Accumulation of Cd by a freshwater mussel (Pyganodon grandis) is reduced in the presence of Cu, Zn, Pb, and Ni

1999 ◽  
Vol 56 (3) ◽  
pp. 467-478 ◽  
Author(s):  
A R Stewart
Keyword(s):  
Water Column ◽  
Half Life ◽  
Metal Uptake ◽  
Freshwater Mussel ◽  
Laboratory Studies ◽  
Metal Mixture ◽  
Nonequilibrium Conditions ◽  
Pyganodon Grandis ◽  
Anodonta Grandis ◽  
Concentration Levels

The effects of a metal mixture on Cd bioavailability and uptake in the freshwater mussel Pyganodon grandis (formerly Anodonta grandis grandis) were investigated in a limnocorral experiment in a Precambrian Shield lake during the summer of 1992. Differences in the partitioning of Cd in water, sediment, and mussels were identified between limnocorrals treated with Cd alone or with Cd and a mixture of metals (Cu, Zn, Pb, and Ni) at three concentration levels. Loss of Cd from the water column was slower in treatments with the metal mixture (22- to 34-day half-life) than in the treatment with Cd alone (11-day half-life). Despite the higher concentrations of Cd in the water column in treatments with the mixture of metals, the mussels accumulated proportionally less Cd as the metal concentrations increased. These relationships were observed in mussels exposed for 40 days ([Cd] <4.4 µg·L-1) and 80 days ([Cd] = 4-14 µg·L-1). The uncoupling of the effects of the metal mixture on Cd bioavailability and uptake suggests that laboratory studies may be appropriate for characterizing metal uptake in mussels exposed to mixtures of metals under nonequilibrium conditions. The significant deviation in the behavior of Cd in the presence of the metal mixture emphasizes the need to further investigate regulatory approaches that focus on individual contaminants.

scholarly journals Radiocesium in the Taiwan Strait and the Kuroshio east of Taiwan from 2018 to 2019

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Wei-Jen Huang ◽  
Ming-Ta Lee ◽  
Kuei-Chen Huang ◽  
Kai-Jung Kao ◽  
Ming-An Lee ◽  
...  
Keyword(s):  
Water Column ◽  
Surface Waters ◽  
Half Life ◽  
North Pacific Ocean ◽  
Taiwan Strait ◽  
Depth Range ◽  
Near Surface ◽  
Activity Concentrations ◽  
The Taiwan Strait ◽  
The Kuroshio

AbstractThe release of anthropogenic radiocesium to the North Pacific Ocean (NPO) has occurred in the past 60 years. Factors controlling 137Cs (half-life, 30.2 year) and 134Cs (half-life, 2.06 year) activity concentrations in the Kuroshio east of Taiwan and the Taiwan Strait (latitude 20° N–27° N, longitude 116° E–123° E) remain unclear. This study collected seawater samples throughout this region and analyzed 134Cs and 137Cs activity concentrations between 2018 and 2019. A principal component analysis (PCA) was performed to analyze the controlling factors of radiocesium. Results of all 134Cs activity concentrations were below the detection limit (0.5 Bq m−3). Analyses of water column 137Cs profiles revealed a primary concentration peak (2.1–2.2 Bq m−3) at a depth range of 200–400 m (potential density σθ: 25.3 to 26.1 kg m−3). The PCA result suggests that this primary peak was related to density layers in the water column. A secondary 137Cs peak (1.90 Bq m−3) was observed in the near-surface waters (σθ = 18.8 to 21.4 kg m−3) and was possibly related to upwelling and river-to-sea mixing on the shelf. In the Taiwan Strait, 137Cs activity concentrations in the near-surface waters were higher in the summer than in the winter. We suggest that upwelling facilitates the vertical transport of 137Cs at the shelf break of the western NPO.

