Cosmetics can contain harmful compounds such as heavy metals. Several metals have a cumulative effect on the body, especially fatty tissues, and may have different health effects on the human body over the long term. Therefore, the main objective of this study was to assess the health risks of heavy metals in cosmetics in Iran. Also, in this study, Monte Carlo simulation was used to investigate uncertainties. In this study, heavy metals data of cosmetics were extracted from studies carried out at intervals 2010–2018. International and Iranian databases such as Google Scholar, Web of Science, Springer, Science Direct, PubMed, Scopus, Irandoc, Magiran, Scientific Information Database (SID), and Information Institute for Scientific (ISC) were searched for this purpose. In this study, the index of the Margin of Safety was calculated to determine the risk of human contact with metallic impurities in cosmetic products used by humans. In the selected period, 11 studies were conducted on the measurement of heavy metals in cosmetics in Iran. In these studies, cosmetics such as eye shadow, eye pencil, powder, cream, and lipstick were studied. The Margin of Safety (MoS) values calculated for different metals were higher than the established safe standard by WHO. The highest and lowest amount of systemic exposure dosage in all types of cosmetic investigated (lipstick, cream, eye pencil, face powder, and eye shadow) was related to Fe and Hg. The mean hazardous quotient (HQ) for Cd, Cr, Ni, Cu, Mn, Zn, Pb, and Hg was 1.05E-03, 1.03E-01, 7.95E-03, 2.59E-03, 1.05E-03, 4.98E-03, 7.22E-04, 1.85E-01, and 1.35E-05, respectively. The highest HQ (6.10E-01) was found for Pb, which was observed in the cream.

Although Chinese government has implemented a series of laws, regulations, and policies to deal with air pollutants, air pollution is still one of the biggest concerns in China. Most of the cities in China suffered from extremely high air pollution levels and cannot meet the national air quality standards. In this study, we attempt to measure individuals’ average marginal willingness to pay (MWTP) in Beijing with the hedonic price model. We combine an extensive housing transaction dataset with emission data of six air pollutants from 2013 to 2016 in Beijing, China. When estimating the hedonic price function, we apply both ordinary least squares (OLS) and panel model with various fixed effects to better control for unobservables. The empirical results reveal that the concentrations of CO, NO₂, PM₂.₅, and PM₁₀ are significantly negatively correlated with housing prices. However, we found an insignificant relationship with the concentration of SO₂ and the concentration of O₃ appears to positively increase the housing values. Policy implications based on these results were also discussed.

Desorption of hydrophobic organic contaminants (HOCs) from sedimentary materials plays a vital role in dictating the fate and transport of HOCs in the environment. Desorption irreversibility is a commonly observed phenomenon in laboratory sorption/desorption studies of HOCs. A desorption-resistant fraction (DRF) typically exists during the desorption process. To correctly evaluate the DRF of HOCs can considerably contribute to the understanding of availability and bioavailability of HOCs. This can substantially benefit contaminant remediation and cleanup operations. Conventional batch method to measure the DRF replies on repetitive washing of the sediments, which is time-consuming and can be impractical. This study presents an experimental protocol to quantify the DRF of the sediment-sorbed organic contaminants in a rapid manner. This protocol utilizes cosolvent to expedite desorption kinetics and adopts an ultrafiltration/centrifugation combined method to achieve a complete separation of sediment and solution phases. This proposed experimental protocol can facilitate the quantification of the DRF of sorbed contaminants to understand and minimize the uncertainties associated with risk-based pollution remediation approach. This protocol has the potential to be widely used in environmental studies to characterize sorption and desorption properties of HOCs with soil and sedimentary materials.

Natural colloids (NCs) are ubiquities in aquatic environments, which play an important role in the fate and transport of metal elements. Combined with a multi-method analytical approach, this study investigates the spectral characteristics and the contamination of metals of NCs from the five tributaries of Poyang Lake and the lakes in Nanchang City. Results showed that NCs in river samples were characteristic by the smaller molecular weight, lower chromophoric dissolved organic matter (CDOM) concentration, higher aromaticity, and higher CDOM contribution to the organic carbon than those in lake samples. Based on the parallel factor analysis model, three fluorophores were identified, including two humic-like components (C1 and C2) and a protein-like component (C3). NCs in river and lake waters were dominant by the humic-like substance (C1) and the protein-like substance (C3), respectively, with the relatively high fluorescence intensity for all the fluorophores in lake samples. Furthermore, NCs from the river samples were primarily terrestrial NCs with a high degree of humification. The average detection frequency of metal elements was nearly 50% for both river and lake samples, whereas the concentrations of the metal elements were higher in lake samples. Principal component analysis (PCA) results showed that the contamination of the detected metals could divide into three categories, with relatively high concentrations of Ba, Pb, Zn, Al, Sr, and Fe in lake samples. Moreover, PCA results showed that NCs in lakes with higher values of the absorbance and fluorescence parameters were associated with the higher concentration of metal elements, revealing that the spectral characteristic could be the proxy indicator of the contamination of metal elements of NCs.

