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Marine water contamination

Marine waters can be negatively impacted by human activities.  Marine water contamination risks include chemical, radiation, physical, and microbiological hazards. 

Examples of marine water risks and links to extra information are shown below.

Hazard

Risks from

Examples


Chemical
Fuel spillsOil and fuel leaks from marine vessels contaminate the marine environment and a concern when food sources and marine animals are affected.
Summary of spill incidents in BC and Yukon
Sunscreen

Swimmer pollution from sunscreen (suntan lotion) is known to damage coral reefs. Chemicals such as zinc oxide, found in sunscreen, cause bleaching
News story      Science article

Radiation
Iodine-131, Cesium-134, Cesium-137
A massive earthquate and tsunami in Japan in March 2011 caused the nuclear power plant in Fukushima to fail. Several radioactive isotopes were released into the marine environment from nuclear fuel leaks. 
Fukushima    Woods Hole Institute
Acoustic waves 
& sound
Marine mammals including southern resident killer whales are negatively impacted by the sounds of commercial and recreational vessels. 
ECHO    Statement of practice
Physical
Debris
A massive earthquake and tsunami in March 2011 washed out structures in Japan.  Debris from the event was found on North American coast-lines several years later.
Tsunami debris (NOAA)
Plastics, microplastics
and garbage
There are an estimated five trillion pieces of plastic floating in the sea, a major source of pollution. Plastics and microplastics are found in marine species and have been found in our foods.  
Science article
Micro-biological
Norovirus
Norovirus is the most common foodborne illness in Canada. Over one million people(1 in 8)  become ill with foodborne norovirus every year.  When human sewage enters the marine environment it can contaminate our food supply.  This has caused several outbreaks of norovirus in recent years.
Foodborne illness in Canada
Science article


Norovirus contamination in BC's marine environment led to foodborne illnesses

Norovirus illness in raw oyster consumers was investigated by a working group chaired by Environmental Health, BCCDC in 2017.  Many agencies participated in this working group, including industry, academia and representatives from regional, provincial, federal and international regulatory and health agencies. 

The working group concluded there were several transmission routes of norovirus into the marine environment.  All originated from human sewage sources.

The working group also concluded that environmental conditions in 2016 and 2017 allowed norovirus in sewage sources to survive and reach shellfish farms. FULL REPORT and Executive Summary

In 2018, the most plausible source of human sewage contaminating BC oysters was from commercial vessels. FULL REPORT


The documents shown represent the collective discussions of the working group.  


Executive summary and

Summary working group report on the environmental transmission of norovirus into oysters.  


These reports summarize the discussions of the working group into the plausible sources of marine contamination during the 2016-2017 norovirus outbreak that was responsible for 458 norovirus illnesses in Canadian consumers.


Comments from the Medical Director, Environmental Health Services

Two further control options to consider for managing the risk of norovirus illness from consuming raw oysters are presented.



This report describes a new control measure implemented following the 2016-2017 outbreak allowing illness triggers to rapidly close implicated shellfish farms.  It also summarizes the 2018 norovirus outbreak liked to oysters that caused 176 norovirus illnesses in Canadian oyster consumers.
 
Supplemental supporting documents used in the working group

During the working group a literature search and literature review was conducted to explain norovirus survival in marine environment conditions focusing on the impacts of climate and sewage sources.  
In addition to this document and End Notes reference library was created and shared with members that contains many other references and documents.  This is available on request from fpinfo@bccdc.ca.


BCCDC’s federal field epidemiologist, Emma Cumming, gathered climate and marine data to model norovirus illness and environmental factors.  There was limited illness data to inform random forest modelling, and this type of analysis was not feasible.  These data are presented in a series of descriptive time series charts in this report.  The data sets are housed at BCCDC for future use.  If you would like to collaborate on a project involving this data please contact us at fpinfo@bccdc.ca 

Mr. Ron Hein, a registered onsite wastewater practitioner, provided an overview of issues impacting onsite sewage systems regulated under the Ministry of Health Sewerage System Regulation to the working group.

One of the first activities performed in the working group was to ask the opinions of stakeholders which of the plausible hypotheses that led to the norovirus outbreak were believed to be more or less likely to have caused the marine contamination.  The results of the first survey are shown here, and a follow-up survey conducted after the working groups meetings are in the final report. 
 


SOURCE: Marine water contamination ( )
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