Uranium in groundwaters of southeastern Manitoba, Canada

1988 ◽  
Vol 25 (12) ◽  
pp. 2089-2103 ◽  
Author(s):  
R. N. Betcher ◽  
M. Gascoyne ◽  
D. Brown
Keyword(s):  
Lake Agassiz ◽  
Clay Deposits ◽  
Groundwater Samples ◽  
Paleozoic Sedimentary Rock ◽  
The Mean ◽  
High Concentrations ◽  
Mineral Coatings ◽  
Sand And Gravel ◽  
Bedrock Aquifer ◽  
Bedrock Aquifers

Anomalously high levels of naturally derived uranium have been found in groundwater samples from wells completed in overburden and bedrock aquifers in southeastern Manitoba. Uranium analyses were carried out on groundwater samples collected from 287 individual wells in a 15 500 km2 area. The mean U concentration in all samples was 58.3 μg/L; the maximum value was 2020 μg/L. Uranium concentrations were highest in samples from Precambrian rock aquifers, averaging 115.6 μg/L, and were lowest in samples from Paleozoic sedimentary rock aquifers, averaging 3.5 μg/L.Uranium concentrations up to 250 μg/L were found in groundwaters in or associated with Lake Agassiz clay deposits. These high concentrations are thought to result principally from release of U from the organic component of the clays, either by oxidation or desorption. Leakage of uraniferous groundwater from the clays appears to provide a significant source of U to underlying sand and gravel aquifers and to the Precambrian bedrock aquifer. Uranium within the bedrock is also being released to solution by oxidation of uraniferous hematite found as mineral coatings and fracture fillings in highly weathered zones. Uranium solubility in many Precambrian bedrock groundwaters is increased by recharge of these aquifers by ground waters from overburden materials that contain high [Formula: see text] concentrations.

Studies of the oestrous cycle, oestrus and pregnancy in the koala (Phascolarctos cinereus)

Reproduction ◽  
2000 ◽  
pp. 49-57 ◽  
Author(s):  
SD Johnston ◽  
MR McGowan ◽  
P O'Callaghan ◽  
R Cox ◽  
V Nicolson
Keyword(s):  
Luteal Phase ◽  
Post Partum ◽  
Plasma Concentrations ◽  
External Genitalia ◽  
Oestrous Cycle ◽  
Phascolarctos Cinereus ◽  
Pregnant Females ◽  
Peripheral Plasma ◽  
The Mean ◽  
High Concentrations

As an integral part of the development of an artificial insemination programme in the captive koala, female reproductive physiology and behaviour were studied. The oestrous cycle in non-mated and mated koalas was characterized by means of behavioural oestrus, morphology of external genitalia and changes in the peripheral plasma concentrations of oestradiol and progestogen. The mean (+/- SEM) duration of the non-mated oestrous cycle and duration of oestrus in 12 koalas was 32.9 +/- 1.1 (n = 22) and 10.3 +/- 0.9 (n = 24) days, respectively. Although the commencement of oestrous behaviour was associated with increasing or high concentrations of oestradiol, there were no consistent changes in the morphology or appearance of the clitoris, pericloacal region, pouch or mammary teats that could be used to characterize the non-mated cycle. As progestogen concentrations remained at basal values throughout the interoestrous period, non-mated cycles were considered non-luteal and presumed anovulatory. After mating of the 12 koalas, six females gave birth with a mean (+/- SEM) gestation of 34.8 +/- 0.3 days, whereas the remaining six non-parturient females returned to oestrus 49.5 +/- 1. 0 days later. After mating, oestrous behaviour ceased and the progestogen profile showed a significant increase in both pregnant and non-parturient females, indicating that a luteal phase had been induced by the physical act of mating. Progestogen concentrations throughout the luteal phase of the pregnant females were significantly higher than those of non-parturient females. Parturition was associated with a decreasing concentration of progestogen, which was increased above that of basal concentrations until 7 days post partum.

