The uncontrolled release of waste from maritime transportation into the sea may trigger mucilage by increasing the heavy metal and plankton load in the Marmara Sea, a maritime professor from Bursa Technical University warned Friday.
Professor Sinan Uyanık, dean of Bursa Technical University's (BTU) Maritime Faculty, told Anadolu Agency (AA) that research on the effect of maritime transport pollution on mucilage formation undertaken by his department in coordination with the Faculty of Engineering and Natural Sciences began two years ago.
Within the scope of the research, which was supported by the Scientific and Technological Research Council of Türkiye (TÜBİTAK) – 1001 Mucilage Research Special Call, samples taken from the ballast tanks of the ships were examined.
Uyanık revealed that mucilage considered a threat to the marine ecosystem is caused due to a combination of multiple external factors involving various microorganisms, with intense maritime trade being one of them.
He also noted that within the scope of the research, the most used routes in line with the ship traffic information of the Marmara Sea in 2020 were determined by taking the samples from both ballast water of the tankers operating in these areas and from the water discharged by the ships to the port wastewater treatment plant.
It was also found that the 10 countries that sent and received the most cargo from these ships to Türkiye were Russia, Greece, Ukraine, Romania, Italy, Egypt, Bulgaria, France, Israel and Spain.
"In our analysis of ballast water samples, we examined various pollutants including pH, conductivity, biochemical oxygen demand, total organic carbon, nitrogen, phosphorus, and heavy metals such as iron, manganese, and chromium," Uyanık explained.
"Additionally, we conducted a microbiological analysis to identify bacteria and plankton species present in the water. This involved studying plankton under a light microscope, analyzing the genetic composition of organisms and investigating their potential impact on mucilage formation," he added.
According to their findings, it was revealed that the ballast water of ships contains heavy metal concentrations ranging from 300 to 500 ppm which is significantly higher than the normal levels of 3-5 ppm found in domestic wastewater, Uyanık noted.
Adding that heavy metals and phytoplankton in ballast tanks, particularly in older ships, can lead to stress and contribute to the mucilage issue he said that the levels of phytoplankton detected in treated ballast water were 50 to 100 times higher than expected.
While the discharge of untreated terrestrial, domestic and industrial wastewater into the Marmara Sea is a major contributor to mucilage, maritime transport also plays a role, the professor reiterated highlighting that it's important to note that maritime trade alone is not the sole cause of mucilage, but it contributes as an additional factor.
"Furthermore, we found that the plankton species responsible for mucilage originate from different countries, which should not be the case," he noted.
To mitigate these issues, it is crucial for ships to implement ballast treatment systems and avoid uncontrolled discharge of ballast water in Turkish inland waters. These systems can prevent the transport of invasive species and plankton associated with mucilage formation, Uyanık suggested.
Mentioning that the International Maritime Organization (IMO) introduced regulations requiring the treatment of ballast water on ships to prevent the transport of invasive and alien species to different countries with the Marpol Convention signed by the countries engaged in maritime trade, Uyanık urged the strict implementation of ballast water treatment regulations to prevent pollution in the Marmara Sea.