Experiments conducted over a period of 6 weeks using Brassica napus callus cells grown in vitro under Eu(III) or U(VI) stress showed that B. napus cells were able to bioassociate both potentially toxic metals (PTM), 628 nmol Eu/gfᵣₑₛₕ cₑₗₗₛ and 995 nmol U/gfᵣₑₛₕ cₑₗₗₛ. Most of the Eu(III) and U(VI) was found to be enriched in the cell wall fraction. Under high metal stress (200 μM), cells responded with reduced cell viability and growth. Subsequent speciation analyses using both metals as luminescence probes confirmed that B. napus callus cells provided multiple-binding environments for Eu(III) and U(VI). Moreover, two different inner-sphere Eu³⁺ species could be distinguished. For U(VI), a dominant binding by organic and/or inorganic phosphate groups of the plant biomass can be concluded.

Improving the competitiveness of biodiesel production by microalgae cultures requires the application of several strategies to obtain a high content of lipids, rapid biomass growth and a capacity to adapt to different kinds of environment, with the aim of using non-renewable nutrient sources. Therefore, the use of an individual indigenous microalgae strain or a consortium from natural or anthropogenic sites is now considered an alternative for biofuel production. This study examined the temporal behaviour of secondary metabolites produced by a native microalgae and yeast consortium isolated from wastewater, which was characterized by a genetic identification method based on the MiSeq system. The predominant species in the consortium was Scenedesmus obliquus, representing 68% of the organisms. In addition, the consortium contained a number of yeast species, including Candida pimensis (43%), Arthroderma vanbreuseghemii (23%), Diaporthe aspalathi/Diaporthe meridionalis (25%) and Hericium americanum (3%). This indigenous co-culture of microalgae and yeast showed biomass productivity of 0.06 g l⁻¹ day⁻¹, with a content of 30% (w/w) carbohydrates, 4% (w/w) proteins and 55% (w/w) lipids. Transesterification of the extracted lipids produced fatty acid methyl esters (FAMEs), which were analysed by gas chromatography (GC). The FAMEs included methyl pentadecanoate (1.90%), cis-10-pentanedecanoic acid methyl ester (1.36%), methyl palmitate (2.64%), methyl palmitoleate (21.36%), methyl oleate (64.95%), methyl linolenate (3.83%) and methyl linolelaidate (3.95%). This composition was relevant for biodiesel production based on the co-culture of indigenous microalgae and yeast consortia.

Biodiesel production from the transesterification of triglycerides produces crude glycerol as a by-product with a percentage of glycerol typically 20–80% (w/w) depending on the specific conditions of the transesterification process. This crude glycerol requires further purification in order to achieve commercial value and to increase the profitability of biodiesel production. For this reason, the main objective of this work was to obtain glycerol with a purity greater than 90% (w/w) starting from water-free crude glycerine as obtained from the IPN-GBD-1000® transesterification process and treating it via single-step neutralization according to green chemistry principles. For this purpose, sulphuric (H₂SO₄) and citric (C₆H₈O₇) acids were evaluated as neutralizers by adding dilute acid solutions to crude glycerine under mild conditions. The physicochemical characterization of both crude and purified glycerol was carried out by means of infrared spectroscopy (FTIR), ¹H and ¹³C nuclear magnetic resonance (NMR) and thermogravimetric analysis (TGA). The results indicated that the neutralization method herein developed allowed the obtaining of glycerol with purities of 98.5% and 84.37% (w/w) and treatment efficiencies of 98.5% and 46.7% for sulphuric and citric acid treatments, respectively. In addition, the environmental viability of the sulphuric acid process was evaluated through the calculation of green metrics such as environmental factor, water factor and mass intensity, through which significant environmental advantages were confirmed. The one-step neutralization process reported herein generates zero waste when sulphuric acid is used; it also decreases the water consumption 17-fold and reduces 3-fold the use of raw materials per mass unit of purified glycerol compared to the conventional acidification-neutralization process.

