Encroachment, disposal of untreated domestic and industrial wastewater and dumping of solid wastes have degraded the overall quality of the river Turag, which is located in Dhaka—the Capital City of Bangladesh. The p...Encroachment, disposal of untreated domestic and industrial wastewater and dumping of solid wastes have degraded the overall quality of the river Turag, which is located in Dhaka—the Capital City of Bangladesh. The present study investigated the extent of pollution of sediments of this river and analyzed the regional variability for the concentrations of Cr, Pb, Zn, Cu and Cd—all of concern because of their potential toxicity, using atomic absorption spectrophotometer. As per US EPA sediment quality guideline, metal concentrations ranged between Cd: 0.00 - 0.80, Cr: 32.00 - 75.50, Cu: 46.30 - 60.00, Pb: 28.30 - 36.40, and Zn: 94.60 - 190.10 mg/kg in the Turag river sediments. Cr, Cu, Zn belongs to moderately to highly polluted, Pb and Cd belongs to not polluted for Turag river. The heavy metals contamination in the sediments were also evaluated by applying Index of geo-accumulation (Igeo), contamination factor (Cf), pollution load index (PLI) etc. Toxicity characteristics leaching procedure (TCLP) test (US EPA 1311) for sediment samples have been performed also for metals (Pb, Cd, Cr, Cu and Zn) to determine the readily toxicity level of heavy metals. Sieve analysis of sediment performed in this study to determine the physical characteristic of sediment samples. The metal concentrations are well below the regulated level as per US EPA. This index can be complemented with the contamination index, which allows more site-specific and accurate information on contaminant levels. If the aim of work on contamination evaluation is to assess the overall contamination of a study area, the indices are highly appropriate.展开更多
Microplastics(MPs)are synthetic contaminants that have received global attention due to their ubiquitous occurrence,extreme durability,and capacity to harm ecosystems and human health.This study investigated the occur...Microplastics(MPs)are synthetic contaminants that have received global attention due to their ubiquitous occurrence,extreme durability,and capacity to harm ecosystems and human health.This study investigated the occurrence of MPs in three fish species(Channa striata,Puntius sophore and Anabas testudineus)collected from two locations(Ashulia Bridge and Mirpur Road)of the Turag River,which flows alongside the Dhaka city,Bangladesh.MPs abundance(items/individuals)was highest in Channa striata(3.8±0.6)from the Ashulia Bridge area and lowest in Puntius sophore(1.8±0.4)from the Mirpur Road area.Fiber was found to be the most dominant(89e93%)form of MPs followed by fragments(21 e35%),films(0e26%)and foams(0e5%).The dominant color of MPs was blue(69e83%),then red(20 e33%),black(11e14%),green(8e20%),and purple(6e8%).The majority(56e71%)of the MPs assessed were<0.5 mm in size,followed by 0.5e1.0 mm(29e33%)and 1e5 mm(38e53%).ATR-FTIR examination revealed three specific polymer varieties-PP(40%),PS(30%)and LDPE(30%).The results of this study provided a baseline of MPs pollution in one of the major protein sources freshwater fishes and raised concern on public health particularly who consume fishes from the urban waterways.展开更多
To assess the magnitude of water quality decline in the Turag River of Bangladesh,this study examined the seasonal variation of physi-cochemical parameters of water,identified potential pollution sources,and clustered...To assess the magnitude of water quality decline in the Turag River of Bangladesh,this study examined the seasonal variation of physi-cochemical parameters of water,identified potential pollution sources,and clustered the monitoring months with similar characteristics.Water samples were collected in four distinct seasons to evaluate temperature,pH,dissolved oxygen(DO)concentration,five-day biochemical oxygen demand(BOD 5),chemical oxygen demand(COD),electrical conductivity(EC),chloride ion(Cl^(-))concentration,total alkalinity(TA),turbidity,total dissolved solids(TDS)concentration,total suspended solids(TSS)concentration,and total hardness(TH)using standard methods.The analytical results revealed that 40%of water quality indices were within the permissible limits suggested by different agencies,with the exception of EC,Cl^(-)concentration,TA,turbidity,DO concentration,BOD 5,and COD in all seasons.Statistical analyses indicated that 52%of the contrasts were significantly different at a 95%confidence interval.The factor analysis presented the best fit among the parameters,with four factors explaining 94.29%of the total variance.TDS,BOD 5,COD,EC,turbidity,DO,and Cl?were mainly responsible for pollution loading and were caused by the significant amount of industrial discharge and toxicological compounds.The cluster analysis showed the seasonal change in surface water quality,which is usually an indicator of pollution from rainfall or other sources.However,the values of different physico-chemical properties varied with seasons,and the highest values of pollutants were recorded in the winter.With the change in seasonal tem-perature and increase in rainfall,the seasonal Turag River water followed a self-refining trend as follows:rainy season>pre-winter>summer>winter.展开更多
