particularly damaging when released into freshwater environments.
Phenols and Sulphides: Measured in milligrams per litre. These are by-products of
gasification and carbonization processes and can also be present in drainage water
from coal stockyards, etc.
Metals (typically cadmium [Cd], mercury [Hg], chromium [Cr], nickel [Ni],
vanadium [V], zinc [Zn], copper [Cu], arsenic [As] and boron [B]): Measured in
milligrams per litre. Metals can leach out of fuel stockpiles and are often released
from the various ashes and wastes that arise from energy industries.
(b) Measuring Methods:Measurement methods for water discharges are
straightforward and well established and should conform to widely adopted
international standards, such as the International Organization for Standardization
(ISO) standards.
(c) Limitations of the Indicator: (i) When the quality of the water body itself is
monitored, it is not always possible to distinguish between pollution resulting from
energy activities and pollution from other activities, such as those in the industrial and
agricultural sectors. For this reason, it is preferable to monitor direct discharges from
the activity as they enter the water body. (ii) It is difficult, and perhaps not helpful, to
aggregate into a single indicator the measurements for all pollutants taken at different
times and points along the watercourse. Therefore, this indicator is in fact a number of
different indicators, depending on the number of pollutants being measured. (d) Alternative Definitions/Indicators: An alternative indicator is annual water
pollutant discharges (as a mass emission – concentration x flow) and their percentage
changes. It would also be useful if policy-relevant information on emission targets
were to be included in the indicator (if such targets exist for a given country). This
allows an assessment of the ‘distance to target’ for a country, and hence whether
existing pollution abatement measures are sufficient to meet existing national or
international targets.
Alternatively, the percentage change in discharges over time (e.g. the percentage
change in discharges between 1990 and 2000) may be considered; that is, indexed
emissions relative to a 1990 baseline.
