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Ministry of Agriculture & Rural Development CARD Project Progress Report 002/05/VIE Technical and economic feasibility of applying the Better Management Practices (BMP) to household aquaculture in Vietnam MS-3: Initial Environmental Assessment Report May, 2007 Table of content List of figures……………………………………………………………………………….. 1 List of tables…………………………………………………………………………………. 1 1. Introduction………………………………………………………………………………. 2 2. Methodology……………………………………………………………………………… 2 3. Results…………………………………………………………………………………….. 3 3.1 Sampling site map and environmental quantity in Hung Hoa, Nghe An…………….... 3 3.2 Sampling site map and environmental quantity in Thach Ha, Ha Tinh…………….…. 5 3.3 Sampling site map and environmental quality in Vinh Hung, Thua Thien-Hue……… 7 3.4 Environmental issues discovered and possibly suggested remedies…………………... 9 4. Conclusion and recommendation……………………………………………………….. 12 References…………………………………………………………………………………… 13 List of figures Fig. 1. Map of Vietnam with project locations………………………………………………. 2 Fig. 2. A diagram of the project site in Hung Hoa commune, Nghe An Province………….. 3 Fig. 3. Outlook of the Shrimp farming site of Thach Ha commune, Ha Tinh province……... 5 Fig. 4. Water temperature fluctuation in an intensive shrimp pond during culture period…... 6 Fig. 5. Diagram of project site in Vinh Hung commune, Thua Thien-Hue province………... 7 Fig. 6. Well- invested and separated canal system…………………………………………... 11 List of tables Table 1. Level of parameters of water and soil in the project area…………………………... 4 Table 2. Results of water and soil quality analysis in Thach Ha site………………………… 6 Table 3. Results of water and soil quality analysis in Thua Thien-Hue site………………… 8 Table 4. The review of facing issues and suggested solutions in Nghe An site……………... 9 Table 5. Review of facing issues and responding remedy in Ha Tinh site…………………... 10 Table 6. Review of facing issues and responding remedy in Hue sites……………………… 11 1. Introduction An initial environment quality assessment and determining possible impacts on the culture is the objective of help desk officers and planners to assess impacts of the project in relation to environment effects. The assessment shall provide a survey of environmental effects likely to ensure if an aquaculture project is implemented successfully. An initial assessment is also the key to see what positive and/or negative impacts are after project implementation. Usually an assessment will be based on easily accessible information, former research, the local population’s view, etc. In the content of the CARD project, three shrimp culture sites namely Hung Hoa, Thach Ha and Xuan Vinh commune respectively located in Nghe An, Ha Tinh and Hue provinces were selected for involvement. This selection was based on given criteria such as concentrated shrimp farming, voluntary cooperation, good production history, and already evaluated socio-economic conditions. 2. Methodology Sampling and surveying sites as red indication in the map below: On-field measurements: • pH: measured with a portable pH meter (YSI 52) • Salinity: use of refractometer (Spec T2000) • Dissolved Oxygen (DO): measured with an oxygen meter (YSI 52) • Temperature (ToC): measured with a digital thermometer (Themo 100) • Transparency (cm): measured with Sechi disk Laboratory analysis: Water and bottom soil sampling and analysis for COD (mg/l), BOD (mg/l), Alkalinity (mg/l), Fe (mg/l), PO43--P (mg/l), Total Ammonia Nitrogen (mg/l), Nitrite (mg/l), Sulfide (mg/l), Oil residual (mg/l), Soil composition followed Standard Methods (APHA, 1998). Fig. 1. Map of Vietnam with project locations The running river water was used as a supply source, and sampled using a