A practice-oriented method for the analysis of coplanar tetra- to heptachlorinated terphenyls.

Polychlorinated terphenyls (PCT) were produced and used on industrial scale in the last century. Today, PCT are formed especially during combustion and some chemical conversion processes. As being persistent, low volatile chlorinated aromatics, they are continuously emitted into the environment from primary and secondary sources. Blatant knowledge gaps exist concerning environmental behavior, toxicology, and ecotoxicology of this presumably ubiquitously present substance group because of the non-availability of a generally accepted, practice-oriented, and validated analytical method for the PCT. Here, a novel and easy to conduct analytical method is presented that is applicable to environmental samples. This method is based on a thorough clean-up of the sample extracts, followed by a separation of 29 tetra- to heptachlorinated coplanar reference congeners and their quantification by means of gas chromatography coupled with mass spectrometry. For the validation of the analytical procedure, the parameters selectivity, detection limit, limit of decision, limit of quantification, measuring and method precision, linearity, specifity, and recovery rates were considered. By the method validation, it was demonstrated that this novel procedure for the analysis of PCT in environmental samples like soils/sediments, fats, and combustion residues is fit for purpose.

The Human Health Assessment to Phthalate Acid Esters (PAEs) and Potential Probability Prediction by Chromophoric Dissolved Organic Matter EEM-FRI Fluorescence in Erlong Lake.

Phthalate acid esters (PAEs) are suspected to cause wide environmental pollution and have adverse effects on human health. Three priority control phthalates, namely dimethyl phthalate (DMP), diethyl phthalate (DEP), and dibutyl phthalate (DBP), were determined in 45 water samples from the largest drinking water source in Jilin Province. Chromophoric-dissolved organic matter (CDOM), which are composed of complex compounds and are a proxy for water quality, can be monitored using a fluorometer. This study attempted to understand the correlations of the CDOM fluorescence regional integration (FRI) components with PAEs and CDOM characteristics under seasonal and spatial variations in the Erlong Lake. The characteristics of the CDOM absorption parameters in different water samples showed a higher aromatic content and molecular weight in October because of increased terrestrial inputs. The Σ3PAEs concentrations ranged from 0.231 mg L-1 to 0.435 mg L-1 in water, and DEP contributed to more than 90% of the Σ3PAEs. The FRI method identified five fluorescence components: one tyrosine-like (R1), one tryptophan-like (R2), one fulvic-like (R3), one microbial protein-like (R4), and one humic-like (R5) component. However, significant relationships exist between DEP and R3 (R² = 0.78, p < 0.001), R4 (R² = 0.77, p < 0.001), and R5 (R² = 0.58, p < 0.001). Quantifying the relationship between CDOM and PAEs was highly significant, because the results will simplify the componential analysis of pollutants from a spatiotemporal perspective as compared to traditional chemical measurements. The human health risk assessment results revealed no human health risk (HQ < 1) in the Erlong Lake basin.

Synthesis of coplanar PCT as reference substances for the residue analysis of polychlorinated terphenyls.

In the course of the development of a new and reliable analytical method for the PCT, a group of environmental contaminants, six coplanar terphenyl congeners were synthesized and characterized by means of spectroscopic methods. These congeners are 3,3″,4,4″,5-pentachloro-p-terphenyl, 3,3″,4,5,5″-pentachloro-p-terphenyl, 3,3″,4,5″-tetrachloro-m-terphenyl, 3,3″,4,4″,5-pentachloro-m-terphenyl, 3,3″,5,5',5″-pentachloro-m-terphenyl, and 3,3″,4,4″,5,5″-hexachloro-m-terphenyl. A combination of silica gel column chromatography and preparative NP-HPLC was successfully applied for the first time for the isolation of especially the asymmetrically chlorinated target compounds from product mixtures of the syntheses. For the 29 coplanar, tetra- to heptachlorinated meta- and para-indicator congeners which are envisaged to be used within the analytical method, a simplified systematic nomenclature is suggested. Furthermore, calculation results for all torsion angles of the preferred conformations of the substances are given. The practical relevance of the calculated conformation optima is exemplarily demonstrated by the chromatographic behavior of the PCT compounds.

Occurrence of polychlorinated terphenyls (PCTs) in indoor particulate matter.

In the course of a routine investigation concerned with polychlorinated biphenyl (PCB) contamination of dust collected in classrooms of a junior high school, a group of electron capture detector (ECD)-sensitive compounds with high boiling points were found in addition to PCBs. Using gas chromatographic-mass spectrometric techniques, these compounds were identified as polychlorinated terphenyls (PCTs). Additional measurements indicated that the PCTs were present only in particulate matter collected from the tops of fluorescent light frames but not in air samples obtained concomitantly in the classrooms. Attempts to identify the PCT emission source were unsuccessful. A survey of the literature revealed that PCTs are ubiquitously distributed environmental contaminants, although no data on their indoor occurrence have been reported to date. In view of the toxic effects of PCTs, which seem to be as important as those of PCBs, further attention should be given to the possible presence of PCTs in indoor environments.

