Heterogeneous photocatalytic reaction has been generally applied for degradation of toxic contaminants.Degradations of a compound using the same kind of catalyst that was synthesized differently are commonly found in ...Heterogeneous photocatalytic reaction has been generally applied for degradation of toxic contaminants.Degradations of a compound using the same kind of catalyst that was synthesized differently are commonly found in literature.However,the reported degradation intermediates are normally inconsistent.This issue is especially important for the degradation of toxic compounds because intermediates may be more toxic than their parent compounds and understanding the reason is necessary if appropriate catalysts are to be designed.This work systematically compares the photocatalytic degradation of diuron,a toxic recalcitrant herbicide,on two forms of zinc oxide(ZnO),i.e.,conventional particles with zinc-and oxygen-terminated polar surfaces as the dominating planes,and nanorods with mixed-terminated nonpolar surfaces.Experimental and theoretical results indicate that both the rate of reaction and the degradation pathway depend on the adsorption configuration of diuron onto the surface.Diuron molecules adsorb in different alignments on the two surfaces,contributing to the formation of different degradation intermediates.Both the aliphatic and aromatic sides of diuron adsorb on the polar surfaces simultaneously,leading to an attack by hydroxyl radicals from both ends.On the other hand,on the mixed-terminated surface,only the aliphatic part adsorbs and is degraded.The exposed surface is therefore the key factor controlling the degradation pathway.For diuron degradation on ZnO,a catalyst confined tomixed-terminated surfaces,i.e.,ZnO nanorods,is more desirable,as it avoids the formation of intermediates with potent phytotoxicity and cytogenotoxicity.展开更多
This study investigated the adsorption potential of diuron and linuron in selected soil samples collected from agricultural area of Gaza Strip, Palestine and correlated the adsorption results to the soil properties. T...This study investigated the adsorption potential of diuron and linuron in selected soil samples collected from agricultural area of Gaza Strip, Palestine and correlated the adsorption results to the soil properties. The adsorption experiments are based on the batch equilibrium technique and UV-Spectrophotometer method to determine the equilibrium concentration of both herbicides. Results of adsorption experiment showed that linuron and diuron are adsorbed in various amounts in Gaza soils according to the variation in pH, organic matter and clay content. Adsorption isotherms of both herbicides were linear in the tested concentration. Fitting the adsorption data to Freundlich equation showed good fitting and Freundlich constants were less than one indicating physical adsorption processes. It is concluded that soil organic matter and pH affect the adsorption of both herbicides. These results provided a better understanding of the behavior of diuron and linuron in Gaza soils.展开更多
This study investigated the leaching potential of diuron and linuron in different soil types in Gaza Strip, Palestine under laboratory and field conditions. Leaching potential was evaluated by tin columns and bioassay...This study investigated the leaching potential of diuron and linuron in different soil types in Gaza Strip, Palestine under laboratory and field conditions. Leaching potential was evaluated by tin columns and bioassay technique using Molokhia as test plant. The responses of the test plant were regressed versus concentrations of the herbicide to estimate linear regression equation and the regression coefficient. The obtained results indicate strong positive association between Molokhia and concentrations of diuron or linuron;accordingly it was used in the bioassay and estimation of the concentrations of the tested herbicides in the leaching depth. Leaching potential was very low in North Gaza and Kkan Younis soil, whereas in the Meddle zone soil was very large. Leaching potential under laboratory conditions was larger that under field conditions. The bioestimated concentrations in soil layer under field conditions were sever folds of magnitude lower than those under laboratory conditions. The interesting outcome of this study is that leaching potential is dependent on soil clay fraction, soil organic matter, and soil pH. These results provided answers to the questions raised by farmers in Gaza Strip.展开更多
