Comparative health risk of inhaled exposure to organic solvents, toxic metals, and hexavalent chromium from the use of spray paints in Taiwan

Abandonment of fibreglass reinforced plastic fishing boats in Kerala, India, and chemical emissions arising from their burning

Little information exists on the fate and impacts of boats constructed of fibreglass reinforced plastic (FRP) once they reach their end-of-life. In this study, the number of abandoned fishing boats constructed of FRP or constructed of plywood-wood and sheathed by FRP has been determined along the coast of Kerala, India, and chemical emissions have been estimated when boats are burned as a means of disposal. A total of 292 abandoned boats were observed across eight coastal transects constructed around selected landing centres, with abandonment ranging from 13 to 48 per km (average = 29 km-1). This results in the generation of 1420 kg of FRP debris (glass mat and epoxy resin) per km of coastline. A controlled combustion experiment, simulating open burning, revealed that 63% of original boat mass is emitted to the atmosphere, with the remainder forming a burnt residue. Total concentrations of polychlorinated dibenzo-p-dioxins and dibenzofurans emitted and remaining were found to be 2.6 ng Nm-3 and 249.6 μg kg-1, respectively, with respective calculated toxicity equivalence (TEQ) levels of 437.6 pg TEQ Nm-3 in air emissions and 26.6 μg TEQ kg-1 in the residue. These figures are equivalent to the total emission from FRP boat burning of about 17,000 μg TEQ t-1. Burning also generates significant quantities of potentially toxic metals, with resulting concentrations of Co, Cr and Cu close to or exceeding soil guideline values. The study calls for a greater awareness of the impacts arising from boat abandonment and burning amongst fishermen, and guidelines or regulatory protocols regarding safe and sustainable boat disposal or recycling.

Seasonal Disparities of Human Health Risk and Particle-Bound Metal Characteristics Associated with Atmospheric Particles in a Fishery Harbor

The effects of atmospheric pollution from ship emissions have been considered for several harbors worldwide. The health risk assessment and source apportionment of particle-bound metals in a fishery harbor were investigated in this study. The most abundant metal elements in particulate matter (PM) on all sampling days in three seasons were Fe (280.94 ± 136.93 ng/m3), Al (116.40 ± 71.25 ng/m3), and Zn (110.55 ± 26.70 ng/m3). The ratios of V/Ni were 1.44 ± 0.31, 1.48 ± 0.09 and 1.87 ± 0.06 in PM10, PM2.5, and PM1, respectively. Meanwhile, the ratios higher than 1 indicated that fuel oil combustion from ship emission in fishery harbor. The highest deposits of total particle-bound metals in the human respiratory tract were in the head airway (HA), accounting for 76.77 ± 2.29% of the total particle-bound metal concentration, followed by 5.32 ± 0.13% and 2.53 ± 0.15% in the alveolar region (AR) and tracheobronchial (TB) region, respectively. The total cancer risk (CR) of inhalation exposure to local residents exceeded 10-6. Mean total CR values followed the sequence: autumn (1.24 × 10-4) > winter (8.53 × 10-5) > spring (2.77 × 10-6). Source apportionment of related metal emissions was mobile pollution emissions (vehicle/boat) (37.10-48.92%), metal fumes of arc welding exhaust (19.68-34.42%), spray-painting process (12.34-16.24%), combustion emissions (6.32-13.12%), and metal machining processes (9.04-16.31%) in Singda fishing harbor. These results suggest that proper control of heavy metals from each potential source in fishing harbor areas should be carried out to reduce the carcinogenic risk of adverse health effects.

Dielectric constants of organic pollutants determine their strength for enhancing microbial iron reduction

Physicochemical properties are essential characteristics of organic compounds, which not only impact the fate of organic pollutants but also determine their application in biological processes. Here, we first found that the dielectric constants (ɛ) of organic pollutants negatively correlated to their strength for enhancing microbial Fe(III) reduction. Those with lower ɛ values than 2.61 potentially promoted the above process following the sequence carbon tetrachloride (CT) > benzene > toluene > tetrachloroethylene (PCE) due to their different ability to deprotonate the phosphorus-related groups on the outer cell membrane of iron-reducing bacteria Shewanella oneidensis MR-1 (MR-1). The stronger deprotonation of phosphorus-related groups induced more negative charge of cell surface and more strongly increased cell membrane permeability and consequently stimulated faster release of flavin mononucleotide (FMN) as an electron shuttle/cofactor for Fe(III) reduction. These findings are significant for understanding the biogeochemistry in multi-organic contaminated subsurface and providing knowledge for remediation strategies and current production.

