Fish in the Black Sea are contaminated with heavy metals (Hg), pesticides and other toxic substances - these are the findings of studies done in 2015 and 2016 under Descriptor 9 (Contaminants in fish and other seafood) of the MSFD (IO-BAS Monitoring Program). They show an exceedance of the concentrations in 2016 in mullet and Black Sea mackerel compared to the maximum permitted concentrations.
This has a negative impact on the health of fish, their reproduction and the general condition of the populations. Contamination of fish also leads to risks to human health when consumed.
The document describes contaminants found in fish of the species Mullus barbatus ponticus and Trachurus mediterraneus ponticus. Here are some of the main substances that have been discovered:
Toxic Substances:
PBDE (Polybrominated Diphenyl Ethers): These are flame retardants that are toxic and can cause various health issues in humans, including hormonal disruptions and nervous system problems.
Hexabromocyclododecane (HBCD): Another toxic substance used as a flame retardant, which can adversely affect the reproductive and endocrine systems.
Mercury (Hg): A heavy metal that is highly toxic, especially in its organic form (methylmercury). It can cause severe damage to the nervous system and kidneys.
Pesticides:
Heptachlor and Its Epoxides (Heptachlor Epoxide-cis and Heptachlor Epoxide-trans): These are chlorinated hydrocarbons used as pesticides, known for their persistence in the environment and toxicity, which can lead to carcinogenic effects and liver damage.
Perfluorooctanoic Acid (PFOA) and Perfluorooctane Sulfonate (PFOS): Although not pesticides in the traditional sense, these perfluorinated compounds are used in industry and can also have toxic effects on the liver and endocrine system.
These substances pose serious risks to both health and the environment, highlighting the critical importance of understanding this pollution.
Sources of Pollution:
PBDE (Polybrominated Diphenyl Ethers)-PBDEs are commonly used as flame retardants in products such as electronics, furniture, textiles, and plastics. They can enter the environment through:
Waste Disposal: Improper handling of waste from electronic devices and furniture can cause PBDEs to leak into soil and water.
Industrial Emissions: Manufacturing processes or the burning of products containing PBDEs can release these substances into the air, which then settle into water bodies.
Hexabromocyclododecane (HBCD)
HBCD is also used as a flame retardant, mainly in insulation materials and building products. During building demolition or improper disposal of construction materials containing HBCD, this substance can enter the environment. Production and processing of HBCD-containing products can release this chemical into air and water.
Mercury (Hg)
Mercury is a heavy metal that can enter the environment from various sources.
Coal Combustion: Burning coal for energy production is a primary source of atmospheric mercury. This mercury can settle into water bodies, where it transforms into methylmercury, the toxic form that accumulates in fish.
Mining Activities: Mining often involves the use of mercury, which can spread into the environment.
Heptachlor and Heptachlor Epoxides
Heptachlor was used as a pesticide for controlling insects and rodents. In the past, it was widely used in agriculture to treat soils and crops, and residues from these applications can persist in the environment for a long time. Heptachlor was also used to treat wood against termites, leading to localized soil contamination that can affect groundwater.
Perfluorooctanoic Acid (PFOA) and Perfluorooctane Sulfonate (PFOS)
These perfluorinated compounds are used in numerous industrial and consumer products due to their water- and grease-resistant properties. Manufacturing products like Teflon-coated cookware, water-repellent textiles, fire-fighting foams, and others can lead to contamination of water bodies with PFOA and PFOS. Improper disposal of products containing these chemicals or poor industrial waste management can contribute to pollution.
Polycyclic Aromatic Hydrocarbons (Fluoranthene, Benzo(b)fluoranthene, Benzo(k)fluoranthene)
Polycyclic aromatic hydrocarbons (PAHs) are toxic compounds formed by the incomplete combustion of organic materials like coal, oil, wood, and tobacco. Emissions from engines, industrial processes, home heating with wood or coal, and activities related to oil refining and coal processing are sources of this pollution.
All of these pollutants (and this is not an exhaustive list—there are others that have not been evaluated) accumulate in marine ecosystems and can build up in fish, which then end up on our plates.
Summary of the Assessment for the Second Evaluation Period 2012–2017 According to Research Under Bulgaria’s New Marine Strategy Project:
Descriptor 1 Biodiversity (Marine Mammals): Status is "Poor."
Descriptor 1 Biodiversity - Fish Species Not Targeted by Commercial Fishing: Status is "Poor."
Descriptor 1 Biodiversity – Benthic Habitats and Descriptor 6 – Sea Floor Integrity: Status is "Poor/Unknown."
Descriptor 1 Biodiversity - Pelagic Habitats (Phytoplankton and Zooplankton Communities): Status is "Poor/Unknown."
Descriptor 2 Non-native Species: Status for the second evaluation period 2012–2017 is "Unknown."
Descriptor 3 Exploitation of Fish and Shellfish Species Targeted by Commercial Fishing: Status is "Poor."
Descriptor 4 Food Webs: Status is "Unknown."
Descriptor 5 Eutrophication: Status is "Poor."
Descriptor 7 Hydrographic Changes: Status is "Poor."
Descriptor 8 Contaminants in the Marine Environment: Status is "Poor."
Descriptor 9 Contaminants in Fish and Other Marine Food: Status is "Poor."
Descriptor 10 Marine Litter: Status is "Unknown."
Descriptor 11 Underwater Noise and Energy: Status is "Unknown."
These findings indicate that no species are in good condition. Pollution of fish in the Black Sea with heavy metals, pesticides, and other toxic substances poses a serious threat to the marine ecosystem and human health. Studies clearly show that the allowable concentrations of hazardous substances in fish have been exceeded, leading to reduced reproductive capacity, general population decline, and species disappearance. These pollutants, which include PBDEs, mercury, heptachlor, and other harmful chemicals, not only harm ecosystems but also pose a serious risk to people who consume contaminated fish, especially children and those with chronic illnesses.
Conclusion:
The monitoring of the Black Sea underscores the urgent need for immediate measures to improve the sea’s ecological state. To protect marine ecosystems and human health, it is crucial to take prompt and coordinated actions to reduce pollution. The Black Sea is almost a closed water body, which significantly hinders its natural purification and makes pollution especially critical. Additionally, the Danube River, which flows through numerous European countries, brings in significant pollutants from industry and agriculture, exacerbating the environmental situation in the sea.
A Shared Responsibility
Government institutions, industries, and society must work together to enforce stricter regulations, improve waste management, and adopt eco-friendly practices. We urge everyone to support efforts to reduce the release of toxic chemicals into the environment. With our combined efforts, we can protect biodiversity and ensure a healthier future for generations to come.
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