S) is a typical estuary of the semi-arid tropical regions
and supports traditional communities with fisheries (mollusks, fish, and crustacean). It is also responsible for an important
part of the biological production of the adjacent coastal waters.
Materials and methods
Trichiurus lepturus (Actinopterygii: Perciformes) is a pscivorous marine straggler. Fish from this species ( n = 104) were captured in a trapping barrier used by the local traditional population and using an otter trawl net along the
main channel of the low estuary during two dry seasons (D1 = November, December 2005, January 2006; D2 = November, December
2006, January 2007) and the end of a rainy season (R = August, September, October 2006). Fish muscle samples were preserved
cold and then freeze-dried prior to analysis of its total mercury (Hg-T) contents. Total mercury was determined by cold vapor
atomic absorption spectrometry (CV-AAS) with sodium borohydride as a reducing agent.
Results The studied individuals ( n = 104) were sub-adult (30–70 cm, 71 ind.) and adult fish (>70 cm, 33 ind.). Weight (W) (204.1 ± 97.9 g, total biomass = 21,229.7 g)
and total length (TL) (63.1 ± 10.1 cm, range 29.5–89.0 cm) presented a significant ( p < 0.05) correlation. Two-way ANOVA ( n = 81) showed that TL and W had significant differences ( p < 0.05) among seasons, being higher in D1 than in D2 and R, respectively. Moreover, season vs. month interaction were detected
for the variables length and weight. For the variable weight was detected significant difference for the factor month ( p < 0.05). It suggests that the fish enter the estuary at the end of the rainy season and increase in length and weight during
the time they spend in the estuary. Fish from this estuary are shown to be fit for human consumption (125.3 ± 61.9 μgHg-T
kg –1 w.wt.; n = 104). Fish mercury contents increased with size and weight. Correlations between TL and Hg-T ( r = 0.37286) and between W and Hg-T ( r = 0.38212) were significant ( p < 0.05). Dryer months showed higher mercury concentrations in fish (D1 773.4 ± 207.5 μgHg-T kg –1 d.wt., n = 27; D2 370.1 ± 78.8 μgHg-T kg –1 d.wt., n = 27; R 331.2 ± 138.5 μgHg-T kg –1 d.wt., n = 27). The variable mercury concentration showed differences in relation to the factor season ( p < 0.05), where fish captured during the first dry season showed the highest concentration of mercury. The correlation between
Hg-T and rainfall (Rf) showed a negative correlation ( r = –0.56; p < 0.05).
Discussion The main likely source of mercury to this estuary is diffuse continental run off, including urban and industrial effluents.
Since concentration of mercury in fish tissue is negatively correlated to rainfall, but positively correlated with fish length
and weight, it suggests that fish growth in this estuary results in mercury uptake and concentration on the fish tissue. In
the dry season of 2005–2006, when rainfall remained below the historic average, fish bioaccumulated significantly more mercury
than in the dry season 2006–2007, when rainfall was within the predictable historic average. It is suggested that less rainfall,
and consequently less particulate matter and less primary production in the estuary, make mercury more available to the higher
levels of the estuarine food chain. In the case of higher rainfall, when river flow increases and water quality in the estuary
is reduced, mercury probably is quickly exported associated to the particulate matter to the adjacent coastal waters where
it then disperses. This species is a potential routine bioindicator for mercury contamination of the biota, but so far was
used only with a limited number of individuals and contexts.
Conclusions Fish from the Goiana River estuary can still be safely consumed by the local population. However, any further contamination
of this resource might lead to total mercury levels above the recommended limits for pregnant women and small children. The
proposed heavy dependency of total mercury levels in fish on water quality indicates that land use and water quality standards
must be more closely watched in order to guarantee that best possible practices are in place to prevent bioaccumulation of
mercury and its transfer along the food chain. Human interventions and climatic events which affect river water flow are also
playing a role in the mercury cycle at tropical semi-arid estuaries.