Diuron is a herbicide widely used in the Middle East;its field application creates many environmental problems. This study investigated the bioremediation of Diuron in soil environment by Cyanobacterial mats collected...Diuron is a herbicide widely used in the Middle East;its field application creates many environmental problems. This study investigated the bioremediation of Diuron in soil environment by Cyanobacterial mats collected from Gaza Wadi. Various concentrations of Diuron were injected in water saturated soil samples pre-treated with Cyanobacterial mat for several periods. Percent growth of Jews mallow as a test plant was taken as indicator of biodegradation of Diuron. Results showed that Diuron was degraded in soil and degradation was more pronounced when Diuron was incubated with Cyanobacterial in the irrigation water. Larger applied rate of Cyanobacterial mat did not affect the biodegradation of Diuron. These encouraging results suggest that application of Cyanobacterial mat could be a suitable method to remediate soil pollution.展开更多
The digestion regularity of MCPA, ametryn and dim＇on which were the active ingredients of 55% MCPA · ametryn · diuron WP in sugarcane leaves and soil of sugarcane plantation collected from Changsha of Hunan...The digestion regularity of MCPA, ametryn and dim＇on which were the active ingredients of 55% MCPA · ametryn · diuron WP in sugarcane leaves and soil of sugarcane plantation collected from Changsha of Hunan Province and Haikou of Hainan Province in 2009 and 2010were studied in the paper, and the results showed that these three agents had rapid digestion. The final residue test showed that beth MCPA and ametryn had not been detected in the study; the average resi- dues of diuron in the soil collected from Hunan Province in 2009 and 2010 were 0.018 and 0.015 mg/kg, respectively which were slightly larger than the critical value of 0. 013mg,/kg; diuron had no been detected in other treatments.展开更多
The pollution level of diuron in seawater and sediments in the west coastal sea area of Zhoushan Island from 2011 to 2013 was investigated. Results revealed that the concentration of diuron in seawater varies from les...The pollution level of diuron in seawater and sediments in the west coastal sea area of Zhoushan Island from 2011 to 2013 was investigated. Results revealed that the concentration of diuron in seawater varies from less than (3.0 to 52.1) ng·L-1, with an average level of less than 11.1 ng.L-1. The annual average content was less than 7.9 ng.L-1, 13.9 ng.L-1, and 12.3 ng.L-1 in 2011, 2012, and 2013, respectively. The concentrations of diuron in marine sediments also varied from less than (0.3 to 3.9) ng.g-1 (dry weight), with an average concentration of less than 1.13 ng g-1 (dry weight). The annual average concentration was less than 0.851 ng.g-1, 1.328 ng.g-1, and 1.202 ng.g-1 in 2011, 2012, and 2013, respectively. The accumulation of diuron in seawater and sediments may pose a potential risk to the marine ecosystem of the investigated sea area.展开更多
Diuron (N-(3,4-dichlorophenyl)-N,N-dimethylurea) is one among the booster biocides substituted tributyltin as an antifouling agent. It has continued to be used ever since, though little is known about their levels in ...Diuron (N-(3,4-dichlorophenyl)-N,N-dimethylurea) is one among the booster biocides substituted tributyltin as an antifouling agent. It has continued to be used ever since, though little is known about their levels in the maritime setting of Zanzibar. This paper details the occurrence and distribution of diuron around the coastline of Zanzibar Island. The reported concentrations of diuron in water ranged from Below Detection Limit to 1321.67 ± 52.3 ng/L at Bwawani. Majority of the sites showed levels above Environmental Risk Limit of 430 ng/L as proposed by the Dutch Authorities. The findings suggest the contamination is elevated especial in Harbor, Bwawani, Chapwani and even at Marine Protected Areas such Mnemba Island where the value of 620.33 ± 5.70 ng/L was recorded. The main possible sources of the contamination are cargo shipping, passenger speedboats, fishing, and tourism activities taking places in these areas. Therefore, future studies on the antifouling biocide diuron particularly on long term monitoring, chronic exposure, risk assessment, organisms’ responses and pollution models will add special value towards better understanding of the mechanisms and sustainable marine ecosystem health.展开更多
