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How and in what ways do human activities pollute oceans? - Coggle Diagram
How and in what ways do human activities pollute oceans?
Nuclear waste
the main sources of radiation in the oceans is from nuclear accidents and sunken nuclear submarines
Nuclear waste disposal:
1946-93, >200,000 tonnes of radioactive waste were dumped in the world's oceans, mainly in metal drums
most dumped nuclear waste came from the UK & Soviet Union
by 1991, US had dropped >90,000 barrels and at least 190,000 cubic meters of radioactive waste in the North Atlantic and Pacific
other countries e.g. Belgium and the Netherlands disposed of tonnes of radioactive waste in the North Atlantic in 1960s-80s
Nuclear waste processing:
nuclear fuel reprocessing plant at La Hague, France, directly on the coast and "legally discharges 33m litres of radioactive liquid into the sea each year"
recent years, La Hague several incidents involving increased radioactivity levels
dumping of nuclear waste in drums was banned in 1993 by the London Convention on the Prevention of Marine Pollution
discharging liquid contaminated with radiation into the ocean is still permitted internationally
Nuclear weapons testing:
1946, US first country to test atomic bomb in a marine area, over Pacific Bikini Atoll
next few decades, >250 nuclear weapons tests were carried out on the high seas, 193 of the conducted by France in French Polynesia, US 42 mainly in Marshall Islands and the Central Pacific
Nuclear accidents: Fukushima 2011:
11 March 2011, Magnitude 9 earthquake - 14m high tsunami damaged the power generators of Fukushima Nuclear Power Plant
Classified Level 7 Nuclear Event (highest possible) by the IAEA
Relevant radionuclides:
radionuclides of the elements iodine and caesium, particularly relevant in terms of the radioactive contamination of the environment & humans
radioactive iodine (half-life 8 days) released in a reactor accident disappears from the environment after about 3 months
contamination with radioactive caesium (half-life 30 years) remains in the environment for a long time, responsible for radiation still in Fukushima (Ceasium-137 has moved across ocean to USA overtime)
Impacts on marine life:
radioisotopes released into the atmosphere from the Fukushima power plant fell into the ocean
water used to cool reactors flushed radioisotopes into the sea.
phytoplankton take up radioisotopes from seawater
contaminants move up the food chain
some contaminants end up in faecal pellets and other detrital particles that settle to the seafloor and accumulate in sediments
some radioisotopes in sediments may be remobilised into overlying waters and absorbed by seafloor-dwelling organisms
Fukushima water plan:
Japan's plan to dump more than 1m tonnes of treated water from gripped power plant ; over period of 30 years
fear amongst Japanese fishers & coastal communities, as well as opposition by neighbouring countries e.g. China, South Korea & those in the Pacific Island Forum
1985, South Pacific Nuclear Free Zone Treaty prohibit testing & use of nuclear devices & dumping of radioactive wastes
the process of decommissioning Fukushima could take up to 4 decades
Japanese gov say they need to release water as it is running out of space
2020, Greenpeace say "only acceptable solution" is to continue long term storage and processing of contaminating water (Citizens Committee on Nuclear Energy agree even if just for a while)
Japanese gov insist effects of radiation on human health as a result of discharge is small (0.00081mSv/year), but medical experts have serious concerns about enormous volume and potential fallout of even small amounts of Tritium
even at very low levels, harmful effects have been demonstrated
Radioactive sources form Fukushima accident:
atmospheric fallout = 15PBq, mid March 2011 peak
direct discharge = 5PBq, early April 2011 peak
groundwater discharge ongoing = 12-15TBq
river runoff ongoing = 10-12TBq
Domestic and agricultural pollutants
farm runoff accounts for 20% of ocean pollution
Agriculture
= nitrogen and phosphorus in animal manure and chemical fertilizers, necessary to grow crops, but can be lost from the farm fields and negatively impact air and downstream water quality
Stormwater
= precipitation falls on our cities and towns & runs across hard surfaces, carries pollutants, including nitrogen and phosphorus, into local waterways
Wastewater
= sewer and septic systems are responsible for treating large quantities of waste, systems do not always operate properly or remove enough nitrogen and phosphorus before discharging into waterways
Fossil fuels
= electric power generation, industry, transportation, and agriculture have increased the amount of nitrogen in the air through use of fossil fuels
Other domestic
= fertilizers, yard and pet waste and certain soaps and detergents contain nitrogen and phosphorus and can contribute to nutrient pollution if not properly used or disposed; hard surfaces and type of landscaping can also increase the runoff during wet weather.
