Anthropic impact of mining and industrial activities on benthic foraminiferal assemblages in estuaries of Cornwall and Scotland (UK)

Coastline environments were used for the waste disposal either directly or due to the accumulation of contaminated deposits from catchments. Contaminants, such as ecotoxic metal(loid)s, could pose a hazard to the ecosystem, and their dispersion should be monitored to limit risk. Such tasks posed a challenge due to the contaminant dispersion and dilution into the water column and sediments. Foraminifera offered a bio-monitoring tool that was able to record estuarine contamination diffusion. Our research aimed to investigate the effects of anthropogenic activities on benthic foraminifera, analysing the composition, diversity, and distribution of assemblages. Mining and industrial activities' impacts on benthic foraminiferal assemblages were investigated in two UK estuaries: a) the Hayle Estuary (Cornwall) and b) the Firth of Forth (Edinburgh). Chemical analyses were performed to verify the nature of the bottom sediments. Benthic foraminifera were identified in 11 samples collected from the two analysed areas. Diversity parameters (Species’ Richness, Foraminiferal Density, dominance, Shannon, and the Fisher-α index) were calculated to quantify the foraminiferal assemblages within the context of environmental parameters. Chemical analyses revealed concentrations of As, Cu, Pb, and Zn exceeding environmental limits in Hayle Estuary, while Cr and, occasionally, Pb and Zn were found in the Firth of Forth samples. Foraminiferal assemblage was mainly composed of Haynesina germanica, Ammonia parkinsoniana, and Elphidium williamsoni. Diversity indices showed low values in impacted areas, along with morphological abnormalities in foraminiferal tests. Multivariate statistical analysis established correlations between abiotic factors (contaminant concentrations) and biotic factors (species abundance and diversity indices). It revealed a distinct separation of sampling site groups, primarily influenced by the type and degree of contamination.