Marine Pollution Flashcards
Main categories of marine pollution
- Toxic substances
- Solid waste inc. plastic debris
- Sewage and eutrophication
- Warm water sources
- Noise
- Light
Acute pollution discharge
catastrophic but a relativley quick event, short term
Chronic pollution discharge
continuous input of toxic substance or other anthropogenic factor (causes degredation of the environment) long term
Acute effect of oil spills
e.g. Oiling
Chronic effect of oil spills
e.g Changes
in community structure
Point pollution sources
Point source – discrete entry point
* E.g. oil spills, sewage outflow, factory
wastewater pipe
Diffuse pollution sources
Diffuse – variety of geographic points
* E.g. rainfall run-off, CO2, plastic pollution
*Biomagnification
An increase in the
biological concentration of a chemical with increasing trophic position
Bioaccumulation
Corresponds to the
process by which the intake of a chemical, via dietary or environmental
exposure routes, exceeds elimination
Toxic substances (Heavy metals) - Sources
Sources:
*Mining e.g. Mercury (Hg) and gold mines
* Manufacturing e.g. Hg from pulp mills (prior to regulation) and Cadmium (Cd) from battery factories
* Coal-burning powerplants (Hg as aerosols)
* Sewage e.g. Cd
* Agriculture e.g. insecticides and fungicides
Toxic substances (Heavy metals) - Effects
- Methyl-mercury bioaccumulates in food chain and causes Minimata disease in humans
- Denature proteins e.g. Zinc (Zn) and Cu
- Bind to blood pigments e.g Cu
- Renal function e.g. Cd in sea turtles and dugongs consumed by humans
Persistent Organic Pollutants (POPs) - Sources
- Agricultural run-off e.g. pesticides and herbicides
- Anti-fouling paint e.g. Tributyltin (TBT)
- Industrial additives e.g. Polychlorinated biphenyls (PCBs)
Persistent Organic Pollutants (POPs) - Effects
- Slow degradation
- Biomagnification and bioaccumulation
- Eggshell thinning e.g. DTT
- Carcinomas
- Reproductive failure
- Impacts on immune, endocrine (hormones) and nervous system function
Oil and Polycyclic aromatic hydrocarbons (PAHs) - Sources
- Small amount of natural release (seeps)
- Human activity e.g.
- Leaks from marine terminals, harbours, offshore drilling, tankers and barges
- Washout from land via drains & rivers
- Intentional washing of tanks
Oil and Polycyclic aromatic hydrocarbons (PAHs) - Effects
- Oil fouling – ingestion, suffocation and hypothermia
- Cascading effects e.g. Coastal vegetation die-off -> increased turbidity
- PHAs (lipophilic) – Cancers, tissue abnormalities and
reduced reproductive rates - Chemical dispersants (Surfactants) also toxic