Cardiac biomarkers as sensitive tools to evaluate the impact of xenobiotics on amphibians: the effects of anionic surfactant linear alkylbenzene sulfonate (LAS)

Abstract

Amphibian populations have been experiencing a drastic decline worldwide. Aquatic contaminants are among the main factors responsible for this decline, especially in the aquatic environment. The linear alkylbenzene sulfonate (LAS) is of particular concern, since it represents 84% of the anionic surfactants' trade. In Brazil, the maximal LAS concentration allowed in fresh waters is 0.5mgL, but its potential harmful effects in amphibians remain unknown. Therefore, this study aimed to analyze the effects of a sublethal concentration of LAS (0.5mgL) for 96h on sensitive cardiac biomarkers of bullfrog tadpoles, Lithobates catesbeianus (Shaw, 1802). For this, we measured the activity level (AL - % of animals), in situ heart rate (f - bpm), relative ventricular mass (RVM - % of body mass), in vitro myocardial contractility and cardiac histology of the ventricles. Tadpoles' AL and f decreased in LAS group. In contrast, the RVM increased, as a result of a hypertrophy of the myocardium, which was corroborated by the enlargement of the nuclear measures and the increase of myocytes' diameters. These cellular effects resulted in an elevation of the in vitro contractile force of ventricle strips. Acceleration in the contraction (TPT - ms) also occurred, although no alterations in the time to relaxation (THR -ms) were observed. Therefore, it can be concluded that even when exposed to an environmentally safe concentration, this surfactant promotes several alterations in the cardiac function of bullfrog tadpoles that can impair their development, making them more susceptible to predators and less competitive in terms of reproduction success. Thus, LAS concentrations that are considered safe by Brazilian by regulatory agencies must be revised in order to minimize a drastic impact over amphibian populations. This study demonstrates the relevance of employing cardiac biomarkers at different levels (e.g., morphological, physiological and cellular) to evaluate effects of xenobiotics in tadpoles.

Life Cycle Assessment of Linear Alkylbenzene Sulfonate Production: An Adaptation to the Brazilian Context

“…Linear Alkylbenzene Sulfonate, known as LAS (Figure 1), is one of the most widely used surfactants worldwide in the formulation of commercial detergents, the same in 2018 accounted for 84% of the anionic surfactant market [4,5], as it has an excellent acceptance in the market due to its high cleaning potential when compared to that of ordinary soap, the surfactant sodium lauryl ether sulfate (LESS) [6].…”

Adsorption and Degradation of Organics in Wastewater on Municipal Sludge

“…Currently, increasing consumption of drinking water generates a large amount of wastewater with the development of the city and intensifies the pressure on the environment. Major pollutants of municipal wastewater come from human excrement, production activities, and waste from animals; and the main components are microorganisms, sugars, oils, proteins, urea, and fats, , of which 60% are organic matters (suspended matters accounting for more than 75%) . Once the pollutant content exceeds the carrying capacity of the water environment, serious environmental problems would arise and threaten human health, ecosystems, and the sustainable development of water resources. , Adsorption is an important method for pollutant control because of its simple operation and high efficiency .…”

Anuran heart development and critical developmental periods: A comparative analysis of three neotropical anuran species

“…Similar findings were reported for humans chronically exposed to several agrochemicals (Sekhotha et al, 2016). Jones‐Costa et al (2018) demonstrated the relevance of employing morphological, physiological, and cellular features of the heart as biomarkers to evaluate the effects of xenobiotics in anuran tadpoles.…”