Gulf of Mexico Hypoxic “Dead” Zone:
one of the worlds largest human caused dead zones, caused by hypoxia
approx 22,000km² of habitat potentially unavailable to fish and seabed species
size of the zone varies each year depending on flooding and river discharge
in the Gulf, the nitrogen causes algae blooms, they die &are broken down by bacteria which remove oxygen from the water in the process
river freshwater is lighter so sits on top of the saline seawater, prevents mixing that usually carries oxygen from surface waters to deeper ones
algal blooms cause dangerous toxins that can sicken or kill species, raise treatment costs for drinking water & hurt industries depending on clean water
Fossil fuels burning at sea
Key info:
over 90% of world trade is carried across the world's oceans by some 90,000 marine vessels
shipping relies on burning fossil fuels: releasing emissions & particulates
largest vessels produce 5,000 tonnes of sulphur/year
air pollution is up to 3x higher near ports, affecting human health
growth of cruise ship industry has raised traffic and pollution in areas such as steep sided fjords of Norway & Alaska
Annually sea transport contributes:
3% of global CO2
13% of global SOx (sulphur oxide)
18-30% of global NOx (nitrogen oxide)
Shipping capacity & amount of ships overtime:
since 1970, capacity of container ships has increased up to almost 25,000TEU from 1,000TEU
significant growth, particularly from 1940s
overtime more & larger ships have been ordered
largest ever container ship was the Ever Alot, 24,004TEU, 400m long
Shipping routes:
3 choke points of Strait of Gibraltar, Strait of Hormuz and Strait of Malacca
Norway, Spain and Italy all have high NOX as they are popular cruise ship locations
How cruise ships destroy the world:
worse than all cars combined (4.6 billion metric tons / year) (cruise ships can be 1 million times more)
sulphur fuel, worse than diesel or petrol
respiratory diseases & cancer
dumping of sewage in international waters
destruction of marine ecosystems
Main European port cities:
cruise ships in ports emit 2-5x more cancerous gases than the entire car fleet in the same city
Southampton, over 6X more Sox emissions from cruise ships than cars (3,189kg vs 19,734kg)
electric or hybrid container / cruise ships could be a solution
Oil
more info in case study
every year motor oil contributes 240m gallons of oil to the oceans
amount of motor oil entering oceans is 8x greater than the Deepwater Horizon oil spill
natural oil seeps account for 50% of oil pollutants in the ocean
around 450,000 marine birds killed each year by flushing, loading and discharges from oil tankers
Plastics
more info in case study
Context:
least 8m tons of plastic end up in our oceans every year
9% of plastic ever produced has been recycled, 12% incinerated
79% go to landfill, dumps, and the natural environment
plastic is on shorelines of all the continents, found more often near popular tourist destinations and densely populated areas
Summary:
plastic pollution is having a negative impact on our oceans and wildlife health
ACs generate more plastic waste per person
management of plastic waste that determines the risk of plastic entering the ocean, Acs have effective waste management systems
improvement of waste management systems across the world critical to reducing plastic pollution
20% all plastic waste in the oceans comes from marine sources
more than 1/2 plastics in the Great Pacific Garbage Patch come from fishing nets, ropes and lines
plastic is a unique material with many benefits: it’s cheap, versatile, lightweight, and resistant; valuable material for many functions
environmental benefits: critical role in maintaining food quality, safety and reducing food waste
trade-offs between plastics and substitutes (or complete bans) are therefore complex and could create negative knock-on impacts on the environment
Pollutant sources
Point source
= clearly identifiable locations
Non-point sources
- several dispersal locations e.g. ships
Originates from on land
- winds & rivers