Targeting Metal Impurities for the Detection and Quantification of Carbon Black Particles in Water via spICP-MS

Fate and Toxicity of Carbon Black to Phytoplankton in Natural Lakes: Insight into the Role of Phototransformation

Concern over the contamination of freshwater ecosystems with carbon black (CB) is increasing. Here, the toxicity of CB to phytoplankton (Chlorella pyrenoidosa) was evaluated; upon exposure, the median effective concentration for 72 h was 23.4 mg/L. CB underwent significant photooxidation during 15 days of light irradiation, although phototransformation was generally completed by day 7. Algal growth inhibition induced by phototransformed CB (TCB) at 1 mg/L was 64.1% greater than that induced by parent CB. Mechanistically, 1) phototransformation triggered the release of highly toxic byproducts, which inhibited algal growth by 18.9%; 2) metabolomic results demonstrate that the suppression of carbon and nitrogen assimilation in algal cells induced by TCB was 13.2-53.7% greater than that induced by CB; 3) TCB exhibited reactive oxygen species production ability, which triggered more significant algal membrane damage. A full-factorial experiment (26+1 runs) showed that the combined effect of temperature and suspended mineral particles, as well as electrical conductivity, was the primary environmental factor that mediated CB and TCB toxicity, respectively. The predicted toxicity of CB and TCB in Taihu Lake exhibited significant regional distribution, and TCB posed a greater environmental risk in aquatic ecosystems than CB. These findings highlight the importance of particulate contaminant transformation and environmental factors when evaluating their environmental risk.

Comprehensive Multidimensional Analysis of Metal(loid)-Containing Dust in Plastic Sports Facilities: Insights into the Potential Sources and Health Risks

Dust released from widely established plastic sports courts and synthetic turf poses potential environmental and health risks. Herein, we systematically investigate the metal(loid) characteristics, potential sources, and health risks of 162 dust samples from 17 campuses in Beijing, using complementary analytical techniques. Bulk analysis revealed higher levels of Zn, Pb, Cu, Sb, Cd, and Cr than background values, suggesting excessive anthropogenic contamination. Pb and Cr in plastic basketball court and track dust and Zn and Sb in synthetic turf dust were higher than those in other sports facilities. Multielement single-particle inductively coupled plasma time-of-flight mass spectrometry (spICP-TOF-MS) revealed more Fe-, Al-, Si-, Ti-, and Pb-containing particles in the dust. At least 92% toxic Pb-containing particles were composed of multiple elements. The significant correlations between Pb and Cr contents on individual dust particles support their common potential source from inorganic pigments (crocoite, PbCrO4). Pb, Sb, As, and Cr in the dust pose higher health risks through intake. The risks were estimated to be approximately 3-5 times higher for children than for adults. Additionally, highly toxic Cr(VI) and As(III) species were observed in the sweat and gastric juice leachate of dust, highlighting severe threats of the metal(loid)s to human health.

Interlaboratory comparison of centrifugal ultrafiltration with ICP-MS detection in a first-step towards methods to screen for nanomaterial release during certification of drinking water contact materials

A key requirement for evaluating the safety of nano-enabled water treatment devices is measuring concentrations of insoluble nanomaterials released from devices into water that may be ingested by consumers. Therefore, there is a need for simple technique that uses commonly available commercial laboratory techniques to discriminate between nanoparticles and dissolved by-products of the nanomaterial (e.g., ionic metals). Such capabilities would enable screening for particulate or dissolved metals released into water from nanomaterial-containing drinking water contact materials (e.g., paint coatings) or devices (e.g., filters). This multi-laboratory study sought to investigate the use of relatively inexpensive centrifugal ultrafilters to separate nanoparticulate from ionic metal in combination with inductively-coupled plasma mass spectrometry (ICP-MS) detection. The accuracy, precision, and reproducibility for the proposed method were assessed using mixtures of nanoparticulate and ionic gold (Au) in a standard and widely utilized model water matrix (NSF International Standard 53/61). Concentrations for both ionic and nanoparticulate gold based upon measurements of Au mass in the initial solutions and Au permeating the centrifugal ultrafilters. Results across different solution compositions and different participating labs showed that ionic and nanoparticulate Au could be consistently discriminated with ppb concentrations typically resulting in <10 % error. A mass balance was not achieved because nanoparticles were retained on membranes embedded in plastic holders inside the centrifuge tubes, and the entire apparatus could not be acid and/or microwave digested. This was a minor limitation considering the ultrafiltration method is a screening tool, and gold concentration in the permeate indicates the presence of ionic metal rather than nanoforms. With further development, this approach could prove to be an effective tool in screening for nanomaterial release from water-system or device materials as part of third-party certification processes of drinking water compatible products.