CA-Sept17-Doc.7.8a
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74th CA meeting – item 7.8a: PT 21 - Analysis of EU freshwater marina scenarios and proposals for a PEC calculation tool
- Development of freshwater marina scenarios
To date, no EU harmonised scenarios for the environmental risk assessment of antifouling products exist. This caveat was recognised by the BPCs ad hoc WG on environmental exposure (AHEE). Further to the work on saltwater marinas (see Annex 1, for further information on saltwater marinas), a work plan for the development of harmonised freshwater marina scenarios was proposed at WG-II-2017 by RIVM[1] and the NL CA. The aim was to collect EU based freshwater marina data, develop an Excel calculation tool for freshwater, including cross-validation of the modelled data and PNECs, to be finalised at July 15, 2017.
This plan built on the experience gained during the development of the saltwater marina scenarios. Six MS showed an active interest in the development of harmonised freshwater scenarios (FR, UK, AD, DE, CH and NL). Data on freshwater marina characteristics for different EU MS had not yet been collected and were submitted by participants.The type of data include parameters like marina dimensions, number of berths, water characteristics and flow rate of the water body adjacent to the marina.
An analysis of these data was performed following a procedure comparable to that performed for saltwater pleasure craft marinas. Results were shared with the members of the dedicated PT21 freshwater group, consisting of WG ENV experts from the MS that had agreed to participate, and presented at WG-III-2017.After discussing the freshwater marina analysis the WG concluded that a comparable PEC calculation tool for freshwater should be developed based on these data. NL (RIVM) developed this tool, which was finalised by mid-July.The Excel tool for freshwater marinas provides the 90th percentile of calculated PEC values both inside and outside the marina in water as well as sediment. This structure of the tool as well as the output is kept fully in line with the Excel calculator tools for saltwater marinas.
After final agreement by the WG ENV the final Excel tools for both saltwater and freshwater will be made available via ECHAs website.
Does the CA meeting consider that the agreements made at the 70thCA meeting for the saltwater models apply to the freshwater models as well? I.e.
1) the risk assessment should be based on concentrations inside the freshwater marina and
2) the 90th percentile of the distribution of PECs is to be used as a realistic worst case scenario.
- Underwater area of pleasure craft
In parallel with the development of the freshwater marina scenarios, a revision of the default value for the underwater area of pleasure craft was undertaken by NL (RIVM). The underwater surface or 'wetted surface area' (WSA) is the area of the boat treated with antifouling paint. It is proportional to the predicted environmental concentration. A well underpinned default value is therefore relevant for the risk assessment. A draft report on the calculation methodology and a new default WSA value for pleasure craft were discussed at WG III ENV 2017. A revised version of the proposal for a new default value is currently circulating in a written commenting procedure among WG experts. Different default values for saltwater and freshwater craft have now been proposed. Would a revised default value be accepted, this can be easily incorporated in the Excel calculator tools discussed in the two previous sections.
- Commercial shipping on freshwater
NL have enquired WG ENV experts on their interest to develop exposure models for PT21 products applied to commercial ships sailing on freshwater. There is limited interest by other MS for such scenarios. Scenario development is currently put on hold.
Annex 1: Summary of scenario development saltwater marinas
The BPC ad hoc Working Group on Environmental Exposure (AHEE) highlighted the lack of EU harmonised exposure scenarios for the environmental risk assessment of PT21 products on pleasure craft. Realising this would hamper the mutual recognition procedures, it prompted the development of exposure scenarios for saltwater marinas, led by the UK CA.
The scenario development built on an existing data collection of saltwater marina characteristics which had been discussed and endorsed at TM III 2013. The model used for the estimation of emissions of antifouling active substances from pleasure craft at berth in marinas is called MAMPEC[2]. Predicted environmental concentrations (PEC) for a series of marinas are calculated. This provides a distribution of PECs from which a percentile is drawn, which gives the final PEC to be used in the risk assessment. The analysis showed that the calculation of a percentile from series of PECs provides a workable alternative to defining one 'standardised marina', e.g. the agreed marina in the Emission Scenario Document (OECD). The drawback of the latter option is that it provides variable results; one (modelled) marina will not provide a realistic worst case PEC for different active substances.
The end result of the scenario development is an 'easy to use' Excel calculation tool. Active substance properties as well as PNECs, agreed at EU substance approval level are already integrated in the tool. Only few additional product specific parameters need to be entered by applicants or eCA experts in order to obtain the result needed for the risk assessment.
The saltwater marina tools and accompanying PT21 product authorisation guidance were presented to the CA meeting (nr. 70) by UK in February 2017. The CA meeting was informed on the technical background and development of the tools and responded to questions asked by the WG ENV, related to the PEC calculation. The 70th CA meeting agreed to 1) base the risk assessment for pleasure craft on concentrations (PEC) inside the marinas and 2) to use the 90th percentile of PEC values be as realistic worst case scenario in the development of the new guidance document.
[1]National Institute for Public Health and the Environment (RIVM), the Netherlands.
[2]Deltares. 2016. MAMPEC. Marine antifoulant model to predict environmental concentrations (computer program). Version 3.1. Delft, The Netherlands, Deltares.