Whole organism concentration ratios in freshwater wildlife from an Australian tropical U mining environment and the derivation of a water radiological quality guideline value

2019 ◽  
Vol 198 ◽  
pp. 27-35 ◽  
Author(s):  
Che Doering ◽  
Julia Carpenter ◽  
Blake Orr ◽  
David Urban
Keyword(s):  
Mining Environment ◽  
Guideline Value ◽  
Quality Guideline ◽  
Concentration Ratios

scholarly journals Risk assessment of Ni, Cr, and Si release from alkaline minerals during enhanced weathering

2020 ◽  
Vol 5 (1) ◽  
pp. 166-175
Author(s):  
Fatima Haque ◽  
Yi Wai Chiang ◽  
Rafael M. Santos
Keyword(s):  
Risk Assessment ◽  
Environmental Protection Agency ◽  
Hazard Index ◽  
Carcinogenic Risk ◽  
Contamination Level ◽  
Potential Threat ◽  
Silicate Minerals ◽  
Guideline Value ◽  
Quality Guideline ◽  
Index Value

AbstractCalcium- and magnesium-rich alkaline silicate minerals, when applied to soil, can aid in carbon dioxide sequestration via enhanced weathering. The weathering of these silicate minerals is also associated with the release of heavy metals such as Ni and Cr, depending on the composition of the parent rock, and also labile Si. This paper critically analyses the risk associated with the release of Ni, Cr, and Si from alkaline silicate minerals as a result of enhanced weathering to evaluate its potential to be applied as a soil amendment. Based on the available data in the literature, this study evaluates the soil contamination level and quantifies the risk these elements pose to human health as well as the environment. To assess these potential threat levels, the geoaccumulation index was applied, along with the method recommended by the US Environmental Protection Agency for health risk assessment. The main findings of this study indicate the potential release of Ni, Cr, and Si to exceed the soil quality guideline value. The geochemical index suggests that the analyzed samples are in the class 0–3 and represents sites that lie between uncontaminated zones to highly contaminated zones. The hazard index value for Ni and Cr is greater than unity, which suggests that Ni and Cr release poses a non-carcinogenic risk. The probability of labile Si concentration in the soil to exceed the critical value is found to be 75%.

Photoelectrochemical experiments under various solar light concentration ratios

1999 ◽  
Vol 09 (PR3) ◽  
pp. Pr3-301-Pr3-306
Author(s):  
O. Enea ◽  
J. Blanco ◽  
S. Malato ◽  
M. I. Maldonado
Keyword(s):  
Solar Light ◽  
Light Concentration ◽  
Concentration Ratios

Microbiological Performance of Multi-Stage Stabilization Ponds for Effluent Use in Agriculture

1991 ◽  
Vol 23 (7-9) ◽  
pp. 1517-1524 ◽  
Author(s):  
M. M. Saqqar ◽  
M. B. Pescod
Keyword(s):  
Environmental Parameters ◽  
Complete Removal ◽  
Faecal Coliform ◽  
Winter Period ◽  
Intestinal Nematode ◽  
Stabilization Ponds ◽  
Multi Stage ◽  
Guideline Value ◽  
Temperature Dependent Model ◽  
Egg Removal

The paper presents data on total and faecal coliform removal and on intestinal nematode egg removal achieved in the Al-Samra stabilization ponds in Jordan during the winter period December 1986 to March 1987. A total retention of 34 days in the series of 10 ponds was able to achieve complete removal of nematode eggs at the pond temperature 12-15°C but was not able to meet the WHO guideline value for faecal conforms of ≤ 1000/100 ml. In addition to retention time having a positive effect on faecal conform die-off, it was shown that surface organic loading, pond pH, BOD5 concentration, and depth, influenced the rate of faecal coliform die-off. It became apparent that interactions existed among the operational and environmental parameters but that the simple time-and-temperature-dependent model for faecal conform die-off was no longer appropriate.

