خيارات البحث
النتائج 921 - 930 من 4,935
An adaptive transgenerational effect of warming but not of pesticide exposure determines how a pesticide and warming interact for antipredator behaviour النص الكامل
2019
Tran, Tam T. | Janssens, Lizanne | Dinh, Khuong V. | Stoks, Robby
The impact of pesticides on organisms may strongly depend on temperature. While many species will be exposed to pesticides and warming both in the parental and offspring generations, transgenerational effects of pesticides under warming are still poorly studied, particularly for behaviour. We therefore studied the single and combined effects of exposure to the pesticide chlorpyrifos (CPF) and warming both within and across generations on antipredator behaviour of larvae of the vector mosquito Culex pipiens. Within each generation pesticide exposure and warming reduced the escape diving time, making the larvae more susceptible to predation. Pesticide exposure of the parents did not affect offspring antipredator behaviour. Yet, parental exposure to warming determined how warming and the pesticide interacted in the offspring generation. When parents were reared at 24 °C, warming no longer reduced offspring diving times in the solvent control, suggesting an adaptive transgenerational effect to prepare the offspring to better deal with a higher predation risk under warming. Related to this, the CPF-induced reduction in diving time was stronger at 20 °C than at 24 °C, except in the offspring whose parents had been exposed to 24 °C. This dependency of the widespread interaction between warming and pesticide exposure on an adaptive transgenerational effect of warming is an important finding at the interface of global change ecology and ecotoxicology.
اظهر المزيد [+] اقل [-]Effect of mixed solutions of heavy metal eluents on soil fertility and microorganisms النص الكامل
2019
Liu, Zhongchuang | Lu, Bangjun | Xiao, Hongyan | Liu, Dongsheng | Li, Xiang | Wang, Li-ao | Urbanovich, Oksana | Nagorskaya, Liubov
This study analyzed the effect of heavy metal eluents (0.3 mol/L C₆H₈O₇, 5 × 10⁻⁴ mol/L EDTA, and 0.01 mol/L Na₂S₂O₃) on the content of organic matter, hydrolytic nitrogen, available phosphorus and potassium, and species composition of bacteria and fungi in vegetable soils. The obtained results documented that the treatment of the soil, consisting of shaking the sample with a mixture of eluents, significantly increased the content of organic matter, hydrolytic nitrogen, and available phosphorus and potassium. The mixed solutions of eluents increase the maximum available P in the soil by 279.3%, and hydrolytic N by 30.7%. The eluents affected, to a certain extent, the dominant species of microorganisms in the soil, but did not increase species richness and evenness in all soil samples.
اظهر المزيد [+] اقل [-]Assessing the association between fine particulate matter (PM2.5) constituents and cardiovascular diseases in a mega-city of Pakistan النص الكامل
2019
Lu, Yi | Lin, Shao | Fatmi, Zafar | Malashock, Daniel | Hussain, Mirza M. | Siddique, Azhar | Carpenter, David O. | Lin, Ziqiang | Khwaja, Haider A.
Concerning PM2.5 concentrations, rapid industrialization, along with increase in cardiovascular disease (CVD) were recorded in Pakistan, especially in urban areas. The degree to which air pollution contributes to the increase in the burden of CVD in Pakistan has not been assessed due to lack of data. This study aims to describe the characteristics of PM2.5 constituents and investigate the impact of individual PM2.5 constituent on cardiovascular morbidity in Karachi, a mega city in Pakistan. Daily levels of twenty-one constituents of PM2.5 were analyzed using samples collected at two sites from fall 2008 to summer 2009 in Karachi. Hospital admission and emergency room visits due to CVD were collected from two large hospitals. Negative Binominal Regression was used to estimate associations between pollutants and the risk of CVD. All PM2.5 constituents were assessed in single-pollutant models and selected constituents were assessed in multi-pollutant models adjusting for PM2.5 mass and gaseous pollutants. The most common CVD subtypes among our participants were ischemic heart disease, hypertension, heart failure, and cardiomyopathy. Extremely high levels of PM2.5 constituents from fossil-fuels combustion and industrial emissions were observed, with notable peaks in winter. The most consistent associations were found between exposure to nickel (5–14% increase per interquartile range) and cardiovascular hospital admissions. Suggestive evidence was also observed for associations between cardiovascular hospital admissions and Al, Fe, Ti, and nitrate. Our findings suggested that PM2.5 generated from fossil-fuels combustion and road dust resuspension were associated with the increased risk of CVD in Pakistan.
