In BSAP 2007 the Baltic Sea coastal countries acknowledged that 'there is a need to reduce the nutrient inputs and that the needed reductions shall be fairly shared by all Baltic Sea countries'. Initial estimates of Maximum Allowable Inputs of nutrients to reach the eutrophication targets (clear water) were calculated using the SANBALT model developed by the MARE Research programme in Sweden (Wulff et al 2007). Based on the MAI and agreed allocation principles for dividing the reduction burden between HELCOM countries, nutrient reduction targets were calculated. The reduction targets were derived by comparing MAI for each sub-basin with the average nutrient input during a reference period (1997-2003). Based on those, HELCOM Contracting Parties identified priority actions to reducing nutrient loading to the Baltic Sea.
In the BSAP, the HELCOM Contracting Parties noted that the calculated figures are provisional though based on the best available scientific information at the time, and decided that starting from 2008 all figures related to environmental targets and maximum allowable inputs should be periodically reviewed and revised using a harmonized approach and data.
The documentation for setting BSAP nutrient reduction targets has been compiled into a single document.
In 2010, the HELCOM Moscow Ministerial Meeting agreed to carry out a review of the HELCOM BSAP environmental targets for eutrophication, the maximum allowable inputs and the nutrient reduction targets, as well as the country-wise nutrient reduction targets including updated information on the atmospheric nitrogen deposition by 2012.
Since 2008, work has been on-going to improve the nutrient reduction scheme, including:
the scientific basis for review of the ecological targets for eutrophication of the HELCOM BSAP within the TARGREV project
the Baltic Nest Institute-Sweden (BNI) has further developed its marine models to a new BALTSEM model for calculating the MAI
the HELCOM PLC-5.5 project has compiled an updated and more complete dataset on waterborne and airborne pollution inputs to the Baltic Sea. It covers period of 1994-2010 with input data being normalized to smooth out the influence of weather variation
BNI has developed a new software tool for calculating CART
Allocation principles have been revised.
Furthermore, the HELCOM Expert Group on follow-up of national progress towards reaching BSAP nutrient reduction targets (HELCOM LOAD) has been developing tools for following up on fulfillment by the countries of the nutrient input reduction requirements.
The basis for calculating the revised MAI and updated CART is the best available scientific knowledge. Ecological targets and revised MAI and CART have been developed with the involvement of all the Contracting Parties.
report on the development of revised maximum allowable inputs (MAI) and
updated country allocated reduction targets (CART) of the Baltic Sea
Development of BSAP MAI and CART