The present study was carried out to observe the variation of volatile organic compounds (VOCs) namely benzene, toluene, ethylbenzene, and xylene isomers (BTEX) at three different sites of Delhi, during 2016–2017. Four hourly sampling was carried out day and night separately. Results showed that BTEX concentration was highest in post-monsoon and lowest in monsoon season. Again, daily variation shows that benzene (47%) and toluene (35%) were more during night than day when it was 44% and 33% respectively. Mean concentration of BTEX was observed in following order: ethylbenzene ~ o-xylene < m,p-xylene < toluene < benzene, while overall seasonal variation was observed as follows: post-monsoon > summer > winter > monsoon. Possible emission sources of BTEX were also established through corresponding ratios of individual compounds. Xylene isomers together accounted highest ozone formation potential. The risk assessments of BTEX were carried out in terms of non-cancer (the hazard quotient, HQ) and cancer (the incremental lifetime cancer risk, ILCR) regarding the inhalation exposure only. It was observed that benzene and xylene isomers possessed higher HQs than ethylbenzene and toluene at all sites throughout the study. Again, benzene was found with higher mean ILCR (3.58 × 10⁻⁵) than ethylbenzene (1.47 × 10⁻⁵).

Diatomite is an economical and environmentally friendly adsorbent, and its use has been applied widely for the treatment of water contaminated by heavy metals. Despite this, the mechanism for the removal of the heavy metal Cd(II) remains unclear. In this work, we explored the adsorption mechanism of Cd(II) by diatomite using batch experiment, and characterized the diatomite using scanning electron microscopy, energy-dispersive spectrometry, specific surface area, and pore size distribution analysis. Our results showed that, under the experimental conditions, the kinetic adsorption approached equilibrium within 5 min, and the Sips isotherm model was most suitable for data fitting. EDS characterization of the Cd-loaded diatomite indicated that Cd(II) was adsorbed onto the diatomite. Furthermore, desorption experiments showed that Ca²⁺ and Mg²⁺ in the diatomite caused an ion exchange interaction, and this was primarily responsible for Cd(II) adsorption. Moreover, we found that its contribution to the whole adsorption reaction could reach 80%, while the remainder of Cd(II) was probably trapped in the microporous structure of the diatomite. Additionally, our data indicated that the adsorption mechanism did not change significantly after regeneration. These results have provided special insight into the deep understanding of the mechanism of Cd(II) adsorption by diatomite, and could provide theoretical support and guidance for further development and application of diatomite in the treatment of Cd(II)-contaminated water. Graphical abstract

Microplastics (MPs) are physical anthropogenic pollutants and their ability to act as contaminant vectors in biological matrices is of serious ecosystem and human health concern. In the present study, we have, for the first time, screened and detected MPs in the stomach of a select group of commonly consumed fish species from a municipal water supply lake (Eleyele) in Nigeria. A total of 109 fish samples consisting of eight (8) species: Coptodon zillii (CZ: n = 38), Oreochromis niloticus (ON: n = 43), Sarotheron melanotheron (SM: n = 19), Chrysicthys nigrodigitatus (CN: n = 3), Lates niloticus (LN: n = 3), Paranchanna obscura (PO: n = 1), Hemichromis fasiatus (HF: n = 1), and Hepsetus odoe (HO: n = 1) were collected between February–April, 2018. Fish stomach content was screened for the presence of MPs using the density gradient separation technique (NaCl hypersaline solution) and examined using a fluorescence microscope. MPs were present in all the species screened (except H. fasciatus) with a frequency of 69.7% positive individuals in the examined species. MP prevalence was highest in ON (34%) > CZ (32%) > SM (13%) > CN (6%) and 5% each, for PO HO, and LN. On average, 1–6 MPs with sizes ranging between 124 μm and 1.53 mm were detected per individual. However, the highest number (34) of MPs was detected in the stomach of SM. Principal coordinate analysis (PCA) identified ecological variables such as habitat, feeding mode, and trophic levels as critical factors that may determine and influence MP uptake in fish population. The PCA showed stronger association between fish habitat, feeding mode, and trophic level with MP size and number in the benthopelagic species (ON CZ and SM), compared to demersal species (PO CN HO and LN). Given that MPs can act as vectors for the transfer of pathogens and environmental contaminants (both legacy and emerging), in addition to direct health risks to aquatic organisms, our findings raise concerns on the potential human/wildlife health effects of MPs in these economically and ecologically important food fishes.