scholarly journals Mercury levels in Tarmat Contaminated Beaches and its Marine Organisms living along the Qatari Coasts

2021 ◽  
Author(s):  
Ahmed Helmy Hassan Abouelezz
Keyword(s):  
Total Mercury ◽  
Sediment Accumulation ◽  
Coastal Environment ◽  
Marine Organisms ◽  
Sentinel Species ◽  
Accumulation Factor ◽  
Coastal Species ◽  
Oil Residue ◽  
The Mean ◽  
Concentration Levels

One of the pollutants that affects the coastal environment of Qatar is the vast expanse of oil residue ‘tarmats’ deposited on its beaches. The current study is aimed at gauging the concentration levels of total mercury (THg) in tarmat contaminated sediments and test their presence in selected coastal species. Three biota classes (Gastropoda, Bivalvia, and Crustacea) have been found on the tarmat of Ras Rakan and Umm Tais islands. Layers of hard asphalt-like tarmats and sediments samples were collected from 34 sites, along the coast of Qatar. Moreover, the Biota Sediment Accumulation Factor (BSAF) was calculated for THg through sentinel species. The mean concentrations of THg is 0.089 ± 0.02 μg.g-1. Compared to earlier studies, a relatively higher concentration of THg (0.463 μg.g-1) had been observed.

scholarly journals Biological Risk Assessment of Heavy Metals in Sediments and Health Risk Assessment in Marine Organisms from Daya Bay, China

2020 ◽  
Vol 9 (1) ◽  
pp. 17
Author(s):  
Zexing Kuang ◽  
Yangguang Gu ◽  
Yiyong Rao ◽  
Honghui Huang
Keyword(s):  
Heavy Metals ◽  
Risk Assessment ◽  
Marine Organisms ◽  
Daya Bay ◽  
Ecological Risks ◽  
The Monte Carlo Method ◽  
Accumulation Index ◽  
The Mean ◽  
Primary Pollutant ◽  
Geo Accumulation

The concentrations of heavy metals in sediments and marine organisms in Daya Bay were investigated, and the Monte Carlo method was used to analyze the uncertainty of the results of geo-accumulation characteristics and ecological and health risks. The mean concentrations of metal elements in sediments were in the following order: Zn > Cr > Cu > As > Cd > Hg, while those in marine organisms were Zn > Cu > As > Cr ≈ Cd > Hg. The geo-accumulation index (Igeo) indicated that the primary pollutant was Hg, with 5.46% moderately polluted, and 39.52% for unpolluted to moderately polluted. Potential ecological risks (RI) were between low and high risks, and the contributions of Hg, Cd, and As to ecological risks were 50.85%, 33.92%, and 11.47%, respectively. The total hazard coefficients (THQ) were less than 1, but on the basis of total carcinogenic risks (TCR), the probability of children and adults exceeded the unacceptable risk threshold of 22.27% and 11.19%, respectively. Sensitivity analysis results showed that the concentrations of carcinogenic elements contributed to risk in the order of As > Cd > Cr. Therefore, in order to effectively control heavy metals contamination in Daya Bay, it is necessary to strengthen the management of Hg, Cd, and As emissions.

scholarly journals A sensitive HPLC-FLD method for the quantification of 6-O-demethylmenisporphine isolated from Menispermi Rhizoma in rat plasma

2021 ◽  
Vol 12 (1) ◽  
Author(s):  
Jinxia Wei ◽  
Jia Shao ◽  
Yanan Li ◽  
Yubo Li
Keyword(s):  
Mobile Phase ◽  
Internal Standard ◽  
Rat Plasma ◽  
Hplc Assay ◽  
Isocratic Elution ◽  
Fluorescence Detector ◽  
Limit Of Quantification ◽  
The Mean ◽  
Preclinical Safety ◽  
Concentration Levels

Abstract Background To investigate the pharmacokinetics of 6-O-demethylmenisporphine, an oxoisoaporphine alkaloid with significant anti-tumor activities and isolated from Menispermi Rhizoma, a novel and sensitive HPLC assay was established for 6-O-demethylmenisporphine quantification in rat plasma. Methods Peak responses were detected by a highly selective and sensitive fluorescence detector with 426-nm excitation and 514-nm emission wavelengths. Curcumin was employed as the internal standard (IS). A Capcell Pak C18 column (150 mm × 4.6 mm i.d., 5 μm) and an isocratic elution procedure with a flow rate of 1.0 mL/min were used to exclude the endogenous interfering substance. Acetonitrile-water (68:32, v/v) containing 1% formic acid was employed as mobile phase. A 7-point calibration curve that covered the concentration range of 10–2500 ng/mL was constructed. Results A good linearity was observed with a correlation coefficient (r) of 0.9993. The lower limit of quantification for 6-O-demethylmenisporphine was 10 ng/mL. The mean recoveries of analyte in rat plasma exceeded 80.5%. The precision at four concentration levels was within 11.3% and the accuracy ranged from − 7.6 to 6.7%. Conclusion Using this new HPLC-FLD method, the investigation of plasma samples from rats following oral dosing of neat compound and Menispermi Rhizoma extract was successfully conducted. The results will provide a reference for the evaluation of preclinical safety of 6-O-demethylmenisporphine.

