Toxic effects of combined stressors on Daphnia pulex: Interactions between diazinon, 4‐nonylphenol, and wastewater effluent

Abstract

Contaminant exposure in aqueous systems typically involves complex chemical mixtures. Given the large number of compounds present in the environment, it is critical to identify hazardous chemical interactions rapidly. The present study utilized a prototype for a novel high‐throughput assay to quantify behavioral changes over time to identify chemical interactions that affect toxicity. The independent and combined effects of 2 chemicals, diazinon (an insecticide) and 4‐nonylphenol (a detergent metabolite), on the swimming behavior of the freshwater crustacean Daphnia pulex were examined. Cumulative distance and change in direction were measured repeatedly via optical tracking over 90 min. Exposure to low concentrations of diazinon (0.125–2 µM) or 4‐nonylphenol (0.25–4 µM) elicited significant concentration‐ and time‐dependent effects on swimming behavior. Exposure to 0.5 µM 4‐nonylphenol alone did not significantly alter mean cumulative distance but did elicit a small, significant increase in mean angle, the measure of change in direction. When 0.5 µM 4‐nonylphenol was used in combination with diazinon (0.125–0.5 µM), it augmented the adverse impact of diazinon on the swimming behavior of Daphnia. Additionally, enhanced sensitivity to diazinon was observed in animals exposed to treated wastewater effluent for 24 h prior to a diazinon challenge. The present experiments demonstrate that exposure to 4‐nonylphenol and complex chemical mixtures (e.g., treated wastewater) can enhance the toxicity of exposure to the insecticide diazinon. Environ Toxicol Chem 2015;34:1145–1153. © 2015 SETAC

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“…However, as we previously cited, municipal wastewaters could include complex toxic, carcinogenic and mutagenic organic and inorganic substances which are all difficult to determine (Ricking et al, 2003;Servos et al, 2005;Cristale and Lacorte, 2015). Zein et al (2015) determined similar values of toxicity removal for D. magna after primary and secondary treatment. The potential impact of complex chemical mixtures (e.g., treated wastewater) can enhance the toxicity of exposure to the insecticide.…”

“…The potential impact of complex chemical mixtures (e.g., treated wastewater) can enhance the toxicity of exposure to the insecticide. Complex chemical mixtures exposure in aqueous systems is an input of contaminants in the environment (Zein et al, 2015).…”

“…A number of studies have demonstrated the occurrence of organic contaminants in municipal wastewater treatment plant effluents. These studies mostly concered with occurance of pharmaceuticals, personal care products, diagnostic imaging contrast agents, estrogens and pesticides in wastewaters (Paxéus, 1996;Ternes, 1998;Daughton and Ternes, 2000;Ternes et al, 1999;Boyd et al, 2003;Lindstrom et al, 2002;Lishman et al, 2006;Odjadjare and Okoh, 2010;Rowsell et al, 2010, Zein et al,2015. Hazard assessment of municipal wastewater in Turkey is based on physicochemical parameters e.g.…”

Comparison of Diazinon Toxicity to Temperate and Tropical Freshwater Daphnia Species

“…It was commonly used for insert control in agricultural crops [4,5]. e toxicity of diazinon results from inhibiting the enzyme acetylcholinesterase (AChE), leading to the accumulation of neurotransmitters and altered signal transmission in chemical synapses [6]. In the domestic and international markets, there are more than 500 registered products that contain diazinon as the active substance [4].…”

“…Diazinon generates high acute toxicity to a wide variety of aquatic organisms, leading to a wide range of sublethal biochemical effects, damage to specific target organs and tissues, and adverse ecological impacts. e toxicity of diazinon has extensively studied in fish [4,[9][10][11] and crustaceans [6,12,13], and it has been reported to be moderately toxic to early life stages of zebrafish [4]. e 96 h LC 50 values ranging from 0.32 to 1.53 mg•L −1 for larval and from 2.2 to 10.3 mg•L −1 for adult of several fish have already been recorded [10].…”