Shipbreaking yards are under-explored hotspots for pollution, finds Turkish study

POPs are organic chemicals (chemicals containing carbon bonded to hydrogen, including pesticides and by-products of industrial activity) that endure in the environment, polluting ecosystems and threatening both human and environmental health. They can accumulate within organisms and be transported by land, air, or sea, widening their area of possible impact and influence. In 1995, the United Nations Environment Programme called for global action on these toxic chemicals – action that came first as part of the Aarhus Protocol (in effect since 1998) and secondly via the Stockholm Convention (2004), both of which restrict how POPs are produced, used, managed, and disposed of.

Certain POPs – such as polychlorinated biphenyls (PCBs) and polybrominated diphenyl ethers (PBDEs) – have been granted temporary exemptions that allow their use in industrial components (e.g. transformers, capacitors and vehicle parts). As a result, these POPs often still find their way into the environment. Additionally, once a POP is banned from use, any existing POP chemicals and materials containing the POP then join an ever-growing volume of waste that must be carefully managed to prevent their release into the environment. For instance, the amount of PCB-contaminated materials and wastes has been estimated at 17 million tonnes globally. 

A new study explores how recovering steel from ship parts (such as engines, deck cranes, pumps and switchboards) in shipbreaking can contribute to environmental contamination with POPs. While considered more sustainable than using virgin iron and steel, shipbreaking involves the cutting and removal of components potentially loaded with toxic compounds such as flame retardants – for example cables, rubber seals, vinyl and painted boards. A previous study suggested the average ship may contain around 250 kg of PCBs.

The study focuses on a 30-kilometre stretch of coastline in Aliağa, western Turkey, that not only hosts some of the world’s largest shipbreaking yards but also experiences heavy ship traffic and land-based petroleum, petrochemical, iron-steel, and power plant operations (which may unintentionally produce additional POPs). Previous studies have found POP contamination in sediments collected in the region, but no up-to-date study has been conducted to indicate current levels of contamination, notes the researcher. They therefore searched for 46 types of PCB and 23 PBDEs in surface sediments in the Aliağa area in May 2023. These chemicals – including halogens typically used as insulators, plasticisers or flame retardants – are classified as probable carcinogens, posing a risk to human and environmental health.

Samples revealed that coastal sediments contained significant concentrations of PCBs and PBDEs, of up to 4,750 and 5,053 nanograms per gram of sediment (ng/g), respectively. This is the first time PBDEs have been identified in sediments at shipbreaking yards, says the researcher, and in most sediment samples, concentrations of both types of chemical exceeded guidelines (drawn from the Canadian Environmental Protection Act, 1999). Ecological risk evaluation (based on EU Technical Guidance), showed that levels of some chemicals posed moderate to high risks to benthic ecosystems (those dwelling on or near the ocean floor).

Sediments from Nemrut Bay, which sees more abundant land-based industrial activity, had higher concentrations than those from Aliağa bay. Shipbreaking yard sediments had the highest concentrations, and sediments close to beaches the lowest. Higher-chlorinated PCBs were associated with shipbreaking, and lower-chlorinated PCBs and PBDEs with land-based industrial emissions and urban runoff. 

The researcher contrasted these findings with previous research on PCBs in sediments in the same area. Compared to studies carried out a decade ago, the concentrations of six indicator PCBs had risen (from 125–669 ng/g to 152–1.591 ng/g), reflecting an increase in shipbreaking activity in the area and a rise in associated waste management operations. Earlier studies (2009) identified 48 PCBs; while the precise compounds varied, concentrations (2.7–2,450 ng/g) were around half of those observed in the current study. 

The spatial distribution of PCBs also appears to have shifted notably in the last 15 years. While POP concentrations in Nemrut Bay sediments were previously comparable to those found in shipbreaking yard sediments, the latter now far exceeds the former, highlighting shipbreaking as a leading cause of POP pollution in the region – and emphasising the importance of ongoing monitoring to assess any environmental contamination.

The study identifies shipbreaking as an under-explored hotspot for POP contamination, and one that should be carefully monitored to mitigate and prevent environmental harm. Ship materials should be kept contained during dismantling, and contaminated material should be more carefully disposed of, suggests the researcher. To mitigate ecological risks and protect marine ecosystems, the author calls for urgently improved waste management practices for POP-containing materials; more robust remediation strategies for polluted sediments; strictly enforced cross-country environmental regulation; and immediate intervention via systematic monitoring and best management practices.

Reference: 

Demirtepe, H. (2025) Surface sediments as a sink and risk source for legacy POPs during waste management practices. Environmental Pollution, 373 (2025) 126128. https://doi.org/10.1016/j.envpol.2025.126128