I’m sure many of us have heard of oil spill disasters– when crude oil or refined petroleum products are accidentally released into the environment (E.g. British petroleum’s Deepwater Horizon Oil Spill in 2010, or the Amoco Cadiz oil spill in 1978), and are aware of the significant long-lasting negative impacts that they have on human health and the surrounding environment (D’Andrea & Reddy, 2018; Eklund et al., 2019; Helle et al., 2020; Rafferty, n.d.). 

However, in today’s post, I seek to uncover a pollutive practice that potentially results in 1 million tons of oil being released into our oceans annually, six times more than that of oil spill disasters, but often goes overlooked in the shipping industry (Maritime Intelligence, 2022). This practice is known as illegal blige dumping. 

What is blige dumping?

To understand blige dumping, we must first understand the formation of ‘bilge water’. Shipping vessels contain many complex systems, that include pumps, fittings, and extensive pipe networks. Oily wastewater, formed as a result of pipe leakages, spills, and in the routine maintenance of the ship, subsequently accumulates in the bilge (lowest part of a vessel’s hull), where it has come to be known as “Blige water” (Interpol, 2007; skytruth, n.d.). According to the International Convention for the Prevention of Pollution from Ships (MARPOL) set in place since the 1970s, vessels are required to treat bilge water, filtering the oil away before it can be legally discharged into the sea (Mohit, 2019). 

Why should we care?

However, despite this international law is in place to protect ocean ecosystems, non-profit environmental watchdog SkyTruth, have recently exposed the fact that many shipping vessels continue to illegally dump bilge water directly into oceans, in a bid to reduce cost from utilising pollution prevention equipment (Evanisko, 2020a). In a year-long analysis of radar satellite imagery in 2019– where SkyTruth have systematically searched for cases of illegal blige dumping by observing for dark and opaque slicks– they have found 163 slicks, each averaging 56 km in length. The presence of such slicks indicate likely cases of illegal blige dumping. However, these identified illegal bilge dumping incidents likely only represent a small percentage of total dumping incidents due to limited satellite coverage over the open oceans, where most occurences of bilge dumping are likely to take place (Evanisko, 2020a; Nicholls, 2018). Figure 1 depicts likely bilge dumping events, as recorded by SkyTruth in 2019, while Figure 2 categorises these events into regions. As seen from Figure 1 and 2, many of the observed incidents often coincide with popular shipping routes. 

Figure 1: Likely observed bilge dumping events identified by SkyTruth in 2019. (Evanisko, 2020a).

 

Figure 2: Likely bilge dump incidents identified by SkyTruth in 2019 by region. (Evanisko, 2020a).

This is especially so along the Straits of Malacca and its surrounding region of Southeast Asia, which accounted for approximately 70% of reported incidents in 2019. Figure 3 shows the presence of oily clumps on a beach in Bintan, believed to be as a result of illegal bilge dumping. 

Figure 3: Presence of oily clumps on a beach in Bintan, believed to be the result of daily illegal bilge dumping. (Hicks, 2020).

This is likely due to the Port of Singapore’s prohibition for vessels to discharge their bilge water, together with high costs charged for the removal of bilge water, which propels vessels to discharge their bilge water illegaly before docking into Singapore (Hicks, 2020; shipsandports, 2018). 

When compared to that of accidental oil spills, such as that of the Deepwater Horizon oil spill which released approximately 134 million gallons of oil, the amount of oil released during the dumping of bilge water can be argued to be insignificant (Rafferty, n.d.). However, studies have found such small releases of oil to cause negative impacts to marine ecosystems. For example, Brussaard et al’s (2016) study of short-lived oil spills have found small scale oil spills, similar in scale to that of bilge water dumping, to have “immediate adverse biological effects”, with high bioavailability and toxicity of oil being recorded fairly deep (8m) below the oil slicks, as well as a recorded decline in marine plankton, which can have subsequent knock-on negative effects on the functioning of marine ecosystems (p.1). 

Moving forward

Despite the negative environmental effects of bilge water dumping, many countries lack the political and regulatory pressure to ensure vessels comply with international standards. This is has been assumed to be due to the high costs involved, together with the lack of resources to deploy regular patrols (Hicks, 2020). 

