Catalonia has 255 coastal bathing areas, with excellent water quality levels, exceeding 95%. During the summer season, technicians from the Catalan Water Agency (ACA) analyze more than 3,000 samples to verify that the water is suitable for bathing and free of unwanted microorganisms. Up to nine bi-weekly samplings are carried out on all beaches to ensure optimal quality for bathers and guarantee that all parameters established by the European directive are met.
Laboratories of the Public Health Agency of the Generalitat in Girona, Barcelona, Tarragona, and Tortosa participate in this monitoring, as these are the centers where ACA technicians send samples for analysis. This process requires a certain amount of time, between 24 and 48 hours, since the laboratory techniques applied are not immediate. To analyze whether the sample contains traces of fecal contamination, that is, microorganisms that do not live in the sea but in the human intestine (intestinal enterococci or escherichia coli bacteria), cultures must be grown in petri dishes and, subsequently, with a microscope, count the colonies to see if quality thresholds are exceeded.
Usually, samples test negative, meaning they do not contain fecal contamination, since the existence in Catalonia of 530 wastewater treatment plants ---which serve 97% of the population--- greatly facilitates the management and good quality of coastal waters. Sometimes, however, episodes of fecal water contamination occur due to breakdowns or adverse weather phenomena or very heavy rains that cause floods and the overflow of sanitation systems. It is estimated that one third of the Catalan coast has a high risk of contamination due to rain episodes.
When this happens, the Catalan Water Agency needs to be able to act very quickly, as decisions must be made such as closing beaches or restricting bathing areas where quality cannot be guaranteed. In these episodes of management stress, the usual model of sample analysis in public health laboratories is not ideal, as it requires a long wait to obtain results (between one and two days) and it is not possible to act quickly enough when closing or reopening a beach.
Given this handicap, the ACA has partnered with the Institute of Photonic Sciences (ICFO) to jointly develop a portable device that will allow rapid water quality tests to be carried out on the beach, without the need to transfer samples to a laboratory and with results that will be available in less than three hours and with the same degree of reliability thanks to light technology. The objective is for ICFO to patent this device and for a spin-off, called Sixsenso Aqua, to manufacture and commercialize this rapid control system for bathing waters.
The Agència Catalana de l'Aigua will invest 578,000 euros in this project, which began last September and will be developed over three years. "Having this technology will represent an impressive qualitative leap in our management system," assures Mariona de Torres, head of water quality for the Catalan coast. According to the ACA technician, the device "will be a rapid management tool complementary to the traditional system" that will allow these pollution episodes to be resolved in a matter of hours.
The objective of the ACA and ICFO is to have a prototype ---similar to a portable briefcase--- developed and validated by 2023. So far, all the work and tests carried out have been very satisfactory, which fills the research team with optimism.
How the technology works
ICFO, based in Castelldefels (Barcelona), has been working for eight years on a method for rapid detection of microorganisms in water using light. The collaboration agreement with the ACA consists of carrying out a practical application of an existing technology that will now allow a real problem to be addressed. According to De Torres, one of the great advantages of the device being developed is that it will allow several samples to be integrated into the same analysis, which will provide a global vision of the water quality of a bathing area.
And how will this technology work? The first thing the device will do is subject the water samples to a concentration and filtration process. Secondly, reagents will be applied to the samples that will allow the identification of unwanted microorganisms through a system known as genetic labeling. This is a totally innovative technique that allows the identification of the DNA of the microorganisms under analysis. If they are part of the sample, and once the reagent is applied, these bacteria are marked by a fluorescent light. It is at this moment that the ICFO technology is applied, which allows measuring the intensity of the fluorescent light emitted by the sample. Depending on the intensity level of that fluorescence, it will be possible to determine whether or not the water complies with the established quality parameters. "It's as if we put a light bulb on each bacterium and thus we can measure them and know if the concentration is excessive," explains the ACA executive graphically. The collaboration with ICFO will also allow the creation of a system for monitoring the presence of phytoplankton on the Catalan coast.