Application of the EPA hydrocarbon spill screening model to a hydrocarbon contaminated site in Thailand

2002 ◽  
Vol 10 (1) ◽  
pp. 17-24
Author(s):  
Vasin Mahatnirunkul ◽  
Sirintornthep Towprayoon ◽  
Vladimir Bashkin
Keyword(s):  
Contaminated Site ◽  
Screening Model ◽  
Hydrocarbon Spill

scholarly journals Simulação matemática do transporte de óleo mineral isolante na zona vadosa considerando a constante dielétrica e o índice de plasticidade

2020 ◽  
Vol 34 (3) ◽  
pp. 340-347
Author(s):  
Muriel Edyth Lumsden Szymanski Patricio ◽  
Marcio Roberto Schneider ◽  
Konrad Ziemowit Miotliński ◽  
Admir José Giachini ◽  
Alzete Martins Quadros
Keyword(s):  
Screening Model ◽  
Hydrocarbon Spill

Acidentes ou falhas em equipamentos elétricos em subestações de energia podem resultar em vazamentos de óleo mineral isolante (OMI), ocasionando contaminação do solo e da água subterrânea. A modelagem matemática é uma importante ferramenta para a previsão dos impactos destes vazamentos e para a determinação do tempo de resposta das ações emergenciais. Um dos simuladores mais utilizados neste processo é o Hydrocarbon Spill Screening Model (HSSM), distribuído pela U.S.EPA. Contudo, esse e outros modelos baseados na equação de Nutting (1934), não consideram o efeito da constante dielétrica na determinação da mobilidade dos contaminantes. O objetivo deste estudo contemplou a avaliação da influência da constante dielétrica na modelagem matemática de OMI e analisou a simulação de derramamento de OMI em cinco subestações de energia elétrica com o simulador Hydrocarbon Spill Screening Model (HSSM). Os resultados indicaram que em solos constituídos de argilas expansivas, a inclusão da constante dielétrica na modelagem matemática do transporte na zona vadosa pode representar um acréscimo de até três ordens de grandeza à condutividade hidráulica ao OMI, influenciando as ações de contingenciamento ambiental ponderadas sobre essas estimativas.

scholarly journals Polycyclic aromatic hydrocarbons (PAHs) in soils of an industrial area in semi-arid Uzbekistan: spatial distribution, relationship with trace metals and risk assessment

2021 ◽  
Author(s):  
Benjamin A. Musa Bandowe ◽  
Nosir Shukurov ◽  
Sophia Leimer ◽  
Michael Kersten ◽  
Yosef Steinberger ◽  
...  
Keyword(s):  
Molecular Weight ◽  
Industrial Area ◽  
Copper Smelting ◽  
Contaminated Site ◽  
Background Concentration ◽  
Industrial Complex ◽  
Metal Mining ◽  
Quality Guidelines ◽  
Us Epa ◽  
Semi Arid

AbstractThe concentrations, composition patterns, transport and fate of PAHs in semi-arid and arid soils such as in Central Asia are not well known. Such knowledge is required to manage the risk posed by these toxic chemicals to humans and ecosystems in these regions. To fill this knowledge gap, we determined the concentrations of 21 parent PAHs, 4,5-methylenephenanthrene, 6 alkylated PAHs, and biphenyl in soils from 11 sampling locations (0–10, 10–20 cm soil depths) along a 20-km transect downwind from the Almalyk metal mining and metallurgical industrial complex (Almalyk MMC), Uzbekistan. The concentrations of Σ29 PAHs and Σ16 US-EPA PAHs were 41–2670 ng g−1 and 29–1940 ng g−1, respectively. The highest concentration of Σ29 PAHs occurred in the immediate vicinity of the copper smelting factory of the Almalyk MMC. The concentrations in topsoil decreased substantially to a value of ≤ 200 ng g−1 (considered as background concentration) at ≥ 2 km away from the factory. Low molecular weight PAHs dominated the PAH mixtures at less contaminated sites and high molecular weight PAHs at the most contaminated site. The concentration of Σ16 US-EPA PAHs did not exceed the precautionary values set by the soil quality guidelines of, e.g., Switzerland and Germany. Similarly, the benzo[a]pyrene equivalent concentration in soils near the Almalyk MMC did not exceed the value set by the Canadian guidelines for the protection of humans from carcinogenic PAHs in soils. Consequently, the cancer risk due to exposure to PAHs in these soils can be considered as low.

scholarly journals Air Concentrations of Gaseous Elemental Mercury and Vegetation–Air Fluxes within Saltmarshes of the Tagus Estuary, Portugal

Atmosphere ◽  
2021 ◽  
Vol 12 (2) ◽  
pp. 228
Author(s):  
Rute Cesário ◽  
Nelson J. O’Driscoll ◽  
Sara Justino ◽  
Claire E. Wilson ◽  
Carlos E. Monteiro ◽  
...  
Keyword(s):  
Leaf Area ◽  
Elemental Mercury ◽  
Ambient Air ◽  
Tagus Estuary ◽  
Contaminated Site ◽  
Gaseous Elemental Mercury ◽  
Mercury Flux ◽  
Sarcocornia Fruticosa ◽  
Air Concentrations

