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Domestic Wastewater as a Source of Contaminants in Freshwater Aquifers
in the Mayan Riviera Tourism Region of Mexico
Chris Metcalfe1, Gerardo Gold Bouchot2, Tracy Metcalfe1, Hongxia Li1, Patricia Beddows3 and Hanneke Van Lavieren4
1) Marine Sciences Laboratory, CINVESTAV, Merída, Yucatan State, Mexico2) Department of Earth and Planetary Sciences, Northwestern University, Evanston, IL, USA3) Worsfold Water Quality Centre, Trent University, Peterborough, ON, Canada4) UN University – International Network for Water Environment and Health, Hamilton, ON, Canada Abstract
In this pilot study, we evaluated whether contamination is currently Table 1: Target analytes sampled by SPMDs and POCIS, sources of occurring in the Mayan Riviera region by monitoring selected Passive Sampler Deployment Locations
contamination, methods of analysis and lead analytical laboratory.
December 2008 to January, 2009
fresh water discharge zones using passive sampler technologies. Compound
Lead Laboratory
The fresh water resources within the highly permeable karst We have previously used semi-permeable membrane devices geology of the Yucatan Peninsula of Mexico are vulnerable to (SPMDs) to monitor aquatic environments for water insoluble (i.e. contamination from agricultural, industrial and urban hydrophobic) contaminants, such as PCBs, organochlorine SPMD Extracts:
pesticides (OCs) and polycyclic aromatic hydrocarbons (PAHs), Caribbean coast of the Yucatan Peninsula is one of the as well as surfactants and pesticides applied to golf courses Puerto Aventuras
fastest growing tourism areas in Mexico. There is evidence (Bennett and Metcalfe, 2000; Metcalfe et al., 2000; O’Toole et al., 5 cave systems
that tourism and recreational development in this region is 41+ km of caves
2006; Metcalfe et al., 2008). More recently, a passive sampler was Car wash cenote
being poorly managed, and there is inadequate infrastructure developed for more water-soluble (i.e. hydrophilic) contaminants. 13 cave systems
for the treatment of domestic sewage and control of urban This Polar Organic Chemical Integrative Sampler (POCIS) shows 1) Ak Tulum cave
348+ km of caves
2) Herradura cave
runoff. Therefore, tourism may be a significant threat to the promise as a monitoring tool for polar contaminants, such as The 3 largest subterranean rivers in the world, and the
largest cave in Mexico
POCIS Extracts:
quality of fresh water resources in the region, and may also pharmaceuticals, current use pesticides and endocrine disrupting impact the marine environment as a result of discharges of compounds (Petty et al., 2004; Burki et al., 2006; MacLeod et al., contaminated fresh water into the coastal zone. In this pilot Figure 2: Locations for the deployment of passive samplers in study, we monitored fresh water aquifers for evidence of cave systems near Tulum and Puerto Aventuras in the Mayan contamination by deploying passive samplers in cave systems located at two sites along the Caribbean coast of the Yucatan Sample preparation and analysis
Peninsula (i.e. Tulum, Puerto Aventuras). The passive Flow of Fresh Water and Salt Water
Results and Discussion
and Potential Pathways for
samplers sequestered contaminants from the water over a Contamination
The SPMD and POCIS passive samplers were retrieved in early Several compounds of domestic wastewater origin, including caffeine, one month deployment period from early December, 2008 to January, 2009 and were immediately transported to the cotinine, non-prescription and prescription drugs, and cocaine were early January, 2009. Analysis of extracts indicated that the CINVESTAV research institute in Merida, Mexico for extraction. detected in extracts from passive samplers deployed in cave systems passive samplers accumulated detectable amounts of The SPMDs were dialyzed into hexane as described previously near Tulum and Puerto Aventuras (Figure 4).These data indicate that stimulants (e.g. caffeine), prescription and non-prescription by Metcalfe et al. (2000) and the POCIS adsorbent was extracted domestic sewage is contaminating the fresh water aquifers in the drugs and illicit drugs (e.g. cocaine), which could only have into methanol as described by Petty et al., (2004). The extracts region. The contaminants may then be discharged into the coastal originated from domestic sewage. Contamination of the from the SPMDs and POCIS were then transported to Trent marine zone. Modes of contamination by sewage could be through aquifer by sewage may be occurring as a result of the practice University in Canada, where they were processed for analysis of injection of wastewater into the salt water layer, leaky septic or of injecting domestic wastewater into the salt water zone, various classes of contaminants that indicate sources of sewage distribution systems or through the widespread use of treated leakage from sewage lines and septic systems, or by the use contamination (Table 1). Co-extractives were removed from the sewage for irrigation of the turf on golf courses. This contamination of wastewater for irrigating the turf on golf courses. Results Flow of fresh water
SPMD extracts by gel permeation chromatography (GPC). After Flow of salt water
problem points to the need for more effective sewage management are pending for the analysis of other classes of compounds GPC, some extracts were fractionated by silica gel Contamination
systems and the installation of liners to protect fresh water aquifers. that may indicate other sources of contamination. chromatography and analyzed for PCBs and OCs by gas Data are pending for the other classes of compounds that may chromatography with an electron capture detector (GC-ECD) and Figure 1: Flow of fresh water and salt water in the karst geology indicate other sources of contamination.
