Bioavailability of arsenic, cadmium, iron and zinc in leafy vegetables amended with urban particulate matter suspension

Pollution evaluation and children's multimedia exposure of atmospheric arsenic deposition in the Pearl River Delta, China

The populous Pearl River Delta (PRD) region in China suffers from serious air arsenic (As) pollution. The objective of this study was to explore the pollution situation of atmospheric arsenic deposition in the PRD region, and to evaluate the associated multimedia daily intake in children. The average deposition flux was 3921.7 μg/m²/year during the 2016-2017, and the pollution situation was even worse than that in 2015. A continuously increasing trend of arsenic atmospheric deposition was found. The bioaccessibility of As in the settled dust was determined as about 22% by a physiologically based extraction test (PBET). After corrected with the bioaccessibilities of As in the settled dust and food items, the geometry means (GM) value of daily uptake through multimedia ingestion of produce (dust and diet) originated from arsenic atmospheric deposition was 0.23 μg/kg/day for 1- to 6-year-old children. The contribution of the non-dietary oral exposure (settled dust) was negligible and just accounted for only 0.01% of the daily uptake. This estimated value was much lower than those in the literatures, in which the bioaccessibility of As was not taken into account, concluding that the role of the settled dust in the total daily intake may have been overestimated previously. Milk, eggs and freshwater fish were the dominant pathways for children to intake the products derived from atmospheric arsenic deposition. There still be a concern about the high non-carcinogenic and carcinogenic risk by long-term multimedia ingestion. Special care should be considered toward the emission sources of air arsenic, including the coal combustion from industries and construction dust, etc., to reduce the negative effect of air arsenic in children.

Reviewing chemical and biological risks in urban agriculture: A comprehensive framework for a food safety assessment of city region food systems

Attention to urban agriculture (UA) has recently grown among practitioners, scientists, and the public, resulting in several initiatives worldwide. Despite the positive perception of modern UA and locally grown, fresh produce, the potential food safety risks connected to these practices may be underestimated, leading to regulatory gaps. Thus, there is a need for assessment tools to evaluate the food safety risks connected to specific UA initiatives, to assist practitioners in self-evaluation and control, and to provide policy makers and scholars a means to pursue and assess food safety in city regions, avoiding either a lack or an excess of regulation that could ultimately hinder the sector. To address this aim, this paper reviews the most recent and relevant literature on UA food safety assessments. Food safety indicators were identified first. Then, a food safety assessment framework for UA initiatives was developed. The framework uses business surveys and food analyses (if available) as a data source for calculating a food safety index for single UA businesses and the whole UA landscape of a given city region. The proposed framework was designed to allow its integration into the CRFS (City Region Food System) toolkit developed by FAO (Food and Agriculture Organization of the United Nations), RUAF foundation (Resource Centres on Urban Agriculture and Food Security) and Wilfrid Laurier University.

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Connection of several biological and chemical food safety risks to UA techniques.

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Identifiable food safety risk factors for diverse UA practices.

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Framework for the assessment of food safety levels of UA initiatives.

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Development of a risk-based assessment that can be integrated into the FAO CRFS framework.

Environmentally Friendly Methylcellulose-Based Binders for Active and Passive Dust Control

Particulate matter (PM) is an essential indicator to evaluate air pollution, threatening human health. Although PM control could be achieved by using a variety of polymeric materials, identifying effective and green materials remains elusive in dust control technology. Here, we have employed environmentally friendly cellulose modified by methyl side groups, such as methylcellulose (MC)-based polymers, and evaluated their PM reduction efficiency when utilized in active and passive dust control methods, such as dust suppressants and air filters, respectively. When 25 m/s wind was applied on soil treated by MC-based polymers, PM emissions were reduced 95% or 85% lower than the soil treated by only water or the other cellulose without methyl side groups. The MC-based polymer was also effectively suppressed mineral dust from a local copper mine in Arizona with approximately 50 times lower amounts than a synthetic polymer containing methyl side groups. Furthermore, when MC-based polymers have deposited on filters of commercial face masks, the average filtration efficiency improved to greater than 99% while maintaining airflow resistance. Our results present that environmentally friendly MC-based polymers can act as dust binders that effectively agglomerate air pollutants, preventing the PM emission from dust sources and the inhalation after being suspended in the air; thus, labeling them as essential materials for advanced active and passive dust control technology.

