Aquatic Toxicity Effects and Risk Assessment of ‘Form Specific’ Product-Released Engineered Nanomaterials

The study investigated the toxicity effects of ‘form specific’ engineered nanomaterials (ENMs) and ions released from nano-enabled products (NEPs), namely sunscreens, sanitisers, body creams and socks on Pseudokirchneriella subcapitata, Spirodela polyrhiza, and Daphnia magna. Additionally, risk estimation emanating from the exposures was undertaken. The ENMs and the ions released from the products both contributed to the effects to varying extents, with neither being a uniform principal toxicity agent across the exposures; however, the effects were either synergistic or antagonistic. D. magna and S. polyrhiza were the most sensitive and least sensitive test organisms, respectively. The most toxic effects were from ENMs and ions released from sanitisers and sunscreens, whereas body creams and sock counterparts caused negligible effects. The internalisation of the ENMs from the sunscreens could not be established; only adsorption on the biota was evident. It was established that ENMs and ions released from products pose no imminent risk to ecosystems; instead, small to significant adverse effects are expected in the worst-case exposure scenario. The study demonstrates that while ENMs from products may not be considered to pose an imminent risk, increasing nanotechnology commercialization may increase their environmental exposure and risk potential; therefore, priority exposure cases need to be examined.

Effects of Sodium Chloride on Algae and Crustaceans—The Neighbouring Links of the Water Trophic Chain

Salinity limits the habitable living environment for aquatic organisms. Algae and crustaceans are widely used as bioindicators in freshwater environmental risk assessments. This study aimed to use biotests (Algaltoxkit and Daphtoxkit) to determine the effect of sodium chloride (NaCl) on algae Pseudokirchneriella subcapitata and crustaceans Daphnia magna. Standard biotests were extended to include NaCl effects on algal chlorophyll fluorescence and crustaceans swimming and heart rate. It was found that after 7 days, a 0.24 M of NaCl reduced the growth rate of the algae by 50% (EC50). A NaCl of 0.27 M inhibited the minimum (Fo), maximum (Fm) and variable (Fv) fluorescence by 50%, on average. The crustaceans also responded to NaCl. Those exposed to 0.19 M NaCl during 15 min swam slower by 50% and a 0.27 M immobilised three organisms (EC50). The crustacean immobilisation was less modified by NaCl than swimming. To determine the lethal effect in non-swimming organisms, the heart rate was examined. At 0.35 M of NaCl, all organisms were dead after 30 min, as their hearts did not beat. These studies suggest that physiological and behavioural features are sensitive indicators of the toxic effects of NaCl in algae and crustaceans, before morphological changes are observed.

Investigating The Sub-Acute Responses Of Lemna Minor, Pseudokirchneriella Subcapitata, Euglena Gracilis And Anodonta Grandis To Tributyltin-Hydride And Atrazine In Freshwater

Freshwater resources exist in limited quantities and are subject to increasing demands due to the consumption by residential, commercial and industrial uses. There are concerns that the widely used chemical analysis of drinking water does not deliver timely results. This study examines the efficacy of developing a holistic, multi-organism early-warning biomonitoring technology to assess aquatic toxicity. Sensitive indicator species such as Lemna minor, Pseudokirchneriella subcapitata, Euglena gracilis, and Anodonta grandis have been selected due to their specific behavioural and short-term biochemical responses in the identification of classes of contaminants in aquatic environments. Tributyltin, an antifouling agent in paints used on boats and atrazine, an herbicide widely used on agricultural crops, are evaluated in increasing concentrations to identify behavioural changes in these organisms. These graded responses, upon implementation in models, will warn water treatment operators of incoming contaminants and help identify the nature of the stressor. All organisms displayed some sensitivity to selected concentrations of the two test chemicals. The normal growth rate of L. minor dramatically declined with exposure to TBT (100.0 mg/L) and atrazine (500.0 g/L). Monitoring the biochemical changes, dissolved oxygen production, and also the growth rate, cell counts, of P. subcapitata showed significant effects to similar concentrations of TBT (100.00 g/L) and atrazine (500.00 g/L). The aquatic protest, E. gracilis, alters its cell morphology in the presence of low concentrations of TBT (10.0 g/L) and atrazine (50.0 g/L). Respiration patters of the bivalve, A. grandis, was directly influenced by the two chemicals, TBT (1.0 mg/L) and atrazine (50.0 mg/L). This study demonstrates that biological assessments of water samples deliver a rapid, realistic representation of the surrounding aquatic environment conditions.

