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Plastic pollution has been globally recognized as a critical issue for marine ecosystems and nanoplastics constitute one of the last unexplored areas to understand the magnitude of this threat. However, current difficulties in sampling and identifying nano-sized debris make hard to assess their occurrence in marine environment. Polystyrene nanoparticles (PS NPs) are largely used as nanoplastics in ecotoxicological studies and although acute exposures have been already investigated, long-term toxicity on marine organisms is unknown. Our study aims at evaluating the effects of 40nm PS anionic carboxylated (PS-COOH) and 50nm cationic amino-modified (PS-NH 2 ) NPs in two planktonic species, the green microalga Dunaliella tertiolecta and the brine shrimp Artemia franciscana, respectively prey and predator. PS NP behaviour in exposure media was determined through DLS, while their toxicity to microalgae and brine shrimps evaluated through 72h growth inhibition test and 14 d long-term toxicity test respectively. Moreover, the expression of target genes (i.e. clap and cstb), having a role in brine shrimp larval growth and molting, was measured in 48h brine shrimp larvae. A different behaviour of the two PS NPs in exposure media as well as diverse toxicity to the two planktonic species was observed. PS-COOH formed micro-scale aggregates (Z-Average>1μm) and did not affect the growth of microalgae up to 50μg/ml or that of brine shrimps up to 10μg/ml. However, these negatively charged NPs were adsorbed on microalgae and accumulated (and excreted) in brine shrimps, suggesting a potential trophic transfer from prey to predator. On the opposite, PS-NH 2 -formed nano-scale aggregates (Z-Average<200nm), caused inhibition of algal growth (EC 50 =12.97μg/ml) and mortality in brine shrimps at 14 d (LC 50 =0.83μg/ml). Moreover, 1μg/ml PS-NH 2 significantly induced clap and cstb genes, explaining the physiological alterations (e.g. increase in molting) previously observed in 48h larvae, but also suggesting an apoptotic pathway triggered by cathepsin L-like protease in brine shrimps upon PS-NH 2 exposure. These findings provide a first insight into long-term toxicity of nanoplastics to marine plankton, underlining the role of the surface chemistry in determining the behaviour and effects of PS NPs, in terms of adsorption, growth inhibition, accumulation, gene modulation and mortality. The use of long-term end-point has been identified as valuable tool for assessing the impact of nanoplastics on marine planktonic species, being more predictable of real exposure scenarios for risk assessment purposes., (Copyright © 2017 Elsevier B.V. All rights reserved.)

Swimming speed alteration and mortality assays with the marine crustacean Artemia franciscana were carried out. EC50 and LC50 values after 24-48h exposures were calculated for two reference toxicants, copper sulphate pentahydrate (CuSO4·5H2O) and Sodium Dodecyl Sulphate (SDS), and an ecotoxicological concern organic compound, Diethylene Glycol (DEG). Different end-points have been evaluated, in order to point out their sensitivity levels. The swimming speed alteration (SSA) was compared to mortality values and also to the hatching rate inhibition (literature data). SSA resulted to be more sensitive than the mortality and with a sensitivity comparable to (or even higher than) the hatching rate endpoint., (Copyright © 2015 Elsevier Inc. All rights reserved.)

Artemia sp. is extensively used in ecotoxicity testing, despite criticisms inherent to both acute and long-term tests. Alternative endpoints and procedures should be considered to support the use of this biological model. The hatching process comprises several developmental steps and the cyst hatchability seems acceptable as endpoint criterion. In this study, we assessed the reliability of the hatching assay on A. franciscana by comparing with acute and long-term mortality tests, using two chemicals: Diethylene Glycol (DEG), Sodium Dodecyl Sulphate (SDS). Both DEG and SDS tests demonstrated a dose dependent hatching inhibition. The hatching test resulted more sensitive than acute mortality test and less sensitive than the long-term one. Results demonstrate the reliability and high sensitivity of this hatching assay on a short time lag and support its useful application in first-tier risk assessment procedures.