Liquid Amphiphilic Polymer for Effective Airborne Dust Suppression

Airborne dust is a byproduct of natural and artificial occurrences, including high winds in arid regions and human activities, and it affects most of the world's population. Watering is the most general practice for reducing airborne dust by wetting the surface of the dust source to agglomerate dust particles via the capillary effect, increasing the aerodynamic diameter of (ultra)fine particles and reducing dust emission. However, the short-term effectiveness due to fast water evaporation, requiring frequent watering, is a major disadvantage. Herein, we utilized biocompatible liquid polymers as additives in water to prolong moist conditions of dust sources due to their liquid state. After the water evaporated, the liquid polymers maintained moisture on the dust sources, resulting in significantly reduced (ultra)fine particle emissions and extended effectiveness compared to conventional water treatment. Interestingly, we observed greater dust suppressive effectiveness with liquid amphiphilic polymer than liquid hydrophilic polymer because of the synergistic effect of the liquid state and amphiphilic property of the polymer. Translating lab-scale experiments to pilot-scale field-testing confirmed the potential for utilizing biocompatible liquid amphiphilic polymers to advance airborne dust suppression technology.

Biocompatible liquid amphiphilic polymers significantly reduce airborne dust emissions by prolonging moist conditions at dust sources and enhancing interactions between dust particles.

Estimation of the bioaccessibility and bioavailability of Fe, Mn, Cu, and Zn in Chinese vegetables using the in vitro digestion/Caco-2 cell model: the influence of gut microbiota

The influence of the human gut microbiota on the bioaccessibility and bioavailability of trace elements in vegetables has barely been studied. An in vitro digestion model combining the physiologically based extraction test (PBET) and the Simulator of Human Intestinal Microbial Ecosystem (SHIME) was applied. Results showed that the gut microbiota increased the bioaccessibility of iron (Fe) in ten test vegetables by 1.3-1.8 times, but reduced the bioaccessibility of manganese (Mn), copper (Cu), and zinc (Zn) in vegetables in the colon phase by 3.7% to 89.6%, 24.8% to 100.0%, and 59.9% to 100.0%, respectively. Using the Caco-2 cell model to simulate the human absorption process, the bioavailable contents and the bioavailability of the trace elements were further determined. Swamp cabbage was the best source of Fe and Cu; spinach and lettuce provided the highest amounts of bioavailable Mn and Zn, respectively. Referring to the daily reference intakes of trace elements, the obtained data provide a scientific basis for both reasonable ingestion of vegetables in diets and diversification of diets.

Concentration of heavy metals in vegetables and potential health risk assessment in China

Food safety is an important issue in the world. This study assessed the health risk for the Chinese public when consuming vegetables grown in China, based on 1335 data records from 220 published papers during 2007-2016. The results showed that the average of Pb, Cd, and Hg concentration in vegetables was 0.106, 0.041, and 0.008 mg/kg, which were lower than the maximum allowable concentrations, respectively. Leaf vegetables contained higher heavy metals than root vegetables and fruit vegetables. On a provincial scale, the highest Pb, Cd, and Hg concentrations in vegetables were determined by those in soil and atmosphere. The total health risk index showed that people in Guizhou, Yunnan, Guangxi, Hunan, Guangdong, Hubei provinces in southern China, and Liaoning Province in northeast China, faced a high risk of Pb, Cd, and Hg when consuming vegetables.

Atmospheric particulate matter (PM) effect on the growth of Solanum lycopersicum cv. Roma plants

This study shows the direct effect of atmospheric particulate matter on plant growth. Tomato (Solanum lycopersicum L.) plants were grown for 18d directly on PM10 collected on quartz fiber filters. Organic and elemental carbon and polycyclic aromatic hydrocarbons (PAHs) contents were analyzed on all the tested filters. The toxicity indicators (i.e., seed germination, root elongation, shoot and/or fresh root weight, chlorophyll and carotenoids content) were quantified to study the negative and/or positive effects in the plants via root uptake. Substantial differences were found in the growth of the root apparatus with respect to that of the control plants. A 17-58% decrease of primary root elongation, a large amount of secondary roots and a decrease in shoot (32%) and root (53-70%) weights were found. Quantitative analysis of the reactive oxygen species (ROS) indicated that an oxidative burst in response to abiotic stress occurred in roots directly grown on PM10, and this detrimental effect was also confirmed by the findings on the chlorophyll content and chlorophyll-to-carotenoid ratio.