Emissions of porewater compounds and gases from the subaquatic sediment disposal site “rodewischhafen”, hamburg harbour

1998 ◽  
Vol 37 (6-7) ◽  
pp. 87-93 ◽  
Author(s):  
M. Kussmaul ◽  
A. Groengroeft ◽  
H. Koethe
Keyword(s):  
Water Surface ◽  
Disposal Site ◽  
Dredged Material ◽  
Water Fluxes ◽  
Gas Emissions ◽  
Fine Grained ◽  
Deposit Surface ◽  
Groundwater Samples ◽  
High Concentrations ◽  
Mud Deposit

In the year 1993 a confined and unused harbour basin was used to store 290,000 m3 of fine-grained dredged material from Hamburg harbour. About 70% of the deposit surface was water covered. The edge areas were above the water table and covered with reed. Emissions of dissolved compounds into the groundwater, as well as surface gas emissions were measured from 1994 to 1996. As indicators for water fluxes from the deposit we used NH4+ and HCO3− because of their high concentrations in mud porewater in comparison to groundwater. The average concentrations of NH4+ and HCO3− in the porewater increased during 2 years from 85 to 250 mg NH4+ 1−1 and from 2.0 to 3.1 g HCO3− 1−1, while the groundwater samples showed constant values of 8 mg NH4+ 1−1 and 0.7 g HCO3− 1−1. Furthermore, the average gas emissions over the water surface were 3.2 g CH4 m−2 d−1 and 0.8 g CO2 m−2 d−1. In contrast, no methane and 3.0 g CO2 m−2 d−1 were emitted from land areas. The results indicated, that there were no significant emissions of mud porewater compounds into the groundwater but high CH4-emissions over the water covered surface of the mud deposit.

A mammoth (Mammuthus primigenius) tooth from late Wisconsin deposits near Embden, North Dakota, and comments on the distribution of woolly mammoths south of the Wisconsin ice sheets

1986 ◽  
Vol 23 (7) ◽  
pp. 909-918 ◽  
Author(s):  
C. R. Harington ◽  
Allan C. Ashworth
Keyword(s):  
British Columbia ◽  
Continental Shelf ◽  
North Dakota ◽  
Third Molar ◽  
Ice Sheets ◽  
Lake Agassiz ◽  
Mammuthus Primigenius ◽  
Sand And Gravel ◽  
Woolly Mammoth ◽  
Cass County

A well-preserved third molar of a woolly mammoth (Mammuthus primigenius) was recovered from sand and gravel forming the highest (Herman) prominent strandline of Lake Agassiz near Embden in western Cass County, North Dakota. The Herman strandline is estimated to have formed about 11 500 years BP, and presumably the tooth is of similar age. Perhaps the animal lived in a tundra-like area near the Lake Agassiz shoreline.Additional evidence suggests that woolly mammoths occupied a tundra-like range south of the Wisconsin ice sheets extending from southern British Columbia to the Atlantic continental shelf off Virginia.

scholarly journals Palaeoclimates: the first two billion years

2006 ◽  
Vol 361 (1470) ◽  
pp. 917-929 ◽  
Author(s):  
James F Kasting ◽  
Shuhei Ono
Keyword(s):  
South Africa ◽  
Oxygen Isotopes ◽  
Natural Explanation ◽  
Witwatersrand Basin ◽  
Late Archaean ◽  
Bacterial Sulphate Reduction ◽  
Climatic Constraints ◽  
The Mean ◽  
High Concentrations ◽  
Earth’S Climate

