Aquatic testing guidelines insufficiently control the influence of dilution water toc and hardness on cationic polymer toxicity – A proposal to improve standardized test procedures

Salinas, Edward; Bozich, Jared; Kolbenschlag, Sara; Kary-Heinrich, Miriam; Hopp, Philipp W.; Lukas, Rüdiger; Zok, Sabine; Hidding, Björn

doi:10.1016/j.chemosphere.2020.127473

Cited by 13 publications

(25 citation statements)

References 30 publications

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“…For the homopolymer PQ-6 (6.2 meq/g), LC 50 values increase with MW, ranging from 0.20 mg/L (25 kDa [149]) to 2.00 mg/L (200 kDa [150]). For three PQ-7 grades, EC 50 values range from 0.4 to 10.3 mg/L, increasing at lower charge density and higher water hardness [117]. For PQ-16, EC 50 values increase with increasing MW and decreasing charge density from 0.1-1 mg/L (40 kDa, 6.1 meq/g [98]) to 31.5 mg/L (100 kDa, 2.0 meq/g [97]).…”

Section: Aquatic Organismsmentioning

confidence: 99%

“…Most compiled effect concentrations are based on nominal polymer concentrations due to missing analytical verification of actual test concentrations. This is because sufficiently specific methods for chemical analysis are often lacking [11,111,[114][115][116][117].…”

Section: Environmental Effects Of Water-soluble Synthetic Organic Polmentioning

confidence: 99%

“…Polyquaterniums In laboratory tests, water-soluble cationic polymers generally have a higher toxicity to aquatic organisms than anionic and non-ionic polymers. Their effects are thought to result from electrostatic interactions with negatively charged biological membranes, including bacterial membranes, the outer cell wall of algae, and respiratory membranes such as the gills [41,117,125,[137][138][139]. Aquatic toxicity of cationic polymers was often found to increase with increasing charge density, especially in water with a low OC content [7,12,42,117].…”

Section: Aquatic Organismsmentioning

confidence: 99%

“…Based on the compiled data, the PQs have a moderate or, in most cases, high toxicity to algae: EC 50 values were 0.03 and 0.16 mg/L for PQ-6, 0.04-0.05 mg/L for PQ-10 and between 0.1 and 1.10 mg/L for PQ-16 [31,66,[96][97][98]. For three PQ-7 grades, EC 20 values of 0.06 to 0.32 mg/L were determined in tests with Raphidocelis subcapitata with higher toxicity at higher charge density and lower water hardness ( [117], Additional file 1: Table S11). NOEC values were 0.066 mg/L for PQ-6 [31], and 0.002 and 0.013 mg/L for PQ-10 [66].…”

Section: Aquatic Organismsmentioning

confidence: 99%

“…Generally, algae were expected to be very sensitive to PQs and other cationic polymers [41,141,142]. Effects were attributed to a disruption of the negatively charged outer cell wall [117,139]. At a sufficiently high concentration, PQs can lead to a flocculation of the algae [32,137,[143][144][145].…”

Section: Aquatic Organismsmentioning

confidence: 99%

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Environmental fate and effects of water-soluble synthetic organic polymers used in cosmetic products

2021

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Because of their usually high molecular weight, polymers are generally considered as being of low environmental concern and are, therefore, exempted from registration and evaluation within REACH. This exemption is currently being reviewed by the European Commission. Against this background, data on the environmental fate and effects of selected water-soluble synthetic organic polymers used in cosmetic products were evaluated. The considered polymers include non-ionic polyethylene glycols (PEGs), anionic homo- and copolymers of acrylic acid (AA-P&CoPs), and cationic polyquaterniums (PQs). The PEGs are more amenable to biodegradation than the AA-P&CoPs and the PQs, which biodegrade slowly. In wastewater treatment plants, sorption and precipitation are expected to lead to an effective removal of the considered polymers from the wastewater. Uptake and bioaccumulation in aquatic organisms are limited by the large molecular size and, for AA-P&CoPs and PQs, the ionic charge of the polymers. In aquatic ecotoxicity tests, the PEGs and the AA-P&CoPs showed generally no to low toxicity. Effects of AA-P&CoPs on algae and crustaceans are attributed to the chelation of cationic nutrients in soft water, with toxicity being mitigated at higher water hardness. Toxicity of the cationic PQs to aquatic organisms ranged from absent to high, depending on the polymer structure, charge density and molecular weight, as well as on the test organism and test conditions. The observed effects most likely result from interactions with the organisms’ surfaces. Aquatic toxicity of the PQs is reduced by dissolved organic carbon, suspended solids, sediments minerals, and at higher water hardness, representative of natural conditions. Results from toxicity tests with sediment and soil organisms were only identified for homopolymers of acrylic acid, showing no toxicity. The evaluation of the available ecotoxicity data suggests that test methods may need to be adapted to the respective polymer type, and further standardised to improve reproducibility. Based on the identified data, the considered polymers are likely to be of low environmental concern. However, this conclusion must be seen as preliminary, since environmental concentrations could not be estimated, and further ecotoxicity data are required, e.g., for sediment and soil organisms.

