Microplastics, Sunscreen Chemicals and Repellents Under Study in Quintana Roo Waters

Cancún, Quintana Roo — The environmental group Centinelas del Agua is monitoring water bodies across Quintana Roo to determine the presence and possible effects of microplastics, oxybenzone and compounds associated with insect repellents, the organization’s director general, Alejandro López Tamayo, said.

López Tamayo said the work is currently concentrated in areas including Yalahau, Holbox, Cancún and Playa del Carmen, and will be expanded to cenotes elsewhere in the state. The goal is to establish contamination levels and their potential consequences for ecosystems and for species that matter to fishing communities.

The study covers microplastics, oxybenzone — an ingredient found in some sunscreens — and DDT, which the organization links to products used as repellents. Fieldwork began last year and included monitoring across three seasons.

About 180 tonnes of plastic a year in Holbox

López Tamayo identified Holbox as a particular concern. According to the organization’s estimates, some 180 tonnes of single-use plastic reach the area’s mangroves, wetlands and the Yalahau lagoon each year. Researchers want to determine how much of that pollution degrades and enters the aquatic system.

He added that recent scientific evidence points to the presence of microplastics in coastal communities and possible effects on organs including the liver and kidneys. The next step will be to analyze commercially important species to determine whether fish are taking in these materials through the water column.

New monitoring in cenotes

In parallel, Centinelas del Agua will begin monitoring cenotes in Cancún and other parts of the state, supported by a water quality laboratory set up at its offices in Cancún.

The laboratory has already been used to respond to recent environmental events, including a fish die-off in a lagoon on Isla Mujeres. López Tamayo said another phenomenon observed near Isla Contoy was linked to high water temperatures that reached close to 38 degrees Celsius (about 100 degrees Fahrenheit), a condition that poses a risk to various aquatic species.

Beyond scientific research, the organization runs a program to build ecological sanitation systems and dry toilets for communities that lack sanitary infrastructure.

Drinking water and illness in José María Morelos

López Tamayo said the municipalities considered at greatest risk from water-related problems include José María Morelos, Lázaro Cárdenas and Felipe Carrillo Puerto, along with areas of Playa del Carmen, Punta Laguna and Campamento Hidalgo.

In José María Morelos, he said, the group has identified families consuming contaminated water and cases of gastrointestinal illness, particularly among children. The strategy there is to pair environmental diagnosis with efforts to improve sanitation and access to safe water.

Nichupté lagoon and aeration

As for the Nichupté lagoon, specifically the Bojórquez area, López Tamayo said installing and renovating aerators could help improve oxygen levels in a body of water that has suffered for years from nutrient buildup and a lack of circulation and oxygen.

He said monitoring must accompany those measures and be extended to ecologically important species, including the horseshoe crab, because some infrastructure work is planned close to areas where the species nests.

He recalled that a recovery project was carried out about 14 years ago with the Mexican Institute of Water Technology (IMTA) but was later abandoned, and he argued that citizen oversight of the new measures is needed. According to the information provided, work to renovate the aerators could begin next year.

Results expected in October

López Tamayo said Centinelas del Agua is preparing to present the results of its research, possibly at a press conference in October. The studies are being carried out with specialists from UNAM’s CICSAL unit.

The organization is also working to obtain environmental DNA from cenotes in order to identify the species associated with different water bodies and gain a more precise picture of the ecosystems being monitored.

The director stressed that the purpose of the research is not only to document contamination but to generate information that can drive concrete cleanup and prevention efforts in Quintana Roo communities.