Assessment of the Water Quality of the Western Boundary of Kuching Wetland National Park, Sarawak, Malaysia

摘要

Kuching Wetland National Park (KWNP) is one of the RAMSAR wetlands in Malaysia, a wetland of international importance. Understanding the water quality of the riverine system that drains the KWNP is crucial for sustainable management of the wetland. Hence, the water quality of Sibu Laut River, which forms the western boundary of the park, is described in this study. Three samplings were carried out during low tide along the western boundary of the wetland. Sub-surface and near-bottom water samples at six selected sampling sites were taken and analysed for physico-chemical parameters. The variations between sub-surface and near-bottom water column of those parameters were detectable and due mainly to the influence of tidal currents. A peak of sub-surface organic phosphorus was observed at station 2 next to the village of Sibu Laut whereas elevated near-bottom organic phosphorus was observed at station 4 near to the shrimp farm. Organic phosphorus represents a significant fraction of the total phosphorus, comprising from 59.76% to 83.64% and 62.50% to 78.67% for sub-surface and near-bottom water, respectively. In contrast, inorganic phosphorus was extremely low at most of the stations. There is a significant correlation between organic phosphorus and chlorophyll a, which indicates association of organic phosphorus and phytoplankton in the study area. The present study showed that Sibu Laut River had minimal pollution impact to the wetland, except the elevated sub-surface organic phosphorus near the Sibu Laut Village and elevated near-bottom organic phosphorus near the shrimp farm. Continuous monitoring program is important for early detection of future threats to the water quality of Sibu Laut River.