Thank you for the link and English translation. Some of us know this is a major problem in Cozumel, but unfortunately most are either unaware, ignoring it, or are in flat denial. Coincidentally this topic came up in a Cozumel Facebook group today. I provided the following research study as a factual basis to the argument. The group moderator argued this study proved nothing, was not recent enough, and then my account was banned from further participation.
Note, the Abstract was the only section translated to English by the authors. Due to needing to Google translate this myself, I've omitted the Scientific processes and simply shortened it to the results. Anyone wishing to read the full document please PM your email address and I'll send you the full PDF document. Bold font was added by me to highlight certain text.
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Water quality indicators of coastal lagoons with toursim in!uence: Cozumel and Isla Mujeres, Quintana Roo, México
Adrián Cervantes-Martínez, Martha Angélica Gutiérrez-Aguirre
Universidad de Quintana Roo
Teresa Álvarez-Legorreta
El Colegio de la Frontera Sur
Abstract
The feasibility of recreational use of Laguna Colombia (LC) within the National Marine Park “Arrecifes de Cozumel”, and Laguna Macax (LM), within the natural protected area of Costa Occidental in Quintana Roo was surveyed using physical and chemical indicators of water quality. Activities related to nature observation are currently carried out, but the feasibility to support direct contact recreational activities is unknown. In this study the natural cyclic changes (2010) were considered using the following criteria: a) Ecological criteria of water quality (ce-cca-001/89), b) NOM-001-semarnat-1996, and c) EPA Ecological criteria for estuarine and coastal waters. Twelve indicators of water quality were considered (depth, transparency, water temperature, salinity, dissolved oxygen, pH, chlorophyll, chemistry and biochemistry oxygen demand, and concentration of orthophosphate, nitrate, and nitrite). Statistical tests showed that the lagoons do not have static temporal or spatial features and according to ecological criteria, they exceed the maximum permissible concentration of nutrients and thus the water quality can be classified as poor. Results will be useful in planning the use of these systems in terms of their basic features.
(Note: Below is Google translation)
Water quality indicators LAGUNA COLOMBIA
During the dry months, the greatest variability in the system was explained by the first two axes (82.5%), and the five main variables were the concentration of orthophosphates, nitrites, nitrates, chlorophyll a and silicates (table 1).
Table 1. Analysis of Principal Components (ACP) of variables analyzed in Laguna Colombia, during dry periods. *
AXIS 1 AXIS 2 AXIS 3
Orthophosphates 0.444 -0.237 0.109
Nitrites 0.244 -0.563 0.592
Nitrates 0.175 -0.174 0.211
During the rains, the first three axes explained 89.4% of the variability in the system, and the concentration of nitrates, orthophosphates and COD were the variables with the highest contribution to the first three components (table 2).
Table 2. Analysis of Principal Components (ACP) of the analyzed variables in Laguna Colombia, during rains
AXIS 1 AXIS 2 AXIS 3
Orthophosphates 0.539 0.473 0.111
Nitrites 0.030 -0.050 0.145
Nitrates 0.728 -0.502 0.287
LAGUNA COLOMBIA
• Dissolved oxygen: in the dry season 1 and in the rains the seasons 1, 3, 4 and 7 did not present the minimum limit established in the criteria
Ecological for the protection of marine aquatic life (5 mg L-1). Cervantes-Martínez / Gutiérrez-Aguirre / Álvarez-Legorreta (2015: 60-83) 75 Theory and Praxis No. esp.
• Orthophosphates, nitrates, nitrites: the averages in all the sites of collection and in both climatic periods were higher than the limits maximums established in the ecological criteria for the protection of Marine aquatic life (0.002 μM L-1, 0.04 μM L-1 and 0.002 μM L-1, respectively).
According to the EPA criteria, the water quality of each site analyzed in the lagoon Colombia is poor both in the dry season and in the dry season rains, because at least two or more indicators were classified equally at each site (table 5).