Acute heavy metal toxicity was compared in nauplii of an autochthonous Artemia parthenogenetica (Branchiopoda, Anostraca) from Saline di Cervia (Ravenna, Italy) and of a non native commercially available A. franciscana. No significant difference in sensitivity was detected between two species.

Our research activities target the use of biological methods for the evaluation of environmental quality, with particular reference to saltwater/brackish water and sediment. The choice of biological indicators must be based on reliable scientific knowledge and, possibly, on the availability of standardized procedures. In this article, we present a standardized protocol that used the marine crustacean Artemia to evaluate the toxicity of chemicals and/or of marine environmental matrices. Scientists propose that the brine shrimp (Artemia) is a suitable candidate for the development of a standard bioassay for worldwide utilization. A number of papers have been published on the toxic effects of various chemicals and toxicants on brine shrimp (Artemia). The major advantage of this crustacean for toxicity studies is the overall availability of the dry cysts; these can be immediately used in testing and difficult cultivation is not demanded. . Cyst-based toxicity assays are cheap, continuously available, simple and reliable and are thus an important answer to routine needs of toxicity screening, for industrial monitoring requirements or for regulatory purposes. The proposed method involves the mortality as an endpoint. The numbers of survivors were counted and percentage of deaths were calculated. Larvae were considered dead if they did not exhibit any internal or external movement during several seconds of observation. This procedure was standardized testing a reference substance (Sodium Dodecyl Sulfate); some results are reported in this work. This article accompanies a video that describes the performance of procedural toxicity testing, showing all the steps related to the protocol.

The brine shrimp, Artemia spp., is widely used in ecotoxicology as a target biological model. Although several protocols were available in the early 1980s, only the 24-h acute mortality toxicity test was evaluated in a European intercalibration exercise during that period. Nevertheless, documentation of standard methods serving to provide specifications, guidelines or detailed characteristics of the 24-h protocol is still unavailable. This paper present the results of an intercalibration study of three toxicity-testing protocols using Artemia franciscana : (a) the 24-h static acute mortality test, (b) the 48-h static hatching test and (c) the 14-d static-renewal long-term mortality test. A first tier of experiments was conducted by a reference laboratory, which investigated the repeatability of the three methods. The feasibility and reproducibility of these protocols were then investigated by an intercomparison exercise involving 11 participants for the acute mortality test, seven for the acute hatching test and nine for the long-term mortality test. Protocols were tested on reference toxicants (copper sulphate pentahydrate and sodium dodecyl sulphate). The coefficients of variation were <20% and <50% for intra- and interlaboratory activities, respectively. These results encourage the standardization of the proposed methods and their use as regulatory procedures. [ABSTRACT FROM AUTHOR]

Artemia spp. is an historically popular biological model still requiring an official internationally based standardization. Several endpoints are currently available. Short-term acute endpoints include biomarker (acetylcholinesterase; heat stress proteins; lipid peroxidation; thiobarbituric acid reactive substances; thioredoxin reductase; glutathione-peroxidase; glutathione S -transferase; glutathione reductase; aldehyde dehydrogenase; and adenylpyrophosphatase and Fluotox), hatching (dry biomass, morphological disorders and size), behavioral (swimming speed and path length), teratogenicity (growth), and immobilization (meaning mortality after 5–30 s observation). Long-term chronic tests focus on growth, reproduction and survival or mortality after 7–28 d exposure from larval to adulthood stage. We analyzed each test looking at its endpoint, toxicant and experimental design including replicates, exposure time, number of exposed cysts or organisms and their relative life stage, exposure conditions during hatching and testing (salinity, pH, light intensity, aeration dilution media, and food supply), type of testing chambers, and quality assurance and quality control criteria. Similarities and differences between the identified approaches were highlighted. Results evidenced that hatching 24 h short-term and 14 d long-term mortality are the most promising Artemia spp. protocols that should go forward with international standardization. [ABSTRACT FROM AUTHOR]