Could feeding habit and migratory behaviour be the causes of different toxicological hazard to cetaceans of Gulf of California (Mexico)?

In this work, a suite of diagnostic biomarkers was applied to seven cetacean species to evaluate the role of the feeding habits and migratory behavior in the toxicological status of these species from the Gulf of California, Mexico. We investigate the interspecific differences in cytochrome P450 1A1 and 2B (CYP1A1 and CYP2B, respectively), aryl hydrocarbon receptor and E2F transcription factor 1 and the contaminants levels [organochlorine compounds, polybrominated diphenyl ethers (PBDEs) and polycyclic aromatic hydrocarbons (PAHs)] in four odontocete species (common bottlenose dolphin, long-beaked common dolphin, sperm whale and killer whale) and three mysticete species (blue whale, fin whale, and Bryde's whale) using skin biopsy. Differences in contaminant levels and molecular biomarker responses between the odontocete and mysticete species have been pointed out. The canonical discriminant analysis on principal component analysis factors, performed to reveal clustering variables, shows that odontocete are characterised by the highest levels of lipophilic contaminants compared to the mysticete, with the highest levels of polychlorinated biphenyls, dichlorodiphenyltrichloroethanes and PBDEs detected in killer whale and the lowest levels in Bryde's whale. The biomarker data show interspecific differences amongst the seven species, revealing highest CYP1A and CYP2B protein levels in the mysticete fish-eating species (Bryde's whale). In conclusion, three main factors seem to regulate the biomarker responses in these species: (a) the inductive ability of persistent organic pollutants and PAHs; (b) the different evolutionary process of the two CYPs related to the different feeding habits of the species; (c) the migratory/resident behaviour of the mysticete species in this area.

Effect of PM(10) and O(3) on infant mortality among residents in the Mexico City Metropolitan Area: a case-crossover analysis, 1997-2005.

INTRODUCTION: Consistent evidence has shown a positive association between air pollution and daily mortality among adults. Less is known about its effect on infant mortality and the modification of this association by socioeconomic status (SES). OBJECTIVE: To assess the association of particulate matter with an aerodynamic diameter of ≤10µm (PM(10)) and ozone (O(3)) on infant mortality and its modification by SES. METHODS: We evaluated the relationship of 24 h mean PM(10) and 1h daily maximum O(3) levels with 12 079 all-cause deaths (3903 respiratory deaths) among 1- to 11-month-old infants residing in the Mexico City Metropolitan Area between January 1997 and December 2005 using a case-crossover approach. The data were analysed using conditional logistic regression models, controlling for weather conditions and day of the week. RESULTS: Single-effect models showed, for all-cause mortality, increases of 5.5% (95% CI 1% to 10%) at lag1 and 6.6% (2% to 11.4%) at lag2; cumulative exposure models (0-2 days) showed an increase of 6.3% (0.01% to 32.7%). Respiratory mortality increased marginally at 5.3% (-0.02% to 13.2%) with a 1-day lag and 10% (2.1% to 18%) with a 2-day lag per increase of 38.7 µg/m(3) (IQR) in PM(10) levels. When data were stratified by SES (low, medium, and high), only infants with low and medium SES presented a significant increase in risk of all-cause mortality and respiratory mortality in relation to PM(10). O(3) was only significantly related to respiratory mortality in low SES. CONCLUSION: Our results suggest that in the Mexico City Metropolitan Area, infants with lower SES (low to medium) are at higher risk of mortality when exposed to ambient PM(10) and O(3).

Relationships among personal, indoor, and outdoor fine and coarse particle concentrations for individuals with COPD.

