Abstract
The benthic macroinvertebrate community of
East Fork Poplar Creek (EFPC) in East Tennessee was
monitored for 18 years to evaluate the effectiveness of a
water pollution control program implemented at a major
United States (U.S.) Department of Energy facility. Several
actions were implemented to reduce and control releases of
pollutants into the headwaters of the stream. Four of the
most significant actions were implemented during different
time periods, which allowed assessment of each action.
Macroinvertebrate samples were collected annually in
April from three locations in EFPC (EFK24, EFK23,
and EFK14) and two nearby reference streams from
1986 through 2003. Significant improvements occurred in
the macroinvertebrate community at the headwater sites
(EFK24 and EFK23) after implementation of each action,
while changes detected 9 km further downstream (EFK14)
could not be clearly attributed to any of the actions.
Because the stream was impacted at its origin, invertebrate
recolonization was primarily limited to aerial immigration,
thus, recovery has been slow. As recovery progressed,
abundances of small pollution-tolerant taxa (e.g., Orthocladiinae
chironomids) decreased and longer lived taxa
colonized (e.g., hydropsychid caddisflies, riffle beetles,
Baetis). While assessments lasting three to four years may
be long enough to detect a response to new pollution
controls at highly impacted locations, more time may be
needed to understand the full effects. Studies on the
effectiveness of pollution controls can be improved if
impacted and reference sites are selected to maximize
spatial and temporal trending, and if a multidisciplinary
approach is used to broadly assess environmental responses
(e.g., water quality trends, invertebrate and fish community
assessments, toxicity testing, etc.).