文摘Encroachment, disposal of untreated domestic and industrial wastewater and dumping of solid wastes have degraded the overall quality of the river Turag, which is located in Dhaka—the Capital City of Bangladesh. The present study investigated the extent of pollution of sediments of this river and analyzed the regional variability for the concentrations of Cr, Pb, Zn, Cu and Cd—all of concern because of their potential toxicity, using atomic absorption spectrophotometer. As per US EPA sediment quality guideline, metal concentrations ranged between Cd: 0.00 - 0.80, Cr: 32.00 - 75.50, Cu: 46.30 - 60.00, Pb: 28.30 - 36.40, and Zn: 94.60 - 190.10 mg/kg in the Turag river sediments. Cr, Cu, Zn belongs to moderately to highly polluted, Pb and Cd belongs to not polluted for Turag river. The heavy metals contamination in the sediments were also evaluated by applying Index of geo-accumulation (Igeo), contamination factor (Cf), pollution load index (PLI) etc. Toxicity characteristics leaching procedure (TCLP) test (US EPA 1311) for sediment samples have been performed also for metals (Pb, Cd, Cr, Cu and Zn) to determine the readily toxicity level of heavy metals. Sieve analysis of sediment performed in this study to determine the physical characteristic of sediment samples. The metal concentrations are well below the regulated level as per US EPA. This index can be complemented with the contamination index, which allows more site-specific and accurate information on contaminant levels. If the aim of work on contamination evaluation is to assess the overall contamination of a study area, the indices are highly appropriate.
文摘Microplastics(MPs)are synthetic contaminants that have received global attention due to their ubiquitous occurrence,extreme durability,and capacity to harm ecosystems and human health.This study investigated the occurrence of MPs in three fish species(Channa striata,Puntius sophore and Anabas testudineus)collected from two locations(Ashulia Bridge and Mirpur Road)of the Turag River,which flows alongside the Dhaka city,Bangladesh.MPs abundance(items/individuals)was highest in Channa striata(3.8±0.6)from the Ashulia Bridge area and lowest in Puntius sophore(1.8±0.4)from the Mirpur Road area.Fiber was found to be the most dominant(89e93%)form of MPs followed by fragments(21 e35%),films(0e26%)and foams(0e5%).The dominant color of MPs was blue(69e83%),then red(20 e33%),black(11e14%),green(8e20%),and purple(6e8%).The majority(56e71%)of the MPs assessed were<0.5 mm in size,followed by 0.5e1.0 mm(29e33%)and 1e5 mm(38e53%).ATR-FTIR examination revealed three specific polymer varieties-PP(40%),PS(30%)and LDPE(30%).The results of this study provided a baseline of MPs pollution in one of the major protein sources freshwater fishes and raised concern on public health particularly who consume fishes from the urban waterways.
文摘To assess the magnitude of water quality decline in the Turag River of Bangladesh,this study examined the seasonal variation of physi-cochemical parameters of water,identified potential pollution sources,and clustered the monitoring months with similar characteristics.Water samples were collected in four distinct seasons to evaluate temperature,pH,dissolved oxygen(DO)concentration,five-day biochemical oxygen demand(BOD 5),chemical oxygen demand(COD),electrical conductivity(EC),chloride ion(Cl^(-))concentration,total alkalinity(TA),turbidity,total dissolved solids(TDS)concentration,total suspended solids(TSS)concentration,and total hardness(TH)using standard methods.The analytical results revealed that 40%of water quality indices were within the permissible limits suggested by different agencies,with the exception of EC,Cl^(-)concentration,TA,turbidity,DO concentration,BOD 5,and COD in all seasons.Statistical analyses indicated that 52%of the contrasts were significantly different at a 95%confidence interval.The factor analysis presented the best fit among the parameters,with four factors explaining 94.29%of the total variance.TDS,BOD 5,COD,EC,turbidity,DO,and Cl?were mainly responsible for pollution loading and were caused by the significant amount of industrial discharge and toxicological compounds.The cluster analysis showed the seasonal change in surface water quality,which is usually an indicator of pollution from rainfall or other sources.However,the values of different physico-chemical properties varied with seasons,and the highest values of pollutants were recorded in the winter.With the change in seasonal tem-perature and increase in rainfall,the seasonal Turag River water followed a self-refining trend as follows:rainy season>pre-winter>summer>winter.
