Safety Assessment of Carbonate Salts as Used in Cosmetics.

The Expert Panel for Cosmetic Ingredient Safety (Panel) assessed the safety of 6 carbonate salts which function as absorbents, bulking agents, opacifying agents, pH adjusters, buffering agents, abrasives, and oral care agents in cosmetic products. The Panel reviewed relevant data relating to the safety of these ingredients, and concluded that these carbonate salts are safe in the present practices of use and concentration in cosmetics when formulated to be non-irritating.

Theoretical investigation on the contribution of HO, SO4- and CO3- radicals to the degradation of phenacetin in water: Mechanisms, kinetics, and toxicity evaluation.

Indirect oxidation induced by reactive free radicals, such as hydroxyl radical (HO), sulfate radical (SO4-) and carbonate radical (CO3-), plays an important or even crucial role in the degradation of micropollutants. Thus, the coadjutant degradation of phenacetin (PNT) by HO, SO4- and CO3-, as well as the synergistic effect of O2 on HO and HO2 were studied through mechanism, kinetics and toxicity evaluation. The results showed that the degradation of PNT was mainly caused by radical adduct formation (RAF) reaction (69% for Г, the same as below) and H atom transfer (HAT) reaction (31%) of HO. For the two inorganic anionic radicals, SO4- initiated PNT degradation by sequential radical addition-elimination (SRAE; 55%), HAT (28%) and single electron transfer (SET; 17%) reactions, while only by HAT reaction for CO3-. The total initial reaction rate constants of PNT by three radicals were in the order: SO4- > HO > CO3-. The kinetics of PNT degradation simulated by Kintecus program showed that UV/persulfate could degrade target compound more effectively than UV/H2O2 in ultrapure water. In the subsequent reaction of PNT with O2, HO and HO2, the formation of mono/di/tri-hydroxyl substitutions and unsaturated aldehydes/ketones/alcohols were confirmed. The results of toxicity assessment showed that the acute and chronic toxicity of most products to fish increased and to daphnia decreased, and acute toxicity to green algae decreased while chronic toxicity increased.

Dual inhibition of sodium-glucose linked cotransporters 1 and 2 exacerbates cardiac dysfunction following experimental myocardial infarction.

BACKGROUND: Inhibiting both type 1 and 2 sodium-glucose linked cotransporter (SGLT1/2) offers the potential to not only increase glucosuria beyond that seen with selective SGLT2 inhibition alone but to reduce glucose absorption from the gut and to thereby also stimulate glucagon-like peptide 1 secretion. However, beyond the kidney and gut, SGLT1 is expressed in a range of other organs particularly the heart where it potentially assists GLUT-mediated glucose transport. Since cardiac myocytes become more reliant on glucose as a fuel source in the setting of stress, the present study sought to compare the effects of dual SGLT1/2 inhibition with selective SGLT2 inhibition in the normal and diseased heart. METHODS: Fischer F344 rats underwent ligation of the left anterior descending coronary artery or sham ligation before being randomized to receive the dual SGLT1/2 inhibitor, T-1095, the selective SGLT2 inhibitor, dapagliflozin or vehicle. In addition to measuring laboratory parameters, animals also underwent echocardiography and cardiac catheterization to assess systolic and diastolic function in detail. RESULTS: When compared with rats that had received either vehicle or dapagliflozin, T-1095 exacerbated cardiac dysfunction in the post myocardial infarction setting. In addition to higher lung weights, T-1095 treated rats had evidence of worsened systolic function with lower ejection fractions and reduction in the rate of left ventricle pressure rise in early systole (dP/dtmax). Diastolic function was also worse in animals that had received T-1095 with prolongation of the time constant for isovolumic-pressure decline (Tau) and an increase in the end-diastolic pressure volume relationship, indices of the active, energy-dependent and passive phases of cardiac relaxation. CONCLUSIONS: The exacerbation of post myocardial infarction cardiac dysfunction with T-1095 in the experimental setting suggests the need for caution with the use of dual SGLT1/2 inhibitors in humans.

Functional characterization of a Glycine soja Ca(2+)ATPase in salt-alkaline stress responses.

