Bioaccumulation of pathogenic bacteria and amoeba by zebra mussels and their presence in watercourses

Abstract

Dreissena polymorpha (the zebra mussel) has been invading freshwater bodies in Europe since the beginning of the nineteenth century. Filter-feeding organisms can accumulate and concentrate both chemical and biological contaminants in their tissues. Therefore, zebra mussels are recognized as indicators of freshwater quality. In this work, the capacity of the zebra mussel to accumulate human pathogenic bacteria and protozoa has been evaluated and the sanitary risk associated with their presence in surface water has also been assessed. The results show a good correlation between the pathogenic bacteria concentration in zebra mussels and in watercourses. Zebra mussels could therefore be used as an indicator of biological contamination. The bacteria (Escherichia coli, Enterococcus spp., Pseudomonas spp., and Salmonella spp.) and parasites (Cryptosporidium oocysts and free-living amoebae) detected in these mussels reflect a potential sanitary risk in water.

Identification of free‐living amoebas and amoeba‐resistant bacteria accumulated in Dreissena polymorpha

“…contrasts with the one found by other authors (Mosteo et al, 2016;Bighiu et al, 2019), questioning the possible use of the mollusc as an indicator of water pollution, but it reinforces the option of its possible use in the detection of past discharges. On the other hand, it is possible that some of the bacteria identified as mussel-accumulated bacteria are located inside the amoebas.…”

“…The analysis of the mussels was carried out within 48 h after collection, but some additional specimens were kept until the work was finished in anticipation of possible repetitions or extraordinary analysis. These mussels were preserved in a laboratory-scale aquarium (volume: 100 L) filled with water from the sampling point, under optimal temperature (18 C-20 C) and conditions (calcium content, total hardness, pH, dissolved oxygen and conductivity) previously described (Claudi and Mackie, 1994;O'Neill Jr., 1996;Mosteo et al, 2016). During the maintenance of the zebra mussels from the Sobrón Reservoir in the laboratory scale aquarium, the death of a large number of specimens was observed.…”

“…Due to their condition of filter feeders, Zebra mussels accumulate and concentrate organic compounds, metals and microorganisms from the water into their tissues, even when they are present in low concentrations (Mosteo et al ., 2016). In consequence, they have been considered a possible tool for monitoring the pollution of the ecosystems in which they live (Carrasco et al ., 2008; Parolini and Binelli, 2014; Poma et al ., 2014; Mosteo et al ., 2016; Benito et al ., 2017).…”

Bioaccumulation of Inorganic Elements in Dreissena polymorpha from the Ebro River, Spain: Could Zebra Mussels Be Used as a Bioindicator of the Impact of Human Activities?

“…The bivalve's capacity to accumulate both chemical and microbiological pollutants has been documented in numerous research studies. This makes the zebra mussel a useful tool for biomonitoring freshwater ecosystems where they can be found attached to the substrate (Alcaraz et al , ; Bourgeault et al , ; Camusso et al , ; Mosteo et al , ; Palos Ladeiro et al , ; Voets et al , ).…”

“…The bivalve's capacity to accumulate both chemical and microbiological pollutants has been documented in numerous research studies. This makes the zebra mussel a useful tool for biomonitoring freshwater ecosystems where they can be found attached to the substrate (Alcaraz et al, 2011;Bourgeault et al, 2011;Camusso et al, 2001;Mosteo et al, 2016;Palos Ladeiro et al, 2014;Voets et al, 2009). European (EU) legislation has introduced Environmental Quality Standards (EQS) for biota, through EU Directive 2013/39/UE, which includes 45 priority substances that require EQS, and eight labelled as 'certain other pollutants'.…”