The pollution effect on the denitrifying capacity of methanogenic sludges.

The denitrification process has been studied for biodegradation of some emerging contaminants (ECs). For this, anaerobic sludges from different Wastewater Treatment Plants (WTP) have been used; however, the biodegradation capacity can differ due to the contact they have had with various pollutants, given their origin. This work aims to evaluate the kinetic and metabolic capacity of two denitrifying sludges from different WTPs to biodegrade CH3COO--C and NO3--N. Denitrifying tests were carried out in batches with CH3COO--C (30 mg L-1) in a CN-1 relationship of 1.8 with sludge from a WTP of an educational center (WTP-A) and CH3COO--C (50 mg L-1) to a CN-1 of 1.4 with another from the WTP of Atotonilco de Tula, Hidalgo, México (WTP-B). The results showed that the biodegradation rate of CH3COO--C and NO3--N with the WTP-B sludge was 35 and 75% greater, respectively, compared to the WTP-A sludge. Therefore, we suggest that the consumption difference of substrate is attributable to the sludges of WTP, which have been exposed to a high concentration of a great variety of pollutants.

Biotransformation of 17ß-Estradiol through a Denitrifying Sludge.

17ß-estradiol (E2) is the natural estrogen with the most significant potential for endocrine disruption in the biota of aquatic ecosystems at trace concentrations. It is, therefore, essential to study treatments for water polluted with E2 that would guarantee its complete elimination and mineralization. Denitrification is a biological process shown to have the capacity to completely biodegrade drugs, such as ampicillin. This work is aimed to evaluate the biotransformation of 17ß-estradiol by employing a denitrifying sludge. The assays performed were: (I) abiotic with 3.5 mg E2-C L-1 and (II) denitrifying with 10 mg CH3COO--C L-1 as the reference, 10 mg E2-C L-1 as the sole electron donor, and a mixture of (mg L-1) 10 E2-C with 10 CH3COO--C at C N-1 of 1.1. The E2-C and NO3--N consumption efficiencies were greater than 99%, and HCO3--C and N2 production yields were close to 1 in all assays. The denitrifying sludge could biodegrade up to 10 mg E2-C L-1 as the sole electron donor and when mixed with 10 mg CH3COO--C L-1. No intermediate metabolites were generated from the process.

Metabolomics: A New Approach in the Evaluation of Effects in Human Beings and Wildlife Associated with Environmental Exposition to POPs.

Human beings and wild organisms are exposed daily to a broad range of environmental stressors. Among them are the persistent organic pollutants that can trigger adverse effects on these organisms due to their toxicity properties. There is evidence that metabolomics can be used to identify biomarkers of effect by altering the profiles of endogenous metabolites in biological fluids or tissues. This approach is relatively new and has been used in vitro studies mainly. Therefore, this review addresses those that have used metabolomics as a key tool to identify metabolites associated with environmental exposure to POPs in wildlife and human populations and that can be used as biomarkers of effect. The published results suggest that the metabolic pathways that produce energy, fatty acids, and amino acids are commonly affected by POPs. Furthermore, these pathways can be promoters of additional effects. In the future, metabolomics combined with other omics will improve understanding of the origin, development, and progression of the effects caused by environmental exposure.

Differential expression and immunoreactivity of thyroid hormone transporters MCT8 and OATP1C1 in rat ovary.

Thyroid hormones (THs) regulate several physiological processes in female mammals, many of which are related to reproduction such as steroidogenesis in the ovary, oocyte and granulosa cells maturation, follicular development and differentiation, and ovulation. THs actions require the presence of THs transporters to facilitate their cellular uptake and efflux. MCT8 and OATP1C1 are the principal THs transporters. The aim of the present study was to determine the gene expression and cellular localization of MCT8 and OATP1C1 in the rat ovary during the diestrus-II cycle phase. Ovaries of virgin adult rats were histologically processed. Reverse Transcription-PCR and immunohistochemistry analyses for MCT8 and OATP1C1 were done. MCT8 gene expression level was significantly higher (P ≤ 0.01) than that of OATP1C1 in the rat ovary. MCT8 and OATP1C1 were found in all types of ovarian cells but with different immunoreactivity. MCT8 showed stronger immunoreactivity in tertiary and Graafian follicles, corpus luteum and blood vessels, whereas OATP1C1's immunoreactivity was stronger in stroma cells, tunica albuginea, and blood vessels. Our results provide evidence that THs and their transporters are both necessary for ovarian function and that any alteration in these transporters could interfere with reproductive processes such as ovulation and steroidogenesis, compromising fertility.

Genotoxicological response of the common carp (Cyprinus carpio) exposed to spring water in Tlaxcala, México.

This study evaluated the genotoxic impact of anthropic activities in Huactzinco Spring, using Cyprinus carpio as a biomonitor. In situ and in vivo experimental designs were compared by means of simultaneous 2-week exposures. The water from the spring generated mean micronuclei frequency values (108.6 ± 32 MN/1,000) and DNA fragmentation values (143.4 ± 35 au) which were statistically higher than those for the negative control (10.9 ± 6 MN/1,000 and 67.6 ± 23 au). The in situ and in vivo experiments supported one another. The comet assay proved to be the most sensitive test, with an EC50 value (11.4 % ± 3.4 %) being less than that determined for the micronuclei test (54.8 % ± 3.2 %). The results of this study confirm the usefulness of C. carpio as an environmental contamination biomonitor, and suggest that Huactzinco Spring water constitutes a latent risk to human health and the environment.