In recent decades, the application of antifouling paints to watercrafts has emerged as a significant concern in coastal ecosystems, including coral reefs. Diuron, a booster biocide commonly used as an antifouling agen...In recent decades, the application of antifouling paints to watercrafts has emerged as a significant concern in coastal ecosystems, including coral reefs. Diuron, a booster biocide commonly used as an antifouling agent, is persistent in soil, water, and groundwater. Although it exhibits moderate toxicity to mammals and birds, its primary breakdown product, 3,4-dichloroaniline, is highly toxic and environmentally persistent. The secondary toxicity of Diuron emphasizes its potential to contaminate groundwater. This investigation determined the 96-hour LC50 value for Diuron to be 1.627 ± 0.181 mg/L in Lates calcarifer. A 21-day sublethal exposure of Lates calcarifer to diuron did not yield statistically significant differences (P > 0.05) in fatty acid composition between the fresh and control groups. Both groups demonstrated polyunsaturated fatty acids (PUFAs) as the most abundant fatty acids, followed by saturated fatty acids (SFAs) and monounsaturated fatty acids (MUFAs). However, significant variations (P Lates calcarifer exposed to varying diuron concentrations (50%, 30%, and 10% of the LC50 value). The magnitude of these effects increased with increasing exposure levels. The results of this study indicate that diuron, even at concentrations considered safe, can adversely affect marine organisms, including alterations to their fatty acid composition.展开更多
Diuron is one of the most frequently applied herbicides in sugarcane farming in southern Japan,and Australia.In addition,it is used as a booster substance in copper-based antifouling paints.Due to these various uses,D...Diuron is one of the most frequently applied herbicides in sugarcane farming in southern Japan,and Australia.In addition,it is used as a booster substance in copper-based antifouling paints.Due to these various uses,Diuron is released into the marine environment;however,little information is available on gene expression in corals and their symbiotic algae exposed to Diuron.We investigated the efects of Diuron on stress-responsive gene expression in the hermatypic coral Acropora tenuis and its symbiotic dinofagellates.After seven days of exposure to 1µg/L and 10µg/L Diuron,no signifcant changes in the body colour of corals were observed.However,quantitative reverse transcription-polymerase chain reaction analyses revealed that the expression levels of stress-responsive genes,such as heat shock protein 90(HSP90),HSP70,and calreticulin(CALR),were signifcantly downregulated in corals exposed to 10µg/L of Diuron for seven days.Moreover,aquaglyceroporin was signifcantly downregulated in corals exposed to environmentally relevant concentrations of 1µg/L Diuron.In contrast,no such efects were observed on the expression levels of other stress-responsive genes,such as oxidative stress-responsive proteins,methionine adenosyltransferase,and green/red fuorescent proteins.Diuron exposure had no signifcant efect on the expression levels of HSP90,HSP70,or HSP40 in the symbiotic dinofagellates.These results suggest that stress-responsive genes,such as HSPs,respond diferently to Diuron in corals and their symbiotic dinofagellates and that A.tenuis HSPs and CALRs may be useful molecular biomarkers for predicting stress responses induced by the herbicide Diuron.展开更多
基金funded by the Thailand Research Fund (No. DBG5580006)
文摘Heterogeneous photocatalytic reaction has been generally applied for degradation of toxic contaminants.Degradations of a compound using the same kind of catalyst that was synthesized differently are commonly found in literature.However,the reported degradation intermediates are normally inconsistent.This issue is especially important for the degradation of toxic compounds because intermediates may be more toxic than their parent compounds and understanding the reason is necessary if appropriate catalysts are to be designed.This work systematically compares the photocatalytic degradation of diuron,a toxic recalcitrant herbicide,on two forms of zinc oxide(ZnO),i.e.,conventional particles with zinc-and oxygen-terminated polar surfaces as the dominating planes,and nanorods with mixed-terminated nonpolar surfaces.Experimental and theoretical results indicate that both the rate of reaction and the degradation pathway depend on the adsorption configuration of diuron onto the surface.Diuron molecules adsorb in different alignments on the two surfaces,contributing to the formation of different degradation intermediates.Both the aliphatic and aromatic sides of diuron adsorb on the polar surfaces simultaneously,leading to an attack by hydroxyl radicals from both ends.On the other hand,on the mixed-terminated surface,only the aliphatic part adsorbs and is degraded.The exposed surface is therefore the key factor controlling the degradation pathway.For diuron degradation on ZnO,a catalyst confined tomixed-terminated surfaces,i.e.,ZnO nanorods,is more desirable,as it avoids the formation of intermediates with potent phytotoxicity and cytogenotoxicity.