Probabilistic health risk assessment for exposures to estuary sediments and biota contaminated with polychlorinated biphenyls, polychlorinated terphenyls and other toxic substances.

A Latin Hypercube probabilistic risk assessment methodology was employed in the assessment of health risks associated with exposures to contaminated sediment and biota in an estuary in the Tidewater region of Virginia. The primary contaminants were polychlorinated biphenyls (PCBs), polychlorinated terphenyls (PCTs), polynuclear aromatic hydrocarbons (PAHs), and metals released into the estuary from a storm sewer system. The exposure pathways associated with the highest contaminant intake and risks were dermal contact with contaminated sediment and ingestion of contaminated aquatic and terrestrial biota from the contaminated area. As expected, all of the output probability distributions of risk were highly skewed, and the ratios of the expected value (mean) to median risk estimates ranged from 1.4 to 14.8 for the various exposed populations. The 99th percentile risk estimates were as much as two orders of magnitude above the mean risk estimates. For the sediment exposure pathways, the stability of the median risk estimates was found to be much greater than the stability of the expected value risk estimates. The interrun variability in the median risk estimate was found to be +/- 1.9% at 3000 iterations. The interrun stability of the mean risk estimates was found to be approximately equal to that of the 95th percentile estimates at any number of iterations. The variation in neither contaminant concentrations nor any other single input variable contributed disproportionately to the overall simulation variance. The inclusion or exclusion of spatial correlations among contaminant concentrations in the simulation model did not significantly effect either the magnitude or the variance of the simulation risk estimates for sediment exposures.

Environmental analysis of polychlorinated terphenyls: distribution in shellfish from the Ebro Delta (Mediterranean).

Polychlorinated terphenyls (PCTs) have characteristics almost identical with those of polychlorinated biphenyls (PCBs) and have been used for analogous applications, but only sporadic reports of the occurrence of PCTs in the environment have been published. High-resolution gas chromatography with electron-capture detection (HRGC-ECD) and mass spectrometric detection in the selected ion monitoring mode was used to analyse samples for PCTs. The homologue distribution of Aroclor 5432, 5460, Leromoll 141 and the PCTs in samples of shellfish from the Ebro Delta (Catalonia, Spain) was established, taking into account the contribution of the [M-Cl2]+ fragments. Quantification was achieved by HRGC-ECD. Concentrations were between 790 and 3 ng/g (dry mass).

Polychlorinated terphenyls (PCTs) use, levels and biological effects.

Polychlorinated terphenyls (PCTs) have almost identical characteristics to high chlorinated PCBs: extremely stable, bioaccumulable and biomagnification through food webs might take place. PCT is especially used in investment casting waxes and as a substitute for PCB. In spite of the limited use until now, PCT has been detected in a great variety of environmental samples such as soil, water, shellfish, fish, seals, birds and terrestrial animals. Furthermore, it has been found in paper products and foodstuffs. PCT residues in human tissues--blood, liver, fat and milk--have been detected in some countries. Animal experiments have shown that long-term toxic effects of PCT are of most importance. PCT has a marked inductive effect on the microsomal enzymes in the liver in vertebrates and may cause liver-damage--including tumours. Disturbance of the hormonal--and immunological--systems have also been reported. The most important ecological hazard of PCT--as well as PCB--is the possible disturbance of the reproduction system of the organisms. Many countries do not regulate the use of PCT. In some countries the use of PCT is regulated to closed systems, but the expansion of usage is under consideration in the EEC.

An evaluation of chromatographic methods for the analysis of polychlorinated terphenyls in environmental samples.

Gas chromatography (GC) with packed and capillary columns, high-performance liquid chromatography (HPLC) and thin-layer chromatography have been used to characterize various commercially available mixtures of polychlorinated terphenyls (PCTs). Besides, UV absorption and mass spectrometry data have been collected, and the behaviour of PCTs upon perchlorination to the tetradecachloroterphenyls has been studied. Using GC, the PCT content of a number of paper and sewage sludge samples has been determined. The application of perchlorination/GC as method of analysis often yields unreliable, i.e., too high, results compared with the direct GC pattern-comparison method. In the case of paper samples, hydrogenated terphenyls appear to be the principal interfering compounds.

Polychlorinated terphenyls as an environmental pollutant in Japan.

This paper summarizes the results of the studies made by our group and other investigators in Japan on the residue levels of polychlorinated terphenyls (PCTs) in a variety of items in the environment including the human body. In contrast to widespread distribution of PCBs in the environment, PCT residues were seldom found in samples from aquatic environments such as water and sludge and waterfowl and fish, and, if found, the levels of PCTs were so low as to be practically negligible. Similarly, no significant levels of PCTs were detectable in foodstuffs such as edible oils, vegetables, dairy products and meat and in prepared diets. These findings may be explained by the fact that PCTs are much less volatile and soluble than PCBs and the total industrial output of PCTs was as small as 2700 tonnes which is 1/20 of PCBs produced in Japan. However, the levels of PCTs in human fat and blood were shown to be almost equivalent to PCBs, despite a negligible amount of PCTs being found in food. No clear explanation of human contamination by PCTs has been proposed so far.