According to a new Pacific Environment report, the International Maritime Organization (IMO) should immediately ban scrubber discharge into the marine environment. The report underscores the substantial environmental and human health costs of unrestricted scrubber use, and highlights the economic, ecological and human health consequences of inaction.
Without a ban on the use of scrubbers and the discharge of scrubber wastewater, or a mandate to use cleaner distillate fuels, ecosystems, ocean resources and coastal communities will continue to be threatened and human health risks will increase.
“Scrubber discharge is poisoning our waters and marine environment,” said Kay Brown, Arctic Policy Director for Pacific Environment.
“Our report underscores the destructive toxicity of scrubber discharge on the marine environment, impacting humans, wildlife and Indigenous communities’ subsistence activities. The report reveals that most ships have already recovered their initial capital costs making banning scrubber discharge feasible. It’s time to end the use of scrubbers.”
Key findings
Scrubber economics: Findings align with other studies, showing that the majority of ships equipped with scrubbers have recovered their initial capital costs, or would do so during a phase-out period, making scrubber removal financially viable for most operators. What’s more the cost of scrubber discharge causes significant harm to marine ecosystems, which shifts the economic burden to other stakeholders, with damages quantified in the millions of dollars.
Environmental degradation: Scrubber wastewater is highly toxic, significantly hotter and up to 100,000 times more acidic than the surrounding waters. It contains various pollutants, including heavy metals, polycyclic aromatic hydrocarbons (PAHs), nitrates and nitrites, sulfates and particulate matter.
The presence of heavy metals and PAHs is especially concerning given their ability to persist in marine environments and accumulate within marine species. Even at extremely low concentrations — just 0.001% — scrubber pollutants can harm marine life and disrupt biological processes.
What’s more, ships using heavy fuel oil with scrubbers emit 70% more particulate matter, up to 4.5 times more black carbon and considerably more PAHs into the atmosphere compared to ships running on marine gas oil (MGO). Black carbon pollution is accelerating the Arctic meltdown and global warming.
Human Health risks: Humans are exposed to toxic scrubber discharge via ingestion of contaminated seafood and drinking water, dermal contact and inhalation during recreational ocean activities and inhalation of air pollutants.
PAHs exposure has been linked to DNA damage, endocrine disruption, developmental abnormalities, lung deficiencies such as asthma, and disrupted cognitive development. Compared to other PAHs sources, marine transport emissions — including scrubber-related pollution — contribute to significantly higher carcinogenic risk.
Food security, community impacts: Marine ecosystem disruption from scrubber use on maritime vessels raises significant health and environmental concerns for Indigenous and subsistence fishing communities.
Toxic algal blooms linked to nutrient overload from scrubber-related nitrate and nitrite releases can devastate marine populations, threatening the resilience of communities that rely on seafood.
Elevated PAHs and heavy metal loads in marine organisms also put seafood-dependent communities at higher risk of health complications.
Photo credit: Pixabay/ pamfitzgeraldbya
