February 28th, 2020
During a recent survey trip to the Soko’s islands the OceansAsia team finds masses of surgical masks washing up on the shoreline.
The Soko’s are a small cluster of islands lying off the SW coast of Lantau Island in Hong Kong. OceansAsia is currently carrying out several plastic pollution research projects there due to their remoteness. Twice a month the team visit the islands to carry out micro-plastic surveys as well as a more generalized beach trash accumulation analysis and investigations into the composition of the debris, looking for clues as to where it may be originating from. Also in conjunction with SMRU as part of WWF’s Blue Ocean Initiative we are carrying out drone survey work monitoring ocean surface trash.
Aerial of the research beach at the Soko Islands

One item that was very noticeable as a new addition to the myriad of marine debris is surgical masks. Over time the team has seen the odd mask here and now, however this time they were all along the high tide line and foreshore with new arrivals coming in on the current. Due to the current COVID-19 corona virus, the general population have all taken the precaution to wear surgical masks. When you suddenly have a population of 7 million people wearing one to two masks per day the amount of trash generated is going to be substantial.


As investigators, knowing introduction times of items we find helps narrow down the potential search pattern for the source, and in this case we are 6 weeks into the major usage of surgical masks en-masse. This means that the outer boundary is set at potentially 6 weeks of drifting on currents. We can then overlay the wind and current/tidal action from the past 6 weeks to get a general idea as to potential sources. This is not to assign blame, however if we can locate the source, we can also assume that other similar items that arrived at that time could have travel the same route. When we say similar items, when an item enters the water, its shape and weight play a huge role in where it will end up. Light, high sided items such as plastic bottles and polystyrene boxes have large exposed surfaces that will be mostly affected by the wind whilst heavier items that float lower in the water will be more affected by the current. In the case of masks they likely ended up being blown into the water, but after entering the ocean would largely be affected by current and tidal action with wind only affecting the waters surface.

Some of the many mask found on the beach washed up during the corona virus.
One of many surgical masks washed up on the beach at the Soko Islands