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6
Evaluating Toxic Chemical Management Practices
INTRODUCTION
The third possible use of mass balance in-
formation listed in SARA Section 313~1) is
for assessing "toxic chemical management
practices at facilities currently reporting to
the TRI. These practices are considered to
encompass transportation across and within
facility boundaries, storage and handling,
waste reduction, and on-site tracking and
treatment of toxic chemicals. This chapter
evaluates both EMB and MA practices for
their adequacy in providing data on (a) the
types and amounts of toxic chemicals
managed by a facility; (b) the extent to
which changes in amounts of toxic sub-
stances are attributable to changes in levels
of manufacturing activity; (c) the com-
parability among facilities; (~) their useful-
ness to chemical managers for enhancing the
safety of their management practices; and (e)
their usefulness to the public and govern-
ment in evaluating whether effective prac-
tices are being used to minimize the actual
and potential releases of toxic chemicals into
the environment. The use of mass balance
information for evaluating waste reduction
efficiency is discussed in Chapter 5.
57
CHEMICAL MANAGEMENT PRACTICES
Transportation
Assessing management of transportation
of the chemicals outside of facilities is
beyond the scope of the committees charge.
This section focuses on the movement of
chemicals within and across boundaries of
facilities. However, the methods used to
transport chemicals outside of facilities
might affect toxic chemical management
practices at a facility. For example,
materials brought to a facility by rail might
be offloaded and stored differently from
materials brought by trucks. Different
transportation practices also have different
potentials for routine and accidental releases.
The single and most relevant piece of in-
formation in evaluating toxic chemical
management practices is the annual quantity
of specific chemicals transported across fa-
cility boundaries. Although this information
could be obtained through EMB, it would be
much cheaper and simpler to obtain it from
readily available records, such as invoices
and shipping manifest records. In this case,
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58
information obtained through MA would be
sufficient.
Information supplementing MA data could
contribute to a community's ability to
estimate risks for types and quantities of
chemicals brought to and taken from a site.
Descriptions of changes in physical-chemical
properties (e.g., from a liquid to a solid
material or from a more hazardous to a less
hazardous form) or changes in transport
methods could provide valuable information
to the community in assessing the potential
hazards associated with transport practices
and for developing emergency response
plans.
Storage and Handling of Chemicals
Storage and handling of chemicals at a
facility can encompass a wide range of
activities. Conceivably, these could include
methods of shipping and transfer, quantities
shipped and stored, high-pressure processing
or storage of chemicals, form of storage, un-
loading systems, unloading procedures, safe-
ty systems, frequency of inspection, and
other critical pieces of information necessary
for the management and handling of chemi-
cals.
The probability and severity of a sudden
release of a toxic chemical at a facility relate
to the maximum quantity stored at the fa-
cility. Community knowledge of quantities
of hazardous materials stored is provided for
by TRI reporting. This information, which
is reported annually, is important in assess-
ing a facility's progress in the reduction of
the absolute quantity of chemicals stored on
site and indicates to the public the facilities
where large quantities of dangerous chemi-
cals are stored.
However, the quantity of chemicals stored
can fluctuate relative to a facility's level of
production, which can make interfacility
comparisons difficult, even among similar
types. In these cases, on a conceptual basis,
normalization of the maximum quantity of
chemicals stored on site (by dividing this
quantity by the level of production) could be
useful. However, all proposed normalization
factors lack consistency among various
chemicals and processes (see Chapter 5~.
The probability and severity of a release
are also a function of a chemical's properties
and reactivity; equipment design safeguards,
AL455 BALANCE INFORMATION
operating procedures, operator training,
quality of maintenance and monitoring; and
the chemical's toxicity, transport characteris-
tics, release location, and receptor locations.
This type of information is not provided
through TRI reporting requirements and also
would not be provided through the addition-
al reporting of any type of mass balance in-
formation.
The use of mass balance information
collected within a facility can support chem-
ical management practices that reduce the
presence of toxic chemicals on site. For ex-
ample, maintaining current information on
the chemical quantities stored at a facility
provides an owner or operator with greater
certainty of chemical amounts available and
allows for controlling inventory at a mini-
mum level. A chemical inventory could be
determined at any point from regularly re-
corded mass balance information on the
amount of chemicals brought into a facility
and the amounts shipped out of the same
facility.
For users of chemicals in complex opera-
tions, such as motor vehicle manufacturing,
a unit-specific control of inventory is neces-
sary (Bowditch, l988~. In the case of facili-
ties in which chemical conversions take
place, calculating the usable volume of pro-
cess vessels, piping, storage vessels, and con-
tainers associated with the chemicals might
be needed in addition to mass balance
information.
On-Site Treatment
Waste reduction via process modification
should be the management strategy of choice
before treatment is considered, since treat-
ment always results in residuals and is prone
to episodic chemical releases.
Treatment as a management process
within a facility is used to render chemicals
less toxic (e.g., conversion of hexavalent
chromium to trivalent chromium or bioxida-
tion of chlorinated organic compounds) or to
render them less mobile (e.g., solidify
heavy-metal wastes). Incinerators, waste-
water treatment facilities, and air-pollution
control devices are included in treatment
processes. The efficiencies of such on-site
treatment and the associated releases are
requested as part of TRI reporting.