peristaltic pump with two heads. The water sample was collected for 30 minutes into a plastic bucket. Then a final sample of 1 liter was taken from the well-mixed bucket. All samples were kept cool with ice, and analyzed immediately when reaching the Lab. 3. Results 3.1. Sampling site map and environmental quantity in Hung Hoa commune, Nghe An province. The diagram of Hung Hoa commune and its adjacent land was illustrated as following: Note: Arrow indicates the way water flows. Lam River Dam No. 42 (asphalted road) Head quarters of Commune Mangrove P1-5 Project area R-NA Shrimp pond area 109 ha River port WI-NA 1 km Water inlet IM-NA Wmax:100 m Lmax: 8 km A: 120 ha Shrimp pond area 20 ha Sediment reservoir Fig. 2. A diagram of the project site in Hung Hoa commune, Nghe An Province The project’s ponds are located in a planned shrimp farming system and are considered to be sound design within the system (separated inlet and outlet). However these are connected with a main canal that acts as both supply and discharge line for the whole system in the commune. Additionally, oil pollution from the port (Fig. 2) sometimes may cause detrimental effects to the ecological system. The presence of mangrove habitat near the shrimp ponds will exert several ecological processes that alters environment quality, such as sediment and pollutant retention (natural seawater depuration), desalinization of water, and protection of storm and wind effects. Table 1. Level of parameters of water and soil in the project area Sample coding Parameter RNA WI NA IM NA DC NA P1 NA P2 NA P3 NA P4 NA P5 NA COD (mg/l) 6.8 7.5 5.7 5.4 5.2 6.9 5.8 6.5 7 BOD (mg/l) 6.4 6.3 5.0 5.0 4.0 4.0 4.5 6.0 6.2 30 40 25 40 40 45 45 35 40 Water temp. ( C) 23 22 22 22.4 22 21.4 22 21 21.2 pH (water) 7.3 7.1 7.5 6.4 6 6.3 6.5 6.7 6.4 Salinity (‰) 13 14 16 16 17 18 16 19 20 Alkalinity (mg/l) 90 98 99 95 80 85.5 87 88.8 80 DO (mg/l) 6.5 6.4 7 5.5 6.2 7.1 6.5 6.8 6.4 Fe total (mg/l) 0.33 0.31 0.25 0.26 0.09 0.12 0.14 0.11 0.08 PO4 (mg/l) 0.429 0.345 0.478 0.299 0.232 0.223 0.312 0.303 0.324 TAN (mg/l) 0.533 0.478 0.463 0.544 0.119 0.122 0.213 0.204 0.227 Nitrite (mg/l) 0.034 0.025 0.034 0.029 0.023 0.123 0.028 0.109 0.111 Sulfide (mg/l) 0.021 0.041 0.046 0.073 0.014 0.028 0.048 0.037 0.032 Oil residual (mg/l) 0.140 0.110 0.030 0.205 - - - - - Transparency (cm) o Soil composition pH (soil) - - - - - - - - Muddy Muddy Muddy Muddy Muddy sand sand sand sand sand 4.5 5.5 4.8 5.0 5.6 Note: refer to Fig. 1 for detail of sampling points Table 1 shows that water quality in most of the ponds and adjacent area investigated was considered suitable for aquaculture. It was within the recommended range for shrimp cultivation, except for level of total Fe and oil. Specifically, during the period of water disinfection a variety of oxidative agents was used, like KMnO4 and Chlorine. The pond water was rather poor quality with regard to concentration of total ammonia nitrogen (TAN), and Alkalinity. There was homogeneity in composition of the pond bottom soil, it was muddy sand in all studied ponds that is recognized to be ideal in preventing leaching via the pond bottom. However, the soil is rather acidic (low pH of around 5) which may require a large amount of lime to neutralize during pond preparation. 