Recommendations and perspectives
T. lepturus is largely consumed by coastal populations of tropical and sub-tropical countries all over the world. It is also consumed
by a number of marine mammals over which we have a strong conservation interest. This species is also a link among different
ecosystems along the estuarine ecocline. Therefore, knowledge of its degree of contamination might contribute to public health
issues as well as marine conservation actions. Studies on mercury and other contaminants using this species as bioindicator
(cosmopolitan, readily available) could help elucidating mechanisms through which pollutants are being transferred not only
through the food chain, but also from estuarine–coastal–open waters. In addition, using the same species in marine pollution
studies, especially as part of a mosaic of species, allows for wide range comparisons of marine food chain contamination. 相似文献
3.
Sludge morphology considerably affects the mechanism underlying microbial anaerobic degradation of phenol. Here, we assessed the phenol degradation rate, specific methanogenic activity, electron transport activity, coenzyme F420 concentration, and microbial community structure of five phenol-degrading sludge of varying particle sizes (i.e., < 20, 20–50, 50–100, 100–200, and > 200 μm). The results indicated an increase in phenol degradation rate and microbial community structure that distinctly correlated with an increase in sludge particle size. Although the sludge with the smallest particle size (< 20 μm) showed the lowest phenol degradation rate (9.3 mg COD·gVSS−1 day−1), its methanogenic activity with propionic acid, butyric acid, and H2/CO2 as substrates was the best, and the concentration of coenzyme F420 was the highest. The small particle size sludge did not contain abundant syntrophic bacteria or hydrogenotrophic methanogens, but contained abundant acetoclastic methanogens. Moreover, the floc sizes of the different sludge varied in important phenol-degrading bacteria and archaea, which may dominate the synergistic mechanism. This study provides a new perspective on the role of sludge floc size on the anaerobic digestion of phenol. 相似文献
4.
The aim of the current research was to systematically review and summarize the studies that evaluated the concentration of lead (Pb) and cadmium (Cd) in cow milk in different regions of Iran and to perform a meta-analysis of the findings. Moreover, the non-carcinogenic and carcinogenic risks of Pb and Cd through milk consumption in adult and child consumers were assessed. As a result of a systematic search in the international and national databases between January 2008 and October 2018, 17 reports involving 1874 samples were incorporated in our study for meta-analysis. The pooled concentrations of Pb and Cd were estimated to be 13.95 μg mL−1 (95% CI 9.72–18.11 μg mL−1) and 3.55 μg mL−1 (95% CI − 2.38–9.48 μg mL−1), respectively, which were lower than the WHO/FAO and national standard limits. The estimated weekly intake (EWI) of Pb and Cd through consuming milk was 16.65 and 7 μg day−1 for adults of 70 kg and 45 and 34 μg day−1 for children of 26 kg, respectively, which was well below the risk values set by Joint FAO/WHO Expert Committee on Food Additives (JECFA). The maximum target hazard quotient values (THQs) of Pb and Cd were 5.55E−5 and 5.55E−5 for adults and 5.55E−5 and 5.55E−5 for children, respectively, which were lower than 1 value, suggesting that Iranian consumers are not exposed to non-carcinogenic risk through consuming milk. Moreover, the incremental lifetime cancer risk (ILCR) of Pb estimated to be 2.96E−04 in adults and 1.0E−03 in children, indicating that consumers in Iran are at threshold carcinogenic risk of Pb through consuming milk (ILCR > 10−4). Therefore, planning and policy making for the sustainable reduction of these toxic metals in milk, particularly in industrial regions of Iran, are crucial. 相似文献
5.
Background, aim, and scope The adverse environmental impacts of chlorinated hydrocarbons on the Earth’s ozone layer have focused attention on the effort
to replace these compounds by nonchlorinated substitutes with environmental acceptability. Hydrofluoroethers (HFEs) and fluorinated
alcohols are currently being introduced in many applications for this purpose. Nevertheless, the presence of a great number
of C–F bonds drives to atmospheric long-lived compounds with infrared absorption features. Thus, it is necessary to improve
our knowledge about lifetimes and global warming potentials (GWP) for these compounds in order to get a complete evaluation
of their environmental impact. Tropospheric degradation is expected to be initiated mainly by OH reactions in the gas phase.
Nevertheless, Cl atoms reaction may also be important since rate constants are generally larger than those of OH. In the present
work, we report the results obtained in the study of the reactions of Cl radicals with HFE-7000 (CF 3CF 2CF 2OCH 3) (1) and its isomer CF 3CF 2CF 2CH 2OH (2).
