| 1 | Nutrient dynamics in the Sundarbans mangrove estuarine system of Bangladesh under different weather and tidal cycles显示文摘Introduction:Seasonal and tidal variations in nutrient concentration and water quality were investigated in the western Sundarbans of Bangladesh during the post-monsoon,winter and monsoon seasons during 2010–2011.Methods:Water collected from the surface,middle and bottom layers at six locations of the Kholpetua-Arpangashia river system during high and low tides was analyzed for temperature,salinity,pH,dissolved oxygen(DO),total dissolved solids(TDS),electrical conductivity(EC)and dissolved nutrients(NO3–N,PO4–P,SO4 and NH3–N).Results:The study revealed that nutrient concentrations were influenced by seasonal changes.Mean nutrient levels during post-monsoon,winter and monsoon seasons,respectively,were in the following ranges:nitrate(0.06–0.40,0.06–0.46 and 0.08–0.46 mg/L);phosphate(0.09–0.18,0.05–0.42 and 0.10–0.16 mg/L);sulphate(58.71–86.14,68.68–119.01 and 78.15–136.47 mg/L)and ammonia(0.02–0.08,0.02–0.04 and 0.26–0.38 mg/L).Increased levels of PO4–P,SO4 and NH3–N and lower DO and salinity were recorded during the monsoon period.Most of the experimental sites showed higher NO3–N content during monsoon,whereas few elevated concentrations were observed during post-monsoon and winter periods.High and low tidal waters contained mean nutrient levels in the following ranges:nitrate(0.05–0.46 and 0.04–0.40 mg/L);phosphate(0.05–0.42 and 0.07–0.18 mg/L);sulphate(63.63–125.36 and 58.71–136.47 mg/L)and ammonia(0.02–0.38 and 0.02–0.37 mg/L)without following any distinct fluctuation patterns.The western part of the Sundarbans receives less freshwater input during the monsoon season than other areas of the ecosystem,which reduces the variability of nutrient levels and water quality components.Conclusions:This study provides considerable advances in understanding the seasonality of nutrient distribution with possible tidal influence.The data generated from this study will guide continuing efforts to support a sound management for coastal mangrove ecosystems. | Shak Md Bazlur Rahaman Lipton Sarder Md Sayadur Rahaman Alokesh Kumar Ghosh Sudhin Kumar Biswas SM Shahjahan Siraj Khandaker Anisul Huq Abul Farah Md Hasanuzzaman Shikder Saiful Islam | 2013 | Ecological Processes2013，2，1： | 2 |
| 3 | Multi-media compartments for assessing ecological and health risks from concurrent exposure to multiple contaminants on Bhola Island,Bangladesh显示文摘In this study,a set of coupled multi-media compartments(i.e.,sediment,soil,water and vegetable)was used to assess ecological and health risks from the ingestion of 11 PTEs(Pb,Cd,Cr,As,Hg,Cu,Zn,Ni,Co,Fe,and Mn)and their transportation routes in the water-soil-plant system from the coastal Bhola Island,Bangladesh.The mean concentrations of Cd,Pb,and Co for soil and Cd,Co,and As for sediment were higher than their reference values.In contrast,Cd,Pb,and Ni concentrations in water surpassed the acceptable limits set by national and international laws and were considered unsuitable for drinking purposes.Vegetables demonstrated high Pb and Cd contents,demonstrating a potential food safety risk to the inhabitants.Results of principal component analysis(PCA)revealed that Cd,Pb,Hg,Cu,Ni and Zn sources were likely to be anthropogenic,especially agro-farming inputs,whereas the Fe,As,Cr,Mn,and Co sources were similar to natural origin.So,Cd,Pb and Co are the key contaminants in the study area and pose the elevated health and ecological risks in the coastal area.Cd and Pb exhibited higher ecological risks in soils and sediments,as Pb had the highest bio-accessibility(BA;0.02±0.003)and Cd possessed a high bioaccumulation factor(BCF;0.004±0.006).The self-organizing map analysis recognized three spatial patterns which are good agreement with PCA.The average hazard index(HI)values for soil were above the permissible level(HI>1)set by the respective agency;two times higher HI values were noticed for children than adults,suggesting children are highly susceptible to health risk.Continuous monitoring and source controls for Cd and Pb,along with agro-farming management practices,need to be implemented to reduce the risk of PTE contamination to the aquatic ecosystem and its inhabitants. | Tasrina Rabia Choudhury Tanjeela Islam Abu Reza Md Towfiqul Islam Md Hasanuzzaman Abubakr M.Idris M.Safiur Rahman Edris Alam A.M.Sarwaruddin Chowdhury | 2022 | Emerging Contaminants2022，8，1： | 0 |
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