Formation of Dense and High-Aspect-Ratio Iron Oxide Nanowires by Water Vapor-Assisted Thermal Oxidation and Their Cr(VI) Adsorption Properties

Coral-like and nanowire (NW) iron oxide nanostructures were produced at 700 and 800 °C, respectively, through thermal oxidation of iron foils in air- and water vapor-assisted conditions. Water vapor-assisted thermal oxidation at 800 °C for 2 h resulted in the formation of highly crystalline α-Fe₂O₃ NWs with good foil surface coverage, and we propose that their formation was due to a stress-driven surface diffusion mechanism. The Cr(VI) adsorption property of an aqueous solution on α-Fe₂O₃ NWs was also evaluated after a contact time of 90 min. The NWs had a removal efficiency of 97% in a 225 mg/L Cr(VI) solution (pH 2, 25 °C). The kinetic characteristic of the adsorption was fitted to a pseudo-second-order kinetic model, and isothermal studies indicated that the α-Fe₂O₃ NWs exhibited an adsorption capacity of 66.26 mg/g. We also investigated and postulated a mechanism of the Cr(VI) adsorption in an aqueous solution of α-Fe₂O₃ NWs.

Human health-risk assessment based on chronic exposure to the carbonyl compounds and metals emitted by burning incense at temples

Health effects resulting from the smoke of carbonyl compounds (aldehydes and ketones) and metal-containing incense particles at temples during incense burning periods were evaluated at temple A (without incense reduction activities) and B (with incense reduction activities), Nantou County, in 2018. The predominant size fractions of particles were PM₁, PM_1-2.5, and PM_2.5-10 at both temples. The total particle mass at temple A was approximately 1.1 times that of temple B due to incense reduction at temple B. The most abundant metal elements in all particle size fractions at both temples were Fe, Al, and Zn. Metal species of incense smoke are divided into three groups by hierarchical cluster analysis and heatmaps, showing higher metal contents in groups PM₁, PM_18-10, and PM_18-2.5 at temple A. In contrast, higher metal contents were observed in PM_18-10 and PM_2.5-1 at temple B. Most of the carbonyl species were formaldehyde and acetaldehyde, released during incense burning periods, with concentrations ranging from 6.20 to 13.05 μg/m³ at both temples. The total deposited fluxes of particle-bound metals at temples A and B were determined to be 83.00% and 84.82% using the International Commission on Radiological Protection (ICRP) model. Health-risk assessments revealed that the risk values of metals and carbonyls were above recommended guidelines (10^-6) at temple A. Since worshippers and staff are exposed to incense burning environments with poor ventilation over a long period, these toxic organic compounds and metals increase health risks in the respiratory tract. Therefore, incense reduction is important to achieve healthy temple environments.

Biomarkers of effect as determined in human biomonitoring studies on hexavalent chromium and cadmium in the period 2008-2020

A number of human biomonitoring (HBM) studies have presented data on exposure to hexavalent chromium [Cr(VI)] and cadmium (Cd), but comparatively few include results on effect biomarkers. The latter are needed to identify associations between exposure and adverse outcomes (AOs) in order to assess public health implications. To support improved derivation of EU regulation and policy making, it is of great importance to identify the most reliable effect biomarkers for these heavy metals that can be used in HBM studies. In the framework of the Human Biomonitoring for Europe (HBM4EU) initiative, our study aim was to identify effect biomarkers linking Cr(VI) and Cd exposure to selected AOs including cancer, immunotoxicity, oxidative stress, and omics/epigenetics. A comprehensive PubMed search identified recent HBM studies, in which effect biomarkers were examined. Validity and applicability of the markers in HBM studies are discussed. The most frequently analysed effect biomarkers regarding Cr(VI) exposure and its association with cancer were those indicating oxidative stress (e.g., 8-hydroxy-2'-deoxyguanosine (8-OHdG), malondialdehyde (MDA), glutathione (GSH)) and DNA or chromosomal damage (comet and micronucleus assays). With respect to Cd and to some extent Cr, β-2-microglobulin (B2-MG) and N-acetyl-β-D-glucosaminidase (NAG) are well-established, sensitive, and the most common effect biomarkers to relate Cd or Cr exposure to renal tubular dysfunction. Neutrophil gelatinase-associated lipocalin (NGAL) and kidney injury molecule (KIM)-1 could serve as sensitive biomarkers of acute kidney injury in response to both metals, but need further investigation in HBM studies. Omics-based biomarkers, i.e., changes in the (epi-)genome, transcriptome, proteome, and metabolome associated with Cr and/or Cd exposure, are promising effect biomarkers, but more HBM data are needed to confirm their significance. The combination of established effect markers and omics biomarkers may represent the strongest approach, especially if based on knowledge of mechanistic principles. To this aim, also mechanistic data were collected to provide guidance on the use of more sensitive and specific effect biomarkers. This also led to the identification of knowledge gaps relevant to the direction of future research.

