Speciation of Metals - Chromium
Chromium (Cr) is a steel-grey lustrous metal. It
is used in industry in a diversity of products and processes. In the environment, chromium
is found in two forms - the naturally occuring Cr III and Cr VI which is a by product of
industrial processes. While Cr III is an essential trace element for human health, there
is evidence of Cr VI carcinogenicity in humans. Thus, the strong interest in Cr VI cleanup
at sites. The more toxic nature of chromium VI is also reflected in the much lower cleanup
standards for Cr VI than those for Cr III. New
Approach to Soil Handling for Volatiles
Freezing Samples to Increase 5035 Holding Times
The new method of volatiles sampling, preservation and analysis under EPA method 5035
reduces volatilization during sampling and analysis by minimizing the handling of the
sample. In addition, biodegradation is reduced by preservation with Sodium Biosulfate or
with methanol. Preservation can occur either in the field or the laboratory. Field
preservation has proven difficult and impractical so more often sample preservation occurs
at the laboratory.
Sampling
Volatiles In Soil by 5035
The methodology for sampling soils for volatile organic compounds changed with Update III
to EPA's solid waste manual SW-846. The previous method of collecting, transporting and
handling soil samples has been replaced with method 5035. The use of this method should
significantly reduce losses of volatile compounds during shipping, handling, and analysis.
MTBE - The
Next Challenge
Experts believe that MTBE contamination may be more widespread than we realize.
Considering that MTBE may be a human carcinogen, is the primary oxygenate added to fuels
and is very water soluble, it may be the next great challenge to regulators.
Unfortunately, it may often be misidentified using GC method 8021.
Utilizing TPH
Methods Effectively
A lot of misconceptions still exist about total petroleum hydrocarbon (TPH) analysis. An
understanding of how TPH is preformed by method 8015B and 1664 is essential for the
correct utilization of these procedures and the subsequent quality of information obtained
for environmental monitoring projects.
TPH Method
Overlap
We wish there was one TPH method that would accurately quantify all types of petroleum
contamination. Unfortunately, not only is there no one method for the lighter/volatile and
heavier/extractable constituents, some fuels represent a mixture of both volatile and
extractable hydrocarbons.
Specific
Petroleum Compound Testing
There are a number of misconceptions that commonly exist concerning the testing for
specific petroleum related compounds. Knowing which petroleum compounds degrade the
quickest and what compounds were added to fuels over the history of formulations can be
helpful in dating releases.
TPH 1664 vs.
413.1 and 418.1
The ozone destroying TPH 418.1 and Oil & Grease 413.1 methods have both been replaced
by a single method, EPA 1664. The impetus for this change is that the 418.1/413.1 methods
utilize Freon as the extraction solvent, which is rapidly being eliminated from usage for
all applications.
TCLP vs. SPLP
Extraction Procedures
TCLP extractions are often misapplied. This methodology was developed to estimate the
mobility of specific contaminates that are destined for disposal in municipal landfills.
An alternative extraction, the SPLP procedure, is useful in those situations where the
potentially contaminated material is left in situ, exposed to rainfall, not landfill
lechate.
Analyzing for
Metals by ICP/MS
The advantages of the ICP/MS are numerous. This
instrument offers: very low detection limits, relative freedom from spectral and chemical
interferences, broad elemental coverage, high sample throughput, and simultaneous multiple
element capability. The use of this instrument can significantly improve the quality of
metal data.
