Chemical Pollution
Plants and animals produce countless chemical
substances as part of their life processes. For the purposes of the Ocean
Health Index, ‘chemical’ refers to a
compound or substance that has been purified or manufactured by human
sources.
More than 100,000 chemicals are used commercially (Daly 2006), and many enter the marine environment via atmospheric transport, runoff into waterways, or direct disposal into the ocean.
Three general categories of chemicals are of particular concern in the marine environment: oil, toxic metals, and persistent organic pollutants.
More than 100,000 chemicals are used commercially (Daly 2006), and many enter the marine environment via atmospheric transport, runoff into waterways, or direct disposal into the ocean.
Three general categories of chemicals are of particular concern in the marine environment: oil, toxic metals, and persistent organic pollutants.
Chemical Pollution Infographic
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Which Goals Does This Affect?
How Was It Measured?
It is not yet, and may never be, possible to
measure actual concentrations of the numerous substances found throughout the
ocean, so the following proxy measures were used. Pollution from land-based
organic chemicals was modeled from data on agricultural pesticide use. Pollution from land-based inorganic chemicals
was modeled by estimating runoff from impervious surfaces. Ocean-based pollution
was modeled from data on commercial shipping tracks and ports.
These models only provide rough estimates of pollution intensity. They do not represent all chemicals and they do not distinguish between chemicals that are more or less toxic. Focal studies at the country level may be able to use more detailed data, but they do not yet exist at the global level.
Details about the models used are provided in online Supplementary Information for Halpern et al. (2012).
These models only provide rough estimates of pollution intensity. They do not represent all chemicals and they do not distinguish between chemicals that are more or less toxic. Focal studies at the country level may be able to use more detailed data, but they do not yet exist at the global level.
Details about the models used are provided in online Supplementary Information for Halpern et al. (2012).
Oil
The total amount of oil entering the ocean has
been estimated, but global data on the size and geographic distribution of oil
spills are not available, so oil pollution could not be included as a separate
category within the Ocean Health Index.
However, oil would be among the substances contained in runoff from
impervious surfaces and released by shipping and ports.
‘Oil’ is the general term for any thick, viscous, typically flammable liquid that is insoluble in water but soluble in organic solvents. Plants and animals produce a variety of natural oils, but the Clean Waters goal is primarily concerned with oil derived from geological deposits of petroleum (crude oil) for use as a fuel or lubricant.
Natural oil makes up 47% of the oil in the ocean. About 600,000 metric tonnes of oil enters the ocean naturally each year by seepage through many cracks in the seafloor (NRC 2003), but input from each is typically slow (Wells 1995) and natural seepage is not considered to be pollution.
The other half of the oil comes from anthropogenic sources, including boats, land-based runoff and, to a lesser degree, oil spills. These sources pose a greater threat to marine environments as the oil enters the ocean in concentrated areas at a high rate of flow.
The largest sources of human oil pollution are urban-based runoff and operational discharge of fuel from boating traffic and port operations. Discharge associated with boats constitutes 24% of the total amount of oil in the ocean (UNEP/GPA 2006).
Only 8% of overall oil ocean pollution is a result of spills during transportation or production. However, the toxicity levels of these spills tend to persist over time and have been linked to highly visible local and regional disasters.
After 20 years, oil pollution from the 1989 Exxon Valdez spill persists and, in some areas, is nearly as toxic as initial levels (Exxon Valdez Trustee Council 2009; Raloff 2009).
‘Oil’ is the general term for any thick, viscous, typically flammable liquid that is insoluble in water but soluble in organic solvents. Plants and animals produce a variety of natural oils, but the Clean Waters goal is primarily concerned with oil derived from geological deposits of petroleum (crude oil) for use as a fuel or lubricant.
Natural oil makes up 47% of the oil in the ocean. About 600,000 metric tonnes of oil enters the ocean naturally each year by seepage through many cracks in the seafloor (NRC 2003), but input from each is typically slow (Wells 1995) and natural seepage is not considered to be pollution.