for PAHs by gas chromatography and mass spectrometry (GC- Introduction
near the coastal region of the Yucatan peninsula in Mexico. The MS). Other extracts were analyzed for synthetic musk fragrances green arrows show potential pathways for contamination as a result of injection of wastewater into the salt water layer. by GC-MS or for phenolic estrogens by liquid chromatography Drugs and Stimulants
with tandem mass spectrometry (LC-MS/MS). POCIS extracts Acetaminophen = Analgesic (i.e.Tylenol)
The geology of the Yucatan peninsula in Mexico consists of were analyzed by LC-MS/MS for stimulants (caffeine, cotinine), Conclusion
Naproxen = Anti-inflammatory
Ibuprofen = Analgesic (i.e.Advil)
prescription and non-prescription drugs, and illicit drugs (i.e. Caffeine = Stimulant
Caribbean coast of the Yucatan peninsula, flooded caves Cotinine = Metabolite of nicotine
provide a hydrological conduit that links the inland recharge CBZ = Anti-epileptic (carbamazepine)
Total cocaine = Cocaine plus major metabolite,
areas to springs that discharge into the coastal zone. Passive sampler deployment
Sinkholes called “cenotes” may also provide conduits for An area of the Mayan Riviera on the Caribbean coast, south of direct recharge into these cave systems. The regional Playa del Carmen was selected for the deployment of passive municipality of Solidaridad along the “Mayan Riviera” region samplers. The geology of this region is characterized by of Caribbean coast is a rapidly growing tourism and numerous subterranean cave systems and cenotes; several of recreational area. Planned expansion of tourist numbers and which have been mapped and studied for their hydrogeology. As Figure 4: Mean concentrations (ng/POCIS; n=3) of pharmaceuticals, intensive land development south of Cancun means that illustrated in Figure 2, passive samplers were deployed in 5 cave stimulants and illicit drugs originating from domestic sewage detected in the population will increase markedly over the next 20 years. systems located near two areas: i) the small tourism center of Domestic sewage effluents are currently pumped from Tulum and ii) the gated recreational community of Puerto References:
municipalities and hotels into the saline zone below the Aventuras. Passive samplers were deployed for a period of Bennett, E.R. and C.D. Metcalfe. 2000. Environ. Toxicol. Chem. 19:784-792 Burki, R., E.L.M. Vermeirssen, O. Korner, C. Joris, P. Burkhardt and H. Segner. 2006. Environ. Toxicol. Chem. 25:2077-2086.
freshwater aquifer (Figure 1). As has been shown in the approximately one month from early December 2008 to early MacLeod, S.L., E.L. McClure and C.S. Wong. 2007. Environ. Toxicol. Chem. 26:2517-2529.
Florida Keys, this waste disposal practice has the potential to Metcalfe, T.L., C.D. Metcalfe and E.R. Bennett. 2000. J. Great Lakes Res. 26:55-64.
January 2009. Three SPMDs and three POCIS samplers were Metcalfe, T.L., P.J. Dillon, C.D. Metcalfe. 2008. Environ. Toxicol. Chem. 27:811-818.
contaminate the overlying freshwater aquifer and the coastal housed in each stainless steel shroud (Figure 3). With the help of O'Toole S., C.D. Metcalfe, I. Crane and M. Gross. 2006. Environmental Pollution 140: 99-110.
zone. In addition, there is potential for contamination of the Petty, J.D., J.N. Huckins, D.A. Alvarez, W.G. Brumbaugh, W.L. Cranor, R.W. Gale, A.C. Rastall et al. 2004. Chemosphere 54:695-705.
certified cave divers, the samplers were deployed in the caves by Figure 3: Stainless steel shrouds containing three SPMDs aquifer from spills, irrigation, urban runoff or pesticide and three POCIS passive samplers that were deployed in Acknowledgements: Funding for this research was provided through a research grant from UNU-
tethering them to limestone features in the caves, or they were cave systems in the Mayan Riviera region.
INWEH as part of a project funded by the Global Environmental Fund of the World Bank. Many thanks to the certified cave divers, Dennis Weeks, Robert Schmittner and Jeff Clark, who helped to deploy the samplers.


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