After the discovery of toxic blue green algae in the Selwyn River near a campsite, 63km west of church site, a serious warning is issued by the Canterbury health authorities. The algae (benthic cyanobacteria) may prove really harmful on direct contact with body and may show symptoms like stomach cramps, nausea, rashes tingling and numbness around mouth and fingertips.

It is recommended to rush to a doctor immediately on the experience of such symptoms if come in contact with contaminated water. Animals should be taken to a vet if they come in contact with contaminated river.

These algae can occur naturally but possess a power of increasing their number rapidly in warm climate. The visibility of growth is like mats of black or brown colour attached to rock along the river on river banks.

The alga has been monitored weekly by environmental Canterbury at Selwyn River during summer.

As per a statement issued by Environment Canterbury scientist David Kelly the health warning is nothing but a precautionary measure to ensure complete safety of people and their pets. There is no proper confirmation of presence of toxins in the river till there is a result issued after the tests.