文摘This study investigated the adsorption potential of diuron and linuron in selected soil samples collected from agricultural area of Gaza Strip, Palestine and correlated the adsorption results to the soil properties. The adsorption experiments are based on the batch equilibrium technique and UV-Spectrophotometer method to determine the equilibrium concentration of both herbicides. Results of adsorption experiment showed that linuron and diuron are adsorbed in various amounts in Gaza soils according to the variation in pH, organic matter and clay content. Adsorption isotherms of both herbicides were linear in the tested concentration. Fitting the adsorption data to Freundlich equation showed good fitting and Freundlich constants were less than one indicating physical adsorption processes. It is concluded that soil organic matter and pH affect the adsorption of both herbicides. These results provided a better understanding of the behavior of diuron and linuron in Gaza soils.
文摘This study investigated the leaching potential of diuron and linuron in different soil types in Gaza Strip, Palestine under laboratory and field conditions. Leaching potential was evaluated by tin columns and bioassay technique using Molokhia as test plant. The responses of the test plant were regressed versus concentrations of the herbicide to estimate linear regression equation and the regression coefficient. The obtained results indicate strong positive association between Molokhia and concentrations of diuron or linuron;accordingly it was used in the bioassay and estimation of the concentrations of the tested herbicides in the leaching depth. Leaching potential was very low in North Gaza and Kkan Younis soil, whereas in the Meddle zone soil was very large. Leaching potential under laboratory conditions was larger that under field conditions. The bioestimated concentrations in soil layer under field conditions were sever folds of magnitude lower than those under laboratory conditions. The interesting outcome of this study is that leaching potential is dependent on soil clay fraction, soil organic matter, and soil pH. These results provided answers to the questions raised by farmers in Gaza Strip.
文摘Diuron is a herbicide widely used in the Middle East;its field application creates many environmental problems. This study investigated the bioremediation of Diuron in soil environment by Cyanobacterial mats collected from Gaza Wadi. Various concentrations of Diuron were injected in water saturated soil samples pre-treated with Cyanobacterial mat for several periods. Percent growth of Jews mallow as a test plant was taken as indicator of biodegradation of Diuron. Results showed that Diuron was degraded in soil and degradation was more pronounced when Diuron was incubated with Cyanobacterial in the irrigation water. Larger applied rate of Cyanobacterial mat did not affect the biodegradation of Diuron. These encouraging results suggest that application of Cyanobacterial mat could be a suitable method to remediate soil pollution.
基金Supported by Scientific and Technological Projects of Nanning Municipal Science and Technology Bureau(20132308)
文摘The digestion regularity of MCPA, ametryn and dim＇on which were the active ingredients of 55% MCPA · ametryn · diuron WP in sugarcane leaves and soil of sugarcane plantation collected from Changsha of Hunan Province and Haikou of Hainan Province in 2009 and 2010were studied in the paper, and the results showed that these three agents had rapid digestion. The final residue test showed that beth MCPA and ametryn had not been detected in the study; the average resi- dues of diuron in the soil collected from Hunan Province in 2009 and 2010 were 0.018 and 0.015 mg/kg, respectively which were slightly larger than the critical value of 0. 013mg,/kg; diuron had no been detected in other treatments.
文摘The pollution level of diuron in seawater and sediments in the west coastal sea area of Zhoushan Island from 2011 to 2013 was investigated. Results revealed that the concentration of diuron in seawater varies from less than (3.0 to 52.1) ng·L-1, with an average level of less than 11.1 ng.L-1. The annual average content was less than 7.9 ng.L-1, 13.9 ng.L-1, and 12.3 ng.L-1 in 2011, 2012, and 2013, respectively. The concentrations of diuron in marine sediments also varied from less than (0.3 to 3.9) ng.g-1 (dry weight), with an average concentration of less than 1.13 ng g-1 (dry weight). The annual average concentration was less than 0.851 ng.g-1, 1.328 ng.g-1, and 1.202 ng.g-1 in 2011, 2012, and 2013, respectively. The accumulation of diuron in seawater and sediments may pose a potential risk to the marine ecosystem of the investigated sea area.
