Natural Attenuation - Dealing with Contaminated Sites: From Theory Towards Practical Application - page 989

Table 22.1 (continued)

Aim Method Comments

DP groundwater sampling using, for example,
BAT groundwater sampler

Not suitable for long-term plume monitoring
as measurement is singular

In-situ semi-quantitative groundwater analyses
using DP-MIP

Not suitable for long-term plume monitoring
as measurement is singular

Mass flow rate
reduction

Integral pumping tests at two or more
consecutive control planes with increasing
distance to the source zone

Integral pumping reduces uncertainty of mass
flow rate determination due to spatial
integration

Passive samplers in multiple depths or
multilevel groundwater sampling in
conjunction with depth profiles of hydraulic
conductivity, for example, by DP slug tests
or DP injection logging

Temporal integration of concentration by
passive samplers leads to average temporal
concentrations and thus average mass flow
rates

NA process
identification and
quantification

Proof of plume
stationarity

Time series analyses (e.g., Mann-Whitney-Test
or Mann-Kendall-Test)

Nonparametric statistical tests applied to
concentration time series to prove plume
stability. At least 4 sampling events are
needed.

Qualitative NA proof Distribution of electron acceptors (depletion

within source and plume) and reduced
species of electron acceptors (accumulation
within source and plume)

Standard method

Comparison between reactive and conservative
plume development

If a (measured or calculated) conservative
plume is longer than the contaminant
plume(s), this is a hint for active NA
processes

Presence of metabolites Hint for active NA processes

Chemical fingerprinting (spatial distribution of
ratios of certain contaminant concentrations)

Shift of ratios indicate the preferred
attenuation of certain contaminants