Investigating The Sub-Acute Responses Of Lemna Minor, Pseudokirchneriella Subcapitata, Euglena Gracilis And Anodonta Grandis To Tributyltin-Hydride And Atrazine In Freshwater

Freshwater resources exist in limited quantities and are subject to increasing demands due to the consumption by residential, commercial and industrial uses. There are concerns that the widely used chemical analysis of drinking water does not deliver timely results. This study examines the efficacy of developing a holistic, multi-organism early-warning biomonitoring technology to assess aquatic toxicity. Sensitive indicator species such as Lemna minor, Pseudokirchneriella subcapitata, Euglena gracilis, and Anodonta grandis have been selected due to their specific behavioural and short-term biochemical responses in the identification of classes of contaminants in aquatic environments. Tributyltin, an antifouling agent in paints used on boats and atrazine, an herbicide widely used on agricultural crops, are evaluated in increasing concentrations to identify behavioural changes in these organisms. These graded responses, upon implementation in models, will warn water treatment operators of incoming contaminants and help identify the nature of the stressor. All organisms displayed some sensitivity to selected concentrations of the two test chemicals. The normal growth rate of L. minor dramatically declined with exposure to TBT (100.0 mg/L) and atrazine (500.0 g/L). Monitoring the biochemical changes, dissolved oxygen production, and also the growth rate, cell counts, of P. subcapitata showed significant effects to similar concentrations of TBT (100.00 g/L) and atrazine (500.00 g/L). The aquatic protest, E. gracilis, alters its cell morphology in the presence of low concentrations of TBT (10.0 g/L) and atrazine (50.0 g/L). Respiration patters of the bivalve, A. grandis, was directly influenced by the two chemicals, TBT (1.0 mg/L) and atrazine (50.0 mg/L). This study demonstrates that biological assessments of water samples deliver a rapid, realistic representation of the surrounding aquatic environment conditions.

Development of a Library of Responses for an Early-Warning Biomonitoring System to Detect and Identify Various Aquatic Contaminants

Biomonitors can be implemented in aquatic ecosystems to continuously assess water quality, but existing monitors are still reliant on a single species and unable to identify any stressor. A library of responses could potentially address these drawbacks by stereotyping the responses of several aquatic species to different contaminants. A model for the library was developed by conducting a bioassay on Pseudokirchneriella subcapitata and collecting the response data of Daphnia magna, Hyalella azteca and Lumbriculus variegatus from published ecotoxicological studies. Multivariate statistical tools were then employed to process the response data set and evaluate the ability of the model to distinguish contaminations by atrazine and tributyltin. Based on preliminary tests, the library was able to detect and identify each contaminant within 4 hours with an accuracy of 97%. These findings supported the integration of a library of responses in a biomonitoring system to provide a more comprehensive water quality assessment.

Development of a Library of Responses for an Early-Warning Biomonitoring System to Detect and Identify Various Aquatic Contaminants

Biomonitors can be implemented in aquatic ecosystems to continuously assess water quality, but existing monitors are still reliant on a single species and unable to identify any stressor. A library of responses could potentially address these drawbacks by stereotyping the responses of several aquatic species to different contaminants. A model for the library was developed by conducting a bioassay on Pseudokirchneriella subcapitata and collecting the response data of Daphnia magna, Hyalella azteca and Lumbriculus variegatus from published ecotoxicological studies. Multivariate statistical tools were then employed to process the response data set and evaluate the ability of the model to distinguish contaminations by atrazine and tributyltin. Based on preliminary tests, the library was able to detect and identify each contaminant within 4 hours with an accuracy of 97%. These findings supported the integration of a library of responses in a biomonitoring system to provide a more comprehensive water quality assessment.