This pre-core test indicator and its threshold values are yet to be commonly agreed in HELCOM and the presented thresholds are furthermore not currently approved EQS values, but provisional proposals. The indictor is included as a test indicator for the purposes of the 'State of the Baltic Sea' report, and the results are to be considered as intermediate.
The EU Environmental Quality Standards for diclofenac is proposed as the threshold level for this indicator (see note below). An annual average Environmental Quality Standard (AA-EQS) in marine waters of 0.005 µg/l (5 ng/L) is proposed. A concentration of diclofenac in biota being below 1 µg kg-1 w.w., based on a value protective for avian predators (secondary poisoning), and of 0.007 µg/l (7 ng/L) for marine and freshwaters predators (secondary poisoning) is proposed (Thresholds figure 1).
Thresholds figure 1. Good status is achieved if the concentrations of diclofenac are below the defined threshold values.
The threshold values are in line with the scientific PNEC or NOEC values implying that no harmful effects can be found. However, as the issue is of an emerging nature, it is proposed that the threshold value would initially be evaluated as a trend (where data is suitable and accredited) so that no increase in diclofenac concentration from the current status would be allowed. This is in-line with the EU directive on environmental quality standards (2008/105/EC), Article 3, which states that long-term temporal trends should be assessed for substances that accumulate in sediment and/or biota.
Note: Environmental Quality Standards and thresholds proposed in this indicator document are taken from a draft ´EQS DATASHEET Environmental Quality Standard Dicolofenac´ document, a document that represents an EU/wide study (see Dossier Diclofenac reference). This document contains provisional proposals for EQS values. Since diclofenac has been suggested to be removed from the EU watch list, on the basis that enough data has been collected to determine if it is to be added to the priority list (or not), the thresholds used in this indicator are based simply on the most recent proposals made during the ongoing revision process. The process to determine the EQS thresholds and the position of diclofenac related to monitoring requirements remain to be finalised within the EU and until that has been clarified the most recent EQS proposals are maintained for the test thresholds applied in this indicator.