Ni ddylid tanbrisio cymhlethdod ac amseroldeb y math hwn o waith.  Mae nifer o ffactorau i’w hystyried mewn perthynas ag unrhyw waith adfer, yn enwedig yr amgylchedd.
The complexity and timeliness of this type of work should not be underestimated.  There are a number of factors to be considered in relation to any remediation work, not least environmental.