Ocurrencia Y Persistencia De Microorganismos Patogenos

PATHOGENS AND PHARMACEUTICALS POLLUTANTS AS INDICATORS OF CONTAMINATION AT THE NORTHEASTHERN AQUIFER OF QUINTANA ROO

PRESENCIA DE PRODUCTOS FARMACÉUTICOS Y PATÓGENOS POTENCIALES EN LA PARTE NORESTE DEL ACUÍFERO DE QUINTANA ROO

Rosa M. Leal-Bautista*, Unidad de Ciencias del Agua. Centro de Investigación Científica de Yucatán Calle 8 no. 29 Mza.39 SM 64, Cancún, C. P. 77524

Galdy Hernández-Zárate Instituto Tecnológico de Boca del Río. Laboratorio de Investigación de Recursos Acuáticos. Km. 12 Carretera Veracruz-Córdoba, C. P. 94290, Boca del Río, Ver., México (gahernanitboca@live.com).

Norma A. Jaime M, Universidad de Guanajuato, Facultad de Ingeniería Civil, Div. Ingeniería Ambiental

Germán Cuevas R. Universidad de Guanajuato, Facultad de Ingeniería Civil, Div. Ingeniería Ambiental, Campus Guanajuato-Unidad Belen (german28@quijote.ugto.mx)

Guadalupe Velázquez Oliman, Empresa de Manejo Cultural S.A.

*Correspondig author email: (rleal@cicy.mx*)

*Correspondig author email: rleal@cicy.mx*

SUMMARY

The objective of this research project was to sample groundwater from touristic to non-touristic wells and sinkholes along the Riviera Maya region, to determine the occurrence, source and extent of the fecal contamination, and establish if the recreational activities of this zone is rising as an anthropogenic contamination source. Escherichia coli (E. coli) is one of the most common bio-indicators to asses the bacteriological water quality its presence is related with pathogenic health problems associated to anthropogenic influence such as leaks from septic tanks, and raw wastewater. Despite the limitations and problems associated with the detection of fecal bacteria, this bio-indicator is still present in several water policies around the world.

The study zone was located at Puerto Morelos Quintana Roo, where seven groundwater samples were collected from sinkholes and wells. Bacteriological analysis were performed by the chromogenic substrate technique to determine total coliforms and E. coli, molecular microbiology technique allowed for identification of Vibrio spp., and chromatography method was performed to determine the presence and absence of caffeine. At the field, pH, dissolved oxygen and temperature were determined at the collection of the sample by a multiparametric sonde. Alkalinity, nitrate, nitrite, total nitrogen, phosphate, total suspended solid and chemical oxygen demand (COD) were determined at laboratory. The results reveal that fecal contamination in groundwater at the touristic and non-touristic sampled sites is occurring. However the detection of the Vibrio spp. and the determination of caffeine makes evident that only in the touristic sites the extent of the contamination implies a human source. The others sources of bacteriological contamination can be linked to the type of coastal ecosystems presented along the area of study.

El objetivo de este estudio fue determinar la ocurrencia, la extensión y fuentes de contaminación fecal de muestras de agua subterránea de pozos y cenotes en sitios turísticos y no turísticos en la Riviera Maya y establecer si las actividades recreativas que van en aumento, son fuente de contaminación antropogénica en esta zona. Escherichia coli (E. coli) es uno de los bioindicadores mas común para evaluar la calidad bacteriológica del agua, su presencia está relacionada con problemas de salud por patógenos asociados a influencia antropogénica tales como fugas de tanques sépticos y aguas residuales sin tratar. A pesar de las limitaciones y problemas asociados a la detección de bacterias fecales, este bioindicador continua presente en las diversas políticas de calidad de agua en el mundo.

El estudio se desarrolló en el área de Puerto Morelos, Quintana Roo. México, colectándose siete muestras de agua subterránea de pozos y cenotes. Se efectuaron análisis bacteriológicos mediante las técnicas de sustrato cromogénico para la determinación de Coliformes totales y E. coli y de microbiología molecular para la identificación del genero Vibrio spp.; la detección de cafeína se efectúo mediante técnicas cromatográficas. Los parámetros de campo (pH, oxígeno disuelto, conductividad y temperatura), fueron determinados al momento de la colecta de muestras mediante una sonda multiparamétrica. Los parámetros de alcalinidad, nitratos, nitritos, nitrógeno total, fosfato, sólidos suspendidos totales y Demanda Química de Oxigeno se determinaron en laboratorio. Los resultados revelaron la presencia de contaminación fecal en agua subterránea en sitios turísticos y no turísticos. La presencia del grupo vibrio, y la detección de cafeína confirmaron que la alteración de la calidad del agua en algunos de estos sitios tiene una conexión directa con actividades antropogénicas del tipo turístico. La información colectada en este estudio además de servir a la comunidad científica puede ser adecuado para los miembros de la comunidad de este acuífero costero cárstico para entender la importancia del manejo de las políticas del agua y la importancia de la evaluación del impacto ecológico de las actividades turísticas

