Amphiphilic molecules, such as humic substances and surfactants, are known to increase the apparent aqueous solubility of hydrophobic organic compounds (HOCs) in the aqueous phase because of their molecular structures, which consist of hydrophilic and hydrophobic moieties. In this study, we examined the effect of the structures of humic acid and HOCs on the sorption of four polycyclic aromatic ...

We discuss the problems with and the real possibilities of determining oil pollution in situ in coastal marine waters with fluorescence spectroscopy and of using artificial neural networks for data interpretation. In general, the fluorescence bands of oil and aquatic humic substance overlap. At oil concentrations in water from a few to tens of micrograms per liter, the intensity of oil fluoresc...

Humic substances are ubiquitous components of natural waters with important roles in alleviating metal toxicity to aquatic organisms. Recent literature reports suggest that humic substances may also exert direct influences on biota. This study investigated the influence of two commercially available humic substances on sodium metabolism in Daphnia magna, a hyperregulating freshwater crustacean....

High molecular weight compounds in urban atmospheric particles V. Samburova et al. High molecular weight compounds in urban atmospheric particles V. Samburova et al. Abstract The chemical nature of a large fraction of ambient organic aerosol particles is not known. However, high molecular weight compounds (often named humic-like substances) have recently been detected by several authors and the...

The polymerase chain reaction (PCR) was used to amplify an Escherichia coli 16S ribosomal gene fragment from sediments with high contents of humic substances. Total DNA was extracted from 1 g of E. coli seeded or unseeded samples by a rapid freeze-and-thaw method. Several approaches (use of Bio-Gel P-6 and P-30 and Sephadex G-50 and G-200 columns, as well as use of the Stoffel fragment) were us...

refers to molecular-level characteristics such as elemental composition, functional groups, and molecular conFormation of chemically resistant humic substances might be an formation that influence the inherent biodegradability important process controlling recycling of soil C to the atmosphere. of the molecule. Interactions refers to the intermolecular Humic substances are believed to be resist...

Within the framework of the FUNMIG programme, Loughborough University is performing work to increase understanding of the sorption behaviour of selected radionuclides with various minerals in the absence and presence of competing complexing ligands, such as humic acid (HA). The determination of the distribution ratios (Rd) of binary (metaland humicsolid), and ternary (metal-solid-humic) systems...

Conditional distribution coefficients (K(DOM')) for Hg(II) binding to seven dissolved organic matter (DOM) isolates were measured at environmentally relevant ratios of Hg(II) to DOM. The results show that K(DOM') values for different types of samples (humic acids, fulvic acids, hydrophobic acids) isolated from diverse aquatic environments were all within 1 order of magnitude (10(22.5 +/-1.0)-10...

Increasingly, products containing humic substances are appearing in the turf industry market claiming to reduce water and fertilizer use by increasing soil moisture and nutrient availability. Humic acid is the most common humic substance that has been studied, but results have been highly variable (Cooper et al.; 1998).The response of humic acid is difficult to interpret due to confounding effe...