CAPE TOWN, March 24 (Xinhua) -- Human-made chemicals have become a pervasive component of the world's oceans, embedded within marine dissolved organic matter (DOM) on a global scale, according to a new study.
Led by Jarmo-Charles Kalinski of South Africa's Rhodes University and Daniel Petras of the University of California, Riverside, the study highlights the extent of industrial pollution in marine ecosystems.
According to a statement by Rhodes University, the findings stem from a major international collaboration involving 30 researchers from 19 institutions worldwide and were published in Nature Geoscience on March 16.
The study represents the largest meta-analysis of marine non-targeted mass spectrometry data to date, analyzing 2,315 seawater samples from the Pacific, Atlantic and Indian Oceans. By utilizing high-resolution mass spectrometry and scalable computational tools, the team mapped the presence of human-made organic chemicals, known as xenobiotics, within the ocean's DOM pool.
Researchers found that while pesticides and pharmaceuticals appear largely concentrated near shorelines, industrial compounds such as plastic additives, lubricants and surfactants dominate the human chemical signal even in the open ocean. In typical coastal environments, human-derived molecules accounted for up to 20 percent of detected signals, while about 1 percent persisted even 20 kilometers offshore.
"We found that industrial chemicals, many of which are rarely monitored, may be far more abundant and widespread than previously recognized," Kalinski said in the statement.
Scientists warned that these chemicals could influence marine microbial processes and the ocean's carbon cycle, although the long-term ecological consequences remain largely unknown.
The detected signal acts as a global "chemical fingerprint," allowing researchers to estimate the proportion of human-made molecules, which are described as the "imprint" of pollution, against the background of natural organic matter in the sea.
The research team utilized the combination of standardized mass spectrometry methods with scalable computational tools, which allowed them to treat thousands of samples from unrelated studies as a single, unified dataset.
"This work was only possible because of the efforts of our collaborators around the globe and open science," Petras said. "By making our data public, we hope to accelerate research and enable a more complete understanding of human chemical impacts on the ocean."
Researchers concluded that long-term, standardized monitoring efforts are essential to track human chemical impacts and better understand the risks posed to marine food webs and ecosystem resilience. ■