Overheads (Two Lectures)
Lecture 1:
Ocean Pollution and Hazards
Both human and natural processes contribute to ocean pollution
and oceanic conditions hazardous to humans
Ocean Pollution- I
There are both natural and human sources of oceanic pollution/
hazardous materials
Natural- volcanoes, erosion/ weathering, climate change
Human- solid and liquid waste, accidents, unintended chemical
discharges
Ocean Pollution- II
Sources of pollution may be either:
Point sources (sources that are localized and easily?? identified-
sewage outfalls or dump sites are examples)
Non-point sources (sources that are distributed over a large area
and less easily identified- agrochemicals are one example)
Hazardous Substances
Bacteria/ parasites
Trace metals- e.g., mercury, lead
Chlorinated hydrocarbons- e.g., PCBs, Dioxin, DDT
Gases- e.g., carbon dioxide, methane
Organic wastes- e.g., sewage
Radioactive wastes- e.g., spent fuel from nuclear reactors
Sources of Hazardous Substances
Sewage waste
Manufacturing waste
Energy consumption
Trash disposal
Non-point sources (agrochemicals)
Accidents
Lecture 2:
Human Impact in the Borderland
20 million people live along the edge of the borderland
Intermittent sewage dumps are common
Waters used for cooling power plants create locally anomalous
warm ocean conditions
Threat of ocean dumping
Solid Waste Treatment
LA uses sanitary landfills for most solid waste
Other methods: burning, recycling
Ocean dumping no longer legal in USA
Many other countries still use ocean dumping
Water (Sewage) Treatment
Primary Treatment: physical filtering of water (rural septic
tanks)
Secondary Treatment: physical filtering, aeration, chlorination,
sometimes bacterial breakdown of organic matter (normal urban
treatment)
Tertiary Treatment: add extra chemicals when organic content is
high (Lake Tahoe in the 1970's)
Oil Pollution
Point Sources:
Tanker accidents
Refineries
Natural seeps
Non-Point Sources
Shipping
Urban runoff
Aerosols (car and industrial emissions)