3.2. Sampling site map and environmental quantity in Thach Ha commune, Ha Tinh province Mangrove Project ponds P1-5-HT National dike DC-HT Rice field Water inlet R-HT WI-HT IM-HT Thach Ha river Shrimp culture area Road to Ha Tinh provincial city Fig. 3. Outlook of the Shrimp farming site of Thach Ha commune, Ha Tinh province It was clear that project ponds are under operation in a badly designed canal system, with every pond using the same canal for filling and draining ponds. Like the project site in Nghe An, mangrove may experience environmental advantages, but its density is much lower that that in Nghe An leading to lower depuration capacity. The difference in BOD concentration between river and inside mangrove may be an indicator, at around 1.0 and 0.2 mg/l, respectively. No upgrading and renovation over long time of operation made the ponds shallow and congested leading to difficulty in maintaining suitable water level in ponds. This critically results in wide diurnal fluctuations, even more than 10oC (Fig. 4) that may cause acute stress to the shrimp making them more susceptible to disease infection. The graph below represents daily change in water temperature during the year 2005 (archived data). 35.0 oC 33.0 31.0 29.0 27.0 25.0 Dotted line: temperature at 2 PM Solid line: temperature at 6 AM 23.0 Date 21.0 06/6 16/6 26/6 06/7 16/7 26/7 05/8 15/8 25/8 Source: Archived data 2005 Fig. 4. Water temperature fluctuation in an intensive shrimp pond during culture period High change in water temperature is even more important as shrimp is a cold- blooded animal Table 2. Results of water and soil quality analysis in Thach Ha site Sample coding Parameter RHT WI HT IM HT DC HT P1 HT P2 HT P3 HT P4 HT P5 HT COD (mg/l) 6.3 6.5 6.1 5.4 6.2 6.4 5.3 6.4 5.6 BOD (mg/l) 5.4 5.6 4.9 4.5 4.8 5.0 4.2 5.6 5.0 25 30 35 45 50 45 55 40 60 Water temp. ( C) 21 22 22.5 21 21 20.4 22 20.9 21 pH (water) 7.9 8 7.9 7 6.3 6.5 6.5 6.6 6.4 Salinity (‰) 15 16 16 20 19 18 19 21 19 Alkalinity (mg/l) 112 115 99 100.5 90.6 87.8 100 98.8 105.8 7 7.4 7.3 6.5 7.2 7.3 7.4 8 7.8 Fe total (mg/l) 0.28 0.23 0.15 0.21 0.12 0.08 0.11 0.07 0.05 PO4 (mg/l) 0.229 0.145 0.234 0.343 0.167 0.211 0.224 0.213 0.145 TAN (mg/l) 0.432 0.434 0.353 0.394 0.319 0.248 0.255 0.278 0.308 Nitrite (mg/l) 0.114 0.035 0.056 0.129 0.103 0.056 0.048 0.109 0.081 Sulfide (mg/l) 0.012 0.021 0.042 0.083 0.016 0.018 0.038 0.017 0.021 Oil residual (mg/l) 0.040 0.034 0.030 0.076 - - - - - Soil composition - - - - Sandy mud Sandy mud Muddy sand Sandy mud Muddy sand pH (soil) - - - - 5.6 6.1 5.7 5.9 6 Transparency (cm) o DO (mg/l) As shown in the table, water quality parameters in the project site of Ha Tinh was seen to be better in term of BOD, alkalinity, total ferrous, and pH soil. Like DO level in Nghe An, ponds were under organic treatment and disease germ removal with intensity of oxygenation attributed to high level of DO in water. 3.3. Sampling site mapping and environmental quality in Vinh Hung commune, Thua Thien-Hue province. C6-H L1-H Tam Giang Lagoon Shrimp farming area Pumping station L2-H C1-H C5-H L3-H Pumping station P6-H P1- C2-H L4-H P2-H Culture area P5-H L5-H Concrete supply P3-H Residencing P4-H Discharge C4-H C3-H Fig. 5. Diagram of project site in Vinh Hung commune, Thua Thien-Hue province Culture infrastructure in Thua Thien-Hue project site is currently well-designed and in good operational condition managed by aquaculture cooperative authority that was legally established years ago. Effective community-based management and development has been attributed to successful shrimp production via good planning in crop schedule, culture species selection and disease quarantine, chemicals and antibiotics application. Table 3. Results of water and soil quality analysis in Thua Thien-Hue site Sample coding (16) Parameter L1-H L2-H L3-H L4-H L5-H C1-H C2-H C3-H C4-H C5-H C6-H P1-H P2-H P3-H P4-H P5-H COD (mg/l) 8.5 8.1 7.8 8.4 8.1 12.5 13.4 9.7 11.5 10.5 13.4 - - - - - BOD (mg/l) 7.4 7.0 6.9 7.5 6.9 7.5 6.8 7.2 8.7 8.3 9.8 - - - - - Transparency (cm) 35 38 40 38 35 - 30 40 20 10 30 - - - - - Water temp. (oC) 26 25 26.2 26 26.4 27 27.3 27.5 26.6 27.4 27.3 - - - - - pH (water) 7.9 8.5 7.9 7.8 8.3 6.5 7.1 6.6 6.9 6.3 7.1 - - - - - Salinity (‰) 