However, not all hope is lost. In Europe, the European Maritime Safety Agency (EMSA)– through its CleanSeaNet initiative– have been closely monitoring and identifying possible incidents of illegal bilge dumping through satellite imagery. These information are then provided to the relevant EU countries, for further investigation, and subsequent prosecution of illegal offenders (EMSA, n.d.). Additionally, environmental watchdog SkyTruths have also been working towards automating the detection and identification of possible illegal bilge dumping activities, such that to quickly empower countries with the necessary information to eventually prosecute offenders (Evanisko, 2020b). With such improvements in technology to detect and identify illegal bilge dumping offenders, it is of activists hope, such as that of the members of SkyTruths, that it would compel shipping companies to now comply with international laws, and stop the practice of illegal bilge dumping. 

References

Brussaard, C. P. D., Peperzak, L., Beggah, S., Wick, L. Y., Wuerz, B., Weber, J., Samuel Arey, J., Van Der Burg, B., Jonas, A., Huisman, J., & Van Der Meer, J. R. (2016). Immediate ecotoxicological effects of short-lived oil spills on marine biota. Nature Communications, 7(1), 11206. https://doi.org/10.1038/ncomms11206

D’Andrea, M. A., & Reddy, G. K. (2018). The development of long-term adverse health effects in oil spill cleanup workers of the deepwater horizon offshore drilling rig disaster. Frontiers in Public Health, 6, 117. https://doi.org/10.3389/fpubh.2018.00117

Eklund, R. L., Knapp, L. C., Sandifer, P. A., & Colwell, R. C. (2019). Oil spills and human health: Contributions of the gulf of mexico research initiative. GeoHealth, 3(12), 391–406. https://doi.org/10.1029/2019GH000217

European Maritime Safety Agency. (n.d.). CleanSeaNet service. https://www.emsa.europa.eu/csn-menu.html

Evanisko, T. (2020, February 5). A systematic search for bilge dumping at sea: 2019 in review. SkyTruths. https://skytruth.org/2020/02/title-a-systematic-search-for-bilge-dumping-at-sea-2019-in-review/

Evanisoko, T. Blige dumping at sea: How can this be happening?. https://skytruth.org/2020/04/bilge-dumping-at-sea-how-can-this-be-happening/

Helle, I., Mäkinen, J., Nevalainen, M., Afenyo, M., & Vanhatalo, J. (2020). Impacts of oil spills on arctic marine ecosystems: A quantitative and probabilistic risk assessment perspective. Environmental Science & Technology, 54(4), 2112–2121. https://doi.org/10.1021/acs.est.9b07086

Hicks, R. (2020, March 11). Southeast Asia is the world’s bilge dumping hotspot—what can be done to stop ships discharging waste oil?. Eco-business. https://www.eco-business.com/news/southeast-asia-is-the-worlds-bilge-dumping-hotspot-what-can-be-done-to-stop-ships-discharging-waste-oil/?sw-signup=true

Interpol. (2007). Illegal oil discharges from vessels: Investigate manual. https://www.interpol.int/content/download/14079/file/EN_Oil%20Discharge%20Manual.pdf

Martime Intelligence. (2022, April 6). Illegal discharge, a common threat with disastrous ecological cost that can be mitigated by satellites and drones. https://maritime-intelligence.groupcls.com/illegal-discharge-a-common-threat/

Mohit. (2019, April 18). MARPOL annex 1 explained: How to prevent pollution from oil at sea. Marine Insight. https://www.marineinsight.com/maritime-law/marpol-annex-1-explained-how-to-prevent-pollution-from-oil-at-sea/

Nicholls, D. (2018, January 9). What we can see, in heat maps. SkyTruths. https://skytruth.org/2018/01/what-we-can-see-in-heat-maps/

Rafferty, J. (n.d.). 9 of the biggest oil spills in history. Britannica. https://www.britannica.com/list/9-of-the-biggest-oil-spills-in-history

Ships and Ports. (2018, November 30). Singapore prohibits ‘wash water’ discharge at ports from 2020. https://shipsandports.com.ng/singapore-prohibits-wash-water-discharge-at-ports-from-2020/

SkyTruths. Blige dumping. https://skytruth.org/bilge/