Relevance of the Indicator

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.

Hazardous substances assessment

The status of the Baltic Sea marine environment in terms of contamination by hazardous substances is assessed using several core indicators. Each indicator focuses on one important aspect of the complex issue. In addition to providing an indicator-based evaluation of the status of the Baltic Sea in terms of concentrations of diclofenac in the marine environment, this indicator may in the future be suitable for incorporation into the overall hazardous substances assessment, integrated in conjunction with the other hazardous substances core indicators.


Policy relevance

The Moscow Ministerial Declaration 2010 gives HELCOM a clear obligation to 'further assess the environmentally negative impacts of pharmaceuticals and other substances that are not monitored regularly, with the aim as a first step to assess in a coordinated manner their occurrence in the Baltic Sea and evaluate their impacts on the Baltic biota'. The commitment was followed up by the 2013 HELCOM Ministerial Declaration in which the Contracting Parties agreed to collect information on pharmaceuticals and assess the status of contamination of pharmaceuticals and their degradation products in the marine environment.

Diclofenac was included on the EU first watch list (2013/39/EU) with the stated aim being to gather monitoring data for the purpose of facilitating the determination of appropriate measures to address the risk posed by those substances. Inclusion on such watch list is done when there is insufficient data to assess potential negative impacts on the environment, the assertion being based on results from the prioritization process of hazardous substances under the WFD, research results and similar reports. For those HELCOM Contracting Parties that are also EU members the inclusion on the first watch list has required monitoring at selected representative monitoring stations for a 12-month period, a process that started in 2015 and has now been completed. The outcome of the review process based on this data collection will determine future requirements for those HELCOM Contracting Parties that are also EU members.

There are no current restrictions on the use of diclofenac in the Baltic Sea region, though in India for example, its use is being phased out due to the documented detrimental effects on vultures.

Furthermore, the monitoring of diclofenac and the development of the indicator may have direct relevance to policies related to WWTPs and pharmaceutical disposal/take-back initiatives.


Role of diclofenac in the ecosystem

Relevance image.png

Diclofenac is an active pharmaceutical ingredient belonging to a group called nonsteroidal anti-inflammatory drugs (NSAIDs) that works by reducing hormones that cause inflammation and pain in the body. This pharmaceutical is widely used in the Baltic Sea region, in the format of tablets to be ingested, injections and as creams for topical application.

Low removal rates and poor biodegradation have been reported, though reports on both seem to range dependant on specific condition (as reviewed in Vieno and Sillanpää, 2014). Consequently, effluent waters from some WWTPs can contain high concentrations. Introduction to the Baltic Sea is believed to take place primarily via this route, with rivers transferring diclofenac to the Sea. While concentrations have been shown to decrease rapidly in rivers diclofenac has also been detected in water samples far from known sources (HELCOM 2014).

The strongest evidence of the detrimental effects of diclofenac stems from the terrestrial environment. Residues of diclofenac causing kidney failure is considered to be the main cause for a decline of >95 % in the population of oriental white-backed vulture, one of the (previously) most common raptors in India and Pakistan (Oaks et al, 2004, Shultz et al, 2004; Reddy et al, 2006; Swan et al, 2006; Cuthbert et al, 2006, 2007).

In the aquatic environment diclofenac has been shown to bioaccumulate in fish (Brown et al. 2007; Schwaiger et al., 2004; Brozinski et al., 2013), including diclofenac metabolites (Kallio et al., 2010), and mussels (Ericson et al., 2010). Toxic effects have also been recorded, including kidneys disruption (Schwaiger et al., 2004; Triebskorn et al, 2004; Hoeger et al., 2005), damage to eggs and embryos (Hallare et al., 2004), and altered gene expression (Cuklev et al., 2011). In crabs diclofenac has been shown to cause disruption of osmoregulation (Eades & Waring 2010) and in broadcast spawning marine invertebrates it may have consequences for reproductive success (Zanuri et al., 2017). In mussels diclofenac has been shown to have a number of impacts. Early studies indicated that byssus strength (i.e. the ability to attach to substrates) was impaired and that energy was potentially diverted from growth and reproduction, with possible long term population effects (Ericson et al., 2010). More recent studies using biomarkers have shown a range of alterations indicative of: oxidative stress, gill and digestive gland damage, altered protein folding, impaired immunological response, and energy metabolism changes due to diclofenac or pollutant cocktail exposure (Schmidt et al., 2011; Schmidt et al., 2013, Turja et al., 2014; Gonzalez-Rey and Bebianno, 2014; Turja et al., 2015, Mezzelani et al., 2016). It has also been shown that mussels from more pristine environments were more strongly influenced and that recovery time differed (Kumblad et al., 2015) and suggested that this biomarker approach may offer promise as an environmental status indicator component (Löf et al., 2016). Furthermore, in many cases these impacts were observed at environmentally relevant concentrations and is some systems in the environment itself.

While the general consensus is that acute toxicity appears unlikely, there is significant concern that long term exposure, continual discharges (i.e. increasing environmental deposition), and local environmental factors may be key factors and that specific environmental zones or biological categories may be adversely influenced by diclofenac concentrations. Diclofenac has been shown to be susceptible to photo-degradation, though the process appears highly site-specific, and the breakdown compounds from this action may also be compounds of concern (Schmitt-Jansen et al., 2007). Furthermore, there is evidence to suggest that mixtures of several hazardous compounds, as is commonly found in the environment, can have markedly stronger negative impacts (Cleuvers, 2004) and should be considered, particularly in the light of long term exposure, and that climate change alterations to the environment (e.g. ocean acidification) may influence the potency of diclofenac (Munari et al., 2016).


Human pressures linked to the indicator

General MSFD Annex III, Table 2a
Strong link

Substances, litter and energy

- Input of other substances (e.g. synthetic substances, non-synthetic substances, radionuclides) – diffuse sources, point sources, atmospheric deposition, acute events

Weak link