Integrated environmental assessment of iron ore tailings in floodplain soils and plants after the Fundão Dam disaster in Brazil.

Previous studies of the Doce River basin (Brazil) seem to be contradictory regarding the contamination of soils with potentially harmful elements (PHE). This research aimed to perform an integrated assessment of PHE in the soil-plant-tailing system from the area most affected by the iron waste after the Fundão Dam disaster in 2015. Different fractions of PHE (exchangeable, nonexchangeable, reducible, and pseudo-total) were determined on deposited iron waste (DIW), soil waste mixture (SWM), and control soil (CS) samples. Total contents of PHE in Poaceae were also determined, and Allium cepa bioassays were performed to determine DIW and CS cytotoxicity and/or genotoxicity to plants. The Fe and Mn contaminations were the only ones related to the deposition of DIW on floodplains, and other harmful element content (such as As, Hg, Ni, Cd, Cr, and Pb) was not found above baseline values for soils. In addition, a significant part of the Fe and Mn in DIW is readily available or subject to acidification and prolonged flood reduction processes. The high available content of Fe favored its excessive accumulation by Brachiaria. The DIW chemical conditions reduced biological functions of A. cepa under a controlled environment. However, more drastic effects, such as genetic damage, were not seen. The postdisaster action of covering DIW with CS resulted in undesirable enrichment of Pb on the floodplain soils. The integrated results allow the conclusion that the iron waste is not a time bomb for PHE contamination of soils between the Fundão and Risoleta Neves Hydroelectric Dam (~100 km away from Fundão). Integr Environ Assess Manag 2024;20:117-132. © 2023 SETAC.

The development and application of a novel hazard scoring tool for assessing impacts of cosmetic ingredients on aquatic ecosystems: A case study of rinse-off cosmetics.

The cosmetic industry has been committed to promoting less hazardous products to reduce the environmental impacts of cosmetic ingredients. This requires identifying safer cosmetic ingredients for developing cosmetic formulations that are less harmful to the environment. However, one of the challenges in developing eco-friendly cosmetics relies on integrating all environmental hazard (EH) information of cosmetic ingredients to select the most eco-friendly ones (i.e., ingredients least harmful to the aquatic environment). Thus, we developed a hazard scoring tool (IARA matrix), which integrates data on biodegradation, bioaccumulation, and acute aquatic toxicity, providing a hazard index to classify cosmetic ingredients (raw materials) into categories of EH (low, moderate, high, or very high). The classification of the IARA was based on parameters established by Cradle to Cradle (C2C), the US Environmental Protection Agency (USEPA), and European Regulation 1272/2008, considering the most conservative values of each source. The Leopold matrix was employed as a model for the tool, using a numerical scale from 0 to 6 (lowest to highest EH). According to the IARA, we have successfully demonstrated that ultraviolet (UV) filter ingredients have the highest EH out of 41 cosmetic ingredients commonly used for rinse-off products. In addition to UV filters, triclosan (bactericide) and dimethicone (emollient) presented the second-highest EH for aquatic ecosystems, and humectants presented the lowest hazard index. By applying the IARA in the case study of rinse-off products, we have estimated that the aquatic hazard of cosmetic products can be reduced 46% by identifying less hazardous ingredients and combining them into a cosmetic formulation. In summary, the IARA tool allows the estimation of the EH of cosmetic ingredients, provides safer products, and helps achieve sustainability for cosmetic products. Integr Environ Assess Manag 2023;19:1619-1635. © 2023 SETAC.

The potential use of kraft lignins as natural ingredients for cosmetics: Evaluating their photoprotective activity and skin irritation potential.

The cosmetics market has recently undergone changes as consumers increasingly seek sustainable products. In this context, agro-derived lignins have the potential for cosmetics applications. Thus, this study investigated the photoprotective activity and skin irritation potential (OECD TG 439 with SkinVitro-RHE, an in-house reconstructed human epidermis (RHE) model) of a kraft lignin (LE) and two LE-derived lignins modified by enzymatic reactions to achieve higher molecular weight (Mw) (R1: intermediate Mw and E60: highest Mw). Results showed that LE and R1 lignins present adequate photoprotective activity with averages Sun Protection Factor (SPF) of 33.8 ± 0.02 and 22.7 ± 0.04, respectively. The E60 also present adequate SPF (22.4 ± 0.2); however, due to its poor solubility, this lignin has potential application as a physical filter. In terms of safety, these lignins did not cause skin irritation or cellular and structural damage to the epidermis. Additionally, using an analysis based on the autofluorescence feature of lignin, no sign of the tested lignins was found in exposed RHE models, indicating that these three lignins did not penetrate the skin. Altogether, the results indicate a promising application of kraft lignins for sunscreen products regarding safer alternatives and product sustainability. Also, the SkinVitro-RHE showed to be a good model for evaluating the skin irritation potential of substances, including natural cosmetic ingredients.

Visible-light reduced silver nanoparticles' toxicity in Allium cepa test system.

Silver nanoparticles (AgNPs) are widely used in consumer products due to their antibacterial property; however, their potential toxicity and release into the environment raises concern. Based on the limited understanding of AgNPs aggregation behavior, this study aimed to investigate the toxicity of uncoated (uc-AgNP) and coated with polyvinylpyrrolidone (PVP-AgNP), at low concentrations (0.5-100 ng/mL), under dark and visible-light exposure, using a plant test system. We exposed Allium cepa seeds to both types of AgNPs for 4-5 days to evaluate several toxicity endpoints. AgNPs did not cause acute toxicity (i.e., inhibition of seed germination and root development), but caused genotoxicity and biochemical alterations in oxidative stress parameters (lipid peroxidation) and activities of antioxidant enzymes (superoxide dismutase and catalase) in light and dark conditions. However, the light exposure decreased the rate of chromosomal aberration and micronuclei up to 5.60x in uc-AgNP and 2.01x in PVP-AgNP, and 2.69x in uc-AgNP and 3.70x in PVP-AgNP, respectively. Thus, light exposure reduced the overall genotoxicity of these AgNPs. In addition, mitotic index alterations and morphoanatomical changes in meristematic cells were observed only in the dark condition at the highest concentrations, demonstrating that light also reduces AgNPs cytotoxicity. The light-dependent aggregation of AgNPs may have reduced toxicity by reducing the uptake of these NPs by the cells. Our findings demonstrate that AgNPs can be genotoxic, cytotoxic and induce morphoanatomical and biochemical changes in A. cepa roots even at low concentrations, and that visible-light alters their aggregation state, and decreases their toxicity. We suggest that visible light can be an alternative treatment to remediate AgNP residues, minimizing their toxicity and environmental risks.