Materials and methods Kinetic rate coefficients with Cl atoms have been measured using the discharge flow tube–mass spectrometric technique at 1 Torr
of total pressure. The reactions of these chlorofluorocarbons (CFCs) substitutes have been studied under pseudo-first-order
kinetic conditions in excess of the fluorinated compounds over Cl atoms. The temperature ranges were 266–333 and 298–353 K
for reactions of HFE-7000 and CF 3CF 2CF 2CH 2OH, respectively.
Results The measured room temperature rate constants were k(Cl+CF 3CF 2CF 2OCH 3) = (1.24 ± 0.28) × 10 −13 cm 3 molecule −1 s −1and k(Cl+CF 3CF 2CF 2CH 2OH) = (8.35 ± 1.63) × 10 −13 cm 3 molecule −1 s −1 (errors are 2 σ + 10% to cover systematic errors). The Arrhenius expression for reaction 1 was k
1(266–333 K) = (6.1 ± 3.8) × 10 −13exp[−(445 ± 186)/ T] cm 3 molecule −1 s −1 and k
2(298–353 K) = (1.9 ± 0.7) × 10 −12exp[−(244 ± 125)/ T] cm 3 molecule −1 s −1 (errors are 2 σ). The reactions are reported to proceed through the abstraction of an H atom to form HCl and the corresponding halo-alkyl
radical. At 298 K and 1 Torr, yields on HCl of 0.95 ± 0.38 and 0.97 ± 0.16 (errors are 2 σ) were obtained for CF 3CF 2CF 2OCH 3 and CF 3CF 2CF 2CH 2OH, respectively.
Discussion The obtained kinetic rate constants are related to the previous data in the literature, showing a good agreement taking into
account the error limits. Comparing the obtained results at room temperature, k
1 and k
2, HFE-7000 is significantly less reactive than its isomer C 3F 7CH 2OH. A similar behavior has been reported for the reactions of other fluorinated alcohols and their isomeric fluorinated ethers
with Cl atoms. Literature data, together with the results reported in this work, show that, for both fluorinated ethers and
alcohols, the kinetic rate constant may be considered as not dependent on the number of –CF 2– in the perfluorinated chain. This result may be useful since it is possible to obtain the required physicochemical properties
for a given application by changing the number of –CF 2– without changes in the atmospheric reactivity. Furthermore, lifetimes estimations for these CFCs substitutes are calculated
and discussed. The average estimated Cl lifetimes are 256 and 38 years for HFE-7000 and C 3H 7CH 2OH, respectively.
Conclusions The studied CFCs’ substitutes are relatively short-lived and OH reaction constitutes their main reactive sink. The average
contribution of Cl reactions to global lifetime is about 2% in both cases. Nevertheless, under local conditions as in the
marine boundary layer, τ
Cl values as low as 2.5 and 0.4 years for HFE-7000 and C 3H 7CH 2OH, respectively, are expected, showing that the contribution of Cl to the atmospheric degradation of these CFCs substitutes
under such conditions may constitute a relevant sink. In the case of CF 3CF 2CF 2OCH 3, significant activation energy has been measured, thus the use of kinetic rate coefficient only at room temperature would
result in underestimations of lifetimes and GWPs.
Recommendations and perspectives The results obtained in this work may be helpful within the database used in the modeling studies of coastal areas. The knowledge
of the atmospheric behavior and the structure–reactivity relationship discussed in this work may also contribute to the development
of new environmentally acceptable chemicals. New volatile materials susceptible of emission to the troposphere should be subject
to the study of their reactions with OH and Cl in the range of temperature of the troposphere. The knowledge of the temperature
dependence of the kinetic rate constants, as it is now reported for the case of reactions 1 and 2, will allow more accurate
lifetimes and related magnitudes like GWPs. Nevertheless, a better knowledge of the vertical Cl tropospheric distribution
is still required. 相似文献
6.