文摘Diuron (N-(3,4-dichlorophenyl)-N,N-dimethylurea) is one among the booster biocides substituted tributyltin as an antifouling agent. It has continued to be used ever since, though little is known about their levels in the maritime setting of Zanzibar. This paper details the occurrence and distribution of diuron around the coastline of Zanzibar Island. The reported concentrations of diuron in water ranged from Below Detection Limit to 1321.67 ± 52.3 ng/L at Bwawani. Majority of the sites showed levels above Environmental Risk Limit of 430 ng/L as proposed by the Dutch Authorities. The findings suggest the contamination is elevated especial in Harbor, Bwawani, Chapwani and even at Marine Protected Areas such Mnemba Island where the value of 620.33 ± 5.70 ng/L was recorded. The main possible sources of the contamination are cargo shipping, passenger speedboats, fishing, and tourism activities taking places in these areas. Therefore, future studies on the antifouling biocide diuron particularly on long term monitoring, chronic exposure, risk assessment, organisms’ responses and pollution models will add special value towards better understanding of the mechanisms and sustainable marine ecosystem health.
文摘In recent decades, the application of antifouling paints to watercrafts has emerged as a significant concern in coastal ecosystems, including coral reefs. Diuron, a booster biocide commonly used as an antifouling agent, is persistent in soil, water, and groundwater. Although it exhibits moderate toxicity to mammals and birds, its primary breakdown product, 3,4-dichloroaniline, is highly toxic and environmentally persistent. The secondary toxicity of Diuron emphasizes its potential to contaminate groundwater. This investigation determined the 96-hour LC50 value for Diuron to be 1.627 ± 0.181 mg/L in Lates calcarifer. A 21-day sublethal exposure of Lates calcarifer to diuron did not yield statistically significant differences (P > 0.05) in fatty acid composition between the fresh and control groups. Both groups demonstrated polyunsaturated fatty acids (PUFAs) as the most abundant fatty acids, followed by saturated fatty acids (SFAs) and monounsaturated fatty acids (MUFAs). However, significant variations (P Lates calcarifer exposed to varying diuron concentrations (50%, 30%, and 10% of the LC50 value). The magnitude of these effects increased with increasing exposure levels. The results of this study indicate that diuron, even at concentrations considered safe, can adversely affect marine organisms, including alterations to their fatty acid composition.
基金This work was supported by the Japan Society for the Promotion of Science(JSPS)Grants-in-Aid for Scientifc Research(KAKENHI)(Grant Nos.26281048 and 21H03619).
文摘Diuron is one of the most frequently applied herbicides in sugarcane farming in southern Japan,and Australia.In addition,it is used as a booster substance in copper-based antifouling paints.Due to these various uses,Diuron is released into the marine environment;however,little information is available on gene expression in corals and their symbiotic algae exposed to Diuron.We investigated the efects of Diuron on stress-responsive gene expression in the hermatypic coral Acropora tenuis and its symbiotic dinofagellates.After seven days of exposure to 1µg/L and 10µg/L Diuron,no signifcant changes in the body colour of corals were observed.However,quantitative reverse transcription-polymerase chain reaction analyses revealed that the expression levels of stress-responsive genes,such as heat shock protein 90(HSP90),HSP70,and calreticulin(CALR),were signifcantly downregulated in corals exposed to 10µg/L of Diuron for seven days.Moreover,aquaglyceroporin was signifcantly downregulated in corals exposed to environmentally relevant concentrations of 1µg/L Diuron.In contrast,no such efects were observed on the expression levels of other stress-responsive genes,such as oxidative stress-responsive proteins,methionine adenosyltransferase,and green/red fuorescent proteins.Diuron exposure had no signifcant efect on the expression levels of HSP90,HSP70,or HSP40 in the symbiotic dinofagellates.These results suggest that stress-responsive genes,such as HSPs,respond diferently to Diuron in corals and their symbiotic dinofagellates and that A.tenuis HSPs and CALRs may be useful molecular biomarkers for predicting stress responses induced by the herbicide Diuron.
