Toward eco-justice for all - Environmental Harm: An Eco-justice Perspective - page 162

upon these understandings of risk, we need a framework whereby we
can implement the precautionary principle. All of these observations
point to the necessity of analysing harm and risk in relation to time
and space.
This brings us back to the question of measurement and assessing
how it is that we know what we know. What baseline criteria and tools
can be drawn upon in order to measure harm? What evidence can
be marshalled in support of preventing certain forms of harm? From
which perspective is harm to be assessed, particularly if conflicting
interests are at stake? Whose harm is deemed to be greater in any given
situation? These are moral as well as technical questions (see Chapter
One), but part of the solution to practical problems lies in asking the
right questions to begin with.
Close scrutiny also needs to be given to matters of thresholds and
limits. For example, Mandiberg (2009: 1185-6) describes the difference
between technology-based limits, and quality-based limits in the
context of pollution regulation and notions of environmental harm.
Technology-based limits focus on pollution emerging from
a particular source. They require a source to adopt the best
mechanisms practically available to reduce or eliminate
the pollution…These limits do not, however, reflect an
assessment of how the pollutants in question affect a
particular water body or air quality control region.
Quality-based limits, on the other hand, are more
stringent and do focus on the health of the water body or
air quality control region in question. In setting these limits,
the agency begins with quality goals and works backwards
to impose limits on all sources contributing pollution to
that water body or air quality control region.
Each approach implies a different starting point for analysis, and each
has different implications for any conclusions that are made in relation
to the extent and nature of harm. While there is benefit to be gained in
drawing upon each approach, the nature and extent of environmental
harm nonetheless requires a contextual interpretation based upon
specific trends and incidents: 'For example, a discharge that is slightly
over a water-quality-based limit might not actually harm the health of
the water body, depending upon discharges from other point sources.
On the other hand, a discharge that is significantly over a technology-
based limit might cause substantial environmental harm' (Mandiberg,