The response of soil respiration (Rs) to nitrogen (N) addition is one of the uncertainties in modelling ecosystem carbon (C). We reported on a long-term nitrogen (N) addition experiment using urea (CO(NH2)2) fertilizer in which Rs was continuously measured after N addition during the growing season in a Chinese pine forest. Four levels of N addition, i.e. no added N (N0: 0 g N m−2 year−1), low-N (N1: 5 g N m−2 year−1), medium-N (N2: 10 g N m−2 year−1), and high-N (N3: 15 g N m−2 year−1), and three organic matter treatments, i.e. both aboveground litter and belowground root removal (LRE), only aboveground litter removal (LE), and intact soil (CK), were examined. The Rs was measured continuously for 3 days following each N addition application and was measured approximately 3–5 times during the rest of each month from July to October 2012. N addition inhibited microbial heterotrophic respiration by suppressing soil microbial biomass, but stimulated root respiration and CO2 release from litter decomposition by increasing either root biomass or microbial biomass. When litter and/or root were removed, the “priming” effect of N addition on the Rs disappeared more quickly than intact soil. This is likely to provide a point of view for why Rs varies so much in response to exogenous N and also has implications for future determination of sampling interval of Rs measurement. 相似文献
7.
The solid-solution distribution or partition coefficient (Kd) is a measure of affinity of potentially toxic elements (PTE) for soil colloids. Kd plays a key role in several models for defining PTE guideline values in soils and for assessing environmental risks, and its value depends on edaphic and climatic conditions of the sites where the soils occur. This study quantified Kd values for Cd, Co, Cr, Cu, Hg, Ni, Pb, and Zn from representative soil samples from Brazil’s eastern Amazon region, which measures 1.2 million km 2. The Kd values obtained were lower than those set by both international and Brazilian environmental agencies and were correlated with the pH, Fe and Mn oxide content, and cationic exchange capacity of the soils. The following order of decreasing affinity was observed: Pb?>?Cu?>?Hg?>?Cr?>?Cd?≈?Co?>?Ni?>?Zn. 相似文献
8.
Mercury is a trace element that is potentially dangerous due its high toxicity and tendency to bioaccumulate in organisms. Currently, high mercury concentrations are seen in the environment especially due climate changes. Studies regarding mercury bioavailability in the southwestern Atlantic Ocean using tuna and tuna-like species are rare. The aim of the present study was to use tuna and tuna-like species (Thunnus atlanticus, Thunnus albacares, Katsuwonus pelamis, Euthynnus alletteratus, Coryphaena hippurus and Sarda sarda) as indicators of the availability of total mercury (THg) in oceanic food webs of the southwestern Atlantic Ocean. THg concentrations varied significantly among species for both muscle and liver (Kruskal–Wallis test; H5,130 = 52.7; p < 0.05; H5,130 = 50.1; p < 0.05, respectively). The lowest concentrations were found in C. hippurus (0.008 mg kg−1 wet weight in the muscle and 0.003 mg kg−1 wet weight in the liver), and the highest concentrations were reported in the muscle of T. atlanticus (1.3 mg kg−1 wet weight) and in the liver of S. sarda (2.5 mg kg−1 wet weight). The continued monitoring of tuna and tuna-like species is necessary to assist in their conservation since tuna can be sentinels of mercury pollution. 相似文献
9.
Background, aim and scope Urban motor vehicle fleets are a major source of particulate matter pollution, especially of ultrafine particles (diameters < 0.1 μm),
and exposure to particulate matter has known serious health effects. A considerable body of literature is available on vehicle
particle emission factors derived using a wide range of different measurement methods for different particle sizes, conducted
in different parts of the world. Therefore, the choice as to which are the most suitable particle emission factors to use
in transport modelling and health impact assessments presented as a very difficult task. The aim of this study was to derive
a comprehensive set of tailpipe particle emission factors for different vehicle and road type combinations, covering the full
size range of particles emitted, which are suitable for modelling urban fleet emissions. 相似文献
10.
