Critical issues and alternatives for the establishment of chemical water quality criteria for livestock.

Good water quality for livestock is essential for animal health, supply of safe food and food production economy. Few countries have established water quality criteria for livestock for chemical contaminants. For those that have them, the values are quite variable among each other for the same substance due to differences in the approach for the acceptable daily intakes and algorithms for the calculation. In several countries, including Brazil, these standards are based on international or other countries' data, which differ among protected species, exposure scenarios, and levels of protection. The objective of this work was to discuss critical issues to establish chemical water quality criteria for livestock in Brazil. A discussion about the difficulties involved and the alternatives when sufficient data are not available is presented. Using the Canadian framework for reference, we provide recommendations on a revised framework and alternatives regarding the use of chronic studies as mandatory, defaulting to human health drinking water quality guidelines/criteria for livestock, the use of additional safety factors, and alternatives in the absence of toxicological data.

The introduction of the Salmonella/microsome mutagenicity assay in a groundwater monitoring program.

The objective of this study was to verify the possible inclusion of the Salmonella/microsome mutagenicity assay in a groundwater monitoring program as a complementary assay to assess water quality. Groundwater samples belonging to seven wells from different types of aquifers were analyzed. Three different methods for sample preparation were used: membrane filtration; liquid-liquid and XAD-4 extraction. The filtered samples were tested using TA98, TA100, YG1041 and YG1042 and the water extracts only with TA98 and TA100. No mutagenic activity was observed in any of the 16 filtered samples tested. Out of the 10 samples analyzed using XAD-4 extraction, five showed mutagenic activity with potency ranging from 130 to 1500 revertants/L. Concerning the liquid-liquid extraction, from the 11 samples analyzed, 3 showed mutagenicity. The XAD-4 extraction was the most suitable sample preparation. TA98 without S9 was found to be the most sensitive testing condition. The wells presenting water samples with mutagenic activity belonged to unconfined aquifers, which are more vulnerable to contamination. The data suggest that Salmonella/microsome assay can be used as an efficient screening tool to monitor groundwater for mutagenic activity.

Validation of a method to detect cocaine and its metabolites in nails by gas chromatography-mass spectrometry.

The objective of the present work was to compare previously published methods and provide validation data to detect simultaneously cocaine (COC), benzoylecgonine (BE) and norcocaine (NCOC) in nail. Finger and toenail samples (5mg) were cut in very small pieces and submitted to an initial procedure for external decontamination. Methanol (3 ml) was used to release analytes from the matrix. A cleanup step was performed simultaneously by solid-phase extraction (SPE) and the residue was derivatized with pentafluoropropionic anhydride/pentafluoropropanol (PFPA/PFP). Gas chromatography-mass spectrometry (GC-MS) was used to detect the analytes in selected ion monitoring mode (SIM). Confidence parameters of validation of the method were: recovery, intra- and inter-assay precision, as well as limit of detection (LOD) of the analytes. The limits of detection were: 3.5 ng/mg for NCOC and 3.0 ng/mg for COC and BE. Good intra-assay precision was observed for all detected substances (coefficient of variation (CV)<11%). The inter-assay precision for norcocaine and benzoylecgonine were <4%. For intra- and inter-assay precision deuterated internal standards were used. Toenail and fingernail samples from eight declared cocaine users were submitted to the validated method.

Revisão crítica do uso de testes rápidos imunológicos para verificar o consumo de substâncias psicoativas / Critical review of immunological on-site drug-testing devices

In the last years, numerous on-site drug-testing devices have become avaiable world-wide. These tests are based on antigen-antibody reactions and their main feature is the fast results obtained by color visualization. With the increased popularity of on-site drug testing, matters of performance (sensitivity, specificity) and applicability of these tests have been raised by specialists. In the present paper, fundamentals and efficiency of on-site drug-testing devices are reviewed. The indications and limitations of these devices are also discussed...