Eutrophication Crisis in the Black Sea: World Bank Urges Unified Regional Action

Research by the World Bank and a consortium of research partners, including Ambinete S.P.A., Society and Environment (Ukraine), Oikumena (Moldova), and LAMA (Italy), reveals the serious harm being done to the marine ecosystem. This regional diagnostic is the first output of the BBSEA (Blueing the Black Sea) initiative and provides a critical framework for pollution control in a sea that serves over 160 million people across Bulgaria, Romania, Türkiye, Ukraine, Georgia, and Moldova. Drawing from country-level marine pollution reports and extensive legal and economic analyses, the document sounds the alarm over escalating nutrient loads, crumbling ecosystems, and the failure of fragmented governance systems to stem the tide of pollution.

Rivers, Runoff, and the Reign of Eutrophication

At the core of the crisis is eutrophication, the excessive enrichment of marine waters with nutrients, notably nitrogen (N) and phosphorus (P), largely from agriculture and poorly treated urban waste. These nutrients fuel rampant algae blooms that strip oxygen from the water and upend entire ecosystems. According to the report, rivers carry the bulk of this burden: 80% of nitrogen and 90% of phosphorus enter the Black Sea through riverine systems, with the Danube, Don, and Dnieper being the most significant contributors. Agriculture alone is responsible for 43% of total nitrogen runoff, particularly in countries upstream in the Danube basin and northern Black Sea regions. In contrast, Türkiye, despite having the longest coastline, contributes less agriculturally sourced nutrient pollution per hectare.

Fertilizer usage has spiked across the region. In Bulgaria, phosphorus fertilizer consumption has increased by 137% since 2010. Georgia saw a fivefold increase in fertilizer use between 2010 and 2018, while Ukraine’s inorganic fertilizer use grew 7.6 times from 2000 to 2019. Such figures underscore how modernization in farming, absent strict regulation, has intensified the nutrient imbalance in the Black Sea.

Urban Wastewater and Atmospheric Fallout Add to the Burden

In addition to agriculture, wastewater from urban centers, particularly in Ukraine, Türkiye, and the Russian Federation, contributes significantly to nutrient loads. Although only 2–3% of total nutrients enter the Black Sea through direct municipal wastewater discharges, these have a severe local impact on coastal waters. Ukraine alone accounts for 40% of wastewater-origin nutrient input. In contrast, Romania and Bulgaria show better performance due to EU-compliant treatment infrastructure, but even here, implementation gaps persist. Many smaller coastal towns lack functioning sewage systems altogether, especially in Moldova and Georgia, where sewage often remains untreated due to infrastructure gaps and a lack of enforcement.

Atmospheric deposition also plays a notable role, contributing approximately 214,000 tons of nitrogen and nearly 5,000 tons of phosphorus annually. This comes from industrial emissions, vehicle exhaust, and ammonia from livestock waste, drifting into the sea through rain and wind. Even the Istanbul Strait is a concern, as wastewater discharges from this crucial transit point add more nutrients into an already overwhelmed system.

Economic Fallout: Fisheries Collapse, Tourism Decline, and Public Health Risks

The Black Sea’s environmental decline is no longer just an ecological issue; it’s an economic emergency. Ukraine estimated a $500 million annual loss in fisheries and tourism due to eutrophication alone. In Türkiye, the Black Sea accounts for up to 90% of the national fishery output, making the stakes particularly high. In Bulgaria and Romania, overfishing combined with pollution has decimated fish biodiversity, from 26 commercially valuable species down to just six over the last 30 years.

The tourism sector also suffers. Coastal areas that once attracted international visitors now struggle with degraded beaches, algal blooms, and reduced water quality. In Georgia and Moldova, limited sewage treatment reduces tourism potential. Moreover, public health risks are growing. Heavy metals, PCBs, and pathogens in marine food chains threaten populations dependent on seafood. Studies in Türkiye and Bulgaria have confirmed trace levels of arsenic, mercury, and lead in fish and mussels, although most remained within permissible limits. Still, the accumulation of toxins in sediments and biota raises red flags for future health risks.

A Blueprint for Regional Cooperation and Reform

Despite numerous international treaties and environmental agreements, the report finds that legal and policy enforcement remains fragmented and weak. Bulgaria and Romania have fully transposed EU directives like the Marine Strategy Framework Directive (MSFD) and the Water Framework Directive (WFD), but their implementation is often delayed or under-resourced. Moldova and Georgia have passed significant legislation, Moldova’s Water Law and Georgia’s 2023 Water Resources Act being notable, but both countries face long roads ahead in enacting secondary regulations and building institutional capacity.

To tackle these systemic shortcomings, the report recommends six priority reforms: closing regulatory and legal gaps, investing in pollution monitoring, controlling agricultural runoff through good practices and fiscal incentives, tightening industrial discharge regulations, upgrading wastewater treatment systems, and strengthening oversight of shipping and port operations. Implementing these reforms would not only curb pollution but also unlock economic value in marine tourism, fisheries, and agriculture through a more resilient and sustainable blue economy.

The Black Sea is facing a classic "tragedy of the commons," where collective inaction threatens shared natural capital. But the path forward is clear. With coordinated policy reforms, targeted investments, and strengthened regional cooperation, the Black Sea nations still have a chance to reclaim a cleaner, healthier, and more prosperous marine future. The challenge now is not one of knowledge or tools, but of political will and shared ambition. The BBSEA report offers a roadmap. Whether it is followed remains to be seen.