It is widely accepted that Ca(2+)ATPase family proteins play important roles in plant environmental stress responses. However, up to now, most researches are limited in the reference plants Arabidopsis and rice. The function of Ca(2+)ATPases from non-reference plants was rarely reported, especially its regulatory role in carbonate alkaline stress responses. Hence, in this study, we identified the P-type II Ca(2+)ATPase family genes in soybean genome, determined their chromosomal location and gene architecture, and analyzed their amino acid sequence and evolutionary relationship. Based on above results, we pointed out the existence of gene duplication for soybean Ca(2+)ATPases. Then, we investigated the expression profiles of the ACA subfamily genes in wild soybean (Glycine soja) under carbonate alkaline stress, and functionally characterized one representative gene GsACA1 by using transgenic alfalfa. Our results suggested that GsACA1 overexpression in alfalfa obviously increased plant tolerance to both carbonate alkaline and neutral salt stresses, as evidenced by lower levels of membrane permeability and MDA content, but higher levels of SOD activity, proline concentration and chlorophyll content under stress conditions. Taken together, for the first time, we reported a P-type II Ca(2+)ATPase from wild soybean, GsACA1, which could positively regulate plant tolerance to both carbonate alkaline and neutral salt stresses.

Comparative toxicity of sodium carbonate peroxyhydrate to freshwater organisms.

Sodium carbonate peroxyhydrate (SCP) is a granular algaecide containing H2O2 as an active ingredient to control growth of noxious algae. Measurements of sensitivities of target and non-target species to hydrogen peroxide are necessary for water resource managers to make informed decisions and minimize risks for non-target species when treating noxious algae. The objective of this study was to measure and compare responses among a target noxious alga (cyanobacterium Microcystis aeruginosa) and non-target organisms including a eukaryotic alga (chlorophyte Pseudokirchneriella subcapitata), microcrustacean (Ceriodaphnia dubia), benthic amphipod (Hyalella azteca), and fathead minnow (Pimephales promelas) to exposures of hydrogen peroxide as SCP. Hydrogen peroxide exposures were confirmed using the I3(-) method. SCP margins of safety for these organisms were compared with published toxicity data to provide context for other commonly used algaecides and herbicides (e.g. copper formulations, endothall, and diquat dibromide). Algal responses (cell density and chlorophyll a concentrations) and animal mortality were measured after 96h aqueous exposures to SCP in laboratory-formulated water to estimate EC50 and LC50 values, as well as potency slopes. Despite a shorter test duration, M. aeruginosa was more sensitive to hydrogen peroxide as SCP (96h EC50:0.9-1.0mgL(-)(1) H2O2) than the eukaryotic alga P. subcapitata (7-d EC50:5.2-9.2mgL(-1) H2O2), indicating potential for selective control of prokaryotic algae. For the three non-target animals evaluated, measured 96-h LC50 values ranged from 1.0 to 19.7mgL(-1) H2O2. C. dubia was the most sensitive species, and the least sensitive species was P. promelas, which is not likely to be affected by concentrations of hydrogen peroxide as SCP that would be used to control noxious algae (e.g. M. aeruginosa). Based on information from peer-reviewed literature, other algaecides could be similarly selective for cyanobacteria. Of the algaecides compared, SCP can selectively mitigate risks associated with noxious cyanobacterial growths (e.g. M. aeruginosa), with an enhanced margin of safety for non-target species (e.g. P. promelas).

Effects of Differently Coated Silver Nanoparticles on the Photosynthesis of Chlamydomonas reinhardtii.

Various factors have been invoked to explain the toxicity of silver nanoparticles (AgNP) to microorganisms including particle size and the nature of stabilizing coatings as well as the amount of dissolved silver occurring in AgNP suspensions. In this study we have assessed the effects of nine differently coated AgNP (chitosan, lactate, polyvinylpyrrolidone, polyethelene glycol, gelatin, sodium dodecylbenzenesulfonate, citrate, dexpanthenol, and carbonate) and AgNO3 on the photosynthesis of the freshwater algae Chlamydomonas reinhardtii. We have thus examined how AgNP effects on algae relate to particle size, measured dissolved silver (Agd), and bioavailable silver (Agbioav). Agbioav was indirectly estimated in toxicity experiments by cysteine-silver complexation at the EC50. The EC50 calculated as a function of measured Agd concentrations showed for some coatings values similar to that of dissolved Ag, whereas other coated AgNP displayed lower EC50 values. In all cases, excess cysteine completely prevented effects on photosynthetic yield, confirming the role of Agd as a cause of the observed effect on the photosynthesis. Toxicity was related neither to particle size nor to the coatings. For all differently coated AgNP suspensions, the EC50 values calculated as a function of Agbioav were comparable to the value of AgNO3. Depending on the coatings Agbioav was comparable to or higher than measured Agd.