The effect of type of water supply on water quality in a developing community in South Africa

1997 ◽  
Vol 35 (11-12) ◽  
pp. 35-40 ◽  
Author(s):  
B. Genthe ◽  
N. Strauss ◽  
J. Seager ◽  
C. Vundule ◽  
F. Maforah ◽  
...  
Keyword(s):  
Water Quality ◽  
Water Supply ◽  
Cross Sectional Study ◽  
Cross Sectional ◽  
E Coli ◽  
Guideline Values ◽  
Developing Communities ◽  
Quality Guideline ◽  
And Control ◽  
The Relationship

Efforts to provide water to developing communities in South Africa have resulted in various types of water supplies being used. This study examined the relationship between the type of water supply and the quality of water used. Source (communal taps, private outdoor and indoor taps) and point-of-use water samples were examined for heterotrophic plate counts (HPC), total and faecal coliforms, E. coli, and coliphages. Ten percent of samples were also analysed for enteric viruses, Giardia and Cryptosporidium. Approximately 320 households were included in a case-control study. In addition, a cross-sectional study was conducted. Both studies examined the relationship between different types of water facilities and diarrhoea among pre-school children. The source water was of good microbial quality, but water quality was found to have deteriorated significantly after handling and storage in both case and control households, exceeding drinking water quality guideline values by 1-6 orders of magnitude. Coliphage counts were low for all water samples tested. Enteric viruses and Cryptosporidium oocysts were not detected. Giardia cysts were detected on one occasion in case and control in-house samples. Comparisons of whether in-house water, after handling and storage, complied with water quality guideline values demonstrated households using communal taps to have significantly poorer quality than households using private outdoor or indoor taps for HPC and E. coli (χ2 = 14.9, P = 0.001; χ2 = 6.6, P = 0.04 respectively). A similar trend (although not statistically significant) was observed for the other microbial indicators. The cross-sectional study demonstrated an apparent decrease in health risk associated with private outdoor taps in comparison to communal taps. This study suggests that a private outdoor tap is the minimum level of water supply in order to ensure the supply of safe water to developing communities.

Hydrodesulphurization of thiophene over zirconia and alumina supported Co-Mo catalysts

1989 ◽  
Vol 54 (8) ◽  
pp. 2064-2068 ◽  
Author(s):  
Jiří Sedláček ◽  
Zdeněk Vít
Keyword(s):  
Total Pressure ◽  
Supported Catalysts ◽  
Atomic Concentration ◽  
Commercial Sample ◽  
Sulphur Oxidation ◽  
Como Catalysts ◽  
Zirconia Support ◽  
Como Catalyst ◽  
Concentration Ratios

The zirconia supported CoMo catalysts and the commercial sample CoMo/Al2O3 were characterized by XPS measurements and by testing of activity in the HDS of thiophene at 280 °C and 1 MPa of total pressure. The XPS measurements revealed the better reducibility of molybdenum, higher sulphidability of cobalt and the absence of surface sulphur oxidation in the presence of zirconia support. The surface atomic concentration ratios S/Mo were 1.2 and 2.2 for zirconia and alumina supported catalysts, respectively. The activity of the zirconia supported CoMo catalyst normalized to the overal amounts of active metals was lower than that of the commercial CoMo/Al2O3 catalyst.

scholarly journals Dental Fluorosis in Children from Aguascalientes, Mexico: A Persistent Public Health Problem

Water ◽  
2021 ◽  
Vol 13 (8) ◽  
pp. 1125
Author(s):  
Osiel González Dávila
Keyword(s):  
Public Health ◽  
Health Problem ◽  
Dental Fluorosis ◽  
Tap Water ◽  
Public Health Problem ◽  
Normal Weight ◽  
Fluoride Removal ◽  
Public Elementary Schools ◽  
Ordered Logistic Regression ◽  
Guideline Value

This paper estimates the prevalence and severity of dental fluorosis among participants in the first wave of The Aguascalientes Longitudinal Study of Child Development (EDNA). The analytical sample includes 1052 children in 100 public elementary schools. Dental fluorosis is determined using the Modified Dean’s Index. There is a 43% general dental fluorosis prevalence, and the estimated Community Fluorosis Index is 0.99. Five municipalities report average groundwater fluoride concentrations above the official Mexican guideline value of 1.5 mg/L. In those municipalities, there is a 50% average dental fluorosis prevalence. An ordered logistic regression analysis indicates that obesity in participants increases the likelihood of suffering more severe dental fluorosis symptoms compared with normal-weight participants (OR = 1.62, p < 0.05). Households consuming tap water are more likely to have children suffering more severe dental fluorosis symptoms (OR = 1.63, p < 0.05). Children aged 8 years are more likely to present more severe dental fluorosis symptoms than their peers aged 7 years (OR = 1.37, p < 0.05). Dental fluorosis will persist as a public health problem in Aguascalientes State unless appropriate technologies for fluoride removal from water are installed and operated.

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