A cutting edge technical paper says that all kinds of microorganisms, including those that can harm human health are found in beach sand. A University of Miami researcher and an international team of scientists are recommending that sand be tested as well as ocean water at popular beaches.
The findings should not be surprising for expats here. Beaches at the mouth of the Río Tárcoles on the Gulf of Nicoya are littered with the castoffs of society. Until the Central Valley’s new sewage treatment plant is in full operation, most of the metro area human waste will continue to flow down the river into the gulf.
During periods of heavy storms, the trash is carried across the gulf to the beaches of the Nicoya peninsula.
The part of the beach that is covered with water at high tide and then dries out is called the swash zone. Previous studies have shown that the swash zone of the beach environment, with the wetting and drying processes and the presence of seaweed, algae and sargassum, is prone to regrowth of disease-causing microbes, including unhealthful bacteria, viruses, nematode larva and eggs and harmful yeast and fungi, the university noted in a description of the research.
“Beach sands accumulate contaminants and people can get exposed to these contaminants during beach recreational activities,” said Helena Solo-Gabriele, a professor at the University of Miami College of Engineering and first author of a paper.
The academic article summarizes the consensus of experts at a 2014 conference in Portugal, the university said.
“Hopefully this paper will make a difference in convincing regulators of the need to include sand in beach monitoring programs,” the professor was quoted by the university as saying.
The article, published in the July issue of the Journal of the Marine Biological Association of the United Kingdom, reflects the international experience of all scientific and technical papers published up to date, including data from beaches in the United Kingdom, Portugal and the United States, said a summary.
“This publication is a landmark paper,” said João Brandão, manager of the sand microbiology and public health program at the national institute of health in Portugal, a co-author of the paper. “It wraps it all up and hopefully lays down the foundation for the future,” he said, according to the university summary.
Many of the studies used to develop recommendations were conducted in South Florida and beach locations around the Great Lakes, in Hawaii and in California, said the summary.
The World Health Organization issued a recommendation in 2003 that sand quality be studied, but so far no country has done that, the researchers said. The academic paper suggests using methods that estimate public health risks from various pathogens in the sand, along with other tests.
The laboratory at the Instituto Costarricense de Acueductos y Alcantarillados conducts tests of water at popular Costa Rican beaches, but the tests do not include the sand. In the past, the laboratory has issued warnings about beaches with high fecal coliform counts, particularly in dry weather when there is sewage runoff.