Designed guanidinium-rich amphipathic oligocarbonate molecular transporters complex, deliver and release siRNA in cells.

The polyanionic nature of oligonucleotides and their enzymatic degradation present challenges for the use of siRNA in research and therapy; among the most notable of these is clinically relevant delivery into cells. To address this problem, we designed and synthesized the first members of a new class of guanidinium-rich amphipathic oligocarbonates that noncovalently complex, deliver, and release siRNA in cells, resulting in robust knockdown of target protein synthesis in vitro as determined using a dual-reporter system. The organocatalytic oligomerization used to synthesize these co-oligomers is step-economical and broadly tunable, affording an exceptionally quick strategy to explore chemical space for optimal siRNA delivery in varied applications. The speed and versatility of this approach and the biodegradability of the designed agents make this an attractive strategy for biological tool development, imaging, diagnostics, and therapeutic applications.

Immunotoxicity of washing soda in a freshwater sponge of India.

The natural habitat of sponge, Eunapius carteri faces an ecotoxicological threat of contamination by washing soda, a common household cleaning agent of India. Washing soda is chemically known as sodium carbonate and is reported to be toxic to aquatic organisms. Domestic effluent, drain water and various human activities in ponds and lakes have been identified as the major routes of washing soda contamination of water. Phagocytosis and generation of cytotoxic molecules are important immunological responses offered by the cells of sponges against environmental toxins and pathogens. Present study involves estimation of phagocytic response and generation of cytotoxic molecules like superoxide anion, nitric oxide and phenoloxidase in E. carteri under the environmentally realistic concentrations of washing soda. Sodium carbonate exposure resulted in a significant decrease in the phagocytic response of sponge cells under 4, 8, 16 mg/l of the toxin for 96h and all experimental concentrations of the toxin for 192h. Washing soda exposure yielded an initial increase in the generation of the superoxide anion and nitric oxide followed by a significant decrease in generation of these cytotoxic agents. Sponge cell generated a high degree of phenoloxidase activity under the experimental exposure of 2, 4, 8, 16 mg/l of sodium carbonate for 96 and 192 h. Washing soda induced alteration of phagocytic and cytotoxic responses of E. carteri was indicative to an undesirable shift in their immune status leading to the possible crises of survival and propagation of sponges in their natural habitat.

Morphological alteration, lysosomal membrane fragility and apoptosis of the cells of Indian freshwater sponge exposed to washing soda (sodium carbonate).

Washing soda is chemically known as sodium carbonate and is a component of laundry detergent. Domestic effluent, drain water and various anthropogenic activities have been identified as major routes of sodium carbonate contamination of the freshwater ecosystem. The freshwater sponge, Eunapius carteri, bears ecological and evolutionary significance and is considered as a bioresource in aquatic ecosystems. The present study involves estimation of morphological damage, lysosomal membrane integrity, activity of phosphatases and apoptosis in the cells of E. carteri under the environmentally realistic concentrations of washing soda. Exposure to washing soda resulted in severe morphological alterations and damages in cells of E. carteri. Fragility and destabilization of lysosomal membranes of E. carteri under the sublethal exposure was indicative to toxin induced physiological stress in sponge. Prolonged exposure to sodium carbonate resulted a reduction in the activity of acid and alkaline phosphatases in the cells of E. carteri. Experimental concentration of 8 mg/l of washing soda for 192 h yielded an increase in the physiological level of cellular apoptosis among the semigranulocytes and granulocytes of E. carteri, which was suggestive to possible shift in apoptosis mediated immunoprotection. The results were indicative of an undesirable shift in the immune status of sponge. Contamination of the freshwater aquifers by washing soda thus poses an alarming ecotoxicological threat to sponges.

Surfactant-free synthesis, luminescent properties, and drug-release properties of LaF3 and LaCO3F hollow microspheres.