اظهر المزيد [+] اقل [-]Amino modification enhances reproductive toxicity of nanopolystyrene on gonad development and reproductive capacity in nematode Caenorhabditis elegans النص الكامل
2019
Qu, Man | Qiu, Yuexiu | Kong, Yan | Wang, Dayong
Although amino modified nanopolystyrene could cause toxicity on environmental organisms, the effect of amino modification on nanopolystyrene toxicity is still largely unclear. We here employed Caenorhabditis elegans as an animal model to compare the effects between pristine and amino modified nanopolystyrene particles in inducing reproductive toxicity. Nanopolystyrene (35 nm) could cause the damage on gonad development as indicated by the endpoints of number of total germline cells, length of gonad arm, and relative area of gonad arm. Nanopolystyrene exposure also reduced the reproductive capacity as reflected by the endpoints of brood size and number of fertilized eggs in uterus. Moreover, amino modification enhanced nanopolystyrene toxicity on both the gonad development and the reproductive capacity. Additionally, induction of germline apoptosis and formation of germline DNA damage contributed to the enhancement of nanopolystyrene toxicity in reducing reproductive capacity by amino modification. Our results highlight the potential environmental risk of amino modified nanopolystyrene in inducing reproductive toxicity on gonad development and reproductive capacity of environmental organisms.
اظهر المزيد [+] اقل [-]Correction of in-situ portable X-ray fluorescence (PXRF) data of soil heavy metal for enhancing spatial prediction النص الكامل
2019
Qu, Mingkai | Chen, Jian | Li, Weidong | Zhang, Chuanrong | Wan, Mengxue | Huang, Biao | Zhao, Yongcun
Heavy metal data measured by portable X-ray fluorescence (PXRF), especially by in-situ PXRF, are usually affected by multiple soil factors, such as soil moisture (SM), soil organic matter (SOM), and soil particle size (SPZ). Thus, a correction may be needed. However, traditionally-used correction methods, such as non-spatial linear regression (LR), cannot effectively correct the spatially non-stationary influences of the related soil factors on PXRF analysis. Moreover, these correction methods are not robust to outliers. In this study, robust geographically weighted regression (RGWR) was used to correct in-situ and ex-situ PXRF data of soil Pb in a peri-urban agricultural area of Wuhan City, China. The accuracy of the corrected PXRF data by RGWR was compared with those by non-spatial and spatial but non-robust methods (i.e., LR and GWR). In addition, to find an appropriate method of using the corrected PXRF data for more accurate spatial prediction, we compared robust ordinary kriging with the corrected PXRF data as part of hard data (ROK-CPXRF) and robust ordinary cokriging with the corrected PXRF data as auxiliary soft data (RCoK-CPXRF). Results showed that (i) RGWR obtained higher correction accuracy than LR and GWR on both the in-situ and ex-situ PXRF data; (ii) the accuracy of the RGWR-corrected in-situ PXRF data was increased nearly to that of the RGWR-corrected ex-situ PXRF data; (iii) given the same amount of sample data, ROK-CPXRF obtained higher prediction accuracy than RCoK-CPXRF. It is concluded that the methods suggested in this study may largely promote the application of in-situ PXRF technique for rapid and accurate soil heavy metal investigation in large-scale areas.
