Ecotoxicological study on lead shot from hunting in the Padule di Fucecchio marsh (Tuscany, Italy)

Abstract

Ingestion of lead shot has been recognised as an important cause of death in waterbirds for over a century. Chemical dissolution (oxidation) of lead shot in aquatic environments can make lead more available, distributing it throughout the aquatic ecosystem. The extent of the phenomenon has rarely been investigated in Italy and no systematic information is available for Italian wetlands. We investigated lead shot density and lead concentrations in sediment of the Padule di Fucecchio (Tuscany), one of the largest inland marshes in Italy (2000 ha), in order to evaluate the impact of lead shot from hunting. Moreover, to assess lead accumulation in organisms, red swamp crayfish, Procambarus clarkii (Girard 1852), was chosen as a bioindicator. The results showed a high lead shot density (0–311 shot · m⁻²). Although lead concentrations and lead shot density were slightly less in protected areas than in hunting areas, contamination was widespread throughout the marsh, with a mean lead concentration of 115.6 mg · kg⁻¹ d.w.. Crayfish were subject to heavy uptake of lead, with high concentrations in gut contents (43.84±47.48 mg · kg⁻¹ d.w.) and hepatopancreas (3.217±4.850 mg · kg⁻¹ d.w.). A detailed map of lead contamination was plotted using sediment data. Thematic mapping is a valuable support for environmental remediation and reserve management and assessment of lead contamination concomitant with the banning of lead shot in the area provides a useful database for long-term monitoring of the effectiveness of the ban.

Keywords:

• lead
• shot
• hunting
• geographical information system
• Padule di Fucecchio
• crayfish

Acknowledgements

This research was financed by the administrations of Provincia di Pistoia, Regione Toscana and Comune di Quarrata (PT). The authors thank the Centro di Documentazione, Ricerche e Promozione del Padule di Fucecchio (non-profit organisation) and especially Dr Alessio Bartolini, Dr Enrico Zarri and Dr Federica Briganti for assistance with planning, sampling and data processing. The authors particularly wish to thank the anonymous reviewer for his/her positive judgement of the paper, careful examination of the text and pondered and constructive suggestions.