Loehr and Ward (1987) note that the
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EVALUATING TOXIC CHEMICAL MANAGEMENT PRACTICES
EMB approach can be effective in ensuring
that a waste-management system does not
unknowingly transfer pollutants from one
medium to another in the process of meeting
a particular regulation or effluent limit.
They also indicate, however, that adequate
data rarely are available to permit the
development of meaningful mass balances.
For waste-water treatment, mass balance
information can demonstrate that some
organic pollutants can undergo volatilization
and accumulation in sludge as opposed to
degradation through bioxidation.
A 3-week, multimedia sampling study was
conducted using the EMB approach at a
large petrochemical waste-water treatment
facility to determine the fate of eight or-
ganic chemicals with various characteristics
(Berglund and Whipple, 1986~. This study
illustrates the difficulty of using EMB on a
facility of any complexity. Primarily be-
cause of wide variation in the chemical
makeup and concentration in the influent
waste water, and because of fluctuations in
wind speed and direction (a factor in meas-
uring volatilization losses), EMB did not
provide sufficient closure to assess the
efficacy of waste-water treatment. How-
ever, predictive models were developed, be-
cause data collected through EMB gave in-
sight into the relationship of air release and
sorption to biological process conditions and
chemical properties. EMB data can also be
useful in providing a maximum upper bound
on possible atmospheric emissions from
waste-water treatment (Noll and DePaul,
1987).
There are no obvious applications for
MA in assessing treatment processes, because
MA information typically is concerned with
the flow of chemicals across facility boun-
daries. To assess treatment processes, de-
tailed information is needed on the amounts
of chemicals flowing through the facility be-
fore treatment, and thus within-facility in-
formation is required.
In summary, reporting of mass balance
information, obtained through either EMB
or MA, would not be appropriate in most
cases, for assessing on-site treatment
practices because of the within-facility
complexity and variability of the waste
streams flowing into the treatment systems.
However, collecting EMB information on the
treatment systems could be a useful manage-
ment practice within a facility to indicate
59
the release avenues that require more
thorough investigation.
Gradual and sudden releases of toxic
chemicals can occur as the result of the ab-
sence of management guidelines for prudent
chemical-handling practices at a facility.
Only limited public information is available
concerning adequate chemical management
practices at facilities and whether these
practices are the most effective and are em-
ployed continuously. Useful information is
provided to evaluate the management prac-
tices of a facility when release data reported
to the TRI are combiner] with information
on causes of the release (e.g., employee er-
ror, metal fatigue, inadequate detection and
repair of equipment leaks, and equipment
failures). However, as demonstrated through
the New jersey Industrial Survey, this
additional information could be obtained
only by evaluating the reported release data
in conjunction with a site visit to the report-
ing facility (NJDEP, 1986~.
CONCLUSIONS
EMB and MA are conceptually useful for
assessing and sometimes improving manage-
ment practices, including transportation of
toxic chemicals into and out of a facility,
storage, tracking toxic chemicals on site,
waste reduction, and waste treatment. How-
ever, mass balance information obtained
either through EMB or MA practice is gen-
erally inappropriate from a practical per-
spective. Because of large differences
among the processes within facilities report-
ing TRI information, the practical usefulness
of the EMB and MA data in making com-
parisons between facilities is severely
limited, for assessing transportation,
handling, and storage practices. Only EMB
would be appropriate for assessing waste-
treatment practices. However, the practical
difficulty in achieving closure limits this
e e
app Cation.
The maximum quantity of chemicals on
site is one of the more important factors in
estimating the likelihood and magnitude of a
sudden release. The management practice of
reducing stored quantities usually can be as-
sessed by directly measuring on an absolute
basis the maximum quantity of chemicals
present. This information is currently re-
ported to the TRI. When it is necessary
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60
either to assess inventory control practice at
a facility with widely fluctuating production
rates or to compare practices between facili-
ties, normalization by dividing inventory by
the amount used or produced at the facility
is a means of accomplishing the objective.
All normalization factors, however, fail to
provide a consistent basis for comparisons
among various chemicals ant! facilities.
Information currently reported to the TRI
does not closely link release data to chemi-
cal-management practices except for on-site
waste-treatment practices. Additional facili-
ty-specific information on other manage-
ment practices, such as transportation and
storage and handling, could assist the public
in evaluating whether the most effective
management practices are being used to
control or prevent releases of TRI-listed
chemicals.
AL4SS RAL4NCE INFORMATION
Mass balance information collected! with-
in a facility can be used by that facility to
support certain chemical-management
practices that reduce the presence and
release of TRI-listed chemicals. For
example, mass balance information can
provide the facility with current information
on chemical quantities stored on site and
facilitate controlling its inventory at a
minimum level. Data obtained through EMB
can be used to point out release routes from
waste-treatment processes that need more
complete and direct measurement. Because
MA does not rely on chemical flow data
from within a facility, this approach would
not be useful in assessing waste-treatment
practices.
Representative terms from entire chapter:
mass balance
