Effects of Different Microplastic Types and Surfactant-Microplastic Mixtures Under Fasting and Feeding Conditions: A Case Study on Daphnia magna

Abstract

This study evaluates the mortality and immobilization on Daphnia magna after 24-96 h of exposure to microplastic disper-sions (PP, PE, PVC, PVC/PE), and to microplastic + surfactant solutions both under fasting and feeding conditions. The tested microplastics were analysed with μFT-IR to determine their chemical composition, purity, and dimensions. The results show that: (i) exposure under fasting conditions produces acceptable results on negative controls no later than 24 h; (ii) the disper-sion of microplastics forms homo-agglomerates that are able to affect animals' motility and cause mortality and immobiliza-tion; (iii) different types of tested microplastic produce different effects on endpoints (the most toxic is PVC + surfactant); (iv) in all cases, the effects were reduced under feeding conditions (i.e. 4 times reduction of PE toxicity); (v) effects of surfactant on observed toxicity are microplastic-type dependent; (vi) the age of the animal affected the mortality and immobilization responses after exposure under both fasting and feeding conditions.

Action of Surfactants in Driving Ecotoxicity of Microplastic-Nano Metal Oxides Mixtures: A Case Study on Daphnia magna under Different Nutritional Conditions

“…Dispersions were made by suspension of tested particles in UNI EN ISO 6341:2012 standard freshwater. Experiments previously reported [28,29] determine for each toxicant the dose permitting the survival of a significant fraction of the tested population until the end of the exposure time (96 h).…”

“…ZnO and n-TiO 2 were tested at 1.12 and 113.18 mg/L respectively; microplastic doses were 0.05 mg/L. The selection of microplastics to be tested was done according to Renzi et al [29].…”

Particle Size and Pre-Treatment Effects on Polystyrene Microplastic Settlement in Water: Implications for Environmental Behavior and Ecotoxicological Tests

“…Surfactants are also added during the synthesis of MP which could alter the surface characteristics and thus the adsorption process [8,9]. Nevertheless, surfactants can also bias experiments: Renzi et al [10] recorded a higher mortality and immobilization in toxicological experiments with MP when the surfactant Triton X-100 was used. The surfactant itself had negative effects on the organisms but the more stable dispersion of particles could also lead to increased ingestion and toxicity.…”

Toxicity of plastic consumer products: a biological, chemical and social-ecological analysis

“…In addition, research focuses only on few polymer types, most often on polystyrene (PS) and polyethylene (PE) particles, disregarding other polymer types of high production and consumption, such as polypropylene (PP) and polyvinyl chloride (PVC;PlasticsEurope, 2015;S a et al, 2018). However, the toxicity of microplastics may also depend on the polymer type or on the chemicals that a plastic product, and therefore its fragments, contain (Renzi et al, 2019). One single plastic product can contain hundreds of chemicals .…”

“…Irregular PLA microplastics (3.4 mm; 19.6 mg/L) did not affect feeding, size and population growth of D. magna upon chronic exposure (Gerdes, 2018). In a comparative analysis of irregular PVC, PP and PE particles (10e100 mm; 50 mg/L), PP and PE induced a higher acute toxicity than PVC on D. magna under fasting conditions (Renzi et al, 2019). Schrank et al (2019) compared irregular rigid and flexible PVC (4e276 mm) and reported delay of primiparity in D. magna upon exposure to rigid PVC and alterations in body lengths and reproductive output for flexible PVC.…”