Laboratory and field studies on the degradation of fipronil in a soil

Soil Research ◽  
2002 ◽  
Vol 40 (7) ◽  
pp. 1095 ◽  
Author(s):  
Guang-Guo Ying ◽  
Rai Kookana
Keyword(s):  
Soil Moisture ◽  
Half Life ◽  
Soil Moisture Content ◽  
Soil Surface ◽  
Field Studies ◽  
Transformation Product ◽  
Laboratory Studies ◽  
The Third ◽  
High Soil Moisture ◽  
Sulfone Derivatives

Degradation of a new insecticide/termiticide, fipronil, in a soil was studied in the laboratory and field. Three metabolites of fipronil (desulfinyl, sulfide, and sulfone derivatives) were identified from soils after treatment. Laboratory studies showed that soil moisture content had a great effect on the degradation rate of fipronil and products formed. High soil moisture contents (>50%) favored the formation of a sulfide derivative of fipronil by reduction, whereas low soil moisture (<50%) and well-aerated conditions favored the formation of fipronil sulfone by oxidation. Microorganisms in soil accelerated the degradation of fipronil to sulfide and sulfone derivatives. The third transformation product, a desulfinyl derivative, was formed by photodecomposition of fipronil in water and on the soil surface under sunlight. The desulfinyl derivative degraded rapidly in field soils with a half-life of 41–55 days compared with an average half-life of 132 days for fipronil. The half-life of the 'total toxic component' (fipronil and its metabolites) in field soil was 188 days on average.

scholarly journals Exploring the Environmental Exposure to Methoxychlor, α-HCH and Endosulfan–sulfate Residues in Lake Naivasha (Kenya) Using a Multimedia Fate Modeling Approach

2020 ◽  
Vol 17 (8) ◽  
pp. 2727
Author(s):  
Yasser Abbasi ◽  
Chris M. Mannaerts
Keyword(s):  
Sensitivity Analysis ◽  
Water Column ◽  
Environmental Exposure ◽  
Pesticide Residues ◽  
Half Life ◽  
Mass Fraction ◽  
Passive Sampling ◽  
Lake Naivasha ◽  
Endosulfan Sulfate ◽  
Modeling Approach

Distribution of pesticide residues in the environment and their transport to surface water bodies is one of the most important environmental challenges. Fate of pesticides in the complex environments, especially in aquatic phases such as lakes and rivers, is governed by the main properties of the contaminants and the environmental properties. In this study, a multimedia mass modeling approach using the Quantitative Water Air Sediment Interaction (QWASI) model was applied to explore the fate of organochlorine pesticide residues of methoxychlor, α-HCH and endosulfan–sulfate in the lake Naivasha (Kenya). The required physicochemical data of the pesticides such as molar mass, vapor pressure, air–water partitioning coefficient (KAW), solubility, and the Henry’s law constant were provided as the inputs of the model. The environment data also were collected using field measurements and taken from the literature. The sensitivity analysis of the model was applied using One At a Time (OAT) approach and calibrated using measured pesticide residues by passive sampling method. Finally, the calibrated model was used to estimate the fate and distribution of the pesticide residues in different media of the lake. The result of sensitivity analysis showed that the five most sensitive parameters were KOC, logKow, half-life of the pollutants in water, half-life of the pollutants in sediment, and KAW. The variations of outputs for the three studied pesticide residues against inputs were noticeably different. For example, the range of changes in the concentration of α-HCH residue was between 96% to 102%, while for methoxychlor and endosulfan-sulfate it was between 65% to 125%. The results of calibration demonstrated that the model was calibrated reasonably with the R2 of 0.65 and RMSE of 16.4. It was found that methoxychlor had a mass fraction of almost 70% in water column and almost 30% of mass fraction in the sediment. In contrast, endosulfan–sulfate had highest most fraction in the water column (>99%) and just a negligible percentage in the sediment compartment. α-HCH also had the same situation like endosulfan–sulfate (e.g., 99% and 1% in water and sediment, respectively). Finally, it was concluded that the application of QWASI in combination with passive sampling technique allowed an insight to the fate process of the studied OCPs and helped actual concentration predictions. Therefore, the results of this study can also be used to perform risk assessment and investigate the environmental exposure of pesticide residues.

