Wallingford Bridge (IMAGE) UK Centre for Ecology & Hydrology Caption Samples were taken from sediment in the River Thames by Wallingford Bridge. Credit Bill Nicholls, CC BY-SA 2.0 via Wikimedia Commons Usage Restrictions Credit must be given to the creator. Adaptations must be shared under the same terms. License CC BY-SA Disclaimer: AAAS and EurekAlert! are not responsible for the accuracy of news releases posted to EurekAlert! by contributing institutions or for the use of any information through the EurekAlert system.