In situ air concentrations of gaseous elemental mercury (Hg(0)) and vegetation–atmosphere fluxes were quantified in both high (Cala Norte, CN) and low-to-moderate (Alcochete, ALC) Hg-contaminated saltmarsh areas of the Tagus estuary colonized by plant species Halimione portulacoides (Hp) and Sarcocornia fruticosa (Sf). Atmospheric Hg(0) ranged between 1.08–18.15 ng m−3 in CN and 1.18–3.53 ng m−3 in ALC. In CN, most of the high Hg(0) levels occurred during nighttime, while the opposite was observed at ALC, suggesting that photoreduction was not driving the air Hg(0) concentrations at the contaminated site. Vegetation–air Hg(0) fluxes were low in ALC and ranged from −0.76 to 1.52 ng m−2 (leaf area) h−1 for Hp and from −0.40 to 1.28 ng m−2 (leaf area) h−1 for Sf. In CN, higher Hg fluxes were observed for both plants, ranging from −9.90 to 15.45 ng m−2 (leaf area) h−1 for Hp and from −8.93 to 12.58 ng m−2 (leaf area) h−1 for Sf. Mercury flux results at CN were considered less reliable due to large and fast variations in the ambient air concentrations of Hg(0), which may have been influenced by emissions from the nearby chlor-alkali plant, or historical contamination. Improved experimental setup, the influence of high local Hg concentrations and the seasonal activity of the plants must be considered when assessing vegetation–air Hg(0) fluxes in Hg-contaminated areas.

scholarly journals Characterization and within-site variation of environmental metal concentrations around a contaminated site using a community-engaged approach

Chemosphere ◽  
2021 ◽  
Vol 272 ◽  
pp. 129915
Author(s):  
Patrick Ringwald ◽  
Cecelia Chapin ◽  
Christopher Iceman ◽  
Meghanne E. Tighe ◽  
Matthew Sisk ◽  
...  
Keyword(s):  
Contaminated Site ◽  
Metal Concentrations ◽  
Site Variation

scholarly journals Plutonium complexes in water: new approach to ab initio modeling

2021 ◽  
Vol 0 (0) ◽  
Author(s):  
Mikhail V. Ryzhkov ◽  
Andrei N. Enyashin ◽  
Bernard Delley
Keyword(s):  
Quantitative Estimation ◽  
Water Solution ◽  
Geometry Optimization ◽  
Model Potential ◽  
Water Dissociation ◽  
New Approach ◽  
Molecular Systems ◽  
Screening Model ◽  
Solvent Environment ◽  
Structure Calculations

Abstract Geometry optimization and the electronic structure calculations of Pu Z+ complexes (Z = 3–6) in water solution have been performed, within the framework of the DMol3 and Relativistic Discrete-Variational (RDV) methods. For the simulation of Pu Z+ molecular environment in aqueous solution we used 22 and 32 water molecules randomly distributed around cation. To model the effect of bulk solvent environment we used COSMO (Conductor-like Screening Model) potential for water (ε = 78.54). The obtained results showed that this approach allows the modeling of water dissociation and the formation of hydrolysis products. Our previously suggested scheme for the calculation of interaction energies between selected fragments of multi-molecular systems provides the quantitative estimation of the interaction strengths between plutonium in various oxidation states and each ligand in the first and second coordination shells in water solution.

scholarly journals The Effects of Forest Litter and Waterlogging on the Ecotoxicity of Soils Strongly Enriched in Arsenic in a Historical Mining Site

Forests ◽  
2021 ◽  
Vol 12 (3) ◽  
pp. 355
Author(s):  
Katarzyna Szopka ◽  
Iwona Gruss ◽  
Dariusz Gruszka ◽  
Anna Karczewska ◽  
Krzysztof Gediga ◽  
...  
Keyword(s):  
Pore Water ◽  
Gold Mining ◽  
Vibrio Fischeri ◽  
Chemical Properties ◽  
Forest Litter ◽  
Contaminated Site ◽  
Mining Site ◽  
Soil Pore Water ◽  
Soil Ecotoxicity ◽  
Properties Of Soil

This study examined the effects of waterlogging and forest litter introduced to soil on chemical properties of soil pore water and ecotoxicity of soils highly enriched in As. These effects were examined in a 21-day incubation experiment. Tested soil samples were collected from Złoty Stok, a historical centre of arsenic and gold mining: from a forested part of the Orchid Dump (19,600 mg/kg As) and from a less contaminated site situated in a neighboring forest (2020 mg/kg As). An unpolluted soil was used as control. The concentrations of As, Fe and Mn in soil pore water were measured together with a redox potential Eh. A battery of ecotoxicological tests, including a bioassay with luminescence bacteria Vibrio fischeri (Microtox) and several tests on crustaceans (Rapidtox, Thamnotox and Ostracodtox tests), was used to assess soil ecotoxicity. The bioassays with crustaceans (T. platyurus, H. incongruens) were more sensitive than the bacterial test Microtox. The study confirmed that the input of forest litter into the soil may significantly increase the effects of toxicity. Waterlogged conditions facilitated a release of As into pore water, and the addition of forest litter accelerated this effect thus causing increased toxicity.

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