Interspecific differences in the distribution of adult and juvenile ponyfish (Leiognathidae) in the Gulf of Carpentaria, Australia

1999 ◽  
Vol 50 (7) ◽  
pp. 643 ◽  
Author(s):  
J. Staunton-Smith ◽  
S. J. M. Blaber ◽  
J. G. Greenwood
Keyword(s):  
Linear Increase ◽  
Small Fish ◽  
Common Pattern ◽  
Widespread Species ◽  
Nursery Areas ◽  
Interspecific Differences ◽  
Coastal Species ◽  
The Common ◽  
The Mean ◽  
Coexisting Species

The distribution of leiognathids was investigated at 261 sites spread throughout the Gulf of Carpentaria. Eight species, Gazza minuta, Leiognathus decorus, L. equulus, L. fasciatus, L. leuciscus, L. smithursti, L. splendens and Secutor ruconius, were usually restricted to coastal areas, whereas four species, L. bindus, L. moretoniensis, Leiognathus sp. and S. insidiator, were not. Two other species, L. aureus and L. elongatus, were caught at only one site each. The relationships between size of fish and depth in Albatross Bay were investigated by examining the mean weight and minimum and maximum lengths of different species in 356 trawls. Six of the coastal species showed the common pattern of linear increase in size with depth. This pattern is consistent with the existence of estuarine and/or inshore nursery areas, and supports previous observations of these species. In contrast, three of the widespread species exhibited approximately quadratic relationships between size and depth. This unusual pattern resulted from small fish living in both the shallow inshore areas and deeper offshore areas, and it may reduce competition among the juveniles of the large number of very abundant, coexisting species of leiognathid.

Distribution of mercury and methylmercury in the sediments of a lowland river system

2005 ◽  
Vol 461 (2057) ◽  
pp. 1335-1355 ◽  
Author(s):  
Jason W Birkett ◽  
John N Lester
Keyword(s):  
Point Source ◽  
Total Mercury ◽  
Sewage Treatment ◽  
River System ◽  
Initial Increase ◽  
Surficial Sediments ◽  
Spatial Trends ◽  
The Mean ◽  
Temporal And Spatial ◽  
Temporal And Spatial Trends

Concentrations of total mercury (T-Hg) and methylmercury (MeHg) were determined in surficial sediments from the River Yare, Norfolk, UK over the period 1986–1998, to assess the temporal and spatial trends of contamination arising from a historical point source discharge. The results demonstrate that the spatial distribution pattern follows that of a distinct pollution plume in the sediments with an initial increase 2–3 km downstream from the point source discharge at Whitlingham sewage treatment works (STW) outfall. Temporally, this pollution plume remains evident, although there has been an overall decline in the mean T-Hg concentrations from 5.4 in 1986 to 1.8 mg kg −1 in 1998. The major factor for this improvement has been the reduction in discharge of metals from the STW, together with burial by a fresh overlay of uncontaminated sediments. MeHg concentrations also exhibited a dispersed pollution plume. Mean concentrations of MeHg fluctuated during the study period between 3.3 and 8.5 μg kg −1 . There has been no concomitant decline in MeHg concentrations over this period. MeHg was found to constitute less than 1% of T-Hg concentrations in the sediments. The weak correlations observed between T-Hg and MeHg concentrations indicate external environmental factors have a significant influence on determining MeHg concentrations in the sedimentary compartment.

scholarly journals Assessing the Impact of Housing Features and Environmental Factors on Home Indoor Radon Concentration Levels on the Navajo Nation

2020 ◽  
Vol 17 (8) ◽  
pp. 2813
Author(s):  
Sheldwin A. Yazzie ◽  
Scott Davis ◽  
Noah Seixas ◽  
Michael G. Yost
Keyword(s):  
Radon Concentration ◽  
Indoor Radon ◽  
Decay Product ◽  
Indoor Radon Concentration ◽  
Navajo Nation ◽  
Home Ventilation ◽  
Radon Gas ◽  
The Mean ◽  
The Impact ◽  
Concentration Levels

