Endogenous 1-H-Pyrrole-2,3,5-Tricarboxylic Acid (PTCA) in Hair and Its Forensic Applications: A Pilot Study on a Wide Multi-Ethnic Population.

Over the years, several studies have shown that many factors are likely to affect the results of forensic hair analyses and complicate their interpretation. Among these factors, one of the major drawbacks in hair analysis is the affectability of deposited xenobiotics by cosmetic treatments, which could be eventually used to adulterate the sample. It is well known that some cosmetic treatments containing hydrogen peroxide, such as permanent dyeing or bleaching, lead to the formation of 1-H-pyrrole-2,3,5-tricarboxylic acid (PTCA), a melanin degradation product. Considering that PTCA is also an endogenous compound, spontaneously formed by natural oxidation of melanin, its only detection in hair is not enough to confirm a cosmetic oxidative treatment. For this reason, the aim of the present work was to develop and validate a reliable liquid-liquid extraction method in ultra-high-performance liquid chromatographic-tandem mass spectrometry for the determination of endogenous PTCA in hair from a wide multi-ethnic population (African, Arab, Asian-Pacific, Caucasian, Hispanic and Indian). According to previous studies, untreated hair samples showed a PTCA content of 8.54 ± 5.72 ng/mg (mean ± standard deviation [SD]), ranging between 0.44 and 23.7 ng/mg; after in vitro cosmetic bleaching, PTCA increased to 16.8 ± 6.95 ng/mg (range: 4.16-32.3 ng/mg). Comparing baseline PTCA levels of each subgroup with the others, we could not observe any statistically significant difference, except for Caucasians (P < 0.05), wherein the concentrations were lower. Further studies and a wider sampling are necessary to elucidate the role of PTCA as diagnostic marker of cosmetic hair treatment in forensic field.

Polychlorinated dibenzo-p-dioxins and dibenzofurans in the air of Seveso, Italy, 26 years after the explosion.

This study reports the current levels of polychlorinated dibenzo-p-dioxins (PCDDs) and furans (PCDFs) in air at Seveso, where an explosion in a 2,4,5,-trichlorophenol production reactor occurred 26 years ago. The aims were to assess if residues of the 2,3,7,8-tetrachlorodibenzo-p-dioxin (2,3,7,8-TCDD) released during the accident and still present in soil could contaminate the above air and to investigate other potential sources in the area. Long-term air collection was carried out in zones A and B in Seveso and in a reference location in Milan, and samples were analyzed for PCDD and PCDF concentrations by gas chromatography-mass spectrometry (GC-MS). Experimental results showed that no important contribution to the air concentrations is due to the soil contamination and that contemporary sources essentially control the atmospheric burden of PCDDs and PCDFs in the Seveso area. The theoretical release of 2,3,7,8-TCDD from the soils of zones A and B of Seveso was calculated using the SoilFug model. In the worst case, the model simulated an enrichment in atmospheric 2,3,7,8-TCDD concentrations of 4 and 22% for zones A and B, respectively. The investigation of the potential emission sources in the area indicated that combustion of wood residues from furniture factories may be an additional local source of PCDDs and PCDFs.

Polychlorinated dibenzo-p-dioxins and dibenzofurans in River Po sediments.

The River Po is the main Italian river draining one of the most populated and industrialised regions in Italy. As part of a monitoring project to assess environmental quality in the River Po, we measured the concentrations of polychlorinated dibenzo-p-dioxins (PCDDs) and dibenzofurans (PCDFs) in bottom sediments collected along the whole course of the river, from the spring to the delta, downstream from the confluence of its main tributaries. The aim was to investigate the level of contamination in the main Italian river and the contribution of contaminant loads from the subbasins. Composite sediment samples were collected in summer and winter surveys in low-flow water conditions and analysed by HRGC-HRMS for PCDD and PCDF homologue groups and for the 2,3,7,8-substituted congeners. The spatial trend observed in the Po River for PCDD and PCDF concentrations varied depending on the load of contaminants received from the tributaries and the processes of sedimentation. The sum of PCDD and PCDF concentrations, and the toxic equivalent content, ranged from 121 to 814 and from 1.3 to 13 ng/kg dry weight sediment, respectively. These levels of contamination seem lower than in the sediments of rivers draining highly industrialised areas. The PCDD and PCDF homologue profiles in all the samples were very similar, suggesting a common source of this contamination in the River Po. Principal component analysis suggested that widespread sources, such as urban runoff and domestic wastewaters, are probably the main cause of these levels of PCDDs and PCDFs.