1313 / 2024-09-20 23:59:42

Investigation of plastic related organic chemicals in the marine environment

Air-sea exchange flux,phthalates,Organophosphate flame retardants

Phthalate esters (PAEs) and organophosphate esters (OPEs) are chemicals widely used as plasticizers and flame retardants in a variety of industrial and consumer products. Their extensive use has led to their widespread presence in the environment, where they can persist and accumulate in living organisms. These compounds are concerning due to their toxicity and potential to disrupt endocrine systems, making them a focus of environmental studies.

The document examines the distribution and transport of PAEs and OPEs in the Chinese marginal seas, with a particular emphasis on how air-sea exchanges influence these processes. In the South China Sea, the study found that atmospheric concentrations of OPEs ranged from 66 to 550 picograms per cubic meter (pg/m³), while their concentration in seawater averaged 1180 ± 910 picograms per liter (pg/L). The results of air-sea exchange fluxes revealed both volatilization and deposition of OPEs, depending on the specific compounds involved. Atmospheric particle deposition fluxes ranged from 5 to 71 nanograms per square meter per day (ng/m²/day), and it was estimated that approximately 22 ± 19 tons of OPEs were deposited into the sea via atmospheric deposition annually. At the same time, net fluxes indicated that around 44 ± 33 tons of OPEs were volatilized from seawater into the air annually.

The study also looked at PAEs in the air and seawater of the Bohai and Yellow Seas in spring 2019. Atmospheric concentrations of PAEs in this region ranged from 9.59 to 51.3 nanograms per cubic meter (ng/m³), while concentrations in seawater averaged 466 ± 268 nanograms per liter (ng/L). In summer 2019, the South China Sea saw atmospheric PAE concentrations between 2.84 and 24.3 ng/m³, with seawater concentrations averaging 3.05 ng/L. The study noted that monsoon currents and cyclones significantly impacted the transport and concentration levels of these chemicals.

Additionally, the results showed that the input of PAEs into the environment via atmospheric deposition was substantial, with about 579 ± 222 tons annually. However, PAEs were also volatilizing from the seawater, with a net flux of 1540 ± 1430 tons/year in the Bohai and Yellow Seas. Additionally, sedimentation served as a major sink for PAEs, especially in the Bohai and Yellow Seas. Overall, air-sea exchanges and atmospheric deposition were identified as key processes in the transport of these pollutants.