Chemicals in the marine environment
Large quantities of various man-made chemicals from industrial production are released into the marine environment through human activities via rivers, the atmosphere and direct discharges. Most pollutants are organic compounds, but metals and metal compounds also occur. Once they reach the marine environment, they can cause different types of damage to the ecosystem. Many thousands of environmental pollutants occur in the North Sea and Baltic Sea. Some substances are clearly visible, for example in the form of oil spills. About 2,000 compounds are considered environmentally relevant (pollutants) because they are toxic or due to their slow degradation persistent in the environment. At the same time, many of these pollutants accumulate in the aquatic food web (bioaccumulation), which can increase their effect. Between 100 and 300 of these compounds are currently included in lists of priority substances (EU, EPA, OSPAR, HELCOM).
Monitoring by the BSH
At present, the BSH routinely monitors around 100 organic pollutants and 17 metals that are of particular importance due to their environmental relevance or are regarded as lead substances for entire classes of pollutants. The substances include representatives of the groups petroleum hydrocarbons, polycyclic aromatic hydrocarbons (PAHs, such as benzo(a)pyrene) and chlorinated hydrocarbons (such as lindane, DDT, PCBs), poly- and perfluorinated substances (PFCs, such as PFOS) and heavy metals. The individual pollutants are distributed unevenly in the sea and occur in very different concentrations. In addition to the characteristic chemical properties, there are large differences in the input quantities, the sources of the pollutants (shipping, industry, household, agriculture) and the input paths (direct or diffuse, rivers or atmosphere). Many of the substances occur in very low concentrations, which are only detectable by ultratrace analysis. This places significantly higher demands on sample treatment and measurement.
Routine monitoring on research vessels takes place in the German Bight up to four times a year. The data collected are transferred to the Marine Environment Database (MuDAB), which makes them accessible for use by third parties. In addition, a targeted screening for priority substances (suspected target screening) is carried out as part of special investigations, enabling new environmental hazards to be identified relatively quickly. The BSH also conducts special investigations in the event of accidents (Sandoz accident, Apron Plus) or other events (Elbe flood, 2013) in order to inform the public about current issues.
Maritime oil forensics
One of the BSH's areas of expertise is oil forensics for the identification of polluters. In international cooperation, methods have been developed at BSH to identify oil and petroleum products ("oil fingerprinting"). The aim of these analyses is to be able to assign contamination samples to potential polluters in a court of law by proving that the analytical fingerprint matches ("match"). The web-based oil sample database COSIweb (COSI - Computerized Oil Spill Identification) developed at BSH allows the comparison of oil fingerprints with over 2,500 stored oil samples from all over the world.