Heavy metal contents of selected commercially available oil-based house paints intended for residential use in Ethiopia

Toxicity of Aged Paint Particles to Soil Ecosystems: Insights from Caenorhabditis elegans

Despite the extensive global consumption of architectural paint, the toxicological effects of aged exterior paint particles on terrestrial biota remain largely uncharacterized. Herein, we assessed the toxic effect of aged paint particles on soil environments using the nematode Caenorhabditis elegans (C. elegans) as a test organism. Various types of paint particles were generated by fragmentation and sequential sieving (500-1000, 250-500, 100-250, 50-100, 20-50 μm) of paint coatings collected from two old residential areas. The paint particles exerted different levels of toxicity, as indicated by a reduction in the number of C. elegans offspring, depending on their size, color, and layer structure. These physical characteristics were found to be closely associated with the chemical heterogeneity of additives present in the paint particles. Since the paint particle sizes were larger than what C. elegans typically consume, we attributed the toxicity to leachable additives present in the paint particles. To assess the toxicity of these leachable additives, we performed sequential washings of the paint particles with distilled water and ethanol. Ethanol washing of the paint particles significantly reduced the soil toxicity of the hydrophobic additives, indicating their potential environmental risk. Liquid chromatography-mass spectrometry analysis of the ethanol leachate revealed the presence of alkyl amines, which exhibited a high correlation with the toxicity of the paint particles. Further toxicity testing using an alkyl amine standard demonstrated that a paint particle concentration of 1.2% in soil could significantly reduce the number of C. elegans offspring. Our findings provide insights into the potential hazards posed by aged paint particles and their leachable additives in the terrestrial environment.

International Analysis of Sources and Human Health Risk Associated with Trace Metal Contaminants in Residential Indoor Dust

People spend increasing amounts of time at home, yet the indoor home environment remains understudied in terms of potential exposure to toxic trace metals. We evaluated trace metal (and metalloid) concentrations (As, Cu, Cr, Mn, Ni, Pb, and Zn) and health risks in indoor dust from homes from 35 countries, along with a suite of potentially contributory residential characteristics. The objective was to determine trace metal source inputs and home environment conditions associated with increasing exposure risk across a range of international communities. For all countries, enrichments compared to global crustal values were Zn > Pb > Cu > As > Cr > Ni; with the greatest health risk from Cr, followed by As > Pb > Mn > Cu > Ni > Zn. Three main indoor dust sources were identified, with a Pb-Zn-As factor related to legacy Pb sources, a Zn-Cu factor reflecting building materials, and a Mn factor indicative of natural soil sources. Increasing home age was associated with greater Pb and As concentrations (5.0 and 0.48 mg/kg per year of home age, respectively), as were peeling paint and garden access. Therefore, these factors form important considerations for the development of evidence-based management strategies to reduce potential risks posed by indoor house dust. Recent findings indicate neurocognitive effects from low concentrations of metal exposures; hence, an understanding of the home exposome is vital.

Evaluating the Heavy Metal Risk in Spinacia oleracea L. and Its Surrounding Soil with Varied Biochar Levels: A Pot Experiment

Spinacia oleracea L., as the most widely cultivated green leafy vegetable in China, can threaten human health in cases of its excessive heavy metal content, especially in mining areas of karst landforms. Therefore, the present study mainly investigates whether biochar is useful for remediating heavy metal pollution in soil and S. oleracea and the degree of this improvement in karst areas. The effects of heavy metal exposure on the health of children and adults in S. oleracea and rhizosphere lime soil with six biochar levels are evaluated by a health risk assessment, namely, 4000 g of lime soil (C-0), 160 g of biochar + 3840 g of lime soil (C-160), 240 g of biochar + 3760 g of lime soil (C-240), 320 g of biochar + 3680 g of lime soil (C-320), 400 g of biochar + 3600 g of lime soil (C-400) and 800 g of biochar + 3200 g of lime soil (C-800). The results show that the pH values of the lime soil were positively correlated with Pb, P and K contents and negatively correlated with As, Cr, Hg, Cd and N contents in S. oleracea. The assessments of the potential ecological risk index show that the soil samples for the C-0 and C-160 levels pose moderate ecological hazards, while the soil samples for the C-320, C-800, C-400 and C-240 levels constitute mild ecological hazards. The single noncarcinogenic risks, total noncarcinogenic risk indexes, single carcinogenic risks and total carcinogenic risks values indicate that exposure to heavy metals in lime soil and S. oleracea poses a serious threat to human health. It also presents an unacceptable cancer risk and children are more threatened than adults. Our results suggest that heavy metal pollution of S. oleracea and its rhizosphere lime soil in karst areas still poses a threat to human health after adding biochar, and the relevant local departments need to implement more active measures to solve the excessive heavy metal contents in the local soil and vegetables of this karst regions.

