L. Wolska

Organic pollutants in precipitation: determination of pesticides and polycyclic aromatic hydrocarbons in Gdansk, Poland

Abstract The paper presents the results of determination of selected organic pollutants in atmospheric precipitation. Samples of atmospheric precipitation in the form of rain water and snow were collected in five places in the area of Gdansk, which enabled some conclusions to be drawn on the influence of sampling position on the content of samples. Two different groups of compounds were determined: polycyclic aromatic hydrocarbons (PAHs) and pesticides. All applied analytical methods were previously checked out and used for other types of water samples (e.g. river waters, sea waters, drinking water). Capillary gas chromatography with specific detectors was used for final determination. Samples were collected during two separate periods of six months each, which permits us to find out some qualitative and quantitative changes of organic compounds in an urban area in different seasons. The most often detected pesticides were: terbuthylazine and chlorfenwinfos, whereas bromophos and atrazine occurred rarely. If detected, the concentration of pesticides ranged from 1 to 920xa0ngxa0dm −3 . The total concentration of the measured polycyclic aromatic hydrocarbons varied between 1xa0ngxa0dm −3 and 12.8xa0μgxa0dm −3 . Among all PAHs phenanthrene, fluoranthene and pyrene were the most often determined compounds.

Miniaturised analytical procedure of determining polycyclic aromatic hydrocarbons and polychlorinated biphenyls in bottom sediments.

This work concerns the determination of very low polychlorinated biphenyl (PCB) concentrations in bottom sediment samples in the presence of large amounts of polycyclic aromatic hydrocarbons (PAHs). A procedure for preparing 1 g bottom sediment samples for GC-MS analysis for the content of PAHs and PCBs is proposed. It consumes a few times smaller amounts of solvents than conventionally used procedures. Naphthalene-d8, benzo[a]anthracene-d12 and PCB 209 were used as internal standards for quantitation purposes; average recoveries of these standards were 65, 55 and 60%, respectively. A home-made glass column filled with ca. 500 mg of activated silica gel was used to isolate the PCB fraction. This has no significant effect on the recovery level of PCB (92-119%). Studies of the effect of homogenisation of a bottom sediment sample on the results of PAH and PCB were conducted. Grinding of bottom sediment samples to a particle size of 0.2 mm had no statistically significant effect on the analytical results and can therefore be omitted, which makes the preparation of the samples definitely less labour- and time-consuming. The interlaboratory study proved that the developed procedure for the simultaneous determination of PAHs and PCBs at largely different concentrations in sediment gives accurate and precise results.

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.

Calibration procedure for solid phase microextraction-gas chromatographic analysis of organic vapours in air.

A calibration procedure for solid phase microextraction-gas chromatographic (SPME-GC) analysis of organic vapours in air was described in which GC detector (MS in this case) signal is directly related to concentration of analytes of interest sampled by SPME. Gaseous standard mixtures used for the calibration were generated by means of a home-made permeation-type apparatus described elsewhere, W. Janicki et al., Chem. Anal., 38 (1993) 423 and modified to permit easy sampling of analytes on an SPME fibre. To establish sampling parameters, times for equilibrium partitioning of five selected organic compounds (carbon tetrachloride, toluene, chlorobenzene, p-xylene, n-decane) between gaseous mixtures and the fibre (fused silica fibre coated with 100 mum polydimethylsiloxane) were determined. For 10 min sampling time, the detector response and hence amount sampled on the fibre were linear functions of analytes concentration in a gaseous sample.

Simple device for permeation removal of water vapour from purge gases in the determination of volatile organic compounds in aqueous samples

Abstract A commercially available Nafion tube (a perfluorinated ion-exchange resin membrane separator) inserted in a plastic container filled with 5A molecular sieve was tested on dry water-saturated gas streams containing common volatile pollutants of aqueous environmental samples after a purging cycle. The proposed device was shown to remove water vapour effectively from humidified gas streams ( > 90%) even under continuous operation for more than 10 days. The results showed that the system is compatible with the tested compounds (aliphatic and aromatic hydrocarbons, chlorinated hydrocarbons and some sulphur compounds) because these compounds are practically unaffected on passing through the Nafion dryer tube. The losses of most compounds at the μg/kg level are less than 5%. Therefore, the proposed device is suitable for the removal of water vapour from purging streams and can be used in the determination of these volatile organic compounds in aqueous samples using the purge-and-trap technique.

