Enviromental Waters

Environmental Water (ENV) control authorities are continuously sampling and testing bathing waters to guarantee a safety standard for the population, mostly following rain episodes when faecal contamination arrives in significant quantities to coastal beaches and deltas. The typical method of analysis involves the use of standard culture methods to quantify specific bacteria with sufficient reliability, but such methods provide only a few millilitres for each test and take one or two days to get the results. Thus, there is a need for fast, reliable, and statistically representative results a few hours after the rain episode and in the following hours/days to ensure timely coast re-opening for recreational and touristic activities. 

The analysis classifies bathing waters based on the probability that concentrations of Escherichia coli or intestinal Enterococci will be below classification thresholds, there are no ‘pass’ or ‘fail’ standards.

All the samples are analysed in specialized laboratories taking days, and the classification is based on Most Probable Number (MPN) or standard culture methods but they are slow methods providing errors caused by large number of false negatives because non culturable cells, or false positives because human error preparation or lack of specificity. 

In other hand, ENV control Authorities carry out surveillance on the coast in order to detect and control that the proliferation of some harmful and toxic phytoplankton species doesn’t exceed alarm thresholds by means of microscopy or fluorimetry methods.

The typical method of analysis is to use standard culture,  Define Substrate Technology (DST), fluorimetry or microscopy, all laboratory methods to quantify specific bacteria or phytoplankton with sufficient reliability to meet regulations, but such methods provide only a few millilitres for each test and take between 1 and 12 days to get the results.