Key Points:
Masaryk University, HX (Hurtigruten), and the Norwegian Institute for Water Research conducted a study to analyze cruise ship wastewater to identify organic contaminants to better assess their environmental impact, especially in sensitive marine areas; liquid chromatography-high-resolution mass spectrometry (LC-HRMS) was used for compound identification.
The researchers identified 168 organic compounds across three ships, with 27 compounds common to the trio, including pharmaceuticals, industrial chemicals, food compounds, a pesticide, and a UV blocker.
Concerns were raised that the mixture of effects of contaminants may amplify ecological harm, with compounds like SSRIs and antibiotics raise alarm.
The researchers state a need for improved regulation and monitoring of graywater discharge, and recommend studying pollutant dilution, degradation, and cumulative effects in marine ecosystems.
A joint study by Masaryk University (Brno, Czech Republic), HX (formerly Hurtigruten Expeditions, London, United Kingdom) and the Norwegian Institute for Water Research (Oslo, Norway) aimed to identifyorganic contaminants associated with wastewater discharge from cruise ships as a first step to better evaluate the impact of contaminant emissions on sensitive marine environments. Liquid chromatography-high-resolution mass spectrometry (LC-HRMS) was used for qualitative analyses of the wastewater extracts. A paper based on the study was published in Environmental Science & Technology Letters (1).
One of the fastest-growing industries in the tourism sector, showing a growth rate of 7% from 2019 to 2023, and a forecasted growth of 10% from 2024 to 2028 (2,3), the size, passenger capacity, and amenities of the modern cruise ship makes them comparable to terrestrial settlements. As such, they can inflict similar pressures on the surrounding environment, such as noise, air, and water pollution (4-6). Due to improvements in ship design and technology, as well as receding polar ice, cruising in polar regions has seen a dramatic increase in recent years (7). Between 2018 and 2021, traditional and expedition cruises in Arctic regions such as Greenland, Iceland, Svalbard, and northern Norway have increased by 118% (8). Increasing the number of cruise ships in the Arctic presents an additional and understudied stressor and a source of pollution to the region already under pressure due to climate change, long-range transport of contaminants, and resource exploitation (9-11).
Cruise ships discharge wastewater generated from onboard activities. Many ships have advanced wastewater treatment systems (WWTS) onboard. Passenger ships produce graywater (drainage from dishwashers, galley sinks, showers, laundry, baths, and washbasins) and blackwater (from toilets, sanitary areas, and areas with animals). The volume of graywater discharged by cruise ships in 2023 was estimated to be 14 billion L, a 40% increase from 2014 to 2023, largely driven by the growing number of cruise ships (12). To the best of the research team’s knowledge, there have been only two previous studies which quantified synthetic compounds in treated wastewater (5,13), and no instances of chemical screening have been conducted on treated wastewater intended for offshore discharge from cruise ships while in operation. This inspired the researchers to identify organic contaminants associated with wastewater discharge from cruise ships as a first step in the better evaluation of the impact of contaminant emissions from cruise ships on sensitive marine environments (1).
Wastewater samples were collected from three expedition cruise ships with varying operational ages and conditions. Wastewater samples from the older ships built in the 2000s (Ships 1 and 2) had >11 000 found features, while the newest ship, while Ship 3, built 2020, had 7571. All compounds reported here were identified at confidence level 1 or 2 according to the Schymanski identification confidence levels (SL1, confirmed a with reference standard, or SL2, probable structure; library match or diagnostic evidence) in high-resolution mass spectrometric analysis. From these features, a total of 168 compounds were confirmed at SL1 or the chemical structure was proposed at SL2 in treated wastewater across all three ships: 86, 99, and 78 compounds from Ships 1–3, respectively. Twenty-seven compounds were identified at SL1 or SL2 across all ships, with pharmaceuticals and industrial chemicals (10 each) constituting the majority, followed by five food/natural compounds, one pesticide, and one ultraviolet (UV) blocker (1).