This study characterizes the personal, indoor, and outdoor PM2.5, PM10, and PM2.5-10 exposures of 18 individuals with chronic obstructive pulmonary disease (COPD) living in Boston, MA. Monitoring was performed for each participant for six consecutive days in the winters of 1996 or 1997 and for six to twelve days in the summer of 1996. On each day, 12-h personal, indoor, and outdoor samples of PM2.5 and PM10 were collected simultaneously. Home characteristic information and time-activity patterns were also obtained. Personal exposures were higher than corresponding indoor and outdoor concentrations for all particle measures and for all seasons, except for winter indoor PM2.5-10 levels, which were higher than personal and outdoor levels. Higher personal exposures may be due to the proximity of the individuals to particle sources, such as cooking and cleaning. Indoor concentrations were associated with both outdoor concentrations and personal exposures (as determined by individual least square regression analyses), with associations strongest for PM2.5. Indoor PM2.5 concentrations were significantly associated with outdoor and personal levels for 12 and 15 of the 17 individuals, respectively. Both the strength and magnitude of the associations varied by individual. Also, personal PM2.5, but not PM2.5-10, exposures were associated with outdoor levels, with 10 of the 17 subjects having significant associations. The strength of the personal-outdoor association for PM2.5 was strongly related to that for indoor and outdoor levels, suggesting that home characteristics and indoor particulate sources were key determinants of the personal-outdoor association for PM2.5. Air exchange rates were found to be important determinants of both indoor and personal levels. Again, substantial interpersonal variability in the personal-outdoor relationship was found, as personal exposures varied by as much as 200% for a given outdoor level.

[Particle exposure modeling in the general population and risk of respiratory disease]. / Modelaje de exposición a partículas en población general y riesgo de enfermedad respiratoria.

Total exposure assessment identifies the various sources of exposure to air pollution which affect each individual, thus functioning as a useful tool in clinical and environmental exposure management. A cross sectional survey was performed in order to create a total exposure model of inhaled particulates. This survey involved 544 subjects located within the Mexico City Merced monitoring station, an area covering three kilometers in diameter. Two questionnaires were developed one on housing and the other on respiratory symptoms. A diary on daily activity was kept, and an outdoor monitoring station was also installed. A new technology was adapted and incorporated for personal and indoor monitoring. A correlation of up to 0.38 was identified between the environmental concentrations. Exposures at home and at other extramural activities are most predictive of personal exposure. It was determined that 8.8% of the subjects studied had chronic bronchitis, and that this percentage increases with greater levels of exposure and outdoor sports. These findings conclude that the models are useful for risk assessment and management in Mexico.

[An evaluation of the new program of Master of Sciences in Environmental Health]. / Evaluación del nuevo programa de Maestría en Ciencias en Salud Ambiental.

Our country is presently undergoing a historical, environmental and economic transition, along with an intense industrial expansion. As the rapid industrialization has not run parallel with the strengthening of environmental sanitary infrastructure, metropolitan cities have grown anarchically, turning over excessive amounts of air, water and soil pollutants. The harmonic combination of development, environment and health requires the supervision of trained human resources. The scarcity of such resources is a major restriction to overcome. In response to the lack of human resources devoted to environmental issues, the School of Public Health of Mexico established the Specialty of Environmental Health. In coordination with experts and decision makers from the health services, this specialty was reorganized in a Master of Science Degree in Environmental Health. Several institutions participated in this program actively, either with financial support or with human resources. The major obstacle to the continuity of the Program has been the lack of institutional financial support for students to devote fully to the programs. Nevertheless this Master's Degree is expected to undergo intense development in coming years. In the future, this program will have to reduce its epidemiologic focus and adopt a more general one. Efforts will be directed toward a wider national and international projection.

[Method for estimating the population risk attributable to a transfer station of municipal solid waste]. / Método para estimar el riesgo poblacional atribuible a una estación de transferencia de desechos sólidos municipales.

Due to the great volume of municipal solid waste that is produced daily in the Metropolitan Area of Mexico City a sound management has been an impossible task. This is why during the past few years solid waste transfer stations have been constructed in the City, allowing a more efficient solid waste collection. The attributable risk to the population's health for the operation of such stations needs to be assessed in order to have them working within the urbanized areas without posing a potential risk to the health of the inhabitants of the inhabitants of the surrounding areas.