Track topics on Twitter Track topics that are important to you
In the transition zone between aquifers and aquitards, DNAPL pools of carbon tetrachloride and chloroform accumulate because of heterogeneity in this zone. Natural attenuation occurs at pools and plumes, indicating that remediation might be possible. The aims of the study were: i) to assess the role of heterogeneity in the natural attenuation of these compounds, ii) determine degradation processes within this zone, and iii) identify dechlorinating microorganisms. For this, groundwater concentrations, redox-sensitive parameters, CSIA isotopic and DGGE molecular techniques were used. The main findings at depth of the transition zone were: (1) the important key control played by heterogeneity on natural attenuation of contaminants. (2) Heterogeneity caused the highly anoxic environment and dominant sulfate-reducing conditions, which accounts for more efficient natural attenuation. (3) Heterogeneity also explains that the transition zone constitutes an ecotone. (4) The bacteria size exclusion is governed by the pore throat threshold and determines the penetration of dechlorinating microorganisms into the finest sediments, which is relevant, since it implies the need to verify whether microorganisms proposed for bioremediation can penetrate these materials. (5) Reductive dechlorination caused the natural attenuation of contaminants in groundwater and porewater of fine sediments. In the case of carbon tetrachloride, it was an abiotic process biogenically mediated by A. suillum, a bacterium capable of penetrating the finest sediments. In the case of chloroform, it was a biotic process performed by a Clostridiales bacterium, which is unable to penetrate the finest materials. (6) Both microorganisms have potential to be biostimulated to dechlorinate contaminants in the source and the plume in the transition zone. These outcomes are particularly relevant given the longevity of DNAPL sources and have considerable environmental implications as many supply wells in industrial areas exploit aquifers contaminated by chlorinated solvents emerging from DNAPL pools accumulated on the low-conductivity layers in transition zones.
This article was published in the following journal.
Name: The Science of the total environment
Soil organic carbon plays an important role in the stability and fertility of soil and is influenced by different management practice. We quantified active and passive carbon pools from total soil org...
Liver fibrosis is characterized by the excessive deposition of extracellular matrix (ECM) leading to impaired function and cirrhosis. Previous reports support a role for cadherin-11 (CDH11) in regulat...
Significant progress in C-C bond activation with transition metals has recently enabled the development of several carbon isotope exchange reactions. These methods are based on C-C bond decarboxylativ...
Hyporheic zones are increasingly thought of as natural bioreactors, capable of transforming and attenuating groundwater pollutants present in diffuse baseflow. An underappreciated scenario in the unde...
Chloroform is a recognised cause of acute liver injury, although now rarely encountered in clinical practice. We present a case of inhalational chloroform self-poisoning in a 47-year-old man that pres...
T2* imaging is a method to identify labile iron pools in tumor cells. These iron pools may be linked to better treatment outcomes for specific types of therapy. This is a small pilot study...
A dedicated pre-transition class, as proposed in this study, could help facilitate a smooth transition between pediatric and adult diabetes care. The innovation in this study is that these...
This study seeks to automate the process of youth to adult transition using an existing computerized decision support system in primary care. Subjects will complete the TRAQ readiness ques...
The PREFER Trial primary objective of the trial is to show how much radiation attenuation is provided by XPF in absolute and relative terms.
The purpose of this study is to evaluate the safety and tolerability of two carbon monoxide doses when administered as an inhaled gas for 1 hour in patients receiving kidney transplants.
Poisoning that results from ingestion, injection, inhalation, or skin absorption of CARBON TETRACHLORIDE.
A radiation-protective agent that interferes with sulfhydryl enzymes. It may also protect against carbon tetrachloride liver damage.
Any of several processes for the permanent or long-term artificial or natural capture or removal and storage of carbon dioxide and other forms of carbon, through biological, chemical or physical processes, in a manner that prevents it from being released into the atmosphere.
A potent liver poison. In rats, bromotrichloromethane produces about three times the degree of liver microsomal lipid peroxidation as does carbon tetrachloride.
A solvent for oils, fats, lacquers, varnishes, rubber waxes, and resins, and a starting material in the manufacturing of organic compounds. Poisoning by inhalation, ingestion or skin absorption is possible and may be fatal. (Merck Index, 11th ed)