اظهر المزيد [+] اقل [-]Is eating wild rainbow trout safe? The effects of different land-uses on heavy metals content in Chile النص الكامل
2019
Barrientos, C. | Tapia, J. | Bertrán, C. | Peña-Cortés, F. | Hauenstein, E. | Fierro, P. | Vargas-Chacoff, L.
Cu, Mn, Fe, Zn, Cd and Pb levels were measured in liver and muscle samples of Rainbow Trout Oncorhynchus mykiss collected from three watersheds with different land-uses: native forest, exotic plantation, and agriculture in Chile, during January, April, July, and October 2012. Cd and Pb levels were not detected in the liver and muscle, probably since they are under the detection limits. Higher metal concentrations (liver-muscle tissues) were detected in samples from agriculture and exotic plantation streams, whereas trout from native forest streams had lower metal concentrations. Higher metal concentrations were detected in liver tissue compared to muscle tissue, and both negatively correlated to the length and weight of the fish. This suggest the liver had higher ability to accumulate Cu, Mn, Fe and Zn compared to muscle tissue. The concentration range of Fe and Zn recorded in the muscle are within the range reported by other authors, whereas Mn and Cu concentrations are higher than reported in the literature. However, at all sites the concentration of selected metals were below the limits permitted by current legislation (FAO), and therefore did not put the human population at risk, suggesting that is eating wild rainbow trout safe in Chile.
اظهر المزيد [+] اقل [-]Toxicity of engineered micro- and nanomaterials with antifouling properties to the brine shrimp Artemia salina and embryonic stages of the sea urchin Paracentrotus lividus النص الكامل
2019
Gutner-Hoch, Eldad | Martins, Roberto Borges | Maia, Frederico | Oliveira, Tania | Shpigel, Muki | Weis, Michal | Tedim, João | Benayahu, Yehuda
Toxicity of engineered micro- and nanomaterials with antifouling properties to the brine shrimp Artemia salina and embryonic stages of the sea urchin Paracentrotus lividus النص الكامل
2019
Gutner-Hoch, Eldad | Martins, Roberto Borges | Maia, Frederico | Oliveira, Tania | Shpigel, Muki | Weis, Michal | Tedim, João | Benayahu, Yehuda
Antifouling booster biocides are chemicals used in protective paints to tackle the adhesion of fouling organisms to maritime artificial structures. However, they are also known to exert toxic effects on non-target organisms. Recent research developments have highlighted the potential use of engineered micro/nanomaterials (EMNMs) as carriers of antifouling booster biocides in order to control their release and to reduce the harmful effects on living biota. In the present study, we sought to assess the toxicity of two commercially-available booster biocides: (zinc pyrithione (ZnPT) and copper pyrithione (CuPT)); three unloaded engineered micro/nanomaterials (EMNMs); layered double hydroxides (LDH), silica nanocapsules (SiNC), polyurea microcapsules (PU); , and six novel EMNMs (loaded with each of the two biocides). The exposure tests were conducted on the larval stage (nauplii) of the brine shrimp Artemia salina and on two embryonic developmental stages of the European purple sea urchin Paracentrotus lividus. The findings indicate that the unloaded LDH and PU (i.e. both biocide-free EMNMs) have non/low toxic effects on both species. The unloaded SiNC, in contrast, exerted a mild toxic effect on the A. salina nauplii and P. lividus embryos. The free biocides presented different toxicity values, with ZnPT being more toxic than CuPT in the P. lividus assays. LDH-based pyrithiones demonstrated lower toxicity compared to the free forms of the state-of-the-art compounds, and constitute good candidates in terms of their antifouling efficacy.
