If a site may be contaminated due to past activities (on site or nearby), it must be assessed to determine contamination levels, risks to health and the environment, and remediation steps.
Os gall safle fod yn halogedig oherwydd gweithgareddau'r gorffennol (ar y safle neu gerllaw), mae'n rhaid ei asesu i bennu lefelau halogi, risgiau i iechyd a'r amgylchedd, a chamau adfer.