Fish cages on La Nga river, the southern province of Dong Nai, become empty after the mass fish death happened in the middle of this month.(Photo: VNA) Dong Nai (VNA) - Changes to thewater environment on the La Nga river in the southern province of Dong Nai havebeen blamed for the death of nearly 1,000 tonnes of fish this month,provincial officials have said.
Vice Chairman of the Dong Nai Province People’sCommittee Vo Van Chanh said that as soon as the mass fish death on the river inthe province’s La Nga and Phu Ngoc communes was reported, the SouthernEnvironment Observation Centre, Zone VI Animal Health Department and theprovincial Department of Natural Resources and Environment took water samples.
Test results showed the concentrations ofammonia, nitrite and the chemical oxygen demand (COD) in samples were inexcess of levels allowed in aquaculture farming, Chanh said.
Director of the provincial Department of Agricultureand Rural Development Huynh Thanh Vinh said rain lasting from May 15 toearly morning of May 16 made waste flow into the river, lowering the dissolvedoxygen content in the river’s surface water, killing the fish.
The concentration of ammonia in water riversamples was 4-7 times higher than permitted, the nitrite concentration 2-3times higher than permitted and the COD concentration 3-16 times higher thanpermitted.
Moreover, testers found no signs of commondiseases or infectious diseases that freshwater fish tend to contract.
According to the department, last June, morethan 1,900 tonnes of fish from 132 local households were found dead along the5km La Nga river after heavy downpours.
The low oxygen level in the water and the highdensity of fish were reported as the main cause of the mass deaths at thattime. Pollution from upstream areas swept down by the rains worsened theincident.
As of last December, the provincialPeople’s Committee had spent more than 12 billion VND (516,000 USD) tosupport affected households in Phu Ngoc and La Nga communes.
Vinh said the department planned to help fishfarming households who were affected by the recent mass fish death.
Deputy Prime Minister Truong Hoa Binh on May 28 askedfor further investigation into the cause of the mass fish death and hand outappropriate punishments to those who violated the laws.
Binh also ordered Dong Nai authorities toreview the major sources of waste discharged into the La Nga river,particularly giving focus to the cases that received complaints from thepublic.
A thorough report is expected to be submitted tothe Prime Minister before June 30.-VNA
VNA
