Mercury

Why is Mercury bad?

When consumed, Mercury can be stored within the tissues of animals in a process known as “bioaccumulation”. When there is a high concentration of Mercury in streams or rivers, Mercury begins to bioaccumulate in fish. When humans consume these fish, the Mercury will begin to bioaccumulate in the person’s body. Large predatory fish typically have higher concentrations of Mercury for the same reason. 

Mercury is known to be toxic to human health, affecting the nervous system. It is a long-term health problem; symptoms are slow to develop and usually occur after years of consuming Mercury. Common symptoms include insomnia, memory loss, headaches, and cognitive or muscular dysfunction. It can also cause organs such as the kidney and heart to fail. Mercury is particularly harmful to developing brains in children, and fetuses in pregnant women.

The Oregon Health Authority issues fish consumption advisories for local waterways in Oregon. Their current recommendation in the Scappoose Bay for meals containing locally caught fish is four meals per month for the general public, and one meal per month for vulnerable populations. Vulnerable populations are the young, elderly, pregnant, or people with pre-existing conditions. Click here to view the Oregon Health Authority’s webpage. 

Click here to learn more about Mercury pollution.

Where does Mercury come from?

Mercury occurs naturally in the environment, mostly stored within soil, rocks, and other minerals within the Earth's crust. This Mercury can be released into the environment by natural and human sources. About two-thirds of Mercury in the environment has been released by human activities. Any activity that disturbs land and rocks can release Mercury. Most Mercury is released into the air by combustion. Coal plants, forest fires, burning gasoline, ect. This Mercury travels through the air before being deposited onto the land's surface. From here, rainwater washes Mercury from the land surface, into local waterways.

Mercury is also present in many household devices such as thermometers, thermostats, gauges, electrical switches, fluorescent bulbs, and other similar devices. When these devices are not disposed of properly, i.e. thrown in the trash or poured down a drain, the Mercury can enter the environment. For a complete list, of household devices containing Mercury click here.

Most Mercury is in an inorganic form and does not threaten animals. However, when Mercury is dislodged from soil and minerals and enters waterways, bacteria can combine it with Carbon and convert it to a molecule called Methylmercury. Methylmercury is organic, and when consumed can be stored in the tissue of living animals in a process known as bioaccumulation.

How can we prevent Mercury pollution in our streams?

Do not throw devices containing Mercury into the trash. Instead, utilize the Columbia County Household Hazardous Waste Collection Program to dispose of devices containing Mercury, and many other household items that require special disposal methods such as batteries, chemicals, fuels, ect. Visit the website here to find more information and event dates.

Report illegal dumping to the Columbia County Dump Stoppers Program. Illegal dumping of materials such as tires, electronics, construction debris and more happen regularly and are harmful to the public and the environment. When reported, a county crew will remove the dumped materials. Call 503-397-7229 to report a dump or visit their website here.

Most Mercury entering our waterways enters the atmosphere from fossil fuel combustion, travels long distances, and is deposited on our land surfaces. Stormwater from rainfall then washes this Mercury from the land surface, into a stream. Mercury is not alone here, stormwater is known to carry many pollutants such as pesticides, and fertilizer into streams as well. Additionally, the force of stormwater also causes erosion and washes valuable topsoil away. Since Mercury is present in soil, erosion also causes Mercury pollution.

The way to prevent this is by increasing our land’s ability to absorb water, to decrease the amount of runoff from the surface. Urban Stormwater controls such as bioswales are used for this purpose. On agricultural land, buffers of vegetation between fields and streams are used. Regulations to control erosion resulting from human activities have been in place for decades. If you are concerned about erosion on a stream in your property, contact the Scappoose Bay Watershed Council here to discuss a stream restoration project.