Aquatic Pollution and Coastal Management

Unit 10 : Radioactive pollution

10.4.2.Anthropogenic Activity

Radiation from “Fallout” from Nuclear Tests
The nuclear explosions carried out for bomb testing or for beneficial uses such as for mining, excavation of harbours and canals release huge quantity of radioactive elements into the environment. After explosion, larger particles will reach the earth 's surface within few hours, but small particles will remain in the atmosphere for a long time and come to surface by rainfall or snow. These small particles will strongly adhere to the leaves of vegetation from where they pass on to the herbivores and finally to the man through milk or meat. In the aquatic environment fallout elements will form complexes with organic detritus, from which they are readily transferred to the aquatic organisms.

Radiation from Nuclear Waste Disposal
Nuclear waste dumping within the land or in the ocean leads to radiation pollution. for example ,the nuclear waste dumped into the Pacific, a short distance off the coast of San Francisco by United States between 1946 and 1965 the drums broke open and the waste entered the food chain in a matter of few decades. Radiation irradiated the small plankton on which small fish feeds on and these small fishes are food for the large fishes which will be eaten by the human beings. In food chain dilution does not occur, but the concentration of toxic substances occurs.

Radiation from Nuclear and Thermal Power Stations
The present day nuclear power plants use the energy released from the fission of nuclear fuels. The most common fuels used for fission are uranium, thorium, and plutonium. The spent material obtained from the reactors after useful utilization is reprocessed for the recovery of unburned uranium, plutonium and some other important isotopes. In the entire nuclear fuel cycle (operation from mining of fuel to its final disposal) at most of all stages liquid, gaseous and solid radioactive wastes are released, which have a tremendous potential to contaminate the environment.

Radiation from Radioactive Consumer Goods and from Electronic Devices
Small sources of radiation are more or less wide spread throughout the population which includes the luminous dials of wrist watches and alarm clocks, shoe fitting, X-ray fluoroscopes, TV set, fluorescent lamps, telephone dials and electronic components of various devices which may be more than 5 of the total background radiation received by man.

Radiation from Medical Use of Radiation and Radioactive Drugs
The use of x-rays and radioisotopes for the diagnostic procedures and treatment of malignant and non-malignant condition in medical field adds to the radioactive contamination.

Radiation from Occupational Exposure
Radiation pollution also occurs from the exposure of persons professionally engaged in handling radiation sources and radioactive substances.