Term Paper: Chemical Runoff Pollution in the Ocean
Each year, incredibly large amounts of pollution and waste enter the ocean from
the earth’s surface. This has many harmful effects on marine organisms and is causing
many problems in marine ecosystems. One of the main contributors to pollution in the
ocean is runoff. Runoff is a nonpoint source of pollution where fertilizers, bacteria,
pesticides, and other harmful chemicals are carried into the ocean by rivers, streams,
precipitation, storm drains and other modes of transportation. A nonpoint source of
pollution is one where the source is not directly putting pollution in the ocean, or the
source is ill defined. Allowing these toxic substances to enter into the ocean has
detrimental effects on the entire marine ecosystem, from coral reefs and zooplankton to
fish and whales. This research paper will cover the different types of runoff, point and
nonpoint sources of pollution, the consequences of runoff, and how we can help reduce
the amount of pollution that goes into the ocean through runoff.
There are a variety of toxic chemicals and harmful pollutants that can reach the
ocean through runoff and have negative effects on the marine environment. They
include plastics, pesticides, oils, fertilizers, sewage, bacteria, aerosol pollutants,
sediments, acids, mercury and other heavy metals. These substances reach the ocean in
a large range of ways. According to WWF (World Wildlife Fund) Global, over 80% of
pollution in the ocean comes from land-based activities.
One source of runoff that might not be as well known as others is snowmelt
runoff. This occurs when snow accumulates pollutants as well as carries them to drains
or rivers, and eventually into the ocean. Snowfall can absorb aerosol pollutants simply
by falling through the troposphere and onto the earth’s surface. When it melts, it also
carries surface pollutants such as oils, fertilizers, and pesticides into streams and storm
drains. There are three kinds of snowmelt runoff: pavement melt, roadside melt, and
previous area melt. Pavement melt is when the sun heats up paved areas covered with
snow and causes them to melt. As mentioned earlier, the melted snow carries pollutants
indirectly into the ocean. Second, roadside melt is when larger piles of snow build up
around roads and melt slowly, causing a steady stream of oils and other harmful
chemicals to flow into storm drains and rivers. These oils and chemicals from the road
are easily amassed due to snowplows clearing the roads. Lastly, previous area melt
occurs on non-paved areas such as grass or fields. This is a large contributor to the
runoff of fertilizers and pesticides, and can be accelerated by precipitation.
Another source of pollution is soil erosion runoff, which is a nonpoint source
that occurs mainly due to rainfall. The direct cause of soil erosion runoff is the impact
of raindrops on the soil’s surface. When rainfall hits and breaks down the soils surface,
it is known as sheet erosion. When the top layer of the soil is destroyed, the soil is
broken down and results in surface runoff. Surface runoff occurs when the soil has
absorbed water to its full capacity and causes the water to flow into streams or drains.
