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Mitigating fish-killing algal blooms with PAC modified clays: efficacy for cell flocculation and ichthyotoxin adsorption

conference contribution
posted on 2023-05-23, 12:55 authored by Andreas SegerAndreas Seger, Gustaaf HallegraeffGustaaf Hallegraeff
Flocculation of harmful algal cells through treatment with modified clay minerals offers great promise in reducing clay loadings required for effective cell removal, yet the ichthyotoxin adsorptive properties of such modified clays have received little attention. We here compare Chattonella marina (raphidophyte) cell removal by conventional (kaolin, bentonite) and polyaluminium chloride (PAC) modified clays (bentonite and Korean loess), while newly exploring the capacity of PAC and PAC modified clays to mitigate C. marina and Alexandrium catenella (dinoflagellate) ichthyotoxicity (quantified with the RTgill-W1 cell line assay). Conventional clays proved ineffective in reducing C. marina cell numbers (14±5% removal at 0.5 g L-1), but treatment efficacy could be much improved through modification of bentonite and Korean loess with PAC (85±5% removal at 0.1 g L-1). Ichthyotoxin adsorption by PAC and PAC modified clays proved species specific. While both PAC (0.1 g L-1) and PAC modified clays (0.25 g L-1) could completely eliminate C. marina cytotoxicity, only bentonite clay proved effective in mitigating the negative impact of lysed A. catenella preparations on the gill cell line (69±10% gill cell viability). This work highlights how application of modified clays extends beyond improved cell flocculating properties to also include adsorption of selected ichthyotoxins.

Funding

Australian Research Council

History

Publication title

Proceedings of the 17th International Conference on Harmful Algae 2016

Editors

LAO Proenca, GM Hallegraeff

Pagination

154-157

ISBN

9788799082766

Department/School

Institute for Marine and Antarctic Studies

Publisher

International Society for the Study of Harmful Algae (ISSHA), Intergovernmental Oceanographic Commission of UNESCO

Place of publication

Copenhagen, Denmark

Event title

17th International Conference on Harmful Algae 2016

Event Venue

Florianopolis, Brazil

Date of Event (Start Date)

2016-10-09

Date of Event (End Date)

2016-10-14

Rights statement

Copyright 2017 The International Society for the Study of Harmful Algae.

Repository Status

  • Restricted

Socio-economic Objectives

Fisheries - aquaculture not elsewhere classified

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