Pharmacokinetics of Intermittent Intraperitoneal Cefazolin in Continuous Ambulatory Peritoneal Dialysis Patients

1999 ◽  
Vol 19 (1) ◽  
pp. 65-70 ◽  
Author(s):  
Harold J. Manley ◽  
George R. Bailie ◽  
Rupesh D. Asher ◽  
George Eisele ◽  
Reginald F. Frye
Keyword(s):  
Body Weight ◽  
Peritoneal Dialysis ◽  
Continuous Ambulatory Peritoneal Dialysis ◽  
Rate Constant ◽  
Half Life ◽  
Elimination Rate ◽  
Pharmacokinetic Parameters ◽  
Number Of Patients ◽  
The Mean ◽  
Concentration Levels

Objective To investigate the pharmacokinetic parameters of intermittent intraperitoneal (IP) cefazolin, and recommend a cefazolin dosing regimen in continuous ambulatory peritoneal dialysis (CAPD) patients. Design Prospective nonrandomized open study. Setting CAPD outpatient clinic in Albany, New York. Patients Seven volunteer CAPD patients without peritonitis. Three of the patients were nonanuric while 4 were anuric. Interventions Cefazolin (15 mg/kg total body weight) was given to each patient during the first peritoneal exchange. Blood and dialysate samples were collected at times 0, 0.5, 1, 2, 3, 6 (end of the first antibiotic-containing dwell), 24, and 48 hours after the administration of IP cefazolin. Urine samples were collected in nonanuric patients over the study period. Results The mean ± SD amount of cefazolin dose absorbed from the dialysate after the 6-hour dwell was 69.7% ± 8.0% of the administered dose. The cefazolin absorption rate constant from dialysate to serum was 0.21 ± 0.1 /hr (absorption half-life 3.5 ± 0.8 hr). The mean serum concentrations reached at 24 and 48 hours were 52.4 ± 3.7 mg/L and 30.3 ± 5.9 mg/L, respectively. The mean dialysate cefazolin concentrations reached at 24 and 48 hours were 15.1 ± 3.4 mg/L and 7.9 ± 1.4 mg/L, respectively. The cefazolin serum elimination rate constant was 0.02 ± 0.01 /hr (elimination half-life 31.5 ± 8.8 hr). The total cefazolin body clearance was 3.4 ± 0.6 mL/min. In the 3 nonanuric patients the mean renal clearance of cefazolin was 0.6 ± 0.4 mL/min. The peritoneal clearance of cefazolin was 1.0 ± 0.3 mL/min. The systemic volume of distribution of cefazolin was 0.2 ± 0.05 L/kg. No statistical difference was detected in pharmacokinetic parameters between anuric and nonanuric patients, although this may be due to the small number of patients in each group. Conclusion A single daily dose of cefazolin dosed at 15 mg/kg actual body weight in CAPD patients is effective in achieving serum concentration levels greater than the minimum inhibitory concentration for sensitive organisms over 48 hours, and dialysate concentration levels over 24 hours. Caution is warranted in extrapolation of dosing recommendations to patients who maintain a significant degree of residual renal function.

Population ecology of the freshwater mussel Anodonta grandis grandis in a Precambrian Shield lake

1990 ◽  
Vol 68 (9) ◽  
pp. 1931-1941 ◽  
Author(s):  
J. D. Huebner ◽  
D. F. Malley ◽  
K. Donkersloot
Keyword(s):  
Yellow Perch ◽  
Live Weight ◽  
Freshwater Mussel ◽  
Dry Weight ◽  
Fine Sand ◽  
Turnover Time ◽  
Experimental Lakes Area ◽  
Precambrian Shield ◽  
Sublittoral Zone ◽  
Anodonta Grandis

