The term practicable appears in:
EPA S89(1) “It shall be the duty of … (b)the Secretary of State, as respects any trunk road which is a special road and any relevant highway or relevant road for which he is responsible … to ensure that the land is, so far as practicable, kept clear of litter and refuse“.
The term is akin to “physically possible” without the need to take account of cost, time and trouble as opposed to “reasonably practicable” were these considerations would come into play.
This definition of “reasonably practicable” was set out by the Court of Appeal (in its judgment in Edwards v. National Coal Board,  1 All ER 743) as follows:
“‘Reasonably practicable’ is a narrower term than ‘physically possible’ … a computation must be made by the owner in which the quantum of risk is placed on one scale and the sacrifice involved in the measures necessary for averting the risk (whether in money, time or trouble) is placed in the other, and that, if it be shown that there is a gross disproportion between them – the risk being insignificant in relation to the sacrifice – the defendants discharge the onus on them.”
If parliament had wanted cost considerations to be taken into account in the determination of what was to be considered “practicable” in the EPA they could have employed terms used in other legislation such as:
TEEP -technically, environmentally and economically practicable.
BATNEEC Best available techniques not entailing excessive cost
But they did not.
Use of “reasonably practicable”;
Section 2(1) of the Health and Safety at Work etc Act 1974 states: It shall be the duty of every employer to ensure so far as is reasonably practicable, the health, safety and welfare at work of all his employees