Sediments are complex environments, with varying physicochemical characteristics, such as composition and type of organic matter, particle size distribution, and pH. Contaminated sediment is a significant environmenta...Sediments are complex environments, with varying physicochemical characteristics, such as composition and type of organic matter, particle size distribution, and pH. Contaminated sediment is a significant environmental problem affecting many marine, estuarine and freshwater environments throughout the world. Most assessments of water quality have historically focused on water-soluble compounds, with relatively little attention paid to sediment. The aim of this research is to assess the physical and chemical parameters of sediments from Nwaja Creek, Niger Delta, Nigeria. Monitoring of this sediment quality is an important part of preserving and restoring the biological integrity of water bodies as well as protecting aquatic life, wild life and human health. Sediment samples from Nwaja Creek were sampled from seven sampling stations along the creek for over three months May to July, 2015, rainfall peak period, for assessment of their physical and chemical characteristics, such as grain size, organic carbon, pH, conductivity, nitrate and phosphate. These parameters are known to influence the interactions and dynamics of pollutants within sediment matrix. Sediment particle size distribution indicates that they have higher proportion of clay (clay > silt > sand), the mean percentage composition of clay, silt and sand ranged between 64.28% ± 22.04% - 72.36% ± 14.00%, 18.71% ± 12.03% - 27.32% ± 22.17% and 8.40% ± 6.28% - 9.76% ± 4.59% respectively. TOC in the study area is generally above 1% across all stations during the study period with a range between 0.98% and 4.58%. Minimal monthly and spatial variations are observed in particle distribution, pH (3.9 - 8.5) and phosphate (5.5 - 15.5 kg/mg) while significant variations are observed in conductivity (23.0 - 567.0 uS/cm), total organic carbon (0.98% - 4.58%) and nitrate (0.45 - 11.9 mg/kg) concentration. It is concluded that physicochemical characteristics of the sediments from Nwaja Creek are influenced by anthropogenic sources rather than natural as shown by the elevated phosphate and nitrate levels because the Niger Delta geology is not essentially rich in nitrate and its excess in surface or groundwater is considered as pollutant.展开更多
In this study, eleven soil samples and twenty-twoplants samples were collected in the vicinity of eleven industries and a thermal station was analyzed for zinc, copper, iron, lead and cadmium. Soil sample from Egbin t...In this study, eleven soil samples and twenty-twoplants samples were collected in the vicinity of eleven industries and a thermal station was analyzed for zinc, copper, iron, lead and cadmium. Soil sample from Egbin thermal station had the highest concentration of Zn (141.06 mg/kg) and Cu (131.70 mg/kg). Soil from international textile had the highest level of Fe and the soil from Ni-chemtex had the highest concentration Pb and Cd was the highest in soil from Guinness (28.91 mg/kg, 59.80 mg/kg and 1.72 mg/kg respectively). The highest concentrations of the heavy metals were observed from different plants species. Analyses of variance (p < 0.05) showed that heavy metal variation in plant and soil samples were not significant (p > 0.5). There were positive correlations between the heavy metals in the soils and the plant samples indicated that the plants obtained the heavy metals from the soil. Plants having BCF values less than one had limited ability to accumulate, translocate and phytoextract heavy metals. These plants in this study with higher Bioconcentration Factor value especially those greater than one (Croton lobatus, Borreria sp., Cy-athula prostrata, Lantana camara, Ficus sp., Mimosa pudica, Eclipta prostrata, Commelina sp. etc.) were suggested for further research and assessment on their bioaccumulation abilities and phy-toremediation potential.展开更多
文摘Sediments are complex environments, with varying physicochemical characteristics, such as composition and type of organic matter, particle size distribution, and pH. Contaminated sediment is a significant environmental problem affecting many marine, estuarine and freshwater environments throughout the world. Most assessments of water quality have historically focused on water-soluble compounds, with relatively little attention paid to sediment. The aim of this research is to assess the physical and chemical parameters of sediments from Nwaja Creek, Niger Delta, Nigeria. Monitoring of this sediment quality is an important part of preserving and restoring the biological integrity of water bodies as well as protecting aquatic life, wild life and human health. Sediment samples from Nwaja Creek were sampled from seven sampling stations along the creek for over three months May to July, 2015, rainfall peak period, for assessment of their physical and chemical characteristics, such as grain size, organic carbon, pH, conductivity, nitrate and phosphate. These parameters are known to influence the interactions and dynamics of pollutants within sediment matrix. Sediment particle size distribution indicates that they have higher proportion of clay (clay > silt > sand), the mean percentage composition of clay, silt and sand ranged between 64.28% ± 22.04% - 72.36% ± 14.00%, 18.71% ± 12.03% - 27.32% ± 22.17% and 8.40% ± 6.28% - 9.76% ± 4.59% respectively. TOC in the study area is generally above 1% across all stations during the study period with a range between 0.98% and 4.58%. Minimal monthly and spatial variations are observed in particle distribution, pH (3.9 - 8.5) and phosphate (5.5 - 15.5 kg/mg) while significant variations are observed in conductivity (23.0 - 567.0 uS/cm), total organic carbon (0.98% - 4.58%) and nitrate (0.45 - 11.9 mg/kg) concentration. It is concluded that physicochemical characteristics of the sediments from Nwaja Creek are influenced by anthropogenic sources rather than natural as shown by the elevated phosphate and nitrate levels because the Niger Delta geology is not essentially rich in nitrate and its excess in surface or groundwater is considered as pollutant.
文摘In this study, eleven soil samples and twenty-twoplants samples were collected in the vicinity of eleven industries and a thermal station was analyzed for zinc, copper, iron, lead and cadmium. Soil sample from Egbin thermal station had the highest concentration of Zn (141.06 mg/kg) and Cu (131.70 mg/kg). Soil from international textile had the highest level of Fe and the soil from Ni-chemtex had the highest concentration Pb and Cd was the highest in soil from Guinness (28.91 mg/kg, 59.80 mg/kg and 1.72 mg/kg respectively). The highest concentrations of the heavy metals were observed from different plants species. Analyses of variance (p < 0.05) showed that heavy metal variation in plant and soil samples were not significant (p > 0.5). There were positive correlations between the heavy metals in the soils and the plant samples indicated that the plants obtained the heavy metals from the soil. Plants having BCF values less than one had limited ability to accumulate, translocate and phytoextract heavy metals. These plants in this study with higher Bioconcentration Factor value especially those greater than one (Croton lobatus, Borreria sp., Cy-athula prostrata, Lantana camara, Ficus sp., Mimosa pudica, Eclipta prostrata, Commelina sp. etc.) were suggested for further research and assessment on their bioaccumulation abilities and phy-toremediation potential.