Anodonta grandis grandis is found in about half of 50 Experimental Lakes Area lakes surveyed but is abundant in only some of these lakes, including lake 377. Lake 377 is a typical small Precambrian Shield lake, 27.7 ha in area and 17.9 m in maximum depth, with [Ca2+] of [Formula: see text], conductivity of 25 μmho∙cm−1 (1 mho = 1 S), and alkalinity of [Formula: see text]. The water renewal time of approximately 187 days is shorter than that of most Precambrian Shield lakes. Bottom sediments in the sublittoral zone ranged from fine sand through granules to cobbles and boulders. Several species of possible glochidial host fish including yellow perch were collected from lake 377. The size of the mussel population, estimated by depth-stratified random sampling, was 36 800 ± 12 000 (± 95% confidence interval). Mean density was 0.133 mussels/m2 lake surface, and maximum density was 4.3 mussels/m2. Mussels were most abundant in the 1.5- to 3.1-m depth stratum. Mean lengths and weights in collections ranged from 77 to 87 mm and from 43 to 56 g, respectively. Maximum length and weight were 117.9 mm and 109.6 g, respectively. Based on external annuli, mussels live to 15+ years in lake 377. Flesh and shell averaged 25.1 and 23.2% of live weight, respectively. Calcium constituted 44.7% of the ash weight of shell. We estimated a standing dry weight biomass of mussels of 330–390 mg∙m−2 and dry weight production of 60 mg∙m−2∙year−1. This is [Formula: see text] of the estimated annual dry weight algal production. The shells of live mussels contain [Formula: see text] of the total calcium in lake 377. Despite oligotrophic conditions and low [Ca2+], lake 377 supports a substantial population of A. g. grandis growing at a moderate rate. Lake 377 may be a favourable habitat for this species because of its short water-turnover time.

In situ evaluation of options for chemical treatment of hepatotoxic cyanobacterial blooms

1997 ◽  
Vol 54 (8) ◽  
pp. 1736-1742 ◽  
Author(s):  
A K-Y Lam ◽  
E E Prepas
Keyword(s):  
Water Column ◽  
Cyanobacterial Blooms ◽  
Laboratory Studies ◽  
Surrounding Water ◽  
Potential Health ◽  
Cyanobacteria Blooms ◽  
Ph Shock ◽  
Alum Treatment ◽  
Phytoplankton Cells

Closed-bottom limnocorrals were placed in a hardwater lake in central Alberta to compare the effect of two alternative approaches to chemical removal of toxic phytoplankton blooms. Reglone A, which lyses phytoplankton cells, and lime-alum, which precipitates intact phytoplankton cells out of the water column were both effective in removing phytoplankton from the water column. Our results were consistent with laboratory studies in that treatment with Reglone A removed phytoplankton (primarily cyanobacteria) blooms with a concomitant increase in dissolved microcystin (exo-MCYST) and phosphorus concentrations in the surrounding water whereas lime-alum treatment did not. Maximum exo-MCYST concentrations in the water phase of the lime-alum treated limnocorrals were 32-fold lower than those recorded in the Reglone-treated limnocorrals. Treatment with lime alone caused a sharp rise in pH (to >10), and the observed increase in exo-MCYST was likely due to pH shock. Exo-MCYST concentration in the Reglone-treated enclosures remained high for the duration of the experiment (>5 days). As microcystin did not partition onto lake sediments in laboratory studies, our limnocorrals results were probably a good indication of microcystin dynamics in lakes. Thus, the use of chemicals such as lime-alum that precipitate out intact phytoplankton cells lessens the potential health risk where microcystins are present.