اظهر المزيد [+] اقل [-]Toxicity of engineered micro- and nanomaterials with antifouling properties to the brine shrimp Artemia salina and embryonic stages of the sea urchin Paracentrotus lividus النص الكامل
2019
Gutner-Hoch, Eldad | Martins, Roberto | Maia, Frederico | Oliveira, Tânia | Shpigel, Muki | Weis, Michal | Tedim, João | Benayahu, Yehuda
Antifouling booster biocides are chemicals used in protective paints to tackle the adhesion of fouling organisms to maritime artificial structures. However, they are also known to exert toxic effects on non-target organisms. Recent research developments have highlighted the potential use of engineered micro/nanomaterials (EMNMs) as carriers of antifouling booster biocides in order to control their release and to reduce the harmful effects on living biota. In the present study, we sought to assess the toxicity of two commercially-available booster biocides: (zinc pyrithione (ZnPT) and copper pyrithione (CuPT)); three unloaded engineered micro/nanomaterials (EMNMs); layered double hydroxides (LDH), silica nanocapsules (SiNC), polyurea microcapsules (PU); , and six novel EMNMs (loaded with each of the two biocides). The exposure tests were conducted on the larval stage (nauplii) of the brine shrimp Artemia salina and on two embryonic developmental stages of the European purple sea urchin Paracentrotus lividus. The findings indicate that the unloaded LDH and PU (i.e. both biocide-free EMNMs) have non/low toxic effects on both species. The unloaded SiNC, in contrast, exerted a mild toxic effect on the A. salina nauplii and P. lividus embryos. The free biocides presented different toxicity values, with ZnPT being more toxic than CuPT in the P. lividus assays. LDH-based pyrithiones demonstrated lower toxicity compared to the free forms of the state-of-the-art compounds, and constitute good candidates in terms of their antifouling efficacy. | published
اظهر المزيد [+] اقل [-]Role of surface functionalities of nanoplastics on their transport in seawater-saturated sea sand النص الكامل
2019
Dong, Zhiqiang | Zhu, Ling | Zhang, Wen | Huang, Rui | Lv, XiangWei | Jing, Xinyu | Yang, Zhenglong | Wang, Junliang | Qiu, Yuping
The transport and retention of nanoplastics (NP, 200 nm nanopolystyrene) functionalized with surface carboxyl (NPC), sulfonic (NPS), low-density amino (negatively charged, NPA−), and high-density amino (positively charged, NPA+) groups in seawater-saturated sand with/without humic acid were examined to explore the role of NP surface functionalities. The mass percentages of NP recovered from the effluent (Meff) with a salinity of 35 practical salinity units (PSU) were ranked as follows: NPC (19.69%) > NPS (16.37%) > NPA+ (13.33%) > NPA− (9.78%). The homoaggregation of NPS and NPA− was observed in seawater. The transport of NPA− exhibited a ripening phenomenon (i.e., a decrease in the transport rate with time) due to the high attraction of NP with previously deposited NP, whereas monodispersed NPA+ presented a low Meff value because of the electrostatic attraction between NPA+ and negatively charged sand. Retention experiments showed that the majority of NPC, NPS and NPA+ accumulated in a monolayer on the sand surface, whereas NPA− accumulated in multiple layers. Suwannee River humic acid (SRHA) could remarkably improve the transportability of NPC, NPS, and NPA− by increasing steric repulsion. The strong attraction between NPA+ and the deposited NPA+ in the presence of SRHA triggered the weak ripening phenomenon. As seawater salinity decreased from 35 PSU to 3.5 PSU, the increase in electrostatic repulsion of NP-NP and NP-sand enhanced the transport of NPC, NPS, and NPA−, and the ripening of NPA− breakthrough curves disappeared. In deionized water, NPC, NPS, and NPA− achieved complete column breakthrough because the electrostatic repulsion between NP and sand intensified. However, the Meff values of NPA+ in 3.5 PSU seawater and deionized water presented limited increments of 15.49% and 23.67%, respectively. These results indicated that the fate of NP in sandy marine environments were strongly affected by NP surface functionalities, seawater salinity, and coexisting SRHA.
