Groundwater in Changchun City, Jilin Province of China tends to be influenced by human activities. Chemical types of groundwater were detected in both shallow and deep groundwater were: HCO3--Ca2+ and HCO3--Ca2+·...Groundwater in Changchun City, Jilin Province of China tends to be influenced by human activities. Chemical types of groundwater were detected in both shallow and deep groundwater were: HCO3--Ca2+ and HCO3--Ca2+·Mg2+ or HCO3--Mg2+·Ca2+; SO42--Ca2+ and SO42--Ca2+·Mg2+; Cl--Ca2+; and CO32--Na+. The deteriorations of groundwater quality due to the increase of TDS, NO3-+ NO2-(as Nitrogen) and TH contents have been observed from 1991 to 1998. Scatter analyses showed strong positive correlations between Ca2+, Cl-and NO3-ions and weak negative correlations between the depth of water table and Ca2+, SO42-, Cl-and NO3-ions. A mapping of contaminant index based on Chinese standard of groundwater showed that a large proportion of the groundwater in 1998 was deteriorated by human process. Despite their low values of sodium adsorption ratio (SAR), the most of the sampled wells were not suitable for drinking and agriculture purposes due to higher contents of NO3-, NO2-and Mn2+ ions.展开更多
With the development of economic activities, marine oil pollution is becoming an increasing serious problem. Instead of dissolved in seawater, petroleum hydrocarbons are more easily enriched in sediments, which poses ...With the development of economic activities, marine oil pollution is becoming an increasing serious problem. Instead of dissolved in seawater, petroleum hydrocarbons are more easily enriched in sediments, which poses a serious threat to benthos. In this paper, the research progresses on toxicity of marine petroleum hydrocarbon for polychaetes were reviewed in recent years, including the toxic mechanism of petroleum hydrocarbons, the feeding habits, the effects of petroleum hydrocarbons on the antioxidant defense system, the nervous system damages, the molecular damages of polychaetes under the stress of petroleum hydrocarbon, the accumulation and metabolism of petroleum hydrocarbons in polychaetes. The future research direction were also prospected.展开更多
The electrochemical behavior of X70 pipeline steel in (0.5mol·L-1 Na2CO3+1 mol·L-1 NaHCO3) solution was studied by potentiodynamic polarization and electrochemical impedance spectroscopy (EIS). X-ray photoel...The electrochemical behavior of X70 pipeline steel in (0.5mol·L-1 Na2CO3+1 mol·L-1 NaHCO3) solution was studied by potentiodynamic polarization and electrochemical impedance spectroscopy (EIS). X-ray photoelectron spectroscopy (XPS) and scanning electron microscopy (SEM) were used to analyze the composition and microstructure of the surface film. The results showed that there were two anodic peaks at -600 mV and -350 mV. The surface film formed at -600 mV mainly consisted of ferrous carbonates and ferrous hydroxycarbonates. It had a small reaction resistance. It was metastable and possessed poor protective property. Numerous pits and microcracks existed on the film, which could be the active paths for the initiation of stress corrosion cracking. The surface film formed at -350 mV, mainly consisted of ferric oxides. It has high reaction resistance and offered good protection for the substrate.展开更多
The objective was to evaluate the effect of aqueous infusion of cracked soursop seeds on two different concentrations as an organic dewormer compared to a commercial one in GNE （gastrointestinal nematodes） egg popul...The objective was to evaluate the effect of aqueous infusion of cracked soursop seeds on two different concentrations as an organic dewormer compared to a commercial one in GNE （gastrointestinal nematodes） egg population in crossbred hair sheep （Blackbelly-Khatadin） of the northen region of Veracruz. The aqueous infusion was prepared adding 93.5 g of cracked soursop seeds in 1,875 mL of boiled water and let stand for 12 h. Crossbred ewes were randomly assigned to receive every 19 days： （1） 10 mL of cracked soursop infusion orally （n = 27）, （2） 15 mL of cracked soursop infusion orally （n = 27）, and （3） 2 mL of Febendazole subcutaneously （n = 26）. Feces （2-5 g） were collected directly from the rectum of each animal on the following days： 0, 19, 38 and 57 days post treatment. Nematode egg population was determined using the technique of McMaster. Statistical analysis was done using ANOVA （analysis of variance）. There was a reduction overtime （P = 0.05） in all treatments in parasite egg population. There were no differences （P = 0.10） in egg population across treatments. In conclusion, aqueous infusion of soursop cracked seeds proved to be an environmentally friendly and effective alternative in the control of gastrointestinal parasites in crossbred hair sheep in the region of northern Veracruz.展开更多