Conclusions
According to the analysis carried out in the Colombia lagoons and following the Ecological Criteria for Water Quality CE-CCA-001/89, NOM-001-ECOL-1996 and the estuarine and coastal water quality criteria of the EPA, the water has four characteristics that as analyzed in the previous section and the WQI in Table 5 can be summarized as follows:
1. The gaps exceed the maximum permissible concentration limits of nutrients, according to ecological criteria for protection of marine aquatic life
2. Water quality can be classified as poor according to the criteria of the EPA.
3. In appearance, this condition is static (similar) on the spatial scale.
4. The recreational use of direct contact in these lagoons is not recommended.
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A few things trouble me about this study.
1. Obviously the overload of orthophosphate, nitrite, and nitrates (more on this in a moment).
2. This lagoon is far to the south of Cozumel, mostly away from the population, nestled into the center of protected marine reserve. Nearest human influence would be the Punta Sur Eco-Park, followed by Palancar Beach Club and then Iberostar Resort. This would mean these areas are having an impact upon lagoon water miles away (Palancar Beach Club, Iberostar) from the point of source.
3. The study concludes that humans should not come in contact with this water. The water isn't just a little dirty - it's contaminated to the extent that we shouldn't go near it.
4. This lagoon floods out to the Colombia and Palancar reefs. This lagoon water that is so contaminated that humans should not come in contact with it provides our favorites dive sites with a nutrient bath every time it rains. Anyone still wonder why Palancar and Cedral dive sites are so covered in nuisance algae?
Lets circle back to my concern #1. For those readers unaware about orthphosphates, nitrates, and nitrites I'll provide a quick Google explanation of them.
Orthophosphates are also called reactive phosphates. They are the most common in water treatment situations, as they directly contribute to the eutrophication of a body of water. Eutrophication is the enrichment of nutrients for plant growth in water, leading to problems for the ecosystem. (Here's looking at you Palancar, Cedral)
Nitrate and nitrite are found in many places in the environment. They are introduced through the application of fertilizer containing nitrogen compounds; through decomposing animal wastes; and through septic systems and sewage treatment facilities.
Now, lets circle back to my concern #2. We know septic systems in porous limestone, particularly limestone as shallow as found in Cozumel, is not sufficient. So improperly treated wastewater is literally dripping into our water reserves, and now we know this water is headed out to sea. Here is another study which includes the same author as the study above -
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Evidence of preferential flow to the sea from the Cenote Caletita, in Cozumel, Mexico
Ismael A. Sánchez y Pinto1, Adrián Cervantes-Martínez2, Roger A. González Herrera1, Mónica E. Vázquez Campos2 Martha A. Gutiér rez-Aguir re2
Fecha de recepción: junio 2014 Fecha de aprobación: enero 2015
ABSTRACT:
The "Cenote Caletita" is located in Isla Cozumel, Quintana Roo, Mexico. Similar to other islands of calcareous origin, the aquifer recharge depends exclusively on precipitation and discharge occurs through natural dissolution conduits (locally known as Öjo de aqua" or water spring when the discharge occurs below the water level in estuaries or the sea). This paper presents the results of a field test with sodium fluoresce in and the physico-chemical study of the island underwater karst subsystem, comprising the "Cenote Caletita" and two coastal springs. The physical and chemical data in the studied systems, were similar to each other, water temperature = 24.7 0.04 (C), dissolved oxygen = 0.32 0.1 (mg/L), salinity 15.6 0.09 (ups), conductivity = 25.5 0.13 (mS/cm), indicating a possible interconnection between them. To corroborate this, a tracer test was carried out. It was found that the flow rate ranges from 11 cm/s at the injection point (Cenote Caletita) and between 5 and 7 cm/s in the springs (whereby discharge occurs to the sea). Dispersion coefficients, estimated by tracer tests, ranged between 0.03 and 0.55 m2/s. The study of preferential groundwater flowpaths is emerging in the area; however, having no history of similar works in the region, it is confirmed for the first time, the preferential groundwater flow in the karstic system of Cozumel Island.
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Now think about the worst areas of Cozumel reefs. Palancar and Cedral becoming overrun with nuisance algae thanks to Colombia Lagoon. Paradise Reef the hardest hit (thus far) reef with SCTLD. Not coincidentally, adjacent to Paradise Reef is the Caleta and Marina Cozumel harbors, which include the Cenote Aerolito. Chankanaab Reef adjacent to another cenote. The worst reefs of Cozumel are all adjacent to known cenote discharge points. Coincidence?