Environmental Engineering Reference
In-Depth Information
World-wide use of HPV chemicals alone is estimated at 2-3 billion tons, meaning
300-400 kg per person in terms of the world's population. The direct emission from
such exorbitant amounts into the environment is also huge, given that many of the
chemicals are completely discharged into the environment, i.e., most of the agricultural
chemicals (fertilizers and pesticides).
In addition to the regulated and controlled direct emission of chemical substances
during their production, use and waste phase, there are other environmental loads due
to the following:
-
Energy use;
-
Water use;
-
Nonrenewable resource depletion;
-
Greenhouse gas emissions;
-
Embedded/embodied energy;
-
Non-regulated chemical emissions to air and water.
3 RISK OF HAZARDOUS CHEMICALS DURINGTHEIRWHOLE
LIFE CYCLE
Life cycle assessment (LCA) is a way of measuring the environmental, social or eco-
nomic impact of a specific supply chain or product. The technique measures the
impact of all processes from cradle to grave—this includes processing the raw material,
manufacturing, distribution, end-of-life use and waste.
Life cycle and LCA of chemical substances is complicated by a complex web of
production steps (production, intermediates and formulation), a large variety of uses
during their service life such as professional and private uses and by waste treatment
including disposal, utilization and recovery as shown in Figure 2.2.
All these steps should be assessed one by one by collecting information on the
relevant volumes (masses), technologies and emission rates of the technologies. Sum-
ming up all the emissions, we can predict the concentration of the chemical substance
in the environment at local, regional or global levels. To estimate the environmental
concentration from the emitted amount we have to characterize the environmental
transport and fate properties of the chemicals such as partition between physical
phases, reactivity, degradation, accumulation, etc.
Figure 2.2 shows that a wide range of combinations may influence the emis-
sion: production and use may occur simultaneously or far away from each other
(additional transport and storage). The intermediate may be used on the same
site, at another location of the same company or at the premises of another com-
pany. The chemical may be used directly, in form of chemical, or in products. It
can be used by professionals or by private people, e.g., in households where the
exposure may be large (children) and poorly controlled. Formulation means mix-
ing and blending with other chemical substances, while manufacturing of articles
from chemicals may involve a very complex assemblage of chemical substances
resulting in an object which, during production, is given a special shape, surface
or design which determines its function to a greater degree than does its chemical
composition.
Search WWH ::




Custom Search