PRELIMINARY INVESTIGATION OF WATER QUALITY IN SEVERAL AQUACULTURAL FARMS IN HANOI CITY, QUANG NINH, NAM DINH AND HA TINH PROVINCES

Abstract

In recent years, aquaculture in our country has been remarkably developed both
in terms of the area and production, contributing significantly to the development of
the national economy. This article presents the monitoring results of water quality at
several aquacultural farms in Hanoi, Quang Ninh, Nam Dinh and Ha Tinh provinces
during the period from January to November 2016. The results showed that:
pH = 7.3 - 8.5; COD: 16.3 - 35.8 mg/l; Ammonium content: 0.034 - 0.327 mgN/l;
Nitrite content: 0.005 - 0.156 mgN/l; Nitrate: 0.169 - 3.437 mgN/l; Phosphate
content: 0.004 - 0.203 mgP/l; P total: 0.057 - 0.338 mgP/l and dissolved silica: 1.05 -
3.90 mgSi/l. At some monitoring points, the levels of ammonium and phosphate in
Quang Ninh and Hanoi exceeded the permitted standards QCVN 10-MT:2015/BTNMT
and QCVN 38:2011/BTNMT. Among the water samples studied, the water samples
from the shrimp area always had the highest nutrient contents.