Leaching of 239,240Pu and 241Am from Thule Nuclear Bomb Particles Investigated by Sequential Extraction

Dr. Hassan Abbas is a Pakistani-American academic whose interest area lies in South and Central Asia. He is presently a Professor and Chair of the Department of Regional and Analytical Studies at National Defense University, Washington, DC. Similar to his previous books, Hassan Abbas has taken up yet another topic that revolves around the statehood of Pakistan.

Download Full-text

Sequential extraction procedure to obtain the composition of terrigenous detritus in marine sediments

MethodsX ◽

10.1016/j.mex.2020.100888 ◽

2020 ◽

Vol 7 ◽

pp. 100888

Author(s):

Margit H. Simon ◽

Daniel P. Babin ◽

Steven L. Goldstein ◽

Merry Yue Cai ◽

Tanzhuo Liu ◽

...

Keyword(s):

Sequential Extraction ◽

Marine Sediments ◽

Extraction Procedure ◽

Sequential Extraction Procedure

Download Full-text

The Use of a Sequential Extraction Technique to Characterize Soil Trace Evidence Recovered from a Spade in a Murder Case in Brazil*

Journal of Forensic Sciences ◽

10.1111/1556-4029.14491 ◽

2020 ◽

Vol 65 (6) ◽

pp. 1921-1934 ◽

Cited By ~ 1

Author(s):

Samara Alves Testoni ◽

Vander Freitas Melo ◽

Lorna Anne Dawson ◽

Joice Malakoski ◽

Edimar Cunico ◽

...

Keyword(s):

Sequential Extraction ◽

Extraction Technique ◽

Trace Evidence

Download Full-text

An Assessment of Heavy Metal Contamination in the Nakdong River Around the Weir

Water ◽

10.3390/w13050684 ◽

2021 ◽

Vol 13 (5) ◽

pp. 684

Author(s):

Hee Won Son ◽

Sun Hee Shim ◽

Haeseong Oh ◽

Jung Hyun Choi

Keyword(s):

Heavy Metals ◽

Sequential Extraction ◽

Environmental Protection Agency ◽

Heavy Metal Contamination ◽

Environmental Research ◽

Residual Fraction ◽

Nakdong River ◽

Risk Assessment Code ◽

The Nakdong River ◽

Reducible Fraction

In this study, the concentrations and characteristics of copper (Cu), zinc (Zn), and lead (Pb) contamination in sediment samples were investigated using aqua regia extraction and Tessier’s five-step sequential extraction. Based on the concentration of metals, the influence of the Hapcheon-Changnyeong weir on sediments in the Nakdong River was assessed. The origins of the contaminants, their bioavailability, and their mobility were determined using sequential extraction. Greater concentrations of heavy metals were found in samples collected closer to the weir. The largest proportion of Cu was identified in the residual fraction based on sequential extraction, whereas Zn was predominantly found in the reducible fraction. Iron-manganese in the reducible fraction of Zn has the potential to leach back to the water body. In addition, the combined concentration of fractions 1 and 2 of Cu comprised more than 20% of total amount that still has potential to affect the water quality. The results of this study were compared with existing sediment standards set out by the NIER (National Institute of Environmental Research), Canada, and US EPA (United States Environmental Protection Agency) guidelines, as well as the risk assessment code (RAC). The concentrations of heavy metals exceeded the standards set by the Canadian guideline by up to four times in particular samples, highlighting the need for continual monitoring.

Download Full-text

The undetected loss of aged carbon from boreal mineral soils

Scientific Reports ◽

10.1038/s41598-021-85506-w ◽

2021 ◽

Vol 11 (1) ◽

Author(s):

Geert Hensgens ◽

Hjalmar Laudon ◽

Mark S. Johnson ◽

Martin Berggren

Keyword(s):

Organic Carbon ◽

Boreal Forest ◽

Soil C ◽

Earth Systems ◽

Nuclear Bomb ◽

C Cycle ◽

Water Extractable Organic Carbon ◽

High Lability ◽

Mineral Soils ◽

Terrestrial Biomes

AbstractThe boreal forest is among the largest terrestrial biomes on earth, storing more carbon (C) than the atmosphere. Due to rapid climatic warming and enhanced human development, the boreal region may have begun transitioning from a net C sink to a net source. This raises serious concern that old biogenic soil C can be re-introduced into the modern C cycle in near future. Combining bio-decay experiments, mixing models and the Keeling plot method, we discovered a distinct old pre-bomb organic carbon fraction with high biodegradation rate. In total, 34 ± 12% of water-extractable organic carbon (WEOC) in podzols, one of the dominating boreal soil types, consisted of aged (~ 1000 year) labile C. The omission of this aged (i.e., Δ14C depleted) WEOC fraction in earlier studies is due to the co-occurrence with Δ14C enriched modern C formed following 1950s nuclear bomb testing masking its existence. High lability of aged soil WEOC and masking effects of modern Δ14C enriched C suggests that the risk for mobilization and re-introduction of this ancient C pool into the modern C cycle has gone undetected. Our findings have important implications for earth systems models in terms of climate-carbon feedbacks and the future C balance of the boreal forest.

Download Full-text

Environmental Availability of Potentially Toxic Elements in an Agricultural Mediterranean Site

Environmental and Engineering Geoscience ◽

10.2113/eeg-2129 ◽

2019 ◽

Vol 25 (2) ◽

pp. 169-178 ◽

Cited By ~ 9

Author(s):

Dimitrios Alexakis ◽

Dimitra Gamvroula ◽

Eleni Theofili

Keyword(s):

Sequential Extraction ◽

Toxic Elements ◽

Soil Depth ◽

Extraction Procedure ◽

Potential Ecological Risk ◽

Potentially Toxic Elements ◽

Geochemical Partitioning ◽

Exchangeable Fraction ◽

High Bioavailability

ABSTRACT Total contents of 36 potentially toxic elements are summarized for agricultural topsoil (n = 12; soil depth = 0–20 cm), subsoil (n = 12; soil depth = 20–40 cm), and representative rock samples collected from a Mediterranean site (Megara Plain, Greece). The five-stage sequential extraction procedure for the geochemical partitioning of cadmium (Cd), cobalt (Co), chromium (Cr), copper (Cu), manganese (Mn), and nickel (Ni), proposed by Tessier, was applied to topsoil and subsoil collected from the study area. Soil Cd was highly associated with exchangeable fraction, illustrating high bioavailability of this element. The order of mobility of the elements was as follows: Cd > Cu > Co > Zn > Ni > Cr > Mn. Results from sequential extraction experiments illustrated that the bioavailability of Cu, Co, and Zn is moderate, while Ni, Cr, and Mn presented low bioavailability, indicating that these elements could pose a limited threat to the quality of crops. Cadmium is the chief contamination controlling factor posing moderate potential ecological risk. The contamination sources of the examined elements are discussed.

Download Full-text