The other half of the oil comes from anthropogenic sources, including boats, land-based runoff and, to a lesser degree, oil spills. These sources pose a greater threat to marine environments as the oil enters the ocean in concentrated areas at a high rate of flow.
The largest sources of human oil pollution are urban-based runoff and operational discharge of fuel from boating traffic and port operations. Discharge associated with boats constitutes 24% of the total amount of oil in the ocean (UNEP/GPA 2006).
Only 8% of overall oil ocean pollution is a result of spills during transportation or production. However, the toxicity levels of these spills tend to persist over time and have been linked to highly visible local and regional disasters.
After 20 years, oil pollution from the 1989 Exxon Valdez spill persists and, in some areas, is nearly as toxic as initial levels (Exxon Valdez Trustee Council 2009; Raloff 2009).
What Are The Impacts?
ECOLOGICAL IMPACT
Oil pollution can degrade or destroy marine
ecosystems.
Oil pollution can elevate concentrations of toxic elements (ex. arsenic).
Oil pollution can kill marine life through ingestion, inhalation, absorption and loss of insulation.
Oil pollution can have long-term effects on spawning grounds and fish stock recovery.
Oil pollution can elevate concentrations of toxic elements (ex. arsenic).
Oil pollution can kill marine life through ingestion, inhalation, absorption and loss of insulation.
Oil pollution can have long-term effects on spawning grounds and fish stock recovery.
HUMAN HEALTH IMPACT
Oil pollution can harm those who consume
contaminated water or seafood or have contact with polluted waters through
recreation and clean-up activities.
Symptoms can include chest pain, coughing, dizziness, headaches, respiratory distress and vomiting.
Symptoms can include chest pain, coughing, dizziness, headaches, respiratory distress and vomiting.
ECONOMIC IMPACT
Responding to the ecological impacts of oil
pollution can result in significant economic costs.
Response to the Deepwater Horizon oil spill cost BP US $13 billion dollars. Litigation and compensation for claims cost BP an additional US $15 billion (Telegraph 2011).
Local economies have to deal with costs resulting from contaminated or diminished fish stocks.
The BP Deepwater Horizon oil spill caused Louisiana to lose 50 percent of its seafood production, a US $2.4 billion dollar industry in Louisiana that supplied as much as 30 percent of the domestic seafood for the continental U.S. (Nawaguna-Clemente 2011).
Response to the Deepwater Horizon oil spill cost BP US $13 billion dollars. Litigation and compensation for claims cost BP an additional US $15 billion (Telegraph 2011).
Local economies have to deal with costs resulting from contaminated or diminished fish stocks.
The BP Deepwater Horizon oil spill caused Louisiana to lose 50 percent of its seafood production, a US $2.4 billion dollar industry in Louisiana that supplied as much as 30 percent of the domestic seafood for the continental U.S. (Nawaguna-Clemente 2011).
Find Out More
Woods
Hole Oceanographic Institution [WHOI]
A diagram detailing the route of oil
as it travels from the seafloor through the water column.
U.S.
Senate Committee on Environment & Public Works
A policy brief on the Oil Pollution
Act of 1990 by David Lungren
National
Oceanic and Atmospheric Administration [NOAA]
Six fact sheets evaluating the effect of the Gulf
oil spill on Marine Mammals and Sea Turtles, Seafood Safety, Hurricane, South
Florida, Restoration Efforts, and Cumulative Impacts on Wildlife.
Toxic Metals
Metals are chemical elements that are typically
hard, shiny, malleable, fusible, and ductile, with good electrical and thermal
conductivity. Metals are toxic if they change the structure and function of
proteins and enzymes (GESAMP 2001).
Metals found in the ocean that are highly toxic on their own include mercury, cadmium, lead, arsenic, tin, copper, nickel, selenium, and zinc. Mercury, cadmium, and lead can become even more highly toxic in combination with organic compounds. For example, mercury can form neurotoxic compounds such as methylmercury (CH3Hg), when combined with carbon.
Arsenic, copper, nickel, selenium, tin, and zinc are not highly toxic by themselves but are able to react with organic materials, creating very toxic compounds (UNEP 2006).