Earth's climate during the Archaean remains highly uncertain, as the relevant geologic evidence is sparse and occasionally contradictory. Oxygen isotopes in cherts suggest that between 3.5 and 3.2 Gyr ago (Ga) the Archaean climate was hot (55–85 °C); however, the fact that these cherts have experienced only a modest amount of weathering suggests that the climate was temperate, as today. The presence of diamictites in the Pongola Supergroup and the Witwatersrand Basin of South Africa suggests that by 2.9 Ga the climate was glacial. The Late Archaean was relatively warm; then glaciation (possibly of global extent) reappeared in the Early Palaeoproterozoic, around 2.3–2.4 Ga. Fitting these climatic constraints with a model requires high concentrations of atmospheric CO 2 or CH 4 , or both. Solar luminosity was 20–25% lower than today, so elevated greenhouse gas concentrations were needed just to keep the mean surface temperature above freezing. A rise in O 2 at approximately 2.4 Ga, and a concomitant decrease in CH 4 , provides a natural explanation for the Palaeoproterozoic glaciations. The Mid-Archaean glaciations may have been caused by a drawdown in H 2 and CH 4 caused by the origin of bacterial sulphate reduction. More work is needed to test this latter hypothesis.

Assessment of radon concentration and heavy metal contamination in groundwater samples from some areas of Fazilka district, Punjab, India

2016 ◽  
Vol 26 (3) ◽  
pp. 368-374 ◽  
Author(s):  
Ajay Kumar ◽  
Saurabh Narang ◽  
Rohit Mehra ◽  
Surinder Singh
Keyword(s):  
Environmental Protection Agency ◽  
Radon Concentration ◽  
Inductively Coupled Plasma ◽  
Heavy Metal Contamination ◽  
Atomic Emission ◽  
Inductively Coupled ◽  
Groundwater Samples ◽  
Us Epa ◽  
Safe Limits ◽  
The Mean

Groundwater samples taken from 20 villages of Fazilka district, Punjab, India were analysed for radon concentration using RAD7, which is an electronic radon detector. Radon concentration varies from (1.4 ± 1.0) × 103 Bq/m3 to (4.9 ± 3.0) × 103 Bq/m3, which is much below the safe limits proposed by US Environmental Protection Agency (US EPA) and UN Scientific Committee on the Effects of Atomic Radiation. The mean annual effective dose calculated for these samples was also found to be within the limits provided by WHO and EU council. These samples were also analysed for concentration of certain heavy elements like As, Pb, Zn, Cu, Hg, Ni and Cd using inductively coupled plasma atomic emission spectrometer. Out of these, concentrations of As and Pb were found to exceed the permissible limits suggested by US EPA.

scholarly journals Effect of Injection Pressure of Infiltration Anesthesia to the Jawbone

2016 ◽  
Vol 63 (3) ◽  
pp. 131-138 ◽  
Author(s):  
Kenji Yoshida ◽  
Eri Tanaka ◽  
Hiroyoshi Kawaai ◽  
Shinya Yamazaki
Keyword(s):  
Local Anesthetic ◽  
White Male ◽  
Injection Pressure ◽  
Time Interval ◽  
Time Intervals ◽  
Lidocaine Concentration ◽  
The Mean ◽  
High Concentrations ◽  
Infiltration Anesthesia ◽  
Local Anesthetic Infiltration

To obtain effective infiltration anesthesia in the jawbone, high concentrations of local anesthetic are needed. However, to reduce pain experienced by patients during local anesthetic administration, low-pressure injection is recommended for subperiosteal infiltration anesthesia. Currently, there are no studies regarding the effect of injection pressure on infiltration anesthesia, and a standard injection pressure has not been clearly determined. Hence, the effect of injection pressure of subperiosteal infiltration anesthesia on local anesthetic infiltration to the jawbone was considered by directly measuring lidocaine concentration in the jawbone. Japanese white male rabbits were used as test animals. After inducing general anesthesia with oxygen and sevoflurane, cannulation to the femoral artery was performed and arterial pressure was continuously recorded. Subperiosteal infiltration anesthesia was performed by injecting 0.5 mL of 2% lidocaine containing 1/80,000 adrenaline, and injection pressure was monitored by a pressure transducer for 40 seconds. After specified time intervals (10, 20, 30, 40, 50, and 60 minutes), jawbone and blood samples were collected, and the concentration of lidocaine at each time interval was measured. The mean injection pressure was divided into 4 groups (100 ± 50 mm Hg, 200 ± 50 mm Hg, 300 ± 50 mm Hg, and 400 ± 50 mm Hg), and comparison statistical analysis between these 4 groups was performed. No significant change in blood pressure during infiltration anesthesia was observed in any of the 4 groups. Lidocaine concentration in the blood and jawbone were highest 10 minutes after the infiltration anesthesia in all 4 groups and decreased thereafter. Lidocaine concentration in the jawbone increased as injection pressure increased, while serum lidocaine concentration was significantly lower. This suggests that when injection pressure of subperiosteal infiltration anesthesia is low, infiltration of local anesthetic to the jawbone may be reduced, while transfer to oral mucosa and blood may be increased.