All processes in agro-industries consume water and generate large volumes of nutrient-rich effluents. To recycle effluents from a sugar–alcohol industry in the Northeastern Brazil (Coruripe, Alagoas), the effect of a daily application of a microbial formulation (containing five indigenous bacteria and two fungi), at the entrance of the two first facultative ponds (D, E) of its treatment plant formed by seven ponds (A–G), was evaluated in the sugarcane harvests of 2014/2015 and 2015/2016. Fortnightly, the values of 11 physicochemical parameters were checked and statistically compared (one and two-way ANOVA) in untreated (sedimentation pond A) and post-treated effluent (last facultative pond G), during both harvests. The treated effluent presented statistically significant improvements (p > 0.05), even between harvests, with averages of removal of organic matter of ca. 79.21% and 90.62%, and increases of the dissolved oxygen (DO) of ca. 72% and 74%, as well as the average increase of pH was ca. 42% and 50%. This better quality residue generally satisfied the class III level of the Brazilian Resolution 357/2005 (National Council for the Environment (CONAMA)), for water reuse in sugarcane irrigation on the yellow clay latosol soil, since it still is a light source of organic matter, nitrites and phosphorus, reducing the need of fertilizers for maintaining the productivity with low risk of salinization. According to Pearson’s bivariate correlation coefficient, while the DO and pH have positive correlation, they both have general inverse relation with the other physicochemical parameters evaluated and vice versa. 相似文献
11.
Background, aim, and scope In literature, the environmental applications of green rust (GR) have mainly been pointed out through the reduction of inorganic
contaminants and the reductive dechlorination of chlorinated organics. However, reactions involving GR for the oxidation and
mineralization of organic pollutants remain very scantly described. In this study, the ability of three synthetic Fe(II)–Fe(III)
green rusts, GR(CO 32−), GR(SO 42−), and GR(Cl −), to promote Fenton-like reaction was examined by employing phenol as a model pollutant. Unlike the traditional Fenton’s
reagent (dissolved Fe(II) + H 2O 2), where the pH values have to be lowered to less than 4, the proposed reaction can effectively oxidize the organic molecules
at neutral pH and could avoid the initial acidification which may be costly and destructive for the in situ remediation of
contaminated groundwater and soils. The green rust reactivity towards the oxidative transformation of phenol was thoroughly
evaluated by performing a large kinetic study, chemical analyses, and spectroscopic investigations. 相似文献
12.
Pyrrolizidine alkaloids (PAs) and related N-oxides (PANOs) are secondary plant metabolites thought to be found in approximately 3% of the flowering plants worldwide and exhibiting hepatotoxic properties to humans. As a consequence, beehive products are prone to be contaminated with those compounds by bees foraging PA-producing plants. Downstream contamination can also occur through food items containing honey. Analytical methods based on UHPLC separation and MS/MS detection were developed with a focus on very low LOQs and validated for the analysis of 16 PAs and 14 PANOs in honey, honey-based candies and snacks, as well as beehive product–based food supplements. A maximum level of 182 ng/g of PAs was detected in a Mediterranean honey, and high levels of heliotrine-type compounds were reported for the first time. An extensive sampling of honeys harvested in Belgium was performed (N = 374), the concentration levels were more limited with a maximum of 60 ng/g, and the contamination pattern was dominated by senecionine-type PAs. The PA levels in honey-based candies and snacks were very low, with respective maxima of 7.61 ng/g and 0.36 ng/g. Seventy-five percent among the pre-dosed food supplements based on beehive products were contaminated, with a maximum of 43 ng/g. The highest level was detected in a bee-collected pollen sample (1672 ng/g). The analytical results were consistent with the previously reported data for beehive products and confirmed that PA/PANO contamination in these food commodities is recurrent. 相似文献
13.
