ASOC
Last summer over 120,000 people travelled to Antarctica by ship. On their journey south these scientific researchers, station support staff, tourists and fisheries workers together produced hundreds of millions of liters of waste water.
Ship waste water comes from a variety of sources including sewage, bilges, ballast and scrubbers, but one of the largest sources is gray water: runoff from baths, showers, sinks, laundries and kitchens.
It may sound relatively harmless: it’s not.
According to research conducted by the Environmental Protection Agency (and others), gray water from ships can contain heavy metals, chlorine, microplastics, pathogens like fecal coliform, food waste, and pharmaceuticals such as antibiotics. This toxic soup can be released, untreated, from vessels anywhere across the Antarctic.
Despite its known toxicity, there are no restrictions on the dumping of untreated gray water in the Southern Ocean.
Contaminants in gray water can harm marine ecosystems. Some can be ingested or absorbed by organisms, where they may build up or be transmitted to other species that feed on them, leading to physiological changes. Excess nutrients from gray water could create imbalances in fragile polar ecosystems and lead to a cascade of events such as algal blooms, ocean acidification, eutrophication (reduced oxygen), loss of biodiversity, and disruption of food webs.
Gray water can also introduce invasive species. This is a particular threat in parts of Antarctica which are warming rapidly, creating conditions more hospitable to species from the north. In a warmer Antarctica, these newcomers could out-compete Antarctic local species as they struggle to adapt to a changing climate.
Despite its harmful effects on marine ecosystems, there are currently no global regulations preventing the disposal of untreated gray water from ships, and it is not under consideration by the International Maritime Organization.
Antarctica is particularly vulnerable to harm from gray water. In the marine environment most pollutants are eventually dispersed, and some can be broken down by chemical processes, reducing their harmful effects. However, this process happens more slowly in polar waters than elsewhere. Decomposition accelerates in the presence of warmth and light, and the cold temperatures and six months of relative darkness in the polar regions slows it down, potentially exposing vulnerable ecosystems to pollutants for longer.
Why now?
ASOC first raised concerns about unregulated gray water disposal in 2013.
Since then, the number of people travelling to the Antarctic by ship has almost tripled. Most of this traffic is concentrated around the northern Antarctic Peninsula, where the majority of scientific, tourism and fisheries activity take place. This region is a recognized biodiversity hotspot, where enormous swarms of Antarctic krill support penguin, seal and migratory whale populations. This area is also under threat due to warming air and ocean temperatures, extreme sea ice loss, glacial melt, southward migration of Antarctic krill swarms, and population collapse in some penguin colonies.
The added pressure of gray water contamination is the last thing this ecosystem needs.
Image credit: Canva.com
Taking the lead
Antarctica remains one of the planet’s great wildernesses, with a proud legacy of proactive environmental protection. But when it comes to gray water regulation, we are falling behind.
Several Arctic states have recognized the urgent need to manage gray water disposal in territorial waters, with regulations now in place in Alaska, some protected coastal waters of the continental USA, and the Canadian Arctic.
In October 2024, Finland announced the prohibition of gray water disposal at sea, which will be phased in from 1 July 2025 and enter into force in 2030.
What’s next for Antarctica?
We need a circumpolar approach to regulating the disposal of gray water. In the absence of binding regulations from the International Maritime Organization, it falls to the Antarctic Treaty Parties to develop robust regulations, based on the best available science, to protect Antarctic ecosystems from the effects of unregulated gray water disposal.
Antarctic decision makers need data to help them understand the scope, nature and impacts of current gray water disposal practices in the Southern Ocean. Researchers and the shipping industry can support this effort by collecting and sharing data to inform appropriate regulatory policies.
For individuals travelling in Antarctic waters, there is plenty you can do to reduce the volume and toxicity of the gray water you produce during your voyage. See our infographic for more information.
Download our infographic: Gray Water and Microplastics – The Problem and The Solution.
References
Alaska Department of Environmental Conservation. Regulation 18 AAC 69. Chapter 69: Commercial Passenger Vessel Environmental Compliance Program
Finnish Government. Ministry of Transport and Education. Amendments to Act on Environmental Protection in Maritime Transport – prohibitions on discharges to enter into force gradually from next year. https://valtioneuvosto.fi/en/-//1410829/amendments-to-act-on-environmental-protection-in-maritime-transport-prohibitions-on-discharges-to-enter-into-force-gradually-from-next-year. Accessed 6 Feb, 2025.
González-Alonso, S., et al. (2017). Occurrence of pharmaceutical, recreational and psychotropic drug residues in surface water on the northern Antarctic Peninsula region.
Hughes K.A et al. (2020). Invasive non-native species likely to threaten biodiversity and ecosystems in the Antarctic Peninsula region.
Komyakova, V., Vince, J., Haward, M.(2020) Primary microplastics in the marine environment: scale of the issue, sources, pathways and current policy. Report to the National Environmental Science Program, Marine Biodiversity Hub. IMAS, University of Tasmania
Kumar M., et al. (2024) A review on heavy metal-induced toxicity in fishes: Bioaccumulation, antioxidant defense system, histopathological manifestations, and transcriptional profiling of genes.
Malone, T.C & Newton, A. (2020). The Globalization of Cultural Eutrophication in the Coastal Ocean: Causes and Consequences.
Miller M.E., Hamann M., Kroon F.J. (2020) Bioaccumulation and biomagnification of microplastics in marine organisms: A review and meta-analysis of current data.
Oteng-Peprah M., Acheampong M.A., deVries N.K. (2018). Greywater Characteristics, Treatment Systems, Reuse Strategies and User Perception – A Review.
Transport Canada. (2023) Interim Order Respecting the Discharge of Sewage and the Release of Greywater by Cruise Ships in Canadian Waters.
United States Environmental Protection Agency (EPA). (2011). Gray Water Discharges from Vessels.