Uniform LaF3 and LaCO3F hollow microspheres were successfully synthesized through a surfactant-free route by employing La(OH)CO3 colloidal microspheres as a sacrificial template and NaBF4 as the fluorine source. The synthetic process consists of two steps: the preparation of a La(OH)CO3 precursor via a facile urea-based precipitation and the following formation of lanthanide fluoride hollow microspheres under aqueous conditions at low temperature (50 °C) and short reaction time (3 h), without using any surfactant and catalyst. The formation of hollow spheres with controlled size can be assigned to the Kirkendall effect. It is found that the phase and structure of the products can be simply tuned by changing the pH values of the solution. Time-dependent experiments were employed to study the possible formation process. N2 adsorption/desorption results indicate the mesoporous nature of LaF3 hollow spheres. Yb(3+)/Er(3+) (Ho(3+)) and Yb(3+)/Tm(3+)-doped LaF3 hollow spheres exhibit characteristic up-conversion (UC) emissions of Er(3+) (Ho(3+)) and Tm(3+) under 980 nm laser-diode excitation, and Ce(3+)/Tb(3+)-doped LaF3 and LaCO3F emit bright yellow-green and near-white light under UV irradiation, respectively. In particular, LaF3:Yb/Er and LaCO3F:Ce/Tb hollow microspheres exhibit obvious sustained and pH-dependent doxorubicin release properties. The luminescent properties of the carriers allow them to be tracked or monitored during the release or therapy process, suggesting their high potential in the biomedical field.

Metabolomics analysis reveals the response mechanism to carbonate alkalinity toxicity in the gills of Eriocheir sinensis.

Aquatic water with carbonate alkalinity presents a survival challenge to aquatic animals. As an economically important crab, large quantities of Eriocheir sinensis are cultured in carbonate-type saline-alkali ponds, while the toxic effect on E. sinensis from carbonate alkalinity is still unclear. In this study, untargeted liquid chromatography-mass spectrometry metabolomics was performed to investigate the metabolic change caused by culture alkalinity, and confirmed distinct physiological response under gradient alkalinities. There were 39 differential metabolites obtained in the low-alkalinity group (4.35 mmol/L) versus control group, and "arachidonic acid metabolism" was enriched as a core response pathway. 93 differential metabolites were identified in the high-alkalinity group (17.43 mmol/L) versus control group, and a complex response net was manifested through integrated analysis, building by "steroid hormone biosynthesis", "phenylalanine, tyrosine and tryptophan biosynthesis", "phosphonate and phosphinate metabolism", "phenylalanine metabolism", "mineral absorption", "purine metabolism" and "carbon metabolism". This indicated the mobilization of energy reserves and the suppression of protein and amino acid catabolism were manifested in E. sinensis gills to defense high alkalinity stress. In addition, the persistently regulation of key metabolites under various alkalinity, including diuretic compound "spironolactone" and the antiphlogistic compound "LXB4", suggested anti-inflammatory action and excretion regulation were initiated to defend the stress.

A Gγ protein regulates alkaline sensitivity in crops.

The use of alkaline salt lands for crop production is hindered by a scarcity of knowledge and breeding efforts for plant alkaline tolerance. Through genome association analysis of sorghum, a naturally high-alkaline-tolerant crop, we detected a major locus, Alkaline Tolerance 1 (AT1), specifically related to alkaline-salinity sensitivity. An at1 allele with a carboxyl-terminal truncation increased sensitivity, whereas knockout of AT1 increased tolerance to alkalinity in sorghum, millet, rice, and maize. AT1 encodes an atypical G protein γ subunit that affects the phosphorylation of aquaporins to modulate the distribution of hydrogen peroxide (H2O2). These processes appear to protect plants against oxidative stress by alkali. Designing knockouts of AT1 homologs or selecting its natural nonfunctional alleles could improve crop productivity in sodic lands.

Successful application of lead isotopes in source apportionment, legal proceedings, remediation and monitoring.