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Section: Aquatic Organismsmentioning

confidence: 99%

Section: Environmental Effects Of Water-soluble Synthetic Organic Polmentioning

confidence: 99%

Section: Aquatic Organismsmentioning

confidence: 99%

Section: Aquatic Organismsmentioning

confidence: 99%

Section: Aquatic Organismsmentioning

confidence: 99%

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Environmental fate and effects of water-soluble synthetic organic polymers used in cosmetic products

2021

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Understanding Ecotoxicological Responses of Fish Embryos and Gill Cells to Cationic Polymers

Rawlings

Belanger

Connors

et al. 2022

Enviro Toxic and Chemistry

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Cationic polymers are considered by the scientific and regulatory communities as a group of greater interest amongst the polymers in commerce. As a category, relatively little hazard information is available in the public literature. Very few examples exist of published, high-quality polymer characterization and quantification of exposure. In the present study we describe a series of fish embryo toxicity (FET) and fish gill cytotoxicity assays used to establish a baseline understanding of several representative polyquaternium categories (PQ-6, PQ-10, PQ-16) in animal alternative models, accompanied by highquality analytical characterization. Materials were chosen to encompass a range of molecular weights and charge densities to determine the influence of test material characteristics on toxicity. Both chorionated and dechorionated FET assays were generally similar to published acute fish toxicity data. Toxicity was correlated with cationic polymer charge density, and not with molecular weight, and was a combination of physical effects and likely toxicity at the site of action. Toxicity could be ameliorated by humic acid in a dose-dependent manner. Fish gill cytotoxicity results were orders of magnitude less sensitive than FET test responses.

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Environmental hazard of cationic polymers relevant in personal and consumer care products: A critical review

Connors

Arndt

Rawlings

et al. 2022

Integr Envir Assess & Manag

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Historically, polymers have been excluded from registration and evaluation under the Registration, Evaluation, Authorisation and Restriction of Chemicals (REACH) program, the European chemical management program. Recently, interest has increased to include polymers. A tiered registration system has been envisioned and would begin with classes of polymers of greater interest based on certain properties. Cationic polymers are one such class. There is a pressing need to understand the quality and limitations of historical cationic polymer studies and to identify key sources of uncertainty in environmental hazard assessments so we can move toward scientifically robust analyses. To that end, we performed a critical review of the existing cationic polymer environmental effects literature to evaluate polymer characterization and test methodologies to understand how these parameters may affect test interpretation. The relationship between physicochemical parameters, acute and chronic toxicity, and relative trophic level sensitivity were explored. To advance our understanding of the environmental hazard and subsequent risk characterization of cationic polymers, there is a clear need for a consistent testing approach as many polymers are characterized as difficult-to-test substances. Experimental parameters such as dissolved organic carbon and solution renewal approaches can alter cationic polymer bioavailability and toxicity. It is recommended that OECD TG 23 "Aqueous-Phase Aquatic Toxicity Testing of Difficult Test Substances" testing considerations be applied when conducting environmental toxicity assays with cationic polymers.

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Aquatic testing guidelines insufficiently control the influence of dilution water toc and hardness on cationic polymer toxicity – A proposal to improve standardized test procedures

Cited by 13 publications

References 30 publications

Environmental fate and effects of water-soluble synthetic organic polymers used in cosmetic products

Environmental fate and effects of water-soluble synthetic organic polymers used in cosmetic products

Understanding Ecotoxicological Responses of Fish Embryos and Gill Cells to Cationic Polymers

Environmental hazard of cationic polymers relevant in personal and consumer care products: A critical review

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