Many metals occur naturally in the environment, but anthropogenic emissions from industrial and mining activities can increase concentrations of many to toxic levels.
96% of mercury enters the ocean via atmospheric input (GESAMP 2001).
While some metals are deliberately dumped in the ocean, most are found downstream from their sources, including waste dumps, industrial areas, mining operations and metal processing areas.
Metals found in the ocean that are highly toxic on their own include mercury, cadmium, lead, arsenic, tin, copper, nickel, selenium, and zinc. Mercury, cadmium, and lead can become even more highly toxic in combination with organic compounds. For example, mercury can form neurotoxic compounds such as methylmercury (CH3Hg), when combined with carbon.
Arsenic, copper, nickel, selenium, tin, and zinc are not highly toxic by themselves but are able to react with organic materials, creating very toxic compounds (UNEP 2006).
Many metals occur naturally in the environment, but anthropogenic emissions from industrial and mining activities can increase concentrations of many to toxic levels.
96% of mercury enters the ocean via atmospheric input (GESAMP 2001).
While some metals are deliberately dumped in the ocean, most are found downstream from their sources, including waste dumps, industrial areas, mining operations and metal processing areas.
What Are The Impacts?
ECOLOGICAL IMPACT
Results of laboratory studies can demonstrate the
effects of one or several pollutants on growth, reproduction or other
physiological processes in test organisms. Chemical analyses can also reveal
the concentrations of pollutants in the tissues of marine organisms collected
in the wild. However, limited information is available on how wild marine
plants, animals, microorganisms and ecosystems respond to sub-lethal exposure
to the many pollutants they encounter, and how other factors such as
temperature or pH affect those responses.
HUMAN HEALTH IMPACT
Certain metals, such as zinc, are essential to
life in very small amounts, but are toxic in higher concentrations. Others,
such as mercury or cadmium, are not used in normal metabolism and are harmful
when taken into the body. Ingesting toxic metals can have serious effects on
the kidney, liver, immune system, central nervous system and other organs.
Over 90% of methylmercury exposure occurs through the ingestion of contaminated fish and shellfish (USGS 2 2009).
In the past 20 years, mercury concentrations in the Pacific Ocean have increased 30 percent due to increases in human atmospheric emissions from industries and are estimated to rise 50 percent by the year 2050 (Sunderland 2009).
Over 90% of methylmercury exposure occurs through the ingestion of contaminated fish and shellfish (USGS 2 2009).
In the past 20 years, mercury concentrations in the Pacific Ocean have increased 30 percent due to increases in human atmospheric emissions from industries and are estimated to rise 50 percent by the year 2050 (Sunderland 2009).
ECONOMIC IMPACT
In 2004, the U.S. Environmental Protection Agency
(EPA) released recommendations for weekly fish consumption so that high levels
of mercury ingestion could be avoided (EPA 2010).
Expenses can be incurred from health problems attributed to mercury ingestion.
An estimated 637,233 children in the United States are born each year with cord blood mercury levels greater than 5.8 mg/L, a level linked to decreased IQ and other birth defects (Trasande et al 2005).
Expenses can be incurred from health problems attributed to mercury ingestion.
An estimated 637,233 children in the United States are born each year with cord blood mercury levels greater than 5.8 mg/L, a level linked to decreased IQ and other birth defects (Trasande et al 2005).
Find Out More
United States Environmental Protection Agency [EPA]
Fact sheet on mercury content in fish and shellfish.
European
Health and Environment Alliance (HEAL)
Fact Sheet on fish and mercury consumption.
Persistent
Organic Pollutants [POPs]
Persistent Organic Pollutants (POPs) are chemical
compounds that are toxic to humans and wildlife.
POPs include pesticides such as DDT, herbicides, PCBs (a component found in many coolants, flame-retardants, adhesives), and BPA (a compound found in plastics – primarily in plastic bottles).
POPs include pesticides such as DDT, herbicides, PCBs (a component found in many coolants, flame-retardants, adhesives), and BPA (a compound found in plastics – primarily in plastic bottles).
What Are The Impacts?
