4.4 Water Pollution

What is water pollution?

Water pollution is the contamination of water bodies, such as rivers, lakes, and oceans, caused by harmful substances or pollutants, which adversely affect aquatic life and human health.

What are the major sources of water pollution and impacts on ecosytems? (5)

Sewage—> introduces high levels of nutrients, pathogens, and toxic chemicals into the ocean, which suffocates marine life, triggers harmful algal blooms, and degrades critical habitats

Arigultural run-off —> causes eutrophication which depletes water source from oxygen

Urban run-off—> Degrades water quality, harming aquatic life and contaminating drinking water sources

Solid waste disposal—> Contaminates groundwater sources and harms aquatic life

Oil spills —> Oil coats the water surface, affecting marine and freshwater ecosystems, harming aquatic life such as seabirds and leading to long-term environmental damage

What is plastic pollution?

the accumulation of plastic products in the environment, negatively affecting wildlife, habitat and humans

What harm do ocean plastics cause? (wildlife and economic impacts- 4 each)

Wild life impacts:

• injestion

• entanglement

• invasive species (species attaching to plastics and distributing around the world)

• chemical leaching an release toxic additives (BPA)

economic impacts:

• poor water quality

• degrading tourism industry

• fewer recreational activies

How has plasic aggregated into ocean gyres? (4 stages)

1. Plastics are carried by rivers and streams into the ocean

2. Ocean currents transportthese plastics, which then become trapped in the rotating currents of gyres

3. They are formed by global wind patterns and forces created by the Earth's rotation

4. This leads to plastic accumulating in these gyres overtime,forming large patches of debris

For example,the Great Pacific Garbage Patch is a well-known gyre, containing an estimated 1.8 trillion pieces of plastic

how have microplastics accumulated into food chains?

1. Microplastics are ingested by small marine organisms

2. These organisms are then eaten by larger predators in highertrophic levels

3. This leads to bioaccumulation and biomagnification

4. This can eventually lead to microplastics in human food sources

For example, studies have found microplastics in fish and shellfish sold for human consumption, indicating a direct pathway to humans

management to remove

1. Reduction stategies

Implementing policies to reduce plastic production and usage

Promoting alternatives to plastic, such as biodegradable materials

For example,the UK has introduced a ban on single-use plastic straws and drinks

2. Cleanup efforts:

Organising beach cleanups and developing technologies for ocean cleanups to

remove existing plastic pollution

For example,the Ocean Cleanup project aims to remove large quantities of plastic from the Great Pacific Garbage Patch and other water bodies using advanced technology

3. Recycling and waste management:

Improving recycling rates and waste management systems to prevent plastic from entering the ocean

Encouraging the public to recycle and dispose of waste responsibly

What is water quality? what are the characteristics?

the measurement of chemical, physical and biological characteristics of water:

• Chemical characteristics include: levels of dissolved substances like minerals, pollutants and nutrients

• Physical characteristics include water clarity,temperature and turbidity (cloudiness)

• Biological characteristics include the presence of microorganisms (e.g. bacteria) and invasive species

What is water quality measured by?

is highly variable and is often measured using a water quality index (WQI)

What are the different water quality parameters? (7)

1. dissolved oxygen

2. pH

3. temperature

4. Nitrates and phosphates

5. metals

6. Total suspended solids

7. Turbidity

What can water quality paramates be used for?

Water quality parameters can be used for assessing the health of aquatic ecosystems, determining the suitability of water for various uses, and monitoring environmental changes.

what is Biochemical oxygen demand (BOD)

a measure of the amout of dissolved oxygen required by microorganisms to decompose organic material in water

How is BOD measued and what does it provide?

measured in milligrams of oxygen consumbed per litre of sample in five days at 20°C. BOD provides an indirect measure of teh amount of organic matter within a sample.

How does eutrophicaio occur?

when lakes, estuaries and coastal waters recieve inputs of mineral nutrients, especially nitrates and phosphates, often causing excessive growth of phytoplankton

When do algal blooms occur?

if phytoplankton growth had previously been limited by lower concentrations of phosphate and/or nitrate.

Describe the process of eutrophication. (6)

1. nutrient enrichment

2. excessive equatic plant growth

3. algal blooms formation

4. blocking of sunlight

5. decay of phytoplankton and plants leading to oxygen depletion

6. aquatic life die

impact of eutrophication on aquatic life?

The amount of dissolved oxygen in the waterrapidly decreases, so aquatic organisms such as fish and insects may be unable to survive

Dead zones in both oceans and freshwater can occur when there is not enough oxygen to support aquatic life

Hypoxia = low oxygen levels in water

Anoxia = severe or complete depletion of oxygen in water

How is eutrophication demonstrated through positive feedback loops?

increased nutrients—> increase in death of organisms—> increase in demonposition—> increase in nutrients.

Impacts of eutrophication on humans? (3)

1. fisheries (reduced fish stocks)

2. aesthetics (e.g. unpleasant oders)

3. Health (drinking water)

What are the water pollution strategies?

1. Reduction of human activities that produce pollutants (alternatives)

2. reduction of the release of plootuoon into the environment (treatment of wastewater)

3. removal of pollutants from the environmant and restoration of ecosystems