Chromatographic separation of marine organic pollutants

Chiral xenobiotics bioaccumulations and environmental health prospectives

The chiral xenobiotics are very dangerous for all of us due to the different enantioselective toxicities of the enantiomers. Besides, these have different enantioselective bioaccumulations and behaviors in our body and other organisms. It is of urgent need to understand the enantioselective bioaccumulations, toxicities, and the health hazards of the chiral xenobiotics. The present article describes the classification, sources of contamination, distribution, enantioselective bioaccumulation, and the toxicities of the chiral xenobiotics. Besides, the efforts are also made to discuss the prevention and remedial measures of the havoc of the chiral xenobiotics. The challenges of the chiral xenobiotics have also been highlighted. Finally, future prospectives are also discussed.

Enantioselective behavior of alpha-HCH in mouse and quail tissues

alpha-HCH (hexachlorocyclohexane) is chiral and can still be detected in almost all environmental media. In this study, the enantioselective behavior of alpha-HCH in mice (CD1) and quail (Coturnix japonica) was investigated and compared after a single dose of exposure. The primary nerve cell culture was conducted to evaluate the enantioselective metabolic capacity of nerve cells of mouse and quail for alpha-HCH. In various tissues of the mice and quail, the alpha-HCH concentrations showed a typical pattern of first-order dynamics after exposure. The enantiomeric fractions (EFs) in nonbrain tissues of mice decreased substantially, indicating continuous depletion of (+)-alpha-HCH in mice. Tissue-specific EF trends in quail and enantioselective degradation of (-)-alpha-HCH in quail liver were observed. These observations indicated that the dynamic changes of EFs in mice and quail were independent of concentration changes in the same tissues. In brain tissues, the enantioenrichment of (+)-enantiomer was totally independent of their concentrations in blood. The in vitro metabolism of alpha-HCH in the primary nerve cells were negligible, and the slight EF changes in primary nerve cells demonstrated that metabolism, uptake, and excretion in the brain cells would not lead to the observed dramatic enantioenrichment of (+)-alpha-HCH in the brain tissues of the two animals. The enantioselective transport across the blood-brain barrier was the primary cause for the enantioenrichment of (+)-alpha-HCH in the brain tissues.

Ultrasonic extraction followed by sulfuric acid silica gel cleanup for the determination of alpha-hexachlorocyclohexane enantiomers in biota samples

Interest in the analysis of alpha-hexachlorocyclohexane (alpha-HCH) enantiomers as an alternative or complementary approach to elucidating isomer ratios of alpha/gamma-HCH has grown in recent years because it can provide useful information to evaluate the influence of different degradation and transformation processes. In this paper, a simple and rapid method for the determination of alpha-HCH enantiomers in biota samples is described. The method developed consists of ultrasonic extraction, sulfuric acid silica gel cleanup, solid-phase extraction (SPE) column fractionation, and final determination with chiral high-resolution gas chromatography. Ultrasonic extraction greatly shortens the extraction process time, and the sulfuric acid silica gel and SPE cleanup perfectly remove lipids and other interference compounds in the lipid-rich samples. The method is found to be simple, less time-consuming, and easy to operate, thus providing a useful alternative method to assess the enantioselective breakdown of alpha-HCH in biota system.

Preconcentration of contaminants in water analysis

Among the environmental areas, in this review attention will be focused on water matrices and both on organic (e.g., pesticides, herbicides, phenols, polycyclic aromatic hydrocarbons), inorganic species and anion pollutants, since these kinds of substances include a wide number of compounds with different physical and chemical properties and different effects on human health. Analytical methods for control of quality of waters are required to be highly specific and possibly highly sensitive for the determination of even low amounts of pollutants. The main problems encountered during the analysis are the separation of matrix components from the pollutants of interest and the achievement of low detection limits. Therefore an overview on different materials and techniques available for sample concentration and/or matrix removal will be provided and discussed according to the chemical characteristics of the pollutant that has to be enriched.

Enantioselective determination of chiral organochlorine compounds in biota by gas chromatography on modified cyclodextrins

Approaches to the gas chromatographic enantiomer separation of chiral organchlorines (alpha-hexachlorocyclohexane, cis- and trans-chlordane, heptachlor, heptachlorepoxide, oxychlordane, o,p'-DDT, compounds of technical toxaphene and stable atropisomeric polychlorinated biphenyls) are reviewed. Chiral stationary phases based on cyclodextrin derivatives and used for the gas chromatographic enantiomer separation of the chiral organochlorines are described. Enantiomeric ratios of chiral organochlorines in technical mixtures and biological samples are reported and discussed.