ECOLOGICAL IMPACT
The beluga whale population in Canada’s St.
Lawrence estuary has declined from about 5,000 at the beginning of the 1900s to
about 650 animals today. They have one of the highest rates of cancer known in
any wild population, as well as some of the highest levels of POPs and toxic
metals. (Lyons, 2008; Martineau et al.
2002).
POP concentrations increasingly accumulate at each stage in the food web. The highest concentrations are found in ‘apex’ predators that feed at the top of the food web (at a high trophic level).
Low temperatures cause POPs to break down more slowly and accumulate in higher concentrations than in more temperate zones.
POP concentrations increasingly accumulate at each stage in the food web. The highest concentrations are found in ‘apex’ predators that feed at the top of the food web (at a high trophic level).
Low temperatures cause POPs to break down more slowly and accumulate in higher concentrations than in more temperate zones.
HUMAN HEALTH IMPACT
POPs can cause birth defects, increase cancer
risks, disrupt hormone functions and cause reproductive, behavioral, immune
system, and neurological problems in humans.
Inuit populations that consume large amounts of whale and seal fat have health-threatening, heightened blood levels of POPs, including industrial chemicals such as PCBs and pesticides such as DDT, even though such products were made and used thousands of miles away (Kirby, 2008).
Inuit populations that consume large amounts of whale and seal fat have health-threatening, heightened blood levels of POPs, including industrial chemicals such as PCBs and pesticides such as DDT, even though such products were made and used thousands of miles away (Kirby, 2008).
ECONOMIC IMPACT
Because POPs are versatile and inexpensive to
manufacture, many countries continue to allow their use. However, the economic costs to deal with the
resultant pollution can be high.
An estimated 2.8 billion dollars has been spent on dredging and processing POP contaminants from PCB manufacture in the Rhine Delta since 1997.
In the United States, the General Electric company (GE), which dumped polychlorinated biphenyl (PCB) used in manufacturing capacitors, will have to pay an estimated total of 1.4 billion dollars to remove PCB-contaminated sediments from the Hudson River (Greenpeace, 2011).
An estimated 2.8 billion dollars has been spent on dredging and processing POP contaminants from PCB manufacture in the Rhine Delta since 1997.
In the United States, the General Electric company (GE), which dumped polychlorinated biphenyl (PCB) used in manufacturing capacitors, will have to pay an estimated total of 1.4 billion dollars to remove PCB-contaminated sediments from the Hudson River (Greenpeace, 2011).
Get More Information
World
Health Organization
Policy brief-fact sheet addressing country-based
implementation of the Stockholm Convention
World
Bank
Informational paper on Persistent Organic
Pollutants Country Strategy Development: Experiences And Lessons Learned Under
the Montreal Protocol
World Bank
A guidebook from the World Bank on Persistent
Organic Pollutants: Backyards to Borders
References
Banza, C. L. N. et al. High human exposure to cobalt and other metals in Katanga, a mining area of the Democratic Republic of Congo. Environ. Res. 109, 745–752 (2009).
Martineau, D. et al. Cancer in wildlife, a case study: beluga from the St. Lawrence estuary, Québec, Canada. Environ Health Perspect 110, 285–292 (2002).
National Research Council. Oil in the Sea III: Inputs,
Fates, and Effects. National Research Council, (Washington, D.C.: National
Academies Press. 2003)
Sunderland, E. M. Mercury Exposure from Domestic and Imported Estuarine and Marine Fish in the U.S. Seafood Market. Environ Health Perspect 115, 235–242 (2007).
Sunderland, E. M., Krabbenhoft, D. P., Moreau, J. W., Strode, S. A. & Landing, W. M. Mercury sources, distribution, and bioavailability in the North Pacific Ocean: Insights from data and models. Global Biogeochem. Cycles 23, GB2010 (2009).
Trasande, L., Landrigan, P. J. & Schechter, C. Public Health and Economic Consequences of Methyl Mercury Toxicity to the Developing Brain. Environ Health Perspect 113, 590–596 (2005).
PHOTO(S): © Keith A. Ellenbogen