WORKERS at a medical device manufacturing firm were among the hundreds of people who helped test Oxfordshire's water quality on one day.

Irem Bostanci and Luisa Teixeira from Owen Mumford in Woodstock tested for pollution in the River Glyme near their office on Tuesday as part of the WaterBlitz.

Their results and hundreds of others are already live on a new online map showing how much nitrate and phosphate testers found in rivers across the Thames Valley.

Conservation charity Wild Oxfordshire, which helps recruit volunteers for the annual survey, said it was delighted that so many testers were helping reveal hidden pollution.

Program manager Hilary Phillips said: "This year we sent out about 400 testing kits so we're expecting to get 800 samples for Oxfordshire.

"The results are helping to fill in real gaps in our knowledge.

"We need to improve freshwater habitats for wading birds, amphibians and delicate plants: there are a lot of species which are struggling because the water isn't clean enough."

The easy-to-use WaterBlitz kits which volunteers ordered over the internet test for two pollutants – nitrates and phosphates.

These chemicals, which leak into rivers from fertilisers on farmers' fields, act as super fuel for algae which causes it to explode in an 'algal bloom'.

This mega-algae sucks all the oxygen out of the water, suffocating other plants, fish and insects there and downstream.

Volunteers on Tuesday took samples of their local river in just seconds and were able to upload their readings to the live web map using a smart phone app.

The map was created by Oxford's EarthWatch institute, which processes the WaterBlitz results to build a picture of pollution across the Thames Valley.

Since it launched in autumn 2015, Thames Waterblitz volunteers have collected a total of 1,208 samples.

Project co-ordinator Luis Velasquez said: "Each WaterBlitz provides information from areas that would otherwise not be monitored and shows seasonal impacts of climate and land use change are important."

By identifying areas where nutrient discharges are more likely, Mr Velasquez said the WaterBlitz was helping regulatory bodies like the Environment Agency, research institutes and river trusts to improve waterways and reduce the risk of harmful pollution.

The Thames Valley WaterBlitz is also part of Earthwatch's FreshWater Watch project, a global study of the health of freshwater ecosystems.

The next Thames Valley WaterBlitz will be held on Monday, October 2.

Find out how to join in at, call Wild Oxfordshire on 01865 407034 or email