In late 2006, the seaside community in Esperance Western Australia was alerted to thousands of native bird species dying. The source of the lead (Pb) was determined by Pb isotopes to derive from the handling of Pb carbonate concentrate through the Port, which began in July 2005. Concern was expressed for the impact of this on the community. Our objectives were to employ Pb isotope ratios to evaluate the source of Pb in environmental samples for use in legal proceedings, and for use in remediation and monitoring. Isotope measurements were undertaken of bird livers, plants, drinking water, soil, harbour sediments, air, bulk ceiling dust, gutter sludge, surface swabs and blood. The unique lead isotopic signature of the contaminating Pb carbonate enabled diagnostic apportionment of lead in samples. Apart from some soil and water samples, the proportion of contaminating Pb was >95% in the environmental samples. Lead isotopes were critical in resolving legal proceedings, are being used in the remediation of premises, were used in monitoring of workers involved in the decontamination of the storage facility, and monitoring transport of the concentrate through another port facility. Air samples show the continued presence of contaminant Pb, more than one year after shipping of concentrate ceased, probably arising from dust resuspension. Brief details of the comprehensive testing and cleanup of the Esperance community are provided along with the role of the Community. Lead isotopic analyses can provide significant benefits to regulatory agencies, interested parties, and the community where the signature is able to be characterised with a high degree of certainty.

Effects of Na2CO3 stress on photosynthesis and antioxidative enzymes in endophyte infected and non-infected rice.

Endophyte infected and uninfected seedlings of rice (Oryza sativa L.) were subjected to five different levels of Na(2)CO(3) for 2 weeks. Under both Na(2)CO(3) stress as well as no stress, endophyte-infected plants were higher for above-ground dry weight and shoot length, but lower for root length compared to non-infected controls, and there was no significant difference for below-ground dry weight. Chlorophylls and carotenoid contents, net photosynetic rate, transpiration rate, catalase and peroxidase activities increased, but malondialdehyde content declined in the infected plants compared to non-infected controls under Na(2)CO(3) stress. Compared to non-infected controls, water use efficiency, stomatal conductance, chlorophyll fluorescence parameters (F(v)/F(m), F(v)/F(o)) and superoxide dismutase activity in infected plants increased under high concentrations of Na(2)CO(3) while there was no significant difference under low concentrations of Na(2)CO(3). Endophyte infection was concluded to be beneficial to the growth and antioxidative mechanisms in Oryza sativa under Na(2)CO(3) stress.

Siderite (FeCO3) and magnetite (Fe3O4) overload-dependent pulmonary toxicity is determined by the poorly soluble particle not the iron content.

The two poorly soluble iron containing solid aerosols of siderite (FeCO3) and magnetite (Fe3O4) were compared in a 4-week inhalation study on rats at similar particle mass concentrations of approximately 30 or 100 mg/m³. The particle size distributions were essentially identical (MMAD ≈1.4 µm). The iron-based concentrations were 12 or 38 and 22 or 66 mg Fe/m³ for FeCO3 and Fe3O4, respectively. Modeled and empirically determined iron lung burdens were compared with endpoints suggestive of pulmonary inflammation by determinations in bronchoalveolar lavage (BAL) and oxidative stress in lung tissue during a postexposure period of 3 months. The objective of study was to identify the most germane exposure metrics, that are the concentration of elemental iron (mg Fe/m³), total particle mass (mg PM/m³) or particle volume (µl PM/m³) and their associations with the effects observed. From this analysis it was apparent that the intensity of pulmonary inflammation was clearly dependent on the concentration of particle-mass or -volume and not of iron. Despite its lower iron content, the exposure to FeCO3 caused a more pronounced and sustained inflammation as compared to Fe3O4. Similarly, borderline evidence of increased oxidative stress and inflammation occurred especially following exposure to FeCO3 at moderate lung overload levels. The in situ analysis of 8-oxoguanine in epithelial cells of alveolar and bronchiolar regions supports the conclusion that both FeCO3 and Fe3O4 particles are effectively endocytosed by macrophages as opposed to epithelial cells. Evidence of intracellular or nuclear sources of redox-active iron did not exist. In summary, this mechanistic study supports previous conclusions, namely that the repeated inhalation exposure of rats to highly respirable pigment-type iron oxides cause nonspecific pulmonary inflammation which shows a clear dependence on the particle volume-dependent lung overload rather than any increased dissolution and/or bioavailability of redox-active iron.

Thiocyanate, calcium and sulfate as causes of toxicity to Ceriodaphnia dubia in a hard rock mining effluent.

