Population responses of the pulmonate gastropod, Amphibola crenata, reflect estuarine trace metal contamination

ABSTRACT

This study assessed the potential of the mud snail Amphibola crenata as a bioindicator of estuarine health. Multiple sites with varying contaminant inputs were identified within a small, shallow estuary (Avon-Heathcote/Ihutai in the South Island of New Zealand). Population structures of field-collected A. crenata were related to measurements of sediment trace metal profiles. Whole-body soft tissue metal concentrations were significantly positively correlated with sediment trace metals for all elements analysed (arsenic, cadmium, copper, nickel, lead and zinc). In terms of population biomarkers, medium-sized mud snails (7.9–17.9 mm shell length) dominated the population size structure at the most contaminated sites. That sites which were more highly enriched in trace metals were distinguishable by application of a simple population structure assessment, suggests that A. crenata has potential value for evaluating estuarine health. However, further investigation of other biotic and abiotic factors that may influence population structure are required.

KEYWORDS:

• Biomonitoring
• trace elements
• population structure
• bioaccumulation
• bioindicator
• estuary

Acknowledgements

This study was funded by the Avon Heathcote Estuary Ihutai Trust, Brian Mason Scientific and Technical Trust and University of Canterbury. The authors thank Jonathan Hill, Robert Stainthorpe and Jan McKenzie for their valuable assistance in the laboratory and field. CNG is supported by a Campus Alberta Innovates Program Research Chair.

Disclosure statement

No potential conflict of interest was reported by the author(s).

Additional information

Funding

This work was supported by Avon Heathcote Estuary Ihutai Trust, Brian Mason Scientific and Technical Trust and University of Canterbury.