Circumstances and timeframe permitting, certain measures should be taken
before the arrival of the pollution on the shoreline, in a bid to facilitate
the subsequent clean-up operations and limit the impact.
Collecting solid waste and natural debris onshore before the pollution arrives helps to reduce the amount of soiled material and facilitates clean-up operations. According to the extent of beachings, this collection can be carried out either manually or using public works machinery or specialised machinery such as sand screeners. Removal must of course be as selective and methodical as possible.
The apparent protection of bays, estuaries and inlets using booms can be somewhat illusory due to strong currents sweeping across their entrances. However, more limited areas can be protected. Contingency plans should define these areas and include suitable boom deployment plans, with pre-defined anchoring points.
Protection with filtering booms should also be anticipated for creeks, marsh creeks and water intakes in shellfish parks, fish farm basins, salt pans, thalassotherapy centres and other installations using seawater. The options vary according to the size of the sites needing protecting. The main resources available are gillnets, filtering barriers or dams made of earth and other materials. Some of these methods of protection combine the retention function of the netdam and the sorption capacity of sorbents. The industry offers sorbent booms, suitable for relatively small quantities of fluid or finely divided substances. A net filled with straw can constitute a makeshift solution as long as the straw is changed often enough and correctly disposed of when soiled.
Protecting sensitive areas
Capture using a fine mesh net
The use of fine mesh nets attached to the foreshore
at one end above the high tide
mark is an effective method of catching clusters of oil beached at high
tide. This technique is particularly productive on viscous, sticky pollutants,
such as heavy fuel oil.
Adherence to a hard substrate can be reduced by spreading film-forming agents (biofilms) made from alginates which form a film on the substrate before the pollutant arrives. These substances are an effective way of reducing the adherence of oil to hard surfaces such as rocks, riprap and concrete walls. They facilitate clean-up and avoid the need to resort to high pressures or temperatures which may be harmful to the environment, as long as washing occurs at an early stage. They are not harmful to the flora and fauna present.
Finally, during recovery, measures should be taken to protect the soil and vegetation to diminish the impact of the pollution and of pedestrians and machinery. Heavy traffic on the shoreline without suitably adapted access can cause acute degradation of biotopes and contamination of the soil by machinery and soiled equipment.
Filtering system made of oyster shells, feathers
and pozzolana at the entrance to mud flats