HBM4EU chromates study - Reflection and lessons learnt from designing and undertaking a collaborative European biomonitoring study on occupational exposure to hexavalent chromium

The EU human biomonitoring initiative, HBM4EU, aims to co-ordinate and advance human biomonitoring (HBM) across Europe. As part of HBM4EU, we presented a protocol for a multicentre study to characterize occupational exposure to hexavalent chromium (Cr(VI)) in nine European countries (HBM4EU chromates study). This study intended to collect data on current occupational exposure and to test new indicators for chromium (Cr) biomonitoring (Cr(VI) in exhaled breath condensate and Cr in red blood cells), in addition to traditional urinary total Cr analyses. Also, data from occupational hygiene samples and biomarkers of early biological effects, including genetic and epigenetic effects, was obtained, complementing the biomonitoring information. Data collection and analysis was completed, with the project findings being made separately available. As HBM4EU prepares to embark on further European wide biomonitoring studies, we considered it important to reflect on the experiences gained through our harmonised approach. Several practical aspects are highlighted for improvement in future studies, e.g., more thorough/earlier training on the implementation of standard operating procedures for field researchers, training on the use of the data entry template, as well as improved company communications. The HBM4EU chromates study team considered that the study had successfully demonstrated the feasibility of conducting a harmonised multicentre investigation able to achieve the research aims and objectives. This was largely attributable to the engaged multidisciplinary network, committed to deliver clearly understood goals. Such networks take time and investment to develop, but are priceless in terms of their ability to deliver and facilitate knowledge sharing and collaboration.

Exposures in nail salons to trace elements in nail polish from impurities or pigment ingredients - A pilot study

Nail polishes have evolved considerably. Toxic elements, such as lead, have been found in nail polish, and it is unclear if new finishes using metallic effect pigments may be contributing to metals exposure in nail technicians. We characterized concentrations of trace elements in 40 nail polishes, 9 technicians' urine, and 20 technicians' toenail clippings from 8 nail salons in the Boston area in 2017. We also collected 24 salon surface wipes from 3 of the salons. Antimony was not disclosed as a nail polish ingredient, yet concentrations (<15 μg/g) were above existing cosmetics guidelines (0.5 μg/g) in five (13%) of the samples. Aluminum (<11,450 μg/g), barium (<11,250 μg/g), iron (<3,270 μg/g), and magnesium (<2375 μg/g) were disclosed as ingredients and were also found on salon surfaces where nail polish was stored or used. Heavy metal impurities in nail polish were not detected for cadmium. Lead and nickel were found at low concentrations (<0.40 μg/g lead, <0.67 μg/g nickel). Tin (p = 0.003) concentrations were higher in nail polish with finishes compared to without. Barium and strontium (both p = 0.0001) concentrations were higher for red nail polishes compared to all other colors. Of those elements in nail polish and salon surfaces, aluminum and iron were detected in toenails, manganese was detected in urine and toenails, and barium was detected in urine at comparable levels to the general population. Besides preventable antimony levels in nail polish, individual metals in nail polish did not appear to be from impurities but mainly from colorants (i.e., pigments) and not major contributors to nail technician exposure. It is unclear if low-level chronic metals mixtures in nail salons are of health concern.

Volatile organic compound (VOC) emissions and health risk assessment in paint and coatings industry in the Yangtze River Delta, China

Solvent use and paint consumption are significant source sectors of volatile organic compounds (VOCs) emissions in China. The occupational painters have high risk of health effect due to exposure to high VOCs concentration. However, the toxic components in coating environment have not been carefully identified, and the health risks of VOCs exposure have not been sufficiently assessed. This study collected air samples from nine workshops of three major coating sectors in the Yangtze River Delta of China, namely cargo container coating, ship equipment coating, and furniture coating, to evaluate the non-cancer and cancer risk of toxic VOCs exposure to occupational painters under a normal working condition. The results show that the container coating had highest cancer risk (2.29 × 10^-6-5.53 × 10^-6) exceeding the safe limit of 1.0 × 10^-6, while non-cancer risk of all workshops was lower than acceptable level of 1. Ethylbenzene and 1,2-dichloropropane should be targeted for priority removal during the container coating process in attempt to reduce adverse health effect on the occupational painters. This study helps better understand the health risk of VOCs exposure in coating workshops in China and provides information for policy-makers to formulate possible control of specific toxic compounds during coating process.

Application and optimization of ultrasound-assisted deep eutectic solvent for the extraction of new skin-lightening cosmetic materials from Ixora javanica flower

The high demand for cosmetics has had a great impact on the development of innovative products in the cosmetic industry. The availability of raw materials has become a common problem in the cosmetic industry. Materials from nature can act as alternative sources, such as Ixora javanica. Several studies have shown the potential of I. javanica as an antioxidant and skin lightening agent. The objectives of the present study were to develop and optimize a green ultrasound-assisted deep eutectic solvent extraction of I. javanica. Eleven deep eutectic solvents were evaluated based on extraction efficiency parameters; that is, flavonoid and anthocyanin yields; the antioxidant and tyrosinase inhibitory activities of the extracts. The combination of choline chloride and propylene glycol (1:1) was shown to be the optimal deep eutectic solvent for I. javanica extraction. The extraction parameters of temperature, extraction time, and solid-to-liquid ratio were also optimized using response surface methodology. The total flavonoid compound obtained was 33 mg quercetin equivalent/g dried sample under the optimum extraction condition (extraction time of 5 min, temperature of 57 °C, solid-to-liquid ratio of 0.02 g/mL). In sum, this work demonstrates the potential of natural deep eutectic solvent as an organic solvent replacement to obtain high quality Ixora javanica extract, which is a potential new source of skin-lightening cosmetic materials.