THESIS APPROVAL
THESIS APPROVAL
THESIS APPROVAL
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Environmental Conditions in the Lower Chao Phraya River<br />
1. General Information<br />
The lower Chao Phraya river is an important estuary located in Bangkok and<br />
Samutprakarn Province. This estuary occupied the area approximately 58 km<br />
extending from the mouth of the river to Rama VII Bridge. The mouth of the river is<br />
opened to the upper Gulf of Thailand. Water change in this area was controlled by<br />
diurnal tides. The volume and salinity of water are mainly affected by influence of<br />
precipitation, freshwater and seawater. The bottom of the estuary was constituted of<br />
fine sediment mainly composed of mud.<br />
2. Water Qualities and Sediment Properties<br />
The Office of Environment Policy and Planning (2001) reported that water<br />
qualities in the lower Chao Phraya river were in rather bad condition. Most of all<br />
parameters were within the Thailand National Water Quality Classification for<br />
industrial purpose, except for DO, biochemical oxygen demand (BOD) and ammonianitrogen<br />
(NH3-N) which declined below the criteria. The measurement of water<br />
quality recorded during 1994 and 1999 for DO, BOD and NH3-N were 1.6, 3.2 and 1<br />
mg/l, respectively.<br />
It is obvious that the rapid increase in population and coastal development lead<br />
to water quality change. Ngamprayad (1999) found that the frequency of low DO<br />
tends to be greater in urbanized and industrialized zones. Pollution sources, such as<br />
urban runoff, sewage disposal, and industrial effluents, contribute to the loading of<br />
organic pollutants to the water and bottom sediment of the estuary (Wattayakorn,<br />
2003). According to Pollution Control Department (2000), the average BOD loading<br />
from domestic waste in Chao Phraya river was approximately 19-1,377 mg/l while the<br />
industrial loading estimated 230-29,000 mg/l. It is evidence that the industrial activity<br />
was the major source of organic matter in this area followed by the domestic waste.<br />
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