The research team admits that there is a significant gap in understanding of the types of compounds present in ship wastewater discharges. This is an issue that increases in urgency as the cruise industry expands, especially in sensitive polar regions, and as sustainable development and tourism become more important priorities. They believe that water in shipping lanes and cruising routes should be studied to evaluate the effectiveness of dilution and degradability in marine water, particularly in areas where ships are permitted to discharge wastewater, with special emphasis being placed on compounds consistently identified across multiple vessels, including selective serotonin reuptake inhibitors (SSRIs), antibiotics, and other substances which pose environmental concerns at increased concentrations. In addition, the mixture effects of the various chemicals found in wastewater should be thoroughly examined, as the combined presence of different pharmaceuticals and industrial chemicals may result in additive or synergistic effects that can intensify their harmful impact on marine ecosystems. Furthermore, the current regulations and treatment standards of graywater may need reevaluation as an understanding of the impact of trace organic contaminants on marine systems is established (1).
References
1. van der Schyff, V.; Stiborek, M.; Šimek, Z. et al. Occurrence of Pharmaceuticals and Other Anthropogenic Compounds in the Wastewater Effluent of Arctic Expedition Cruise Ships. Environ. Sci. Technol. Lett. 2025, 12 (5), 648-654. DOI: 10.1021/acs.estlett.5c00209
2. Chrysafis, K. A.; Papadopoulou, G. C.; Theotokas, I. N. Measuring Financial Performance through Operating Business Efficiency in the Global Cruise Industry: A Fuzzy Benchmarking Study on the “Big Three.” Tour Manag. 2024, 100, 104830, DOI: 10.1016/j.tourman.2023.104830
3. Cruise Lines International Association (CLIA). State of the Cruise Industry Report. 2024. https://cruising.org/resources/2024-state-cruise-industry-report (accessed 2025-04-25)
4. Eckhardt, S.; Hermansen, O.; Grythe, H.; et al. The Influence of Cruise Ship Emissions on Air Pollution in Svalbard-a Harbinger of a More Polluted Arctic? Atmos. Chem. Phys. 2013, 13, 8401– 8409, DOI: 10.5194/acp-13-8401-2013
5. Vicente-Cera, I.; Moreno-Andrés, J.; Amaya-Vías, D.et al. Chemical and Microbiological Characterization of Cruise Vessel Wastewater Discharges Under Repair Conditions. Ecotoxicol. Environ. Saf. 2019, 169, 68– 75, DOI: 10.1016/j.ecoenv.2018.11.008
6. Lloret, J.; Carreño, A.; Carić, H. et al. Environmental and Human Health Impacts of Cruise Tourism: A Review. Mar. Pollut. Bull. 2021, 173, 112979, DOI: 10.1016/j.marpolbul.2021.112979
7. Qi, X.; Li, Z.; Zhao, C. et al. Environmental Impacts of Arctic Shipping Activities: A Review. Ocean Coast Manag 2024, 247, 106936, DOI: 10.1016/j.ocecoaman.2023.106936
8. Chen, Q.; Lau, Y.-Y.; Ge, Y. E. et al. Interactions between Arctic Passenger Ship Activities and Emissions. Transp Res. D Transp. Environ. 2021, 97, 102925, DOI: 10.1016/j.trd.2021.102925
9. Ford, J. D.; Smit, B.; Wandel, J. Vulnerability to Climate Change in the Arctic: A Case Study from Arctic Bay, Canada. Global Environmental Change 2006, 16 (2), 145– 160, DOI: 10.1016/j.gloenvcha.2005.11.007
10. Mayer, L.; Degrendele, C.; Šenk, P. et al. Widespread Pesticide Distribution in the European Atmosphere Questions Their Degradability in Air. Environ. Sci. Technol. 2024, 58 (7), 3342– 3352, DOI: 10.1021/acs.est.3c08488
11. Tolvanen, A.; Eilu, P.; Juutinen, A. et al. Mining in the Arctic Environment - A Review from Ecological, Socioeconomic and Legal Perspectives. J. Environ. Manage. 2019, 233, 832– 844, DOI: 10.1016/j.jenvman.2018.11.124
12. European Maritime Safety Agency. European Maritime Transport Environmental Report 2025. 2025. DOI: 10.2800/3162144
13. Westhof, L.; Köster, S.; Reich, M. Occurrence of Micropollutants in the Wastewater Streams of Cruise Ships. Emerg. Contam. 2016, 2 (4), 178– 184, DOI: 10.1016/j.emcon.2016.10.001