Uranium is naturally found in the environment as a radioactive metal element with high concentrations in the Southwestern US. In this region is the Navajo Nation, which spans approximately 69,930 square kilometers. A decay product of uranium is radon gas, a lung carcinogen that has no color, odor, or taste. Radon gas may pass from soil into homes; and, indoor accumulation has been associated with geographical location, seasonality, home construction materials, and home ventilation. A home and indoor radon survey was conducted from November 2014 through May 2015, with volunteers who reported residence on the Navajo Nation. Home geolocation, structural characteristics, temperature (°C) during radon testing, and elevation (meters) were recorded. Short-term indoor radon kits were used to measure indoor radon levels. 51 homes were measured for indoor radon levels, with an arithmetic mean concentration of 60.5 Becquerels per cubic meter (Bq/m3) (SD = 42.7). The mean indoor radon concentrations (Bq/m3) by house type were: mobile, 29.0 (SD = 22.9); wood, 58.6 (SD = 36.0); hogan, 74.0 (SD = 0.0); homes constructed of cement and wood, 82.6 (SD = 3.5); and homes constructed of concrete and cement, 105.7 (SD = 55.8). A key observation is that house construction type appears to be associated with the mean home indoor radon concentration. This observation has been published in that the basic structural make-up of the home may affect home ventilation and therefore indoor radon concentration levels.

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.

CHEMICAL COMPOSITION AND SOURCE FINGERPRINTING OF DEPOSITIONAL OIL FROM THE KUWAIT OIL FIRES

1993 ◽  
Vol 1993 (1) ◽  
pp. 407-413 ◽  
Author(s):  
Charles B. Henry ◽  
Edward B. Overton
Keyword(s):  
Chemical Composition ◽  
Arabian Gulf ◽  
Fold Increase ◽  
Oil Field ◽  
Oil Sand ◽  
Oil Residue ◽  
Long Time ◽  
The Mean ◽  
Mean Concentration ◽  
Oil Field Fires

ABSTRACT Depositional oil and soot derived from the 1991 Kuwait oil field fires produced huge tar mats in the desert. The concentration of oil in the upper 5 cm of the desert surface ranged from 1.16 to 8.92 percent oil by weight as determined by TPH analysis over a 10 km transect in southern Kuwait. The mean concentration of asphaltenes in the tar mat samples was estimated at 62 percent; a greater than 17-fold increase in concentration over unweathered Kuwait crude oil. The remaining oil forming these tar mats is believed to be derived from petroleum that escaped combustion within the well fires. Results from GC/MS analyses characterize the depositional oil as being significantly altered by evaporative weathering. We suspect that evaporation of the depositional oil will continue, further consolidating the weathered oil, sand, and soot into asphalt-like zones which will remain for a very long time as features of the Kuwait desert. Significant quantities of oil residue from the fires also fell into the Arabian Gulf, contributing to what may be the largest man-made oil spill.

Mercury concentrations in edible tissues of Elasmobranchs, teleosts, crustaceans and molluscs from south-eastern Australian waters

1988 ◽  
Vol 39 (1) ◽  
pp. 39 ◽  
Author(s):  
TI Walker
Keyword(s):  
New Zealand ◽  
Total Mercury ◽  
Soft Tissues ◽  
New South ◽  
New South Wales ◽  
South Eastern ◽  
South Wales ◽  
Muscle Tissues ◽  
Edible Tissues ◽  
The Mean

Mean concentrations of total mercury in the axial muscle tissues from 4 species of elasmobranchs (1.33-3.15 �g g-1) and 14 species of teleosts (0.14-0.73�g g-1) from waters deeper than 75 m were generally higher than the mean concentrations in 23 different species of elasmobranchs (0.13- 1.70 �g g-1) and 30 different species of teleosts (0.01-0.29�g g-1) from shallower waters outside Port Phillip Bay. In 5 of the 11 species of teleosts from Port Phillip Bay, which is shallow, almost landlocked and drains a largely urbanized catchment, mean concentrations were 0.39-0.63�g g-; in the remaining 6 species, they were 0.04-0.27�g g-1. Differences in the diets and the longevity of the species are discussed as possible explanations of the variations in the mercury concentrations. Most of the results were similar to those from other studies undertaken on the same species collected from waters off Tasmania and New South Wales, but tended to be higher than the results for the same species collected from New Zealand waters. Mean concentrations of mercury in various soft tissues from eight species of molluscs were 0.01-0.11�g g-1 and in abdominal and thoracic muscle tissues from three species of crustaceans were 0.03-0.13�g g-1..

National-Scale, Field-Based Evaluation of the Biota−Sediment Accumulation Factor Model

2001 ◽  
Vol 35 (9) ◽  
pp. 1709-1715 ◽  
Author(s):  
Charles S. Wong ◽  
Paul D. Capel ◽  
Lisa H. Nowell
Keyword(s):  
Factor Model ◽  
Sediment Accumulation ◽  
Accumulation Factor ◽  
National Scale ◽  
Scale Field
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