Effect of shrimp pond effluent on soil and sediment qualities in Kung Krabaen bay
1997
Chanin Sangrungruang
Results of the investigation on the effects of effluent from shrimp farms on soil and sediment in Kung Krabaen Bay indicated that the most affected area was wastewater canal. The degree of effect decreased from wastewater canal to shore-line to 500 meters and 1,000 meters offshore which were indicated by organic matter content of soil which decreased from 6.97 to 2.04 to 0.77 to 0.25 percent. Data of sediment collected throughout one year indicated significant effect of monsoon on quantity of sediment trapped from various stations. Significantly higher amount of sediment 2296.7 g/square m/day, were collected in monsoon season comparing to another period which 414.9 g/square m/day were collected. The decreased in organic content of sediment collected in wastewater canal, shore-line, 500 meters offshore and 1,000 meters offshore indicated that less amount of sediment from shrimp farms were carried out to offshore areas. Large portion of sediment trapped in these areas were the old sediment in the Bay that were stirred up by wind and wave action and a large portion of sediment also came in with water mass from the outer sea. The soil and sediment of water supply canal also had high concentration of organic matter (4.84 and 4.31 percent) these canals had also been used as wastewater canal before. At present, some shrimp farms are also release shrimp pond effluent into these canals eventhough it is prohibited.
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