Copper in indigenous and transplanted zebra mussels in relation to changing water concentrations and body weight

Abstract

Zebra mussels, Dreissena polymorpha, were collected monthly from a copper‐contaminated reservoir over a period of nearly 3 years. Copper concentrations in the organisms showed marked fluctuations reflecting changes in the water contamination. Bioconcentration patterns were influenced by the specific capacity of this sentinel organism to biologically integrate the continuously evolving water pollution; the sampling pattern, which inevitably introduced a certain subjectivity into monitoring results; and weight changes in the animals within the yearly cycle. Consequently, the successive monthly indications obtained with the zebra mussels provided a current biological assessment of a complex dynamic contamination situation. In a second experiment, caged mussels from three different populations were transferred for 3 months into the reservoir and sampled on six occasions. Mortality rates, attachment capacity, and a condition index revealed no substantial fitness disturbances in the transplanted organisms. Differences in dry weight throughout the experiment were attributable to the initial characteristics of each population. The influence of body mass on monitoring results was eliminated by replacing copper concentrations (μg/g dry weight) with copper burdens (μg/specimen). In terms of copper burdens, the three transplanted populations exhibited very similar metal patterns. Moderate quantitative differences between introduced and indigenous populations were interpreted as the result of physiological adaptation of the indigenous mussels to their contaminated environment. This study showed that the transfer technique with D. polymorpha is a useful tool for active biomonitoring programs.

Comparison of accumulation of micropollutants between indigenous and transplanted zebra mussels (Dreissena polymorpha)

“…Following the marine biomonitoring programs, freshwater mussels have been used since the late 1980s to monitor the quality of freshwater ecosystems. In Europe, the zebra mussel Dreissena polymorpha has been most frequently used as a freshwater bioindicator for the assessment and biomonitoring of water quality [6][7][8][9][10]. Zebra mussels fulfill the requirements of a good biomonitor for freshwater ecosystems: They are easy to collect and to handle and are available in sufficient numbers, they have a relatively long life span, they are sedentary and resistant to various types of pollution without suffering mortality, and they have a high filtration rate, which favors the bioaccumulation of both organic and inorganic contaminants [6,8,11,12].…”

“…A problem with the use of transplanted organisms for accumulation or effect studies is the reliability of the results. Indigenous mussels might be acclimated or genetically adapted to the local environmental conditions, resulting in differences in accumulation or effects when compared to transplanted organisms [7]. As a consequence, comparison of the accumulation of contaminants between transplanted and indigenous aquatic organisms is needed to evaluate the applicability of caged organisms as a monitoring tool.…”

Caged midge larvae (Chironomus riparius) for the assessment of metal bioaccumulation from sediments in situ

“…However, in their study such comparison was possible only at four sites where a sufficient number of local larvae were found. Mersch et al [11] compared Cu levels in indigenous and transplanted zebra mussels originating from three different sites at one sampling site. Although significantly lower body burdens were found in the transplanted mussels, Cu levels were of the same order of magnitude after three months of exposure.…”

“…23,2004 L. Bervoets et al environmental levels and levels in benthic organisms are found [13,16,18,20]. Active biomonitoring with caged organisms has been performed with several organisms, including aquatic fish [21], invertebrates [2,11,22], and aquatic plants [3,10]. However, validation of the method used by comparing caged and resident organisms has seldom been done.…”

Transplanted Zebra Mussels (Dreissena Polymorpha) as Active Biomonitors in an Effluent-Dominated River

“…For example, the common mussel (Mytilus edulis) has been used as a biomonitor for estuarine and marine ecosystems [1][2][3][4]. Recently, a number of authors have recognized zebra mussel (Dreissena polymorpha) as a suitable monitoring organism in freshwater ecosystems [5][6][7][8][9][10], showing similar characteristics and advantages as Mytilus: They are sedentary, easy to handle, and can be easily transplanted [4,5,11]; they can withstand high pollutant levels without suffering significant mortality and have a high bioaccumulation potential for both organic and inorganic contaminants [12,13]; and, as filter feeders, they are exposed to pollutants via water and suspended particles [11,14,15].…”