اظهر المزيد [+] اقل [-]The climatology of aerosol optical thickness and radiative effects in Southeast Asia from 18-years of ground-based observations النص الكامل
2019
Khan, Rehana | Kumar, Kanike Raghavendra | Zhao, Tianliang
The present study utilizes 18 years of long-term (2001–2018) data collected from six active AERONET sites over the Indo-Gangetic Plain (IGP) and the North China Plain (NCP) areas in Southeast Asia. The annual mean (±SD) aerosol optical thickness at 440 nm (AOT₄₄₀) was found high at XiangHe (0.92 ± 0.69) and Taihu (0.90 ± 0.51) followed by Beijing (0.81 ± 0.69), Lahore (0.81 ± 0.43), and Kanpur (0.73 ± 0.35) and low at Karachi (0.52 ± 0.23). Seasonally, high AOT₄₄₀ with corresponding high Ångström exponent (ANG₄₄₀₋₈₇₀) noticed during JJA for all sites, except Kanpur, suggesting the dominance of fine-mode particles, generally associated with large anthropogenic emissions. Climatologically, an increasing (decreasing) trend was observed over IGP (NCP) sites, with the highest (lowest) percentage of departures in AOT₄₄₀ found over Beijing (Karachi). We further identified major aerosol types which showed the dominance of biomass burning, urban-industrial followed by the mixed type of aerosols. In addition, single scattering albedo (SSA), asymmetry parameter (ASP), volume size distribution (VSD), and complex aerosol refractive index (RI) showed significant temporal and spectral changes, illustrating the complexity of aerosol types. At last, the annual mean direct aerosol radiative forcing at the top, bottom, and within the atmosphere for all sites were found in the range from −17.36 ± 3.75 to −45.17 ± 4.87 W m⁻², -64.6 ± 4.86 to −93.7 ± 10.27 W m⁻², and 40.5 ± 6.43 to 68.25 ± 7.26 W m⁻², respectively, with an averaged atmospheric heating rate of 0.9–2.3 K day⁻¹. A large amount of anthropogenic aerosols showed a significant effect of heating (cooling) on the atmosphere (surface) results obviously, due to an increased rate of atmospheric heating. Therefore, the thermodynamic effects of anthropogenic aerosols on the atmospheric circulation and its structure should be taken into consideration for future study over the experimental sites.
اظهر المزيد [+] اقل [-]Comparison of the health risks associated with different exposure pathways of multiple volatile chlorinated hydrocarbons in contaminated drinking groundwater النص الكامل
2019
Liu, Weijiang | Chen, Liuzhu | Liu, Xin | Chen, Jian | Liu, Rui | Niu, Haobo
A total of 152 groundwater samples were collected around a contaminated site to evaluate the carcinogenic and noncarcinogenic risks of exposure to twelve volatile chlorinated hydrocarbons (VCHs) by oral ingestion, dermal contact and inhalation absorption during showering. Although toxicity data of some VCHs are fragmentary, the results showed that the carcinogenic and noncarcinogenic risks of exposure to VCHs in contaminated drinking groundwater for local residents needs immediate attention. The main risk contributors for the carcinogenic and noncarcinogenic risks are carbon tetrachloride and 1,1,2-trichloroethane through inhalation exposure pathway, respectively. The health risk contribution rates associated with three exposure pathways for a specific VCH were intrinsic to the compound, and the dermal contact corresponded to a negligible contribution for almost every VCH species. Although most of the evaluated VCHs had a higher risk contribution by inhalation than by oral ingestion pathway, the integrated multi-VCH health risk contributions of the three exposure pathways were mainly dependent on the VCH compositions. Drinking boiled water not only decreased the exposure risk but also affected the risk contribution rates of three exposure pathways, which indicates that it is feasible to reduce the risk of VCH exposure during daily activities based on the risk contribution of the exposure pathways. In addition to the VCHs included in the drinking water standards, species such as 1,1,2,2-tetrachloroethane and hexachloroethane also showed a remarkable exposure health risk according to the standardized health risk calculation, which implied that improved drinking water standards are urgently required.
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