Multi-isotope signatures (Cu, Zn, Pb) of different particle sizes in road-deposited sediments: a case study from industrial area

Road-deposited sediments (RDS) are major sources of heavy metal contamination in urban areas and adversely affect surrounding environments and human health. Multi-isotope combinations (Cu, Zn, and Pb), which serve as environmental tracers, enable the identification and management of metal contaminants in RDS. Here, we present Cu, Zn, and Pb isotopic data for the first time in size-fractionated RDS samples collected from industrial areas to describe the relationship between the RDS and total suspended solids (TSS) in runoff, and to explore the feasibility of using multi-isotopes to identify sources of metal contamination. RDS in the industrial study areas had high concentrations of Cu, Zn, and Pb, and their δ65CuAE647, δ66ZnIRMM3702, and 206Pb/207Pb values ranged from − 0.33 to + 0.73‰, − 0.36 to + 0.01‰, and 1.1418 to 1.1616, respectively. The variation in δ65CuAE647 (δ65Cumax-min) was larger than that of δ66ZnIRMM3702 (i.e., δ66Znmax-min), and the isotope values of Zn and Pb (206Pb/207Pb) tended to increase with the concentrations of these elements. Meanwhile, the fine RDS particles (< 63 µm) had similar Cu, Zn, and Pb isotopic compositions to those of TSS. Hierarchical cluster analyses revealed that the < 63 µm RDS fractions were associated with the TSS. Our results also showed that a combination of Pb and either Cu or Zn could be used to distinguish between RDS and non-exhaust emissions (e.g., brake pads, tires, etc.). Multi-isotope approaches utilizing Cu, Zn, and Pb and more robust isotopic data on individual sources of metal contamination could be useful for identifying pollution sources and understanding their environmental impacts.

Heavy Metals in Acrylic Color Paints Intended for the School Children Use: A Potential Threat to the Children of Early Age

Heavy metals are the harmful elements, regarded as carcinogens. Nevertheless, owing to their physical and chemical properties, they are still used in the production of several commercial products. Utilization of such products increases the chance for the exposure of heavy metals, some of them are categorized as probable human carcinogens (Group 1) by the International Agency for Research on Cancer. Exposure of heavy metals to school children at early age can result severe life time health issues and high chance of emerging cancer. Thus, we have performed study relating to the presence of heavy metals in acrylic color paints commonly used by the school children. Acrylic paints of different colors were assayed for seven potential heavy metals manganese (Mn), cobalt (Co), nickel (Ni), zinc (Zn), arsenic (As), cadmium (Cd) and lead (Pb) using microwave digestion and iCAPQ inductively coupled plasma mass spectrometry (ICP-MS) system. The optimized method including paints digestion reagents nitric acid (HNO3, 65%, 5 mL) and hydrofluoric acid (HF, 40%, 2 mL) have offered excellent method performance with recovery values ranged between 99.33% and 105.67%. The elements were identified in all of the analyzed samples with concentrations ranged from 0.05 to 372.59 µg/g. Cd constitutes the lower percentage (0.05%), whereas Zn constitutes high ratio contribution which was tremendously high (68.33%). Besides, the paints contamination was also color specific, with considerably total heavy metal concentrations found in brunt umber (526.57 µg/g) while scarlet color (12.62 µg/g) contained lower amounts. The outcomes of our investigation highlight the necessity for guidelines addressing the heavy metals in acrylic color paints intended for the school children usage.

Health risk assessment of construction workers from trace metals in PM2.5 from Kolkata, India

Construction activities have long been recognized as a pertinent source of PM_2.5 though limited information exists regarding chemical characteristics of aerosols generated during building demolition/construction. A comprehensive investigation was carried out to assess the physical (SEM analysis) and chemical (ICP MS analysis) properties of PM_2.5 in a building demolition and construction site and compared with background. Average concentrations of PM_2.5 at both the sites exceeded the National Ambient Air Quality Standards (NAAQS). Overall trend of the total metal concentrations of PM_2.5 followed the order of (Na, Ca, Al, Mg, Fe, Zn) > (Ti, Sr, Cd, Ba, Pb, V, Cr, Mn, Co, Ni, Cu) in both the sites. Sr, Ba, Mg, Zn, Ti, Cd, Al, Cr, Fe, Co, Mn, V, Ni, Ca, and Zn showed a ∼1.3-3.0 fold increase, and Pb showed the highest increase of almost >3.5 times when compared to the background concentrations. Health risk estimates based on the bio-available concentration of metals indicated that hazard quotient (HQ) values for non-carcinogenic metals were within the prescribed limit (HQ ≤ 1). However, the excess lifetime cancer risk (ELCR) for the carcinogenic metals Pb, Ni, Cd, and Cr(VI) were higher than the guideline limits of USEPA.