Assessment of the impact on the River Adour of ship unloading
This study was requested by the CCI Bayonne, the Basque Country in order to understand the impact of unloading “dry” bulk goods (fertilizer, peat, etc.) in the Tarnos zone.
Given the proximity to the tourist area and beaches used for swimming, particular attention is paid to products being carried on the air and landing on the quays, the hardstanding areas and in the River Adour.
With this in mind, a study on the quality of the water in the River Adour was carried out between 2000 and 2003 which concluded that pollution levels were relatively low; bacteriological pollution being identified as coming from the agglomeration and chemical pollution coming for the most part from further upstream.
However, as part of its environmental protection measures, the CCI wanted to be sure of the impact that might come from its handling activities on the Adour.
Consequently 33 sampling and analysis campaigns, adapted to the type of products being handled, were carried out during ship unloading during 2007. The samples were taken at several different points:
- 1 from the middle of the River Adour opposite the Harbour Master’s Office
- 1 or 2 from the quayside next to the ship
- 1 from the middle of the River Adour opposite the Delure Wharf
- 1 from upstream, near the St Bernard zone.
In addition to these analyses, 3 “overall quality” campaigns were carried out by taking samples when there were no ships present in order to act as a reference and to see whether unloading had a residual influence or not.
The set of standards used during this study when interpreting the results was the SEQ – Water (Système d’Evaluation de la Qualité de l’Eau des rivières or the System for the Assessment of River Water Quality). This set of standards, built up in relation to a “reference” milieu that resembles more a small mountain river is, to date, the only set of standards existing; other sets of standards that particularly take into account the characteristics of an estuary are in the process of being drawn up, but have not yet been finalised.
The SEQ also established precise rules, such as the frequency with which samples should be taken, that were not strictly applied during this study, the aim being to specifically investigate at times when ships were being unloaded.
For these reasons, this set of standards has only been used as an indication.
The SEQ defines 5 grades of water quality (from blue to red).
All the results obtained are shown (see attached presentation)
The general conclusions of this study are as follows:
- increased concentrations on the quayside, next to the ship being unloaded, were observed that were relatively low and almost never led to a change in SEQ grade,
- the impact noted was very localised and not permanent
- the impact is linked to diffused waste and redirected products during cleaning or rainy periods, hence the importance of maintaining the quayside in a clean condition,
- no notable effect on the overall quality of the river.
Even though the impact is limited, the CCI of Bayonne, the Basque Country has undertaken actions in order to reduce this impact even further.
Actions already carried out:
- work carried out on crane buckets in order to reduce airborne loss of products by making the buckets as airtight as possible, knowing that the products do not all have the same physical characteristics (more or less powdery),
- installing ferrules on a hopper allowing the air current to be turned around and so carry the dust towards the hopper (results have not been completely satisfactory),
- setting up rain water and washing water treatment equipment on the handstanding areas (sediment traps linked to hydrocarbon separators); however, the quay includes vents for the evacuation of air at high tides, so this equipment can not be set up on the edge of the quay,
- sweeping equipment was tested in 2007 in order to ensure the cleanliness of the quays: these trials did not give any satisfactory solutions. Cleaning is quite easy in dry weather when the product involved is dry, but on the other hand when it is raining and the product is damp, sweeping is more complicated and clogging problems arise.
- work was started, in partnership with the stevedores, to organise quay sweeping and cleaning. Once the quay has been swept, washing with water from the River Adour remains the only effective way to date to ensure that the quays are thoroughly cleaned. This cleaning is indispensible in order to ensure the safety of the people moving around and working in these areas.
Actions scheduled to be carried out:
- project shared by the industries and the CCI to create an unloading zone using conveyor belts in enclosed compounds: therefore the product is transported from the ship on the belts and from the belts to the warehouses without using lorries. Airborne loss of the products will therefore be greatly reduced.
- Purchase underway of a crane equipped with a dust-retainer hopper.
Even though the impact on the River Adour is not considerable, work is being continued in order to provide even more improvements.