Occurrence, sources, and risk assessment of unconventional polycyclic aromatic compounds in marine sediments from sandy beach intertidal zones.

This study investigated the concentrations of polycyclic aromatic compounds (PACs), including parent polyaromatic hydrocarbons (PAHs) and their nitrated and oxygenated derivatives, in 48 sediment samples from the intertidal region of sandy beaches in Baía de Todos os Santos (BTS), Salvador, State of Bahia, Brazil. The total PAH (∑PAH) concentration, total nitro-PAH (∑nitro-PAH) concentration, and total oxy-PAH (∑oxy-PAH) concentration ranged from 2.11 μg g dry weight (dw) to 28.

Occurrence of 3-nitrobenzanthrone and other powerful mutagenic polycyclic aromatic compounds in living organisms: polychaetes.

In this work we report the occurrence of powerful mutagenic 3-nitrobenzanthrone (3-NBA), in addition to 18 polycyclic aromatic hydrocarbons (PAHs), 6 oxygenated PAHs and 27 nitrated PAHs in polychaete worms. Benzanthrone (BA), another important mutagenic polycyclic aromatic compound (PAC) also was detected in the samples. Polychaete annelids have great ecological relevance, being widely distributed in different environmental conditions, from intertidal zones up to seven thousand feet deep areas.

Evaluation of DNA Methylation Changes and Micronuclei in Workers Exposed to a Construction Environment.

Methylation levels in tumor-suppressor genes and repetitive sequences have previously been used to study the relationship between environmental air pollution and epigenetic changes related to cancer. In this study, we measured the methylation profiles of the promoter regions , and and the repetitive sequence in 59 workers exposed to the construction environment and in 49 unexposed workers. We also evaluated the micronuclei frequency and levels of trace elements in the blood of all workers.

Occurrence of the potent mutagens 2- nitrobenzanthrone and 3-nitrobenzanthrone in fine airborne particles.

Polycyclic aromatic compounds (PACs) are known due to their mutagenic activity. Among them, 2-nitrobenzanthrone (2-NBA) and 3-nitrobenzanthrone (3-NBA) are considered as two of the most potent mutagens found in atmospheric particles. In the present study 2-NBA, 3-NBA and selected PAHs and Nitro-PAHs were determined in fine particle samples (PM 2.

Methodology to examine polycyclic aromatic hydrocarbons (PAHs) nitrated PAHs and oxygenated PAHs in sediments of the Paraguaçu River (Bahia, Brazil).

Conventional methods for determination of polycyclic aromatic compounds (PACs) in sediments usually require large sample sizes (grams) and solvent volumes (at least 100 mL) through the employment of Soxhlet extraction, which is both time (hours) and energy consuming, among other disadvantages. We developed a new analytical protocol for the determination of PACs in sediments using microextraction, which requires small sample masses (25 mg), 500 μL of acetonitrile-dichloromethane mix and sonication for 23 min, followed by GC-MS analysis. The method was validated using the certified reference material SRM 1941b - NIST organic marine sediment, as well as internal deuterated standards.

Application of modified simplex on the development of a preconcentration system for cadmium determination in sediments, food and cigarettes.

A modified simplex algorithm was used to optimize a system of preconcentration for cadmium determination in samples of sediments, cigarettes and food using flame atomic absorption spectrometry. The preconcentration system is based on the sorption of cadmium in a minicolumn packed with Amberlite XAD-2 resin functionalized with 3,4-dihydroxybenzoic acid (DHB). The optimized variables were pH and sampling flow rate and the optimum conditions found for these variables were, respectively 8.

A simple, comprehensive, and miniaturized solvent extraction method for determination of particulate-phase polycyclic aromatic compounds in air.

The method allowed simultaneous characterization of PAHs, nitro-PAHs and quinones in atmospheric particulate matter. This method employs a miniaturized micro-extraction step that uses 500 μL of an acetonitrile-dichloromethane mix and instrumental analysis by means of a high-resolution GC-MS. The method was validated using the SRM1649b NIST standard reference material as well as deuterated internal standards.

Determination of copper in biological samples by flame atomic absorption spectrometry after precipitation with Me-BTAP.

A simple and sensitive method was developed for determination of trace copper by direct precipitation preconcentration and detection with Flame Atomic Absorption Spectrometry (FAAS). The reagent 2-[2'-(6-methyl-benzothiazolylazo)]-4-aminophenol (Me-BTAP) was used as precipitating agent. The experimental conditions for the quantitative precipitation of copper, such as pH, amount of reagents, temperature and the effect of diverse ions on the precipitation have been investigated.