An aqua regia extraction and a total decomposition of soil were compared in terms of thallium determination. A sequential extraction of soil, according to the BCR protocol, was also performed for additional information on thallium distribution in soil fractions. Certified reference material-soil GBW 07401 of Chinese origin, containing 1+/-0.2ppm of thallium was used in these experiments. Thallium was determined by flow injection-differential pulse-anodic stripping voltammetry (FI-DP-ASV). Only 35% of total thallium was extracted in the aqua regia extraction, while the total decomposition led to satisfactory recovery. The sequential extraction showed that only 5% of thallium in GBW 07401 is dissolvable in the four BCR procedure fractions, and that 95% of the element is entrapped in the residual parent matter. These results show that the aqua regia extraction does not ensure complete thallium extraction from soil. Surprisingly, the total decomposition is significantly less time consuming than the aqua regia extraction.
Download full-text PDF |
Source |
---|---|
http://dx.doi.org/10.1016/j.talanta.2005.08.035 | DOI Listing |
PLoS One
January 2025
Department of Epidemiology, School of Public Health, University of São Paulo, São Paulo, Brazil.
Objectives: This study aimed to evaluate socioeconomic inequalities in self-reported oral health among community-dwelling Brazilian older adults and evaluate the oral health factors contributing to the inequalities.
Methods: This was a cross-sectional study with data from the Brazilian National Health Survey conducted in 2019. The dependent variable is the self-report of oral health categorized as good or poor.
Front Microbiol
December 2024
College of Forestry, Gansu Agricultural University, Lanzhou, China.
Alpine wet meadows are known as NO sinks due to nitrogen (N) limitation. However, phosphate addition and N deposition can modulate this limitation, and little is known about their combinative effects on NO emission from the Qinghai-Tibet Plateau in wet meadows. This study used natural wet meadow as the control treatment (CK) and conducted experiments with N (CONH addition, N15), P (NaHPO addition, P15), and their combinations (CONH and NaHPO addition, N15P15) to investigate how N and P supplementation affected soil NO emissions in wet meadow of QTP.
View Article and Find Full Text PDFNeural Netw
December 2024
Faculty of Information Technology and Electrical Engineering, University of Oulu, Finland.
Real-time online optimisation plays a crucial role in high-frequency trading (HFT) strategies. The Markowitz model, as a Nobel Prize-winning framework, is widely used for portfolio management optimisation by framing the problem as a constrained quadratic programming task. While conventional analytical methods are typically effective for solving quadratic programming problems with linear constraints, the introduction of both linear equality and inequality constraints in the Markowitz model necessitates the use of numerical methods.
View Article and Find Full Text PDFSci Total Environ
December 2024
College of Environmental Science and Engineering, Donghua University, Shanghai 201620, China; National-Regional Joint Engineering Research Center for Soil Pollution Control and Remediation in South China, Guangdong Key Laboratory of Integrated Agroenvironmental Pollution Control and Management, Institute of Eco-environmental and Soil Sciences, Guangdong Academy of Sciences, Guangzhou 510650, China. Electronic address:
Microplastics (MPs) and antibiotic resistance genes (ARGs) are both emerging pollutants that are frequently detected in wastewater treatment plants. In this study, the effects of various MPs, including polyethylene (PE), polyvinyl chloride (PVC), and biodegradable polylactic acid (PLA), on nitrification performance, dominant microbial communities, and antibiotic resistance during nitrification were investigated. The results revealed that the addition of MPs increased the specific ammonia oxidation rate and specific nitrate production rate by 15.
View Article and Find Full Text PDFSci Total Environ
December 2024
Engineering Research Center of Watershed Carbon Neutralization, Ministry of Education, Nanchang University, Nanchang 330031, China; School of Resources and Environment, Nanchang University, Nanchang 330031, China. Electronic address:
Iron (Fe) (oxyhydr)oxides and natural organic matter (NOM) are active substances ubiquitously found in sediments. Their coupled transformation plays a crucial role in the fate and release risk of heavy metal(loid)s (HMs) in lake sediments. Therefore, it is essential to systematically obtain relevant knowledge to elucidate their potential mechanism, and whether HMs provide immobilization or mobilization effect in this ternary system.
View Article and Find Full Text PDFEnter search terms and have AI summaries delivered each week - change queries or unsubscribe any time!