Month of harvest and yield components of tea tree. II. Oil concentration, composition, and yield

1996 ◽  
Vol 47 (5) ◽  
pp. 817 ◽  
Author(s):  
GJ Murtagh ◽  
GR Smith
Keyword(s):  
Biomass Yield ◽  
Significant Loss ◽  
Oil Yield ◽  
Energy Reserves ◽  
Tea Tree ◽  
Air Temperatures ◽  
Oil Concentration ◽  
Biomass Yields ◽  
The Mean ◽  
High Concentrations

Changes in the concentration, composition, and yield of oil in coppice growth of tea tree (Melaleuca alternzfolia) were assessed when plants were harvested in different months. Oil concentrations in leaves were lower when plants were harvested in July-September than in other months, but biomass yields were higher. Consequently, there was no consistent effect of harvest month on oil yield. Oil yield varied as much between the same month in different years, as between months within a year. The oil concentration in one harvest was positively related to the biomass yield at the previous harvest of the same plants, suggesting that a carryover of energy reserves contributed to oil production. The oil concentration was also positively related to the mean air temperatures over the 3 months before harvest. The proportion of the economically significant compounds in oil, terpinen-4-01 and 1,8-cineole, was not affected by either the month of harvest or regrowth cycle, but other compounds did change. There was a significant loss of monoterpene olefins from oil which was present at high concentrations.

scholarly journals Impacts of Leachate Percolation on Ground Water Quality: A Case Study of Dhanbad City

2015 ◽  
Vol 17 (1) ◽  
pp. 162-174 ◽  
Keyword(s):  
Water Quality ◽  
Ground Water ◽  
Oxygen Demand ◽  
Quality Analysis ◽  
Solid Waste Disposal ◽  
Ground Water Quality ◽  
Potential Health ◽  
Groundwater Samples ◽  
High Concentrations ◽  
The Impact

<div> <p>This paper presents an assessment of the impact of uncontrolled and unscientific disposal of MSW on ground water in Dhanbad city, India. In this study, ground water quality around municipal solid waste disposal sites was investigated. Ground water quality analysis was carried out on samples collected at various distances from two disposal sites. The study has revealed that the ground water quality near dumping sites does not conform to the drinking water quality standards as per IS:10500. The impacts of indiscriminate dumping activity on ground water appeared most clearly as high concentrations of total dissolved solids, electrical conductivity, chlorides, chemical oxygen demand, and sulphates. High amount of metals like Na, K, Ca, Mg, Cd, Cu, Ni, Fe, Zn and Mn has also been detected in the groundwater samples near dumping area. Leachate characterization study also reveals high potential for groundwater contamination. Presence of feacal coliform contamination in groundwater samples indicates potential health risk for individuals exposed to this water.&nbsp;</p> </div> <p>&nbsp;</p>

scholarly journals Evaluating the Impacts of Agriculture to Groundwater Pollution in a Shallow Aquifer in Eastern Croatia

2011 ◽  
Vol 68 (2) ◽  
Author(s):  
Vilim FILIPOVIĆ ◽  
Dragutin PETOŠIĆ ◽  
Ivan ŠIMUNIĆ ◽  
Ivan MUSTAĆ ◽  
Zlatko SVEČNJAK ◽  
...  
Keyword(s):  
Groundwater Pollution ◽  
Agricultural Land ◽  
Shallow Aquifer ◽  
Nitrogen And Phosphorus ◽  
Potential Threat ◽  
Investigation Area ◽  
Groundwater Samples ◽  
The Mean ◽  
Phosphorus Levels ◽  
Observation Period

