Using Confocal Microscopy and Pigment Analyses to Detect Adverse Insecticide Effects in non-target Freshwater Diatom species - a proof-of-concept Using Nitzschia palea

Anrich Kock; Wihan Pheiffer; Victor Wepener; Nico J Smit; Jonathan C Taylor

doi:10.1007/s00128-023-03741-5

Using Confocal Microscopy and Pigment Analyses to Detect Adverse Insecticide Effects in non-target Freshwater Diatom species - a proof-of-concept Using Nitzschia palea

Bull Environ Contam Toxicol. 2023 Jun 7;110(6):107. doi: 10.1007/s00128-023-03741-5.

Authors

Anrich Kock^{1

2}, Wihan Pheiffer³, Victor Wepener⁴, Nico J Smit⁴, Jonathan C Taylor^{5

6}

Affiliations

¹ Water Research Group, Unit for Environmental Sciences and Management, North-West University, Private bag X6001, Potchefstroom, 2520, South Africa. anrich.kock@gmail.com.
² North-West University, 11 Hoffman Street, Potchefstroom Campus, Building F20, Room 63, Potchefstroom, 2531, South Africa. anrich.kock@gmail.com.
³ DSI/NWU Preclinical Drug Development Platform, North-West University, Private bag X6001, Potchefstroom, 2520, South Africa.
⁴ Water Research Group, Unit for Environmental Sciences and Management, North-West University, Private bag X6001, Potchefstroom, 2520, South Africa.
⁵ Unit for Environmental Sciences and Management, North-West University, Private bag X6001, Potchefstroom, 2520, South Africa.
⁶ South African Institute for Aquatic Bioaffiliationersity (SAIAB), Private Bag 1015, Grahamstown, 6140, South Africa.

Abstract

The persistence of insecticides in aquatic environments is a cause of concern and to date hardly any studies have focused on the effects that DDT and deltamethrin have on non-target freshwater diatom communities. The application of diatoms in ecotoxicological studies is well acknowledged and therefore this study used laboratory bioassays to determine the effects that DDT and deltamethrin have on a monoculture of a diatom indicator species, Nitzschia palea. The insecticides affected the morphology of chloroplasts at all exposure concentrations. These effects were a maximum reduction in chlorophyll concentrations (4.8% and 2.3%), cell viability (51% and 42%), and increases in cell deformities (3.6% and 1.6%) following exposure to DDT and deltamethrin respectively. Based on the results we propose that methods, such as confocal microscopy, chlorophyll-α analysis and cell deformities are useful tools in assessing the effects of insecticides on diatoms.

Keywords: Cell deformities; Chlorophyll; DDT; Deltamethrin; Diatoms; Mixture.

MeSH terms

Chlorophyll
DDT
Diatoms*
Fresh Water
Insecticides* / toxicity
Microscopy, Confocal

Substances

Insecticides
decamethrin
DDT
Chlorophyll