Temperature-dependent toxicities of four common chemical pollutants to the marine medaka fish, copepod and rotifer

Abstract

We hypothesize that chemical toxicity to marine ectotherms is the lowest at an optimum temperature (OT) and it exacerbates with increasing or decreasing temperature from the OT. This study aimed to verify this hypothetical temperature-dependent chemical toxicity (TDCT) model through laboratory experiments. Acute toxicity over a range of temperatures was tested on four commonly used chemicals to three marine ectotherms. Our results confirmed that toxicities, in terms of 96-h LC50 (median lethal concentration; for the marine medaka fish Oryzias melastigma and the copepod Tigriopus japonicus) and 24-h LC50 (for the rotifer Brachionus koreanus), were highly temperature-dependent, and varied between test species and between study chemicals. The LC50 value of the fish peaked at 20 °C for copper (II) sulphate pentahydrate and triphenyltin chloride, and at 25 °C for dichlorophenyltrichloroethane and copper pyrithione, and decreased with temperature increase or decrease from the peak (i.e., OT). However, LC50 values of the copepod and the rotifer generally showed a negative relationship with temperature across all test chemicals. Both copepod and rotifer entered dormancy at the lowest temperature of 4 °C. Such metabolic depression responses in these zooplanktons could reduce their uptake of the chemical and hence minimize the chemical toxicity at low temperatures. Our TDCT model is supported by the fish data only, whereas a simple linear model fits better to the zooplankton data. Such species-specific TDCT patterns may be jointly ascribed to temperature-mediated changes in (1) the physiological response and susceptibility of the marine ectotherms to the chemical, (2) speciation and bioavailability of the chemical, and (3) toxicokinetics of the chemical in the organisms.

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

“…It was apparent that 28 °C and 31 °C were optimal temperatures for the larvae, whereas control larvae showed less growth and activity at 24 °C. This observation of toxicity being lowest at an optimum temperature with toxicity increasing as the temperature moves away from the optimum temperature has been reported by Li et al for the marine fish Oryzias melastigma . There also may have been changes in the chemistry of Al with increasing temperature, which could have altered the exposure to Al at different temperatures.…”

Monitoring and Ecotoxicity Assessment of Emerging Contaminants in Wastewater Discharge in the City of Prague (Czech Republic)

“…Focusing on temperature, Martins et al [48] reported that chronic toxicity of the antibiotic florfenicol in Daphnia magna increased as temperature rose (LC50 = 7.6 and 1.9 mg/L at 20 and 25 • C respectively). Li et al [49] concluded that the toxicity of copper, DDT, triphenyltin, and pyrithione to the medaka fish Oryzias melastigma larvae, the copepod Tigriopus japonicus, and the rotifer Brachionus koreanus were temperature-dependent and the LC50 for all four chemicals decreased as the temperature increases. The same effect was observed in other aquatic species when they were exposed to chlorpyrifos and phenol [50].…”

Effects of chronic exposure to cadmium and temperature, alone or combined, on the threespine stickleback (Gasterosteus aculeatus): Interest of digestive enzymes as biomarkers

“…Unfortunately, there is a lack of information in the literature on this topic, especially about the effects of chronic low-dose chemical exposure combined to other stresses. In fact, several authors have analysed the effects of xenobiotics, and others have reported the effects of their combination with temperature on fish physiology (Hallare et al, 2005;Reynaud and Deschaux, 2006;Li et al, 2014;Andersen et al, 2015;Authman et al, 2015;Guardiola et al, 2015;Olsvik et al, 2016). However, most studies have tested short-term exposure at sub-lethal concentrations which do not reflect actual environmental concentrations of toxicants or the real effects of complex interactions with other stressors such as temperature.…”