A series of Toxicity Identification Evaluations (TIEs) to identify the cause(s) of observed toxicity to Ceriodaphnia dubia have been conducted on a hard rock mining effluent. Characteristic of hard rock mining discharges, the effluent has elevated (∼3000 mg l(-1)) total dissolved solids (TDS) composed primarily of Ca(2+) and SO(4)(2-). The effluent typically exhibits 6-12 toxic units (TUs) when tested with C. dubia. Phase I and II toxicity identification evaluations (TIEs) indicated Ca(2+) and SO(4)(2-) contributed only ∼4 TUs of toxicity, but this was likely an underestimate due to problems with simulating the supersaturated CaSO(4) concentrations in the effluent. Treatment of the effluent with BaCO(3) to precipitate Ca(2+) and SO(4)(2-) revealed that these ions contribute ∼6 TUs of the observed toxicity, but the remaining source(s) of toxicity (up to 6 TUs) remained unidentified. Subsequent investigations identified thiocyanate (SCN(-)) in the effluent at 100-150 µM. Toxicity tests reveal that C. dubia are sensitive to SCN(-) with an estimated IC25 of 8.3 µΜ for reproduction in moderately hard water suggesting between 12 and 18 TUs of toxicity in the effluent. Additional experiments demonstrated that SCN(-) toxicity is reduced in the high TDS matrix of the mining effluent. Testing of a mock effluent simulating the major ion and SCN(-) concentrations resulted in 10.4 TUs, suggesting that Ca(2+), SO(4)(2-) and SCN(-) are the three toxicants present in this effluent. This research suggests SCN(-) may be a more common cause of toxicity in mining effluents than is generally recognized.

Cytotoxicity and genotoxicity of sodium percarbonate: a comparison with bleaching agents commonly used in discoloured pulpless teeth.

AIM: To evaluate the cytotoxicity and genotoxicity of sodium percarbonate (SPC) in comparison with bleaching agents used on discoloured pulpless teeth. METHODOLOGY: The cytotoxicity and genotoxicity of bleaching agents were evaluated both in their pure form as well as at concentrations commonly used in clinical practice. Hydrogen peroxide (HP), carbamide peroxide (CP), sodium perborate (SP) and SPC were diluted in Dulbecco's modified Eagle's medium (DMEM) in series. To evaluate the cytotoxicity, the survival of 3T3/NIH mouse fibroblasts was measured photometrically using an 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide assay after a 24 h-exposure period. Genotoxicity was indicated by micronuclei (MN) formation, and modification of the normal cell was analysed by light microscopy (400x). Statistical analysis was performed by one-way anova, followed by a multiple-comparison Tukey post hoc test (P < 0.05). RESULTS: All groups exhibited a dose-dependent cytotoxicity. However, CP showed a similar cytotoxic effect when compared with DMEM-untreated control (UC) group. HP and SPC were significantly more cytotoxic than SP. The genotoxicity test showed that SPC and SP had an intermediate rate of MN frequency when compared with the UC group. The mean rate of MN frequency for HP was higher and statistically more significant than for the other groups tested. No difference was observed when CP and UC groups were compared. CONCLUSIONS: Sodium percarbonate showed cytotoxicity and genotoxicity similar to those of the other products tested. However, before SPC is used clinically, studies should be conducted to confirm its safety in vivo.

Use of Zinc Carbonate Spiking to Obtain Phytotoxicity Thresholds Comparable to Those in Field-Collected Soils.

Several studies have reported the presence of smithsonite (ZnCO3 ) in soils polluted by zinc mining. The present study aimed to determine upper critical threshold values of Zn phytotoxicity in a substrate spiked with ZnCO3 and to compare them with those obtained in field-collected soils. We studied Zn toxicity to perennial ryegrass (Lolium perenne L.) grown in pots with unpolluted peat treated with increasing concentrations of ZnCO3 that produced nominal total Zn concentrations of 0, 0.7, 1.3, 2.0, 2.6, and 3.3%. To keep constant near-neutral pH value in all the treatments, we used decreasing concentrations of dolomitic lime. In the treatment with total soil Zn of 3.3% (pH 6.8), the foliar Zn concentration of L. perenne was 1914 ± 211 mg kg-1 , falling into the range of 2400 ± 300 mg kg-1 reported for Lolium species grown under similar laboratory conditions in a polluted soil (total soil Zn 5.4%, pH 7.3) collected near a Zn smelter. The value of 92 ± 98 mg kg-1 was obtained for the median effective concentration (EC50) values of 0.01 M KNO3 -extractable Zn using the responses of shoot dry biomass, shoot length, and total pigments. This value falls within the range of 95 ± 46 mg kg-1 reported in other studies for the EC50 values of salt-extractable Zn using field-collected soils. The application of ZnCO3 for spiking was able to mimic foliar Zn concentrations of Lolium species observed in field-collected soils. The effective concentrations of soil Zn obtained in the present study are comparable to those obtained in field-collected soils. Future research should determine effective concentrations of metals using soils spiked with metal-containing compounds that mimic a real source of contamination. Environ Toxicol Chem 2020;39:1790-1796. © 2020 SETAC.