High concentration of nitrogen and phosphorus and imbalance of N/P can lead to the formation of water and the malignant proliferation of toxic microalgae. This study put forward the advanced nutrient removal with the regulation of effluent N/P as the core in order to restrain the eutrophication and growth of poisonous algae. According to the preliminary study and review, the optimal N/P for non-toxic green algae was 50:1. The horizontal sub-surface flow constructed wetland was filled with steel slag and ceramsite to achieve the regulation of effluent N/P. The results showed that steel slag had the stable P removal capacity when treating synthetic solution with low P concentration and the average removal rate for 1.5, 1.0, and 0.5 mg/L synthetic P solution was 2.98 ± 0.20 mg kg−1/h, 2.26 ± 0.15 mg kg−1/h, and 1.11 ± 0.10 mg kg−1/h, respectively. Combined with P removal rate and P removal task, the filling amount of steel slag along the SSFCW (sub-surface flow constructed wetland) was 3.22 kg, 4.24 kg, and 4.31 kg. In order to ensure the stability of dephosphorization of steel slag, the regeneration of P removal capacity was investigated by switching operation of two parallel SSFCW in 20 days for cycle. The N removal was limited for the deficiency of carbon source (COD (chemical oxygen demand)/TN = 3–4), and was stable at 18.5–31.9% which was less affected by temperature. Therefore, by controlling the process of quantitative P removal of steel slag, the effluent N/P in SSFCW can be stable at 40–60:1 in the whole year, so as to inhibit the malignant proliferation of toxic algae. 相似文献
14.
Background, aim, and scope The Arctic holds large stores of minerals, and extracted materials are provided to the world’s economy; in this sense, the
Arctic issue associated with mining is not local but global. In a part of the Arctic region (the Kola Peninsula, 66–70° N
and 28–41° E), metal levels are generally elevated in the lake sediment. There is a question as to what results in elevated
metal levels—a natural process (naturally abundant minerals) or an anthropogenic process (mining and metallurgy). In terms
of solving this question, Staroe lake located on the Kola Peninsula was researched as a case study.
Materials and methods The following parameters were determined in relation with Staroe lake: (1) the current quality of the lake’s water—each 1,000-ml
sample was collected at a surface point and a deep point (near the bottom layer), and the collected samples were directly
analyzed after filtration; (2) atmospheric bulk deposition—bulk deposition was collected using a set of three rainwater samplers
near the lake. In addition, bulk deposition was collected in a background site (250 km to the southwest of the smelter complex)
as a reference; and (3) sediment profile (plus principal component analysis)—lake-bottom sediment was collected by an open-gravimetric
column sampler equipped with an automatic diaphragm. After collection, the sample columns were cut at a 1-cm interval for
analysis. Eigenvalues and variances by factor were calculated from the correlation coefficients.
Results The obtained data show that (1) naturally poor elements (Cu, Ni, Si, and SO 4
2−) dominantly influence the lake’s water quality; (2) they are transported from the anthropogenic sources to the study lake
through the atmospheric pathway; (3) mainly the contents of Cu, Ni, Sr, and Ca have influenced the sediment quality since
the 1950s, corresponding to the industrial movement; and (4) Cu, Ni, and Sr originate from an anthropogenic source (smelter),
and Ca originates from both natural and anthropogenic sources.
Discussion As compared with the Russian standard (San Pin 2.1.980–00), the contents of NO 3
− (50.3 ± 0.1 mg l −1) and particulates (2.3 ± 0.2 mg l −1) exceeded the standard levels (0.7 mg l −1 NO 3
− and 45 mg l −1 particulates); Staroe lake may be slightly contaminated. However, the contamination factor (comparison with the background
data) implies that Staroe lake is considerably contaminated. There is a strong possibility that fine overburden detritus (<0.1 mm
diameter) may be transported from an open pit to the study lake by natural forces such as wind. Although it is difficult to
suppose that one factor dominantly affects the sediment quality, it follows from a factor analysis that factors 1 and 2 account
for about 70% of the total variance: Factor 1 is the most dominant, and factor 2 is the second most dominant in the variability
of sediment quality. It is considered that Cu, Sr, and Ni in factor 1 originate from anthropogenic sources because they are
poor in sediment rocks.
Conclusions The field survey conducted in Staroe lake can give the following answers to the key objectives: (1) The present water quality
is affected by Cu, Ni, Si, and SO 4
2− in light of the contamination factor, and these elements originate from anthropogenic sources (the smelter and the open pit)
and are transported to the lake through the atmospheric pathway; (2) the sediment profile and statistic analysis show that
the lake quality has been influenced by deposition of metals since the 1950s; and (3) Cu, Ni, Sr, and Ca have influenced the
sediment quality in light of the most dominant factor—Cu, Ni, and Sr originate from an anthropogenic source, whereas Ca comes
from both natural and anthropogenic sources.