Agricultural activities are frequently associated with groundwater pollution. In this study, the goal is to evaluate the nitrate and phosphorus levels and it's impact to the groundwater. The investigation was located in the Eastern Croatia in the area of 6.600 ha of mainly agricultural land. Groundwater quality in the countertop part of the soil profile to 4.0 m depth was monitored by 40 installed hydropedological piezometers. Sampling water from piezometers was carried out every 60 days. In the groundwater samples nitrate, nitrite, ammonia and orthophosphate were analyzed. According to the indicators it was confirmed that at all locations during the observation period mean concentrations of NH4-N, NO3-N, total nitrogen (N) and phosphorus (P) in the groundwater from piezometers occasionally exceeded the value of maximum allowable concentration (MAC) which is prescribed by the Regulations. The mean concentrations of NO3-N were consistent and varied in the range from 2.42 to 4.61 mg NO3-N/l, the mean concentrations of nitrogen from ammonia exceed the permissible value (NH4-N) throughout the year, the average being higher than MAC (0.50 mg NH4-N/l) and were within the range of 0.57 mg NH4-N/l in to 1.21 mg NH4-N/l. The maximum concentration of phosphorus in groundwater were in the range of values from 0.40 to 1.11 mg P/l. Observation of traditional agricultural production in the investigation area with emphasis on leaching of nitrogen and phosphorus shows that it represents a potential threat to the future pollution of groundwater with nitrogen with phosphorus.

The Use of Edible Plants for Rhizofiltration under Different Hydroponic Conditions

2021 ◽  
Author(s):  
juyeon Lee ◽  
minjune Yang
Keyword(s):  
Raphanus Sativus ◽  
Brassica Campestris ◽  
Solid Phase ◽  
Root Surface ◽  
Edible Plants ◽  
Groundwater Samples ◽  
Ph Conditions ◽  
Uranium Accumulation ◽  
High Concentrations ◽  
Hydroponic Conditions

&lt;p&gt;This study conducted a rhizofiltration experiment for uranium-removal with the edible plants (&lt;em&gt;Lactuca sativa, Brassica campestris &lt;/em&gt;L., &lt;em&gt;Raphanus sativus &lt;/em&gt;L., and &lt;em&gt;Oenanthe javanica&lt;/em&gt;) which generally consumed in South Korea. Various batch experiments were performed with different initial uranium concentrations, pH conditions, and genuine groundwater. The results showed the uranium accumulation and bioconcentration factor (BCF) of plant roots increase with an increase in initial uranium concentrations in the solution. Of the four plants, the amount of uranium accumulated in &lt;em&gt;Raphanus sativus &lt;/em&gt;L. roots was 1215.8 &amp;#956;g/g DW with the maximum BCF value of 2692.7. The BCF value based on various pH conditions (pHs 3, 5, 7 and 9) of artificial solutions was highest at pH 3 for all four plants, and the BCF value of &lt;em&gt;Brassica campestris &lt;/em&gt;L. was the maximum of 11580.3 at pH 3. As a result of rhizofiltration experiments with genuine groundwater contaminated with uranium, the BCF values of &lt;em&gt;Raphanus sativus &lt;/em&gt;L. were 1684.7 and 1700.1, the highest among the four species, in Oesam-dong and Bugokdong groundwater samples with uranium concentration of 83 and 173 &amp;#956;g/L. From SEM/EDS analysis, it was confirmed that uranium in contaminated groundwater was adsorbed as a solid phase on the root surface. These results demonstrate that &lt;em&gt;Raphanus sativus &lt;/em&gt;L. not only has a high tolerance to high concentrations of uranium and low pH conditions but also has a remarkable potential for uranium accumulation capacity.&lt;/p&gt;

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