文摘Groundwater in Changchun City, Jilin Province of China tends to be influenced by human activities. Chemical types of groundwater were detected in both shallow and deep groundwater were: HCO3--Ca2+ and HCO3--Ca2+·Mg2+ or HCO3--Mg2+·Ca2+; SO42--Ca2+ and SO42--Ca2+·Mg2+; Cl--Ca2+; and CO32--Na+. The deteriorations of groundwater quality due to the increase of TDS, NO3-+ NO2-(as Nitrogen) and TH contents have been observed from 1991 to 1998. Scatter analyses showed strong positive correlations between Ca2+, Cl-and NO3-ions and weak negative correlations between the depth of water table and Ca2+, SO42-, Cl-and NO3-ions. A mapping of contaminant index based on Chinese standard of groundwater showed that a large proportion of the groundwater in 1998 was deteriorated by human process. Despite their low values of sodium adsorption ratio (SAR), the most of the sampled wells were not suitable for drinking and agriculture purposes due to higher contents of NO3-, NO2-and Mn2+ ions.
基金supported by the National Natural Science Foundation of China(No.21677065).
文摘With the development of economic activities, marine oil pollution is becoming an increasing serious problem. Instead of dissolved in seawater, petroleum hydrocarbons are more easily enriched in sediments, which poses a serious threat to benthos. In this paper, the research progresses on toxicity of marine petroleum hydrocarbon for polychaetes were reviewed in recent years, including the toxic mechanism of petroleum hydrocarbons, the feeding habits, the effects of petroleum hydrocarbons on the antioxidant defense system, the nervous system damages, the molecular damages of polychaetes under the stress of petroleum hydrocarbon, the accumulation and metabolism of petroleum hydrocarbons in polychaetes. The future research direction were also prospected.
基金Supported by State Key Basic Research Plan (G19990650).
文摘The electrochemical behavior of X70 pipeline steel in (0.5mol·L-1 Na2CO3+1 mol·L-1 NaHCO3) solution was studied by potentiodynamic polarization and electrochemical impedance spectroscopy (EIS). X-ray photoelectron spectroscopy (XPS) and scanning electron microscopy (SEM) were used to analyze the composition and microstructure of the surface film. The results showed that there were two anodic peaks at -600 mV and -350 mV. The surface film formed at -600 mV mainly consisted of ferrous carbonates and ferrous hydroxycarbonates. It had a small reaction resistance. It was metastable and possessed poor protective property. Numerous pits and microcracks existed on the film, which could be the active paths for the initiation of stress corrosion cracking. The surface film formed at -350 mV, mainly consisted of ferric oxides. It has high reaction resistance and offered good protection for the substrate.
文摘The objective was to evaluate the effect of aqueous infusion of cracked soursop seeds on two different concentrations as an organic dewormer compared to a commercial one in GNE （gastrointestinal nematodes） egg population in crossbred hair sheep （Blackbelly-Khatadin） of the northen region of Veracruz. The aqueous infusion was prepared adding 93.5 g of cracked soursop seeds in 1,875 mL of boiled water and let stand for 12 h. Crossbred ewes were randomly assigned to receive every 19 days： （1） 10 mL of cracked soursop infusion orally （n = 27）, （2） 15 mL of cracked soursop infusion orally （n = 27）, and （3） 2 mL of Febendazole subcutaneously （n = 26）. Feces （2-5 g） were collected directly from the rectum of each animal on the following days： 0, 19, 38 and 57 days post treatment. Nematode egg population was determined using the technique of McMaster. Statistical analysis was done using ANOVA （analysis of variance）. There was a reduction overtime （P = 0.05） in all treatments in parasite egg population. There were no differences （P = 0.10） in egg population across treatments. In conclusion, aqueous infusion of soursop cracked seeds proved to be an environmentally friendly and effective alternative in the control of gastrointestinal parasites in crossbred hair sheep in the region of northern Veracruz.
