Mercury in Fish
Essay title: Mercury in Fish
Mercury in Fish
& Fish Consumption
Guidelines for the
Saskatchewan, Souris,
Assiniboine, Red and
Winnipeg River Systems
Water Quality Series Number 4
Mercury in Fish:
Problems and Solutions
Monitoring Of Mercury
Although Manitoba has some of the cleanest waters
in the world, mercury contamination of fish does
occur.
The Manitoba Department of Environment has
monitored mercury levels in fish from some major
water systems since 1978. Monitoring has focused
on the major waterways in southern Manitoba.
Monitoring sites are located in or near industrial
areas, urban centers, agricultural zones and
reservoirs.
What Is Mercury?
Mercury is a naturally occurring metallic element
that is generally found in low concentrations in the
air, water and soil.
Where Does Mercury Come
From?
Mercury often occurs in association with other
mineral deposits such as lead, silver and copper.
Mercury is released into the air and water from
these sources under natural conditions, but
considerable amounts may also be added to the
environment due to industrial activities.
Former industrial uses that released mercury to the
environment included the production of chlorine and
caustic soda. Mercury was also used as an
ingredient in slimicides for the pulp and paper
industry and for the control of fungi on seed grain.
Current uses of mercury include mercury based
fungicides for golf courses, dental amalgams, paint
and pharmaceutical industries, and the
manufacturing of thermometers, mirrors, batteries
and electrical switches.
Scientific evidence also indicates that long-term
flooding following construction of reservoirs
accelerates the release of naturally occurring
mercury into the water.
The prime source of elevated mercury levels in
Manitoba waters is from natural sources.
Why Is Mercury A Problem
In Fish?
Mercury is present in the environment in several
forms. Over many years, mercury from atmospheric
deposition or from the watershed accumulates in
lake and river sediments. Micro-organisms coming
into contact with inorganic mercury can convert it to
an organic or methyl-mercury form.
Methyl-mercury can be easily absorbed by fish
either directly through their gills or indirectly from
organisms they consume in their diet. Likewise,
people can ingest methyl-mercury from the fish they
Because both fish and people eliminate methylmercury
slowly, consuming food with high mercury
levels will gradually increase the accumulation of
mercury in the body.
The highest mercury levels will be found in fish that

Get Your Essay

Cite this page

Major Waterways And Pharmaceutical Industries. (July 10, 2021). Retrieved from https://www.freeessays.education/major-waterways-and-pharmaceutical-industries-essay/