Across Europe, only two antibiotics — sulfamethoxazole and sulfamethazine — are widely monitored in rivers by national authorities, according to a 2018 report by the European Commission’s Joint Research Centre.
Other antibiotics, if they are monitored at all, are only done so in a few EU countries. Croatia is one of the countries that does monitor three so-called macrolide antibiotics: azithromycin, erythromycin and clarithromycin.
Hrvatske Vode, the state water utility, says it monitors these antibiotics in line with a European Commission decision (2015/495) to create a watchlist of potentially dangerous substances in water.
But the monitoring only takes place up to four times a year in the same two locations on the Sava river. The nearest is around 10 kilometres downstream from Pliva’s factory.
In most cases, “there were no significant traces of these antibiotics in the water,” Hrvatske Vode said.
Alistair Boxall, coordinator of the largest global study of antibiotics in rivers, said it was best practice to collect samples at many different spots on a given river — from six to 20 per city.
“The problem with monitoring done by regulatory agencies is that they are still looking at only a few chemicals,” he said. “In the UK, we are spending millions on monitoring the chemicals that we actually don’t use anymore and we are ignoring everything else.”
Boxall noted that the EU’s watch list of dangerous substances only contains a few pharmaceuticals.
“There is not much intelligence in the current monitoring system,” he said. “Things could be done more thoroughly, like we did in our study, or we can use some advanced analytical methods. That will certainly tell us more about what is going on in our rivers and what we are exposed to.”