The pressures from some contaminants are increasing in several places, as seen in the upward time trends. Elsewhere, the decreases from previous quality assessments have slowed or stopped.
Input of other substances (e.g., synthetic substances, non-synthetic substances, radionuclides) - diffuse sources, point sources, atmospheric deposition, acute events:
Human activities can introduce a range of hazardous substances (Figure P.1). Radionuclides are assessed in the Radioactive Substances thematic assessment . The pressures associated with synthetic substances and non-synthetic substances relate to increasing levels of contaminants in sediment (PBDE, PAH, PCB, metals, organotins, etc.) and in biota (PBDE, PAH, PCB, metals, organotins, PFAS, etc.). An overview of uses and sources leading to the pressure for each hazardous substance covered is shown in Table P.1.
Figure P.1: Mercury loads to the Greater North Sea
The OSPAR ‘other assessment’ of atmospheric and riverine inputs describes the pathways by which these hazardous substances enter the marine environment. The Offshore Industry Committee thematic assessment and Human Activities thematic assessment provide further details on the mechanisms by which human activities contribute to hazardous substance pressures. These hazardous substances can lead to changes in biodiversity state through effects on mortality, reduced breeding success and species fitness, see:
Generally, there has been no development or improvement over the last 10 years in most OSPAR Regions, indicating that the pressures are stable for hazardous substances in sediment and biota. For some individual hazardous substances, the trends are still edging downwards, but at a very low rate per year, sometimes because of concentration levels close to the detection limits, but for other substances increasing trends are found, contrary to the overall status of Regions.
| PBDE | Historically used as flame retardant, mainly in electronics, clothing and furniture. PBDEs are man-made substances manufactured as groups of PBDEs with different properties. |
|---|---|
| PAH | Combustion products from fossil fuels. Also associated with shipping fuel leaks/spills as well as produced water discharged from oil and gas platforms and applications of coal tar and creosote. Naturally occurring in tar-pits and geological formations. |
| PCB | Wide variety of uses, historically mainly as insulator oil in transformers, but also including electrical switch gears and plasticisers. |
| Tributyltin and other organotins | Historic main use as antifoulant on boat/ship hulls – cause imposex; other uses include antifungals in farming and clothing. Man-made substances not naturally occurring. |
| Arsenic | Alloy to strengthen copper and lead, e.g., in car batteries and in electronics as doping material in integrated circuit and transistors. Used in pesticides, insecticides, and pharmaceuticals. |
| Cadmium | Historically used in rechargeable batteries, anticorrosion, currently mainly as minor constituents of other metal ores like zinc and iron. |
| Chromium | Corrosion-resistant finish on iron, different alloys for high strength steel. |
| Copper | Used as antifoulant on boat / ship hulls and sea farm pens – still in use. Gutter and roof material, water pipes, different alloys including bronze, mined since the Bronze Age, and brass. |
| Mercury | Historically used in dental products, thermometers, batteries, paper industries as floating anode. Currently mainly used in artisanal mining and released from coal burning. |
| Nickel | Part of alloy often used for jewellery, zippers and other clothes and footwear related metal parts. Also in non-corroding steel, magnets, coins and electronics. |
| Lead | Historically one of the first metals used for water tubing. From 1922 to 2022 main uses include methyllead-fuel additive, roofing, electrical wiring, fishing gear, ammunition, plastic additive. |
| Zinc | Building material for e.g., gutters, roofing, sacrificial anodes on ships and marine structures, household products, personal care products and alloys such as brass. |
| PFAS | A large group of substances used as flame retardants in firefighter foams, non-stick coating on cookware, waterproofing for shoes, and for various other purposes including on clothing |
Given the restrictions on the use of a wide range of chemicals, the expectation was that most areas would be found to have a decreasing impact (good status) (Table P.2). However, only for the Irish Sea and Iberian Coast sub-regions in Regions III and IV is a decreasing impact on sediments indicated, and for the Irish Sea also biota, whereas for Region II, the Southern North Sea biota impact is increasing; for sediments, decreasing levels have been observed for both the Southern North Sea and the English Channel. This could indicate an increase in the bioavailability of contaminants and reduced sedimentation or the re-release from sediment of buried contaminants.
Table P.2: Status of Regions based on OHAT model and confidence for the number of stations/time trends for each Region; this is a fair estimate of the confidence for each assessment.
| OSPAR Region | Arctic Waters | Greater North Sea | Celtic Seas | Bay of Biscay and Iberian Coast | Wider Atlantic |
Status | Stable | Poor/Stable | Stable | Stable medium
| Not enough data |
| Confidence | Medium | High | High | Medium | |
| Basis | High agreement, medium evidence) | Southern part more densely populated Poor, northern part with fewer inhabitants stable Medium agreement, robust evidence | Medium agreement, robust evidence | Medium agreement, medium evidence |
The pressures from Physical disturbance to seabed and Changes to hydrological conditions both have the potential to (re)mobilise hazardous substances adsorbed to sediments, making them available to affect biota. These hazardous substances are associated with historic pollution events.
| Activities | State |