Abstract:
Such as many polluted waterbodies in the Colombo district, the Kelani River has also not
escaped the impacts of pollution due to a growing population and urbanisation. A recent study
on water pollution in the Kelani River (Bhuvendralingam et al.. 1995) shows that levels of
BOD, chromium, lead, and faecal coliforms exceed acceptable ambient water quality norms
proposed by Central Environmental Authority (CEA) cf Sri Lanka (bkh, 1992).
The objective of this study was to identify different policy options for controlling pollution
in the Kelani River, and to estimate the costs of the alternative options. In order to simplify
the analysis, the study was restricted to two major pollutants: BOD and chromium.
Chromium was selected because it is generated almost exclusively by industries and BOD was
selected because its sources are considerably more v.iried than chromium, generated by
households, industries, and natural systems.
To examine the economic implications of alternative policy options, the World Bank’s
Decision Support System for Industrial Pollution Control (DSS/IPC) was used. The analysis
of results generated by the DSS/IPC made it clear that there were significant cost differences
between enforcing CEA’s current point source effluent standards and ensuring that only the
required quality standards of ambient water were maintained. The long-run marginal costs
(LRMC) to industries for meeting the CEA’s point source chromium effluent standards was
$ 880,900.00 per ton of chromium removed, while the marginal cost of reducing chromium
pollution just enough to meet the ambient water quality standard for "fish and aquatic life"
was only $ 1,450.00 per ton of chromium removed. The primary study area for application
of the DSS/IPC model to BOD policy issues was the San Sebastian Canal, which is a
tributary of the Lower Kelani River. The analysis of the DSS/IPC generated results suggests
that it was technologically beyond the capacity of the industries currently located on the canal
to reduce their load sufficiently to bring the ambient water quality to satisfy even the
minimum desired level.