Recommendations and perspectives The presented lake survey shows that the dispersion of human-related pollutants via the atmospheric pathway takes place in
the Arctic region. If the current pollution continues without countermeasures, the high-latitude environment may lose its
original characteristics; hence, this subject is important when considering how to implement a wide range of environmental
protection measures in the Arctic. 相似文献
15.
With the progress of technology and the deepening of understanding of biological monitoring, much more attention has been paid to the multiple evaluation of marine pollution monitoring. In view of this, our study aimed at establishing a multi-integrated biomarker indexes approach to evaluate marine condition systematically and comprehensively. In the current study, sampling was conducted in Laizhou Bay, China (S1, S2, and S3) in May, August, and October of 2015. And then, multi-integrated biomarker indexes approach was applied to assess marine PAHs pollution, select appropriate biomarkers, and evaluate marine environmental quality and health status of the clams of Ruditapes philippinarum. As the results showed, S2 was the most PAHs-polluted site while S1 was the least polluted site, and the levels of tPAHs in seawater and sediments ranged from 69.78 to 315.30 ng/L and 163.19 to 565.17 ng/g d.w., respectively. And all three sampling sites had different sources of PAHs. IBR represented DNA damage (F value), the expression of SOD, EROD activity, GST activity, and LPO could be served as biomarkers to monitor the PAHs pollution in Laizhou Bay. And MPI suggested the quality of all three sites: S1 was generally favorable, S2 was moderately polluted, and S3 was lightly polluted. BRI values showed that the order of health status of R. philippinarum was S1?>?S3?>?S2. 相似文献
16.
The DFT-B3LYP method, with the basis set 6-311G( * *), was employed to calculate the molecular geometries and electronic structures of 25 nitroaromatics. The acute toxicity (-lgEC(50)) of these compounds to the algae (Scenedesmus obliguus) along with hydrophobicity described by logK(OW), and two quantum chemical parameters-energy of the lowest unoccupied molecular orbital, E(LUMO), and the charge of the nitro group, [ForQ(NO2), were used to establish the quantitative structure-activity relationships (QSARs). For 18 mononitro derivatives, the hydrophobicity parameter logK(OW) could interpret the toxic mechanism successfully. Dinitro aromatic compounds were susceptible to be reduced to aniline for their electrophilic nature. Their toxicity was controlled mainly by electronic factors instead of hydrophobicity. The electronic parameters, E(LUMO) and Q(NO2), were used to yield the following model: -lg EC(50) = 3.746 - 25.053 E(LUMO) + 6.481 Q(NO2) (n=22, R=0.926, SE=0.206, F=56.854, P<0.001). The predicted toxic values using the above equation are in good agreement with the experimental values. 相似文献
17.
In this paper, we report on techniques for sampling and measuring ethanol in both the gas and aqueous phases of the lower troposphere. In the gas phase, the best sampling conditions were ensured by adsorption on Hayesep Q with a Chromosorb W AW coated with LiCl dryer (method 1) or by cryogenic trapping (method 2). An intercomparison campaign showed good agreement between both methods under various conditions. Method 1 (adsorption on Hayesep Q with dryer) is easier to set up and to carry away from the laboratory. Method 2 (cryogenic trapping) requires longer sampling time (up to 60 min while method 1 requires only 10-15 min). Method 1 is adapted to high concentrations of ethanol (>20 ppb) and low relative humidity (<30%). Method 2 gives more accurate results than method 1 for low ethanol concentrations (1-20 ppb). Comparing these results to previous studies, it is clear that sampling with appropriate solid adsorbents or with stainless steel canisters (with appropriate humidified air and short storage time) is adapted to urban or industrial environments where ethanol concentrations are high. Cryogenic sampling must be preferred for remote places where ethanol concentrations are low. Three techniques were tested for sampling ethanol in the liquid phase, namely solid phase microextraction, purge and trap injection, and direct injection. Among those, the latter was chosen for field measurements of ethanol in rain samples at an urban location. These first ever results at an urban location show concentrations ranging from <1 to 5 microM in rains, which agree with the expected range of concentrations. However, the purge and trap method showed detection limits that were 50 times lower and should be preferred for liquid phase ethanol measurements in rural and remote locations. Combining cryogenic trapping for the gas phase (method 2) and direct injection for the liquid phase is convenient and well adapted for a multiphase study of ethanol in the atmosphere, where simultaneous measurements in both phases are needed. 相似文献
18.