Volatile and semivolatile organo-halogen trace analysis in surface water by direct aqueous injection GC-ECD

A procedure for simultaneous determination of volatile and semivolatile chloroorganic compounds (from trichloromethane to di- and trichlorobenzenes to hexachlorobutadiene) in aqueous samples was developed. The procedure is based on a DAI-GC-ECD technique widely used for trihalomethanes determination in drinking water. The DAI technique application could have been extended to semivolatile chloroorganic compounds by using a Rtx-624 (60 m x 0.32 mm I.D., df 1.8 microns (6% cyanopropyl, 94% dimethyl polysiloxane). Precision (R.S.D.) and detection limits of the DAI-GC-ECD procedure with respect to 12 volatile and semivolatile chloroorganics were determined. Relative standard deviations (R.S.D.) were lower than 22% and the detection limits (concentration equivalent to a peak height three times the baseline noise) range from 0.02 microgram L-1 for trichloroethene and tetrachloroethene to 0.25 microgram L-1 for hexachlorobutadiene to 1.6 micrograms L-1 for 1,2-dichlorobenzene. The method was successfully used to determine chloroorganic pollutants in river water.

Surface water preparation procedure for chromatographic determination of polycyclic aromatic hydrocarbons and polychlorinated biphenyls

A new sample preparation procedure for the analysis of polycyclic aromatic hydrocarbons (PAHs) and polychlorinated biphenyls (PCBs) in water containing suspended particulate matter (SPM) has been developed. A specially designed filtration vessel coupled directly to an SPE cartridge was used for this purpose. SPM separation and analyte isolation/concentration were carried out in a single step. Both the SPE cartridge and the suspended matter collected on the filter were solvent extracted, and analyte recoveries were determined. Analyte recoveries from the filtrate ranged from 64 to 100% of the spiked amount for PAHs with the highest aqueous solubilities, and did not exceed 20% for those with the lowest solubilities. Total recoveries of PAHs from surface water containing 21 mg l(-1) SPM ranged from 65 to 121%. PCB recoveries from the particulate matter reached over 10% of the spiked amount, while those from the filtrate ranged from 20 to 57%. Total PCBs recoveries ranged from 34 to 69%.

Calibration of the thermal desorption-gas chromatography-mass spectrometry system using standards generated in the process of thermal decomposition of chemically modified silica gel

Abstract A calibration method for the thermal desorption gas chromatographic-mass spectrometric (TD-GC-MS) determination of n-propanethiol based on a gas standard mixture generated in the process of thermal decomposition of chemically modified silica gel is proposed. The experimental results indicated that the total amount of n-propanethiol liberated from unit mass of the gel did not depend on the total mass of the gel used. A calibration curve for the TD-GC-MS system for n-propanethiol, determined for the relationship between the mass of n-propanethiol and the mass of the modified silica gel used, was found by a linear regression method and was characterized by a correlation coefficient r=0.99. This means that the amounts of liberated n-propanethiol are directly proportional to the mass of the modified gel used within the examined range of masses of silica gel samples. Consequently, the amount of the analyte (n-propanethiol) can be determined on the basis of mass of silica gel used and hence the modified silica gel can be treated as a standard of the liberated component (n-propanethiol) in this case).

Evaluation of Pollution Degree of the Odra River Basin with Organic Compounds after the 1997 Summer Flood – General Comments

The aim of this study is a qualitative and quantitative characterisation of organic pollutants in post-flood sediments in the Odra basin and the description of their sources with indication of especially polluted sites (so called hot spots) in the most suspected places in the drainage area. It was found that maximum allowable concentration levels for PCBs (polychlorinated biphenyls), VOCs (volatile organic compounds) and pesticides were not exceeded. Among regulated compounds, the exceeding values of the permissible level of concentration were found only for PAHs (polycyclic aromatic hydrocarbons) in sediments. Sixteen investigated samples, out of 72 had very high content of total PAHs. Sampling sites in which concentration levels of PAHs were found high, were located near power plants or roads with heavy traffic.

Using different types of capillary chromatographic columns as denudation traps: a comparison of sorption properties.

The research presented concerns segments of capillary chromatographic columns of different types (WCOT, SCOT, PLOT) used as traps for collection of samples of volatile organic analytes from a stream of air utilizing the equilibrium denudation technique. During the model experiments (utilizing standard mixtures), values of the partition coefficients (Kfs) were determined for volatile organic compounds frequently occurring as pollutants of atmospheric air (benzene, toluene, ethylbenzene, o-xylene, chlorobenzene). The conducted research demonstrated that the stationary phase film thickness did not affect the partition coefficient value. It was also proved that there is no dependence between the manner of applying the stationary phase in the column and the partition coefficient value.