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Key words: Fecal contamination, Caffeine, Karstic Aquifer

INTRODUCTION

The touristic activity has become an important economical activity worldwide, in México this represent the third economical force. The Cancun-Riviera Maya in Quintana Roo; México; due to its natural resources: beaches, jungles, sinkholes, and reef is one of the main Mexican touristic poles. It has reached a great development and growth in Latin America with 20-25% growth per year (SECTUR, 2009). Moreover, this region underlies a vulnerable karstic coastal aquifer at the Yucatán Peninsula, which is considered a groundwater dependent ecosystem (GDE) completely reliant on aquifers for supplies of fresh water. High permeability fractured limestone, such as the one underlying the Cancun-Riviera Maya, allows rapid transport of microbial and chemical contamination resulting in a significant potential increase of pollution affecting the ecosystems. As this activity rises, there is an increase in service and new influx of new inhabitants. In 2005 the overall net migration (immigrants into the state versus emigrants out of the state) in Quintana Roo of persons that have lived in the state for five years or more recorded an influx of 72,306 individuals (INEGI, 2005). In that same year the percentage of immigrants in the state in respect to the rest of the population was estimated at 8.1% (INEGI, 2005). Compared to the influx estimated in 2002 at 5.3% the overall migration into Quintana Roo is on the rise (Hausman, 2009).

Hydrogeologic setting

The Yucatán Peninsula is a large, emergent carbonate platform with developed karst features. Dissolution of carbonate material along fractures is common, promoting the karstic features such as sinkholes, karstic caves of varying width and depth. The study zone present most of the characteristics discussed by some authors such as Perry et al., (2002): 1) beneath almost the entire northern region fresh water lens is underlain by a marine saline intrusion that is in close hydraulic contact with the ocean; 2) the fresh water lens is approximately 10 m thick near the coast and reaches a depth of about 60 m depth; and 3) precipitation across Quintana Roo range 1,500 mm annually to 1,100 mm annually.

The unconfined aquifer of the Yucatán Peninsula serves as the sole source of fresh groundwater throughout Quintana Roo. Rainwater is the main source of aquifer recharge with 15% of the total precipitation infiltrating down to the water table (Moore, 1992).The precipitation rapidly penetrates a surface calcrete layer through fractures and moves through a highly permeable vadose zone to the water table. As consequence there are no surface streams more than few hundred meters long in the northern and northeast peninsula. The high permeable fractured limestone of the Yucatán Peninsula allows for a rapid transport of contaminants. The extreme population growth and the increase in touristic activities have created high potential for microbial and pharmaceutical pollution to occur.

The hydrogeologic characteristics of the Caribbean coast of Quintana Roo allow for the rapid downward infiltration and equally rapid lateral movement of water flow within the subsurface (Back and Hanshaw, 1978). The water table at the northeast part of the Yucatán Peninsula is located at 2.5 meters above sea level at 46 Km from the coast, the hydraulic gradient decrease and the flow of the groundwater discharge at the coast (Perry et al., 1989; 1995; Marin 1990). There are no rivers or streams present throughout northeastern Yucatán due to the relative lack of soil and the presence of highly permeable, karstic limestone. An important karstic feature is a sinkhole or “cenotes”, which are major tourist attractions for the Riviera Maya industry. Cenotes (water-filled sinkholes) are direct conduits to the underlying aquifer.

Contamination Bacteriologic Indicators

Several water quality studies had focused in pathogens and its human health relation. (Seiler et al., 1999; Boehm et al., 2003; Buerge et al., 2003; Siegener et al., 2002; Aquality Env. Co. 2005; Pacheco F.A., 2005). Bacterial enteric pathogens associated with drinking water include E. coli, Shigella, Campylobacter, and Legionella (Maier et al., 2000). Enteric pathogens are those agents that are derived from the intestines of living organisms. Waterborne pathogenic microbes’ reservoirs include animals, humans and the environment.

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