Aluminium, gallium, and molybdenum toxicity to the tropical marine microalga Isochrysis galbana

Abstract

There is a shortage of established chronic toxicity test methods for assessing the toxicity of contaminants to tropical marine organisms. The authors tested the suitability of the tropical microalga Isochrysis galbana for use in routine ecotoxicology and assessed the effects of 72-h exposures to copper (Cu, a reference toxicant), aluminium (Al), gallium (Ga), and molybdenum (Mo), key metals of alumina refinery discharge, on the growth of I. galbana at 3 temperatures: 24 °C, 28 °C, and 31 °C. The sensitivity of both I. galbana and the test method was validated by the response to Cu exposure, with 10% and 50% effect concentrations (EC10 and EC50) of 2.5 μg/L and 18 μg/L, respectively. The EC10 and EC50 values for total Al at 28 °C were 640 μg/L and 3045 μg/L, respectively. The toxicity of both Cu and Al at 24 °C and 31 °C was similar to that at 28 °C. There was no measurable toxicity from dissolved Ga exposures of up to 6000 μg/L or exposures to dissolved Mo of up to 9500 μg/L. Solubility limits at 28 °C for the dissolved fractions (<10 kDa) of Al, Ga, and Mo were approximately 650 μg/L Al, >7000 μg/L Ga, and >6000 μg/L Mo. In test solutions containing >650 μg/L total Al, dissolved and precipitated forms of Al were present, with precipitated Al becoming more dominant as total Al increased. The test method proved suitable for routine ecotoxicology, with I. galbana showing sensitivity to Cu but Al, Ga, and Mo exhibiting little to no toxicity to this species.

A chronic toxicity test for the tropical marine snail Nassarius dorsatus to assess the toxicity of copper, aluminium, gallium, and molybdenum

“…The corresponding EC10 values at these 3 temperatures were 40 mg/L, 115 mg/L, and 320 mg/L Al ( Table 2 and Figure 3B). These effect concentrations were all within the solubility limits of Al (500-650 mg/L) reported for similar conditions at 25 8C [8] and 28 8C [24]. Supplemental Data, Figure S3 shows the solubility of Al at the 3 temperatures tested.…”

“…Comparison of the sensitivity of N. dorsatus to Al with toxicity data recently reported for a range of marine species suggests that this species is relatively sensitive to Al compared with most marine microalgae, coral, and seaweed species but less sensitive than the diatom Nitzschia closterium . Golding et al report an EC10 for the oyster Saccostrea glomerata (100 μg/L total Al based on a 48‐h embryo development end point), which indicates a similar sensitivity to Al as N. dorsatus .…”

“…Because of the lack of toxicity observed, the toxicity of Mo was not investigated at 24 8C or 31 8C. The low toxicity of Mo has been previously reported for other marine species, including the microalgae I. galbana [24] (EC50 >9500 mg/L) and Dunaliella tertiolecta (EC10 ¼ 881 000 mg/L Mo [40]) and the diatom Phaeodactylum tricornutum (EC10 ¼ 169 000 mg/L [40]).…”

The Use of the Marine Microalga Tisochrysis lutea (T-iso) in Standard Toxicity Tests; Comparative Sensitivity With Other Test Species

“…Blue curve from panel (E,F) published in Tato et al (2018). (Trenfield et al, 2015), culture media and cellular density changes to improve sensitivity (Moreno-Garrido et al, 2000), in vivo fluorescence endpoint (Pérez et al, 2010a) and microplate test (Satoh et al, 2005) are some examples of sources of interassay and interlaboratory variability. Interlaboratory calibrations and definition of strict acceptability criteria are needed in order to 2 | Effective concentrations (µg L −1 ) obtained in the growth inhibition test for zinc (Zn), fluoranthene (FLU), chlorpyrifos (CPF), Benzalkonium chloride (BAC), 4-n-nonylphenol (4-n-NP) and triclosan (TCS).…”

“…In the marine environment, the International Standardization Organization (ISO) propose Phaeodactylum tricornutum and Skeletonema costatum, both worldwide spread marine diatoms. In recent years, Isochrysis galbana, culture strain isolated from Tahiti (hereafter T-iso), recently renamed Tisochrysis lutea (Bendif et al, 2013), has been one of the most used marine microalgae in toxicity tests (Moreno-Garrido et al, 2000;Hampel et al, 2001;Yap et al, 2004;Satoh et al, 2005;Campa-Córdova et al, 2006;Correa-Reyes et al, 2007;Garrido-Perez et al, 2008;Debelius et al, 2009;Pérez et al, 2010a;Liu et al, 2011;Fisher et al, 2014;Suratno et al, 2015;Trenfield et al, 2015). This species was selected on the basis of its sensitivity and the ease to culture (Shaw and Chadwick, 1998;Pérez et al, 2009) as well as its economic importance in aquaculture (Renaud et al, 1991).…”