Lecture 10: Environmental challenges and solutions

Identify the range and environmental consequences of major industrial and natural disasters

What is an example of industrial coal disaster and its solutions?

Mine Spoil Tip Collapse: The spillage/slip of the waste rock and soil removed during coal mining

Solutions:

• regulation

• revegetation/reclamation

• understanding of controlling factors
  → physical, hydraulic and mechanical characteristics
  → climatic conditions
  → slope geometry

What is the famous Coal tip disaster?

1966 Aberfan coal tip

• avalanche of black slurry which wiped out every building in its path, including the Pant Glas Junior school

• 144 lives were lost, including 116 children between the ages of 7 and 10

Oil disaster example: Alaska

Exxon-Valdez Spillage 1989

• 11 million gallons (125 olympic sized pools) over 800km coastline

• 400,000 seabirds and 4000 otters dead

• $1b fines, $100m research costs

  Result: 1990 Oil Pollution Act (US) e.g. double hulled oil tankers

Oil disaster example: Gulf of Mexico

• Deepwater Horizon Blow out

• 11 people killed

• 780million litres (300 olympic swimming pools)

Oil spill solutions

• soaking up using:
  → textiles, graphene, magnets, hair/fur

• inflatable booms

• skimming
  → Vacuuming the surface/scooping

• dispersants
  → breaks oil into smaller droplets
  → sinks or degrades momre easily

• Natural attenuation
  → Evaporation, bioremediation

Nuclear disasters: Japan

Fukishima Daiichi accident 2011:

• earthquake triggered a 15m tsunami which disabled the power supply and cooling of 3 reactors

• level 7 on the international nuclear and radiological event scale due to high radioactive releases over days 4-6

• after 2 weeks they were stable again

• the main ongoing task was to prevent release of radioactive materials, particularly in contaminated water

• no deaths or cases of radiation sickness

Nuclear disasters: Ukraine

Chernobyl 1986:

• flawed reactor design and lack of safety culture

• steam explosion and fires released 5% reactor core e.g. Sr, Cs and I

• 30 immediate deaths, in 2005 the UN predicted a further 4,000 deaths from radiation exposure

• new safe confinement structure (NSC) was completed in 2017

• sealed buildings allows remote dismantling of 1986 structure and removal of the contaminated materials

What are the long term effects of chernobyl?

Chernobyl Exclusion Zone (CEZ) covers 2,800 square km of thick forests

• This zone represents the third-largest nature reserve in mainland Europe

• Haven for wildlife such as lynx, bison, deer and other animals

• accidental dna iconic experiment in rewilding

Chernobyl today

2019: NPP started processing the liquid radioactive waste plant - during the first week 2,755kg of liquid radioactive waste was successfully processed

2025: Chernobyl gets go ahead for solid radioactive waste processing (WNN: World Nuclear News)

Hydroelectric power disasters

Displacement of people due to flooding

River systems:

• many systems support unique endemic species that are highly adapted to specific flow conditions

• altering these environments can lead to extinction or genetic bottlenecks

• e.g. the Yangtze River Dolphin is functionally extinct with damming contributiong to habitat loss and population fragmentation

Balbina:

• 7 species of endemic fish wiped out in brazilian amazon hydroelectric dam area

• creation of the dam in the amazon has flooded ~2,400km² rainforest

• biodiversity loss + isolation of species on artificial islands

• transformed fast flowing river to static environments

Deforestation: Amazon rainforest

• ~50,000 species become extinct each year due to deforestation

• 60M indigenous people worldwide depend on forests for their livlehoods

• deforestation accounts for ~10% of global emissions

What are the tipping points of biodiversity in relation to deforestation?

• organism richness decreases with logging intensity

• increases in bird species richness are caused by the influx of habitat generalists

• logging intensity of 38m³/ha would halve mammal richness

• 63m³/ha would halve amphibian richness

What are the key drivers of forest loss in the Amazon?

CATTLE FIELDS

What is eutrophication?

Process by which a body of water becomes overly enriched with nutrients (N and P), often due to runoff from agriculture and sewage

Effects:

• excessive algae growth

• oxygen depletion (hypoxia)

• death of aquatic life

• poor water quality and bad odors

Worlds largest hypoxic zone:

• Gulf of Mexico dead zone

• harm to shrimping industry and kills fish

Effects of mining and its remediation strategies

Effect: open cast ecosystem destruction

Remediation: Land reclamation e.g. China Clay Pit - Eden Project, UK

Effect: Underground mine collapse
→ e.g. Lily gold mine, Barberton South Africa - 3 fatalities

Effect: Acid Mine Drainage - occurs at abandoned mine sites, forms iron oxides and contaminates water which affects water quality
→ e.g. Rio Tinto, Spain - long term water and soil contamination

Remediation: limestone neutralization, constructed wetlands, anoxic limestone drains, and active chemical treatments to raise pH and reduce metal toxicity.

Effect: Dam failure
→ e.g. Minas Gerais, Brazil 2019 - 270 fatalities, 12m m³ iron ore tailings - severely affected quality of water in Paraopeba River

Effect: Processing
→ e.g. Ajka Alumina plant, Hungary 2010 - 700,000m³ of highly caustic red mud slurry , 10 fatalities, contaminated several towns

Arsenic in drinking water

• 3 in 10 people globally lack access to safely managed drinking water

Lecture summary