Occurrence and determination of pesticides in natural and treated waters

Pesticides as environmental pollutants are described in detail along with their sources and paths of entry into various elements of the environment. Comprehensive literature data on the concentration of these pollutants in natural and treated waters and wastewaters are discussed. A wide selection of isolation and preconcentration techniques for these pollutants in water is presented and discussed. An emphasis is put on solid-phase extraction. In the case of the authors' work, a more detailed description is given.

Occurrence and determination of organic pollutants in tap and surface waters of the Gdańsk district

The results of the determination of different classes of organic pollutants (trihalomethanes, polycyclic aromatic hydrocarbons (PAHs), pesticides, volatile hydrocarbons and phenols) in ground water and drinking water sampled at different sites in the Gdańsk District are presented. Different methods were used to determine organic compounds in water: direct aqueous injection or sorption on solid sorbent (XAD-4) and extraction with pentane followed by a gas chromatography-electron capture detection (GC-ECD) for determination of volatile organohalogen compounds: purge and trap with a gas chromatography-flame ionization detection for determination of volatile hydrocarbons; sorption on solid sorbent XAD-4 or C18, elution with organic solvent and GC-ECD for determination of pesticides; sorption on solid sorbent C18, elution with organic solvent and a gas chromatography-mass spectrometry for determination of PAHs and sorption on solid sorbent C18, elution with organic solvent and high performance liquid chromatography-ultraviolet determination of phenols. The proposed methods have been used successfully for the determination of organic compounds in samples of tap, swimming pool, river and sea waters. The content of analysed organic compounds in the water delivered to the water supply system for Gdańsk from the surface water intake in Straszyn and from other selected intakes satisfies Polish, EC and WHO standards. The surface water bodies, i.e., rivers, sea and lakes in the Gdańsk District are not very polluted by anthropogenic compounds originating from municipal and industrial sewages and from agriculture.

Current developments in the analysis of water pollution by polychlorinated biphenyls

A review and discussion of the analytical developments of the last 10 years in the determination of polychlorinated biphenyls (PCBs) in water are presented, including sample treatment, clean-up, identification and determination. Some of the most significant advances have occurred in the area of sample preparation, such as the increased adoption of solid-phase extraction and on-line techniques and the chromatographic separation of PCB congeners, principally by mass spectrometry. Special attention is focused on applications to real samples.

Enantioselective degradation of alpha-hexachlorocyclohexane and cyclodiene insecticides in roe-deer liver samples from different regions of Germany

Remarkably high concentrations of alpha-hexachlorocyclohexane (alpha-HCH), cis-heptachlorepoxide and oxychlordane were found in roe-deer liver samples both from the northern and southern German states Schleswig-Holstein and Baden-Württemberg, respectively. The data revealed no significant regional differences, but they showed some common characteristics: a preferential degradation of (+)-alpha-HCH, and a preferential enrichment of (+)-oxychlordane and of (+)-cis-heptachlorepoxide as determined by chiral capillary gas chromatography using modified cyclodextrin phases. Calculation of the spearman rank correlation coefficients rS supported the assumption that higher concentrations of alpha-HCH may result in a stronger decomposition of the (+)-enantiomer, while higher levels of cis-heptachlorepoxide and oxychlordane appear to lead to a faster decomposition of the respective (-)-enantiomer or a preferential formation of the respective (+)-enantiomer.

Enantioselective and nonenantioselective degradation of organic pollutants in the marine ecosystem

Enantiomeric ratios of 11 chiral environmental pollutants determined in different compartments of the marine ecosystem by chiral capillary gas chromatography and chiral high-performance liquid chromatography allow discrimination between the following processes: enantioselective decomposition of both enantiomers with different velocities by marine microorganisms (alpha-HCH, beta-PCCH, gamma-PCCH); enantioselective decomposition of one enantiomer only by marine microorganisms (DCPP); enantioselective decomposition by enzymatic processes in marine biota (alpha-HCH, beta-PCCH, trans-chlordane, cis-chlordane, octachlordane MC4, octachlordane MC5, octachlordane MC7, oxychlordane, heptachlor epoxide); enantioselective active transport through the "blood-brain barrier" (alpha-HCH); nonenantioselective photochemical degradation (alpha-HCH, beta-PCCH).