Efficacy and toxicity of chlorination to organisms in low salinity shrimp ponds | |
| Author | Husnah |
| Call Number | AIT Diss. no.AQ-01-04 |
| Subject(s) | Water--Purification--Chlorination Aquatic organisms |
| Note | A dissertation submitted in partial fulfillment of the requirement for the degree of Doctor of Technical Science, School of Environment, Resources and Development |
| Publisher | Asian Institute of Technology |
| Series Statement | Dissertation ; no. AQ-01-04 |
| Abstract | A series of experiments was sequentially conducted to determine the effect of cholrine on biological community in water and sediment of low salinity (3-5 ppt) shrimp ponds under field and laboratory conditions. Those experiments consisted of (1) Chlorine demand and bacteria abundance of shrimp pond water in relation to TSS contents, (2) Cholrine demand and bacteria abundance in pond sediment, (3) Response of plankton to various chlorine concentrations and nutrient enrichment, and (4) Acute toxicity of chlorine to referent sizes of black tiger shrimp (Penaeus monodon Fabricius). Water, sediment and shrimp samples were collected from a shrimp pond over a culture period of 150 days. Cholrine demand in pond water and its efficacy todesinfect indigenous bacteria were determined with pond water containing various concentrations of total suspended solids (TSS). To study chlorine effect in pond bottom, sediment cores were collected with PVC tubes, and experiment was conducted in 4 circular concrete tanks containing clay soil, Sediment in those tubes was treated with 4 active chlorine doses to determine bacterial growth response. The acute toxicity and chronic effect of chlorine on plankton were determined by treating pond water with 5 chlorine doses to which plankton mortality was determined 24 hours, and water was further enriched with nitrogen and phosphorus for chronic effect of residual chlorine on plankton growth. Acute chlorine toxicity to Penaeus monodon at the size of 0.02, 2.78, 8.47 and 23.65 g was tested in glass jars under static conditions for 24 hours without media renewal, Concentration of applied and residual chlorine which kills 50 percent of shrimp of each size after 24 hours exposure (24-hLC50) was used as an indicator of the acute toxicity Results show that the efficacy of chlorine toxicity to organisms in pond is greatly influenced by chlorine demand in the water and sediment, and the chlorine demand is closely related to organic matter in particulate from. Cholrine demand in pond water hving TSS of 114 mg/L was higher than that in water with Tss of 69 and 29 mg/L. Chlorine concentration of 50 mg/L was completely consumed within 24 hours in TSS 114 mg/L, compared to 168 hours with TSS of 69 and 29 mg/L. The complete bacteria inactivation occurred when concentration of free and total residual chlorine (FRC and TRC) was at 1.0 and 2.17 mg/L. respectively, In pond water with TSS of 114 mg/L, bacteria was completely inactivated immediately after exposure to 50 mg/L chlorine, with TSS of 69 mg/L the inactivation took as look as 48 hours in 30 mg/L chlorine treatment, and 96 hours in 50 mg/L chlorine Treatment. The chlorine demand of pond sediment with soil pH, clay, organic carbon and TKN content at layers 0-2.5 cm of 7.06, 75.83%, 4.05% and 0.15% respectively, was 0.48 kg active cholrine/m2 soil, Both organic carbon and total Kjedhal nitrogen contributed to chlorine demand in the sediment. Chlorine at a dose of 300 mg/L did not completely inactivate bacteria although concentration of FRC and TRC in overlying water still remained at 20 mg/L at the end of experiment. Chlorine at a dose of 1200 mg/L and 2400 mg/L corresponding to FRC concentration of 433 and 844 mg/L and TRC concentration of 711 and 1333 mg/L, respectively inactivated 100% bacteria within 2 days of contact time. With high chlorine doses, chlorination was effective to inactivate bacteria in sediment to a depth of 2.1 cm only. The results of chlorine effect on plankton show that chlorine concentration as low as 2 mg/L corresponding to TRC concentration of 0.25 mg/L, could effectively reduce more than 50% of primary productivity and killed more than 40% of zooplankton, while it did not completely inactivate the bacteria. The dominant phytoplankton selenastrum sp. was resistant to TRC concentration up to 1.2 mg/L. Xooplankton species of Hexarthra and brachionus were sensitive to TRC concentration as low as 0.25 mg/L . Enrichment of chlorinated water with nitrogen and phosphorus at a ratio of 4:1 and N concentration of 28 mg/L, triggered the growth of phytoplankton in all chlorine treatments. However, the growth of phytoplankton was 48% smaller in 10 mg/L chlorine tratment corresponding to TRC concentration of 1.2 mg/L than that in the control. The number of phytoplankton species increased in all treatments after 3 days of nutrient enrichment and Selenastrum sp. regained dominance after 6 days. Shrimp mortality was mostly influenced by the concentration of combined residual chlorine immediately after chlorine exposure. The 24-h LC50 of applied chlorine concentration for shrimp at size of 0.02, 2.75, 8.47 and 23.65 g, was 6.96, 2.05, 11.50 and 13.34 mg/L corresponding to combined residual chlorine concentration of 0.91, 1.39, 1.74, 1.98 mg/L, respectively. |
| Year | 2001 |
| Corresponding Series Added Entry | Asian Institute of Technology. Dissertation ; no. AQ-01-04 |
| Type | Dissertation |
| School | School of Environment, Resources, and Development (SERD) |
| Department | Department of Food, Agriculture and Natural Resources (Former title: Department of Food Agriculture, and BioResources (DFAB)) |
| Academic Program/FoS | Aquaculture and Aquatic Resources Management (AQ) |
| Chairperson(s) | Lin, C. Kwei; |
| Examination Committee(s) | Yakupitiyage, Amaratne;Preeda Parkpian; |
| Scholarship Donor(s) | Agricultural Ministry of Indonesia; |
| Degree | Thesis (Ph.D.) - Asian Institute of Technology, 2001 |