23 23 24 24 23 18 19 21 21 20 19 - - - - - Alkalinity (mg/l) 110 105 99 123 134 124 119 125 132 DO (mg/l) 7.9 8 7.8 7.5 7.2 6.3 6.4 6.3 5.8 5.2 4.6 - - - - - Fe total (mg/l) 0.18 0.13 0.15 0.21 0.17 0.08 0.11 0.09 0.08 0.14 0.16 - - - - - PO4 (mg/l) 0.342 0.245 0.378 0.299 0.321 0.443 0.367 0.361 0.534 0.564 0.485 - - - - - TAN (mg/l) 0.687 0.665 0.763 0.568 0.439 0.322 0.423 0.420 0.467 0.380 0.470 - - - - - Nitrite (mg/l) 0.034 0.025 0.034 0.029 0.023 0.23 0.098 0.13 0.211 0.184 0.214 - - - - - Sulfide (mg/l) 0.021 0.041 0.076 0.043 0.101 0.128 0.098 0.09 0.134 0.226 0.321 - - - - - Oil residual (mg/l) 0.320 0.280 0.230 0.255 0.158 - - - - - - - - - - - 100.5 112.5 Soil composition - - - - - - - - - - - pH (soil) - - - - - - - - - - - Ponds are under prepararion step (bottom exposure) Sandy mud Sandy Sandy 5.6 6.6 5.8 Muddy sand Sandy mud 5.7 6.3 Data from the table shows that source of supply water had higher level of BOD than that in Nghe An and Ha Tinh, while inside ponds no data recorded due to they were in bottom exposure. Oil pollution that was more serious was blamed on the villagers’ activities. This needed more attention to remove or eliminate when taking water in. 3.4. Environmental issues discovered and possibly suggested remedies In Nghe An: Over the last three yeasr, though most of the shrimp ponds in the area were providing a high rate of economic return, in the long-term the following issues need to be considered and addressed: - Non-separated supply and discharged canal - Oil pollution may occur due to the port built at other side of the river, about 1 km away from main inlet (refer to Fig. 2). - Unplanned and non-controlled chemical utilization and application. - Acoustic pollution may be increasing. - The operating culture area will be converted into waste disposal site for Vinh city. - Therapeutic agents antibiotics present in water add to those used by farmers, increasing antibiotic concentration in culture tanks or ponds. Increase of antibiotic concentration over recommended values can be toxic for cultured species Table 4. The review of facing issues and suggested solutions in Nghe An site Item Issue Suggested solution Water source Oil pollution and contamination caused Watch out for oil contamination prior to water by nearby river port utilization. Low salinity as it is situated far from Water from storage ponds can be of higher coastal line. salinity. Passive water exchange due to Negotiate to finalize cooperative mechanism confliction between agriculture and and schedule aquaculture sectors. No separated water supply and discharge system. Intermittent pollution caused industrial activities upstream. Check for water quality regularly and give by warning to wider culture community Seed quality No strict regulation for disease checking and quarantine for PL (high initial and availability infection rate of White Spot Disease to be stocked) No availability of aeration while Water management culturing at high density. Quite low water level (0.7-1 m) in ponds. PL need compulsorily checking for disease and pathogens before stocking Aeration devices need to be installed. Maintain water depth at least 1m, deepening pond if possible. Some ponds without water exchange Actively water exchange when needed. during crop. Trash fish and low cost home made- feed No longer or limited utilization of low cost are still used causing organic pollution feed. and DO mitigation. Pond preparation did not strictly follow Strict application of pond preparation guidelines provided due to lack of capital technique. Use an appropriate amount of commercial pellet of good quality. investment. No water reservoir and storage systems. Shrimp farming need including a certain water reservoir (at least 20% total area).