Background Levels of Petroleum Residues in the Waters and Surficial Bottom Sediments of the Labrador Shelf and Hudson Strait/Foxe Basin Regions

1986 ◽  
Vol 43 (3) ◽  
pp. 536-547 ◽  
Author(s):  
E. M. Levy
Keyword(s):  
Water Column ◽  
Bottom Sediments ◽  
East Coast ◽  
Background Level ◽  
Surface Microlayer ◽  
Hudson Bay ◽  
Foxe Basin ◽  
Background Levels ◽  
Petroleum Residues ◽  
Concentration Levels

Background levels of petroleum residues in the form of particles floating on the sea and as substances extracted from the surface microlayer, the water column, and the surficial bottom sediments of the Hudson Strait/Foxe Basin and the Labrador shelf regions were measured during 1982 and 1983. No evidence of floating particulate oil was found in either region. Background levels of extractable petroleum residues in the surface microlayer were highly dependent on ambient sea conditions and ranged from 4.1 μg/L at the entrance to Hudson Strait to 28.3 μg/L on the southern Labrador shelf in 1982, and from 4.5 to 20.9 μg/L on the Labrador shelf in 1983 with the general background level at 8.13 μg/L. The background level in the water column in the Hudson Bay/Hudson Strait region was 0.46 μg/L in 1982 whereas that on the Labrador shelf was 0.42 μg/L during 1982 and 0.57 μg/L in 1983 (overall level of 0.51 μg/L). Concentration levels in the surficial bottom sediments depended primarily on the nature of the sediments and ranged from 1.9 μg/g at the eastern end of Hudson Strait to 52.5 μg/g on the continental slope east of Nain Bank with a general background level of 2.04 μg/g. These background levels are similar to those of other areas of the continental shelf off the east coast of Canada and are, presently, well below those known to have adverse biological consequences.

scholarly journals Copper, Cadmium, Chromium and lead bioaccumulation in Stinging Catfish, Heteropneustes fossilis (Bloch) and freshwater mussel, Lamellidens corrianus Lia and to compare their concentration in sediments and water of Turag river

2014 ◽  
Vol 39 (2) ◽  
pp. 231-238 ◽  
Author(s):  
Suman Mandal ◽  
Abu Tweb Abu Ahmed
Keyword(s):  
Heavy Metals ◽  
Freshwater Fish ◽  
Freshwater Mussel ◽  
Dry Weight ◽  
Average Concentration ◽  
Heteropneustes Fossilis ◽  
Standard Level ◽  
Lamellidens Corrianus ◽  
Concentration Levels

The present study was carried out to determine the level of bioaccumulation of some heavy metals namely Copper (Cu), Cadmium (Cd), Chromium (Cr) and Lead (Pb) in freshwater fish Stinging catfish (Heteropneustes fossilis Bloch, 1794) and freshwater Mussel (Lamellidens corrianus Lia, 1834) collected from Turag river during the months of October to December 2010. The accumulation levels were then compared with the concentration levels of sediments and water of the same river. In H. fossilis the average bioaccumulations were Cu 13.27 ± 2.47 mg/kg ; Cd 0.215 ± 0.208 mg/kg ; Cr 1.46 ± 0.431 mg/kg and Pb 0 mg/kg in dry weight while Cu 31.90 ± 6.202 mg/kg ; Cd 0.182 ± 0.025 mg/kg ; Cr 0.0367 ± 0.039 mg/kg and Pb 3.865 ± 1.041 mg/kg in dry weight of L. corrianus. Average concentration of metals in sediments of Turag river were Cu 54.95 ± 9.218 mg/kg ; Cd 0.05 ± 0.011 mg/kg ; Cr 5.575 ± 0.608 mg/kg and Pb 34.89 ± 5.554 mg/kg in dry weight and in water these levels were Cu 0.0253 ± 0.024 ppm ; Cd 0.0012 ± 0.001 ppm ; Cr 0.2335 ± 0.044 ppm and Pb 0.1169 ± 0.041 ppm. The bioaccumulation level of heavy metals in Turag river were higher than the FAO approved standard level. DOI: http://dx.doi.org/10.3329/jasbs.v39i2.17862 J. Asiat. Soc. Bangladesh, Sci. 39(2): 231-238, December 2013

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