Phytoremediation is a cheap and environmentally friendly technique in which green plants in situ are used to clean the soil, sediments and water of heavy metals. This study investigated the phytoremediation potential ...Phytoremediation is a cheap and environmentally friendly technique in which green plants in situ are used to clean the soil, sediments and water of heavy metals. This study investigated the phytoremediation potential of six naturally occurring macrophytes from Nange (a stream in Buea municipality where cars have been driven into and washed for over 20 years). Plant samples were collected before and after car wash, then analysed for copper, zinc, lead and cadmium accumulation. There was an increase in concentration of all the four heavy metals in water after carwash point, with Zn having the highest concentration (0.27 mg/L). Mean concentration of the heavy metals in the water showed that Zn and Pb had the highest concentrations (0.24 mg/L each) while the least concentration was obtained in Cu (0.12 mg/kg). Heavy metal concentrations in the sediments were higher after car wash point than before. Cadmium had the highest concentration (5.58 mg/kg) while Cu had the least (0.75 mg/kg). <em>Ludwigia peruviana</em> had the highest BAFs for all the heavy metals (22.95 for Cu, 33.41 for Zn, 21.79 for Pb and 7.85 for Cd). Species with the leasts were: <em>Anubias barteri</em> for Cu (7.16), <em>Polygonum persicaria</em> for Zn (14.28), <em>Rorippa nasturtium-aquaticum</em> for Pb (11.60) and <em>Vallisneria spiralis</em> for Cd (1.98). <em>L. peruviana</em> had the highest BAC values (Cu = 10.11, Zn = 14.73, Pb = 11.39, Cd = 3.85) and BCF values (Cu = 12.84, Zn = 18.67, Pb = 10.40, Cd = 4.00). <em>A. barteri</em> had the highest TF (Cu = 1.49, Zn = 1.27, Cd = 1.99) except for Pb where both <em>A. barteri </em>and <em>L. peruviana</em> each had a TF of 1.10. While all the six plants were found to be good accumulators of the heavy metals, <em>L. peruviana</em> showed remarkable efficiency indicating that the species is a good candidate for cleaning such environments.展开更多
The goal of this study is to assess the ability of existing car washing stations in Khartoum City using an ArcMap suitability modeling tool. Methods: In Khartoum, an increasing number of vehicle wash stations were ope...The goal of this study is to assess the ability of existing car washing stations in Khartoum City using an ArcMap suitability modeling tool. Methods: In Khartoum, an increasing number of vehicle wash stations were opened every day. The main criteria are street, the slope, the hospitals, the police station, and the school, which have been used to build a model of suitability based on weight overlay in ArcGIS 10.4. The findings revealed two evaluation tendencies. One tendency involves business centers that are located on main roads but are adjacent to residential areas, while another involves business centers that have rezoned residential plots without consideration for ideal site requirements for the environment. There are locations that would be appropriate for vehicle wash centers, according to the final suitability map. On a scale of 1 to 5, less than 30% of the study area is considered suitable for a new car wash regarding class 5. On the other hand, significant areas are available for car wash development in the second value of suitability 4, but as second-ranked suitability. The assessment was accomplished by comparing the final suitability map of car washing centers to the layers which represented them.展开更多
文摘Phytoremediation is a cheap and environmentally friendly technique in which green plants in situ are used to clean the soil, sediments and water of heavy metals. This study investigated the phytoremediation potential of six naturally occurring macrophytes from Nange (a stream in Buea municipality where cars have been driven into and washed for over 20 years). Plant samples were collected before and after car wash, then analysed for copper, zinc, lead and cadmium accumulation. There was an increase in concentration of all the four heavy metals in water after carwash point, with Zn having the highest concentration (0.27 mg/L). Mean concentration of the heavy metals in the water showed that Zn and Pb had the highest concentrations (0.24 mg/L each) while the least concentration was obtained in Cu (0.12 mg/kg). Heavy metal concentrations in the sediments were higher after car wash point than before. Cadmium had the highest concentration (5.58 mg/kg) while Cu had the least (0.75 mg/kg). <em>Ludwigia peruviana</em> had the highest BAFs for all the heavy metals (22.95 for Cu, 33.41 for Zn, 21.79 for Pb and 7.85 for Cd). Species with the leasts were: <em>Anubias barteri</em> for Cu (7.16), <em>Polygonum persicaria</em> for Zn (14.28), <em>Rorippa nasturtium-aquaticum</em> for Pb (11.60) and <em>Vallisneria spiralis</em> for Cd (1.98). <em>L. peruviana</em> had the highest BAC values (Cu = 10.11, Zn = 14.73, Pb = 11.39, Cd = 3.85) and BCF values (Cu = 12.84, Zn = 18.67, Pb = 10.40, Cd = 4.00). <em>A. barteri</em> had the highest TF (Cu = 1.49, Zn = 1.27, Cd = 1.99) except for Pb where both <em>A. barteri </em>and <em>L. peruviana</em> each had a TF of 1.10. While all the six plants were found to be good accumulators of the heavy metals, <em>L. peruviana</em> showed remarkable efficiency indicating that the species is a good candidate for cleaning such environments.
文摘The goal of this study is to assess the ability of existing car washing stations in Khartoum City using an ArcMap suitability modeling tool. Methods: In Khartoum, an increasing number of vehicle wash stations were opened every day. The main criteria are street, the slope, the hospitals, the police station, and the school, which have been used to build a model of suitability based on weight overlay in ArcGIS 10.4. The findings revealed two evaluation tendencies. One tendency involves business centers that are located on main roads but are adjacent to residential areas, while another involves business centers that have rezoned residential plots without consideration for ideal site requirements for the environment. There are locations that would be appropriate for vehicle wash centers, according to the final suitability map. On a scale of 1 to 5, less than 30% of the study area is considered suitable for a new car wash regarding class 5. On the other hand, significant areas are available for car wash development in the second value of suitability 4, but as second-ranked suitability. The assessment was accomplished by comparing the final suitability map of car washing centers to the layers which represented them.
