Contaminated Sediments

Contaminated Sediments

Definition Contamination (dictionary definition) is an impurification of a substance by contact or mixture with something unclean. Sediments (EPA definition) are loose particles of sand, clay, silt and other substances that settle at the bottom of a water body. They come from eroding soil and from decomposing plants and animals, wind, water and ice often carry these particles great distances.

Definition Contaminated Sediments are matters that have been impurified by harmful substances such as pollutants. These pollutants consist of DDT pesticide and PCB or polychlorinated bipheny.

Why a problem? ●

Affects the benthic environment.

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Biomagnification of toxic substances.

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Reduction of variety of species (biodiversity).

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Threat to human health.

Why a problem?

Major Contaminants

Nutrients ● Bulk organics ● Halogenated Hydrocarbons or Persistent Organics ●

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Polycyclic Aromatic Hydrocarbons (PAHs)

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Metals and metalloids

Sources of Contaminants ●

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Point source – comes from a specific, identifiable source. Non point source – cannot be traced to a specific spot.

How does the contaminants reach underneath the water body?

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Oil spills

Mine tailing spills

Oil Spills

Mine Tailings spill

(use of cyanide-contaminates sediments when reaches water)

Species Affected Benthic Environment : worms, clams, mussels, crustaceans, insects ●

Larger fish: trout, bass, salmon

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Fish eating wildlife: mink, pelicans,

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cormorants and bald eagles humans: anglers, hunters, waders,

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swimmers (affected through direct contact)

Locations of Contaminated Sediments in the Philippines Panay Gulf in Guimaras by M/T Solar 1 that sank in 2004 which caused fuel oil spillage (Petron) in the water. ●

Locations of Contaminated Sediments in the Philippines Mine tailings spills in Marinduque Island particularly the rivers of Mogpog and Boac. Marcopping Mining Corporation was the source of the spills in 1993 and 1996. It causes the degradation of river-water quality which consequently led to the loss of livelihood. ●

Locations of Contaminated Sediments in the Philippines Cyanide leakage in Rapu Rapu Island, Albay by the Lafayette Philippines Incorporated in 2005. It resulted to fishkills in the island. ●

Mercury Contamination Associated with Small-

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Scale Gold Mining in the Upper Ambalanga River, Benguet.

How to manage? ●

Natural means

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Artificial means

Disposing sediments isolating the contaminants from the rest of the sediments by separating the smallest grains and separating the oily part of the sediment. ●

Incineration to destroy organic contaminants

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adding of cements to solidify the sediments to

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prevent the release of the contaminants

Bioremediation Bioaugmentation Adding new species of oil-eating bacteria that will speed up the breakdown of hydrocarbons

Bioenhancement Adding nutrients to the environment that

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promote the growth of naturally occurring oil eating bacteria.

Dispersants ●

Chemicals applied directly to the spilled oil in order to remove it from the water surface, where oil can be especially harmful.

The danger Oil slicks on the water surface are particularly dangerous to seabirds and furbearing marine mammals. ●

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Oil interferes with the animal's or bird's

ability to maintain its body temperature, often resulting in death from hypothermia.

Site Remediations ●

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Combined distillation and oxidative treatment of PCB-contaminated sediments Solidification/Stabilization of Soft River sediments using deep soil mixing

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