Organophosphate esters (OPEs) in the marine environment - Review
Major sources and pathways of OPEs in coastal and open oceans
The primary continental sources of organophosphate esters (OPEs) include industry, wastewater treatment plants, electronic waste recycling plants and ambient emissions. Major environmental pathways for OPE dispersal include atmospheric and oceanic transport, air–water exchange, atmospheric dry and wet deposition, sedimentation, bioaccumulation and microbial interactions. OPEs can be transported from continental sources to the open ocean and undergo biogeochemical cycling in various environmental compartments. UV, ultraviolet (Xie et al, 2022, Nat Rev Earth Environ (2022). https://doi.org/10.1038/s43017-022-00277-w)
OPEs have been applied on a large scale as flame retardants, plasticizers and additives in industrial production, household consumer products and personal care products. OPEs can be released into the ambient environment during the production, application and disposal of OPE-related materials. As most OPEs have relatively high solubility in water and are difficult to remove by sewage sludge, they can enter the marine environment through riverine discharge. In additonal, OPEs can emit to the air from OPE-containing materials and households, especially from electric waste treatment. Long-range transport with air and ocean current are responsible for the regional and global distribution of OPEs from industrialized region to open oceans.
The air-seawater diffusive exchange of OPEs in the remote oceans interferes with the long-range environmental transport of OPEs. Atmospheric wet and dry depositions are also important input sources for OPEs in water column. Particularly, snow and rain act as effective scavengers for atmospheric OPEs in high latitude oceans. Besides, the degradation of OPEs under nutrient-limited conditions suggests that these can be a source of new P to the ocean, which requires comprehensive characterization. Remission of OPEs from the cryosphere may alter the concentrations at high latitudes.
Given the pressure of increasing human activities and climate change, future research needs to elucidate the various biogeochemical and geophysical processes of OPEs in the marine environment.
Xie, Z., Wang, P., Wang, X., Castro-Jiménez, J., Kallenborn, R., Liao, C., Mi, W., Lohmann, R., Vila-Costa, M., Dachs, J. (2022): Organophosphate ester pollution in the oceans. Nature Reviews Earth & Environment (2022), doi: 10.1038/s43017-022-00277-w
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Key Points from Xie et al., 2022, Nature Reviews Earth & Environment
- Concentrations of OPEs Higher concentrations of organophosphate esters (OPEs) occur in coastal seas near populated and industrial areas than in the open ocean.
- OPEs and transport to the ocean OPEs are transported to the ocean from terrestrial sources via both atmospheric transport and riverine discharge. Air–water exchange and atmospheric deposition affect the cycling of OPEs.
- Re-emission from melting snow and climate change Re-emission from melting snow and ice in polar regions can impact OPE levels in the High Arctic and the Southern Ocean water columns.
- OPEs and their transformation products OPEs and their transformation products are emerging concerns for marine ecosystems, especially related to their presence in marine mammals and fish.
- Need for international regulation International strategies are needed to manage their environmental emissions.