Influence of Breastfeeding Time on Levels of Organochlorine Pesticides in Human Milk of a Mexican Population.

This study was conducted with the objective of determining whether there is a depuration of organochlorine pesticides in breast milk according to breastfeeding time. In total, 171 samples from mothers that lived in the State of Guerrero, Mexico were analyzed. There was a weak negative relationship between pp'DDE (r = -0.216) and Σ-DDT (r = -0.222) concentrations with the days of lactation. In a comparison analysis, a statistically significant decrease of pp'DDT and pp'DDE levels was observed, as well as the Σ-DDT from the first to the fifth week of lactation. A reduction of 0.188 mg/kg lipid of pp'DDE and 0.181 mg/kg lipid of Σ-DDT per week was obtained. HCB, ß-HCH and op'DDT concentrations were low and had no major fluctuations between subgroups. The low levels found and the observed reduction in time involve less exposure to the infant to these pollutants. Through this methodology changes in levels of certain organochlorine pesticides in various stages of human milk production may be shown.

Organochlorine pesticide levels in breast milk in Guerrero, Mexico.

In Mexico, organochlorine pesticides were used in public health and agriculture programs, causing chronic exposure to the population. Human breast milk samples were collected from 171 mothers who were residents from Guerrero, Mexico. Analysis was carried out by gas chromatography. Median concentrations (mg/kg on fat basis) for the following pesticides were: HCB, 0.009; ß-HCH, 0.004; pp'DDE, 0.760; op'DDT, 0.016; pp'DDT, 0.045; and Σ-DDT, 0.833. These values are lower than in other States in Mexico, and in some countries where the use of these pesticides was banned more than 30 years ago. Differences were found in HCB, pp'DDE and pp'DDT concentrations in groups divided according to age (p < 0.05). The older age groups had higher concentrations, except for the comparison between groups 21-23/24-28 years, which were 0.913 and 0.530 mg/kg of pp'DDE, respectively. Given the restrictions on use, a greater decrease in organochlorine pesticide levels in human milk is expected in a few years.

High removal of chemical and biochemical oxygen demand from tequila vinasses by using physicochemical and biological methods.

The goal of this research is to find a more effective treatment for tequila vinasses (TVs) with potential industrial application in order to comply with the Mexican environmental regulations. TVs are characterized by their high content of solids, high values of biochemical oxygen demand (BODs), chemical oxygen demand (COD), low pH and intense colour; thus, disposal of untreated TVs severely impacts the environment. Physicochemical and biological treatments, and a combination of both, were probed on the remediation of TVs. The use of alginate for the physicochemical treatment of TVs reduced BOD5 and COD values by 70.6% and 14.2%, respectively. Twenty white-rot fungi (WRF) strains were tested in TV-based solid media. Pleurotus ostreatus 7992 and Trametes trogii 8154 were selected due to their ability to grow on TV-based solid media. Ligninolytic enzymes' production was observed in liquid cultures of both fungi. Using the selected WRF for TVs' bioremediation, both COD and BOD5 were reduced by 88.7% and 89.7%, respectively. Applying sequential physicochemical and biological treatments, BOD5 and COD were reduced by 91.6% and 93.1%, respectively. Results showed that alginate and selected WRF have potential for the industrial treatment of TVs.

Use of agave bagasse for production of an organic fertilizer by pretreatment with Bjerkandera adusta and vermicomposting with Eisenia fetida.

Agave tequilana Weber is used in tequila and fructans production, with agave bagasse generated as a solid waste. The main use of bagasse is to produce compost in tequila factories with a long traditional composting that lasts 6-8 months. The aim of this study was to evaluate the degradation of agave bagasse by combining a pretreatment with fungi and vermicomposting. Experiments were carried out with fractionated or whole bagasse, sterilized or not, subjecting it to a pretreatment with Bjerkandera adusta alone or combined with native fungi, or only with native bagasse fungi (non-sterilized), for 45 days. This was followed by a vermicomposting with Eisenia fetida and sewage sludge, for another 45 days. Physicochemical parameters, lignocellulose degradation, stability and maturity changes were measured. The results indicated that up to 90% of the residual sugars in bagasse were eliminated after 30 days in all treatments. The highest degradation rate in pretreatment was observed in non-sterilized, fractionated bagasse with native fungi plus B. adusta (BNFns) (71% hemicellulose, 43% cellulose and 71% lignin) at 45 days. The highest total degradation rates after vermicomposting were in fractionated bagasse pre-treated with native fungi (94% hemicellulose, 86% cellulose and 91% lignin). However, the treatment BNFns showed better maturity and stability parameters compared to that reported for traditional composts. Thus, it seems that a process involving vermicomposting and pretreatment with B. adusta could reduce the degradation time of bagasse to 3 months, compared to the traditional composting process, which requires from 6 to 8 months.