Background, aim, and scope It has been known that the pollutants of electronic wastes (E-wastes) can lead to severe pollution to the environment. It
has been reported that about 50% to 80% of E-wastes from developed countries are exported to Asia and Africa. It has become
a major global environmental problem to deal with ‘E-wastes’. E-waste recycling has remained primitive in Jinghai, China.
This not only produces enormous environmental pollution but also can bring about toxic or genotoxic effects on the human body,
threatening the health of both current residents and future generations living in the local environment. The concentration
of lead in the blood of children in the E-waste polluted area in China is higher than that of the control area. But little
is known about the cytogenetic effect to human beings caused by the pollution of E-wastes. In the present study, experiments
have been performed to investigate the genetics of permanent residents of three villages with numerous E-waste disposal sites
and to analyze the harmful effects of exposure to E-wastes.
Materials and methods In total, 171 villagers (exposed group) were randomly selected from permanent residents of three villages located in Jinghai
County of Tianjin, China, where there has been massive disposal of E-wastes. Thirty villagers were selected from the neighboring
towns without E-waste disposal sites to serve as controls. Chromosomal aberrations and cytokinesis blocking micronucleus were
performed to detect the cytogenetic effect, dic + r (dicentric and ring chromosome), monomer, fragments (acentric fragments,
minute chromosomes, and acentric rings), translocation, satellite, quadriradial, total aberrations, and micronuclear rate
were scored for each subject. DNA damage was detected using comet assay; the DNA percentage in the comet tail (TDNA%), tail
moment (TM), and Olive tail moment (OTM) were recorded to describe DNA damage to lymphocytes.
Results The total chromosome aberration rates (5.50%) and micronuclear rates (16.99%) of the exposure group were significantly higher
than in the control group ( P = 0.000). The percentage of DNA in the comet tail, tail moment, and Olive tail moment detected by comet assay showed that
there was a significant difference in DNA damage in the exposure group ( P = 0.000). The chromosome aberration, micronucleus rate, and DNA damage observed in women were significantly higher than those
in men. Chromosome aberration and micronuclear rates of both smokers and non-smokers in the exposure group are obviously higher
than that in the control group ( P = 0.000).
Discussion The use of outdated (and unsafe) ways to deal with E-wastes can lead to exposure to a variety of substances harmful to human
health. The components of pollution may enter the human body through the air, drinking water, and food chain to damage human
genetic material, resulting in genomic instability. The rates of chromosomal aberration, micronucleus formation, and the degree
of DNA damage in women in the group exposed to electronic waste were significantly higher than in men. The reason for this
may be concerned with the traditional lifestyle of the local residents or the difference of sensitivity to the exposure to
E-wastes or any others. Further investigations are needed to provide evidence to demonstrate this.
Conclusions Here, we report the obviously cytogenetic toxicity to the exposure population by the E-waste pollution for the first time.
E-waste pollution may be a potential agent of genetic mutation, and may induce cytogenetic damage within the general population
exposed to the pollution. These findings need to be considered, and steps should be taken to protect the current population
and future generations from the effects of pollution with E-wastes.
Recommendations and perspectives The above results remind us that the impact of E-waste recycling on environmental quality of Jinghai should be evaluated soon.
Moreover, it is urgent for the government to prohibit E-waste import and its processing by outdated ways. The future studies
such as pollutant details of drinking water, air, and soil in the area as well as epidemiological investigations on the harmful
effect to children must be performed eagerly. All the data available do provide a compelling case for immediate action in
both countries to address workplace health and safety and waste management.
Qiang Liu and Jia Cao contributed equally to this study and share the first authorship. 相似文献
20.
Purpose This study aims to examine whether addition of immobilising agents to a sandy, alkaline (pH = 8.1) soil, which had been contaminated
with Pb and Zn by airborne particles from a Pb/Zn smelter, would substantially reduce metal bioavailability. 相似文献
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