Ocean Acidification and Coastal Marine Invertebrates: Tracking CO2 Effects from Seawater to the Cell.

In the last few decades, numerous studies have investigated the impacts of simulated ocean acidification on marine species and communities, particularly those inhabiting dynamic coastal systems. Despite these research efforts, there are many gaps in our understanding, particularly with respect to physiological mechanisms that lead to pathologies. In this review, we trace how carbonate system disturbances propagate from the coastal environment into marine invertebrates and highlight mechanistic links between these disturbances and organism function. We also point toward several processes related to basic invertebrate biology that are severely understudied and prevent an accurate understanding of how carbonate system dynamics influence organismic homeostasis and fitness-related traits. We recommend that significant research effort be directed to studying cellular phenotypes of invertebrates acclimated or adapted to elevated seawater pCO2 using biochemical and physiological methods.

Oxidative stress, histopathological alterations and anti-oxidant capacity in different tissues of largemouth bass (Micropterus salmoides) exposed to a newly developed sodium carbonate peroxyhydrate granular algaecide formulated with hydrogen peroxide.

Various strategies exist to control noxious cyanobacterial populations, although the application of a newly developed granular compound (sodium carbonate peroxyhydrate 'SCP', trade name 'PAK® 27' algaecide) containing hydrogen peroxide (H2O2) as the active ingredient, has been recently proven as an effective and ecofriendly treatment. However, in aquaculture settings the application of SCP to treat cynobacterial blooms may affect non-targeted biota, such as fish due to H2O2 being known to elicit toxic oxidative stress. Consequently, a better understanding of the side effects as a function of dosing concentrations would help to improve treatment efficacy and fish welfare. Thus, the aim of the current study is to assess the potential risks of SCP to largemouth bass (Micropterus salmoides), a high priced fish in the U.S. To this end, fish were exposed to two recommended doses of SCP corresponding to either 2.5 or 4.0 mg/L H2O2 for 6 days, with a control group in parallel. After 6 days, the effect of SCP exposure on oxidative stress, histopathological changes and anti-oxidant potential in the brain, liver, gills and muscle were investigated. Results show that exposure to 4.0 mg/L H2O2 -SCP incited oxidative damage, evidenced by an over-accumulation of H2O2 and malondialdehyde (MDA) in the brain and liver, which were accompanied by an increment in xanthine oxidase activity. Unlike 4.0 mg/L H2O2, these oxidative stress biomarkers in the brain and liver tissue of 2.5 mg/L H2O2-SCP exposed fish were restrained within control levels and concomitant with an increase in superoxide dismutase (SOD), catalase (CAT), glutathione peroxidase (GPX), glutathione reductase (GR) and glutathione-s-transferase (GST) activity. In contrast, many of these anti-oxidants sentinels in the 4.0 mg/L H2O2 exposed fish were either unaffected or significantly inhibited, which resulted in over-accumulation of H2O2 and MDA. In addition, a series of histopathological alterations were observed, and the most severe brain injuries and liver inflammation were recorded in 4.0 mg/L H2O2-SCP exposed fish. Based on oxidative parameters, both SCP doses resulted in a relatively mild oxidative stress in gills but no effect in muscle, probably explaining the modest anti-oxidative responses in the former and almost complete lack of anti-oxidative responses in the latter. Overall, our findings suggests that the application of SCP at 4.0 mg/L H2O2 to control cyanobacterial blooms in aquaculture settings can possess potential risks to the farmed fish.