Methodological aspects of in vitro assessment of bio-accessible risk element pool in urban particulate matter

In vitro tests simulating the elements release from inhaled urban particulate matter (PM) with artificial lung fluids (Gamble's and Hatch's solutions) and simulated gastric and pancreatic solutions were applied for an estimation of hazardous element (As, Cd, Cr, Hg, Mn, Ni, Pb and Zn) bio-accessibility in this material. An inductively coupled plasma optical emission spectrometry (ICP-OES) and an inductively coupled plasma mass spectrometry (ICP-MS) were employed for the element determination in extracted solutions. The effect of the extraction agent used, extraction time, sample-to-extractant ratio, sample particle size and/or individual element properties was evaluated. Different patterns of individual elements were observed, comparing Hatch's solution vs. simulated gastric and pancreatic solutions. For Hatch's solution, a decreasing sample-to-extractant ratio in a PM size fraction of <0.063 mm resulted in increasing leached contents of all investigated elements. As already proved for other operationally defined extraction procedures, the extractable element portions are affected not only by their mobility in the particulate matter itself but also by the sample preparation procedure. Results of simulated in vitro tests can be applied for the reasonable estimation of bio-accessible element portions in the particulate matter as an alternative method, which, consequently, initiates further examinations including potential in vivo assessments.

Exposure to ingested airborne pollutant particulate matter increases mucosal exposure to bacteria and induces early onset of inflammation in neonatal IL-10-deficient mice

BACKGROUND

Epidemiological associations between early-life air pollution exposure and increased risk of inflammatory bowel diseases have been shown. Our aim was to determine if exposure to airborne particulate matter (PM(10)) during the neonatal period would alter colitis in the interleukin (IL)-10(-/-) mouse model.

METHODS

IL-10(-/-) pregnant dams and pups were fed chow ± PM(10) (9 μg/g) and pups were studied at 10, 14, and 20 weeks. Twenty-week-old mice were given 2% dextran sodium sulfate. Metagenomic analysis of stool was performed. Bacterial translocation was assessed by serum lipopolysaccharide and culturing bacteria from mesenteric lymph nodes and spleen. Cytokine expression was measured in gut homogenates using the MesoScale discovery platform. PM(10) was applied to CMT93 cells ± J744 macrophages, and resistance and cytokine secretion were assessed. THP-1 macrophages were incubated with Escherichia coli HB101 ± PM(10) for assessment of uptake and killing.

RESULTS

PM(10) exposure increased colonic proinflammatory cytokines and bacterial translocation into mesenteric lymph nodes, whereas IL-17A levels were reduced in PM(10)-fed 10-week-old mice. Bifidobacterium was decreased in mice fed PM(10), whereas serum lipopolysaccharide was increased. PM(10) interfered with phagocytosis and killing in THP-1 cells. In coculture, PM(10) increased tumor necrosis factor α and fluorescein isothiocyanate-dextran flux. After dextran sodium sulfate treatment, PM10-fed mice responded with increased colonic tumor necrosis factor α and IL-1β and a larger percentage of PM(10)-fed mice had live bacteria in the mesenteric lymph nodes.

CONCLUSIONS

Our data suggest that early exposure to pollution particulates can result in an earlier onset of intestinal disease in genetically susceptible hosts and can alter responses to gut injury in later life.

Toxicologically important trace elements and organic compounds investigated in size-fractionated urban particulate matter collected near the Prague highway

Urban particulate matter was collected in the most exposed area of Prague, near a busy highway, in order to provide petrographic and chemical characterization useful for health impact assessment in that locality or other applications. Samples were collected from filters of the air conditioning system in two years, 2009 and 2010, and sieved into four grain-size fractions: 0.507-0.119 mm, 0.119-0.063 mm, <0.063 mm and sub-fraction <0.025 mm. Methods of destructive and non-destructive analyses were used for the determination of total analyte (As, Cd, Cr, Mn, Ni, Pb, Zn) contents. Labile forms of some toxicologically important analytes were tested in 2 M HNO(3) extracted solutions. A composition of inorganic and carbonaceous particles of natural and anthropogenic origin and their morphology were studied by optical and electron microscopy. Organic solvent extracts of the samples were analyzed using gas chromatography to compare the organic compound distribution in fractions. Only slight differences between 2009 and 2010 years are visible. The relatively high extractable part of most investigated elements confirms mobility and potential availability to organisms. The changes can be recognized in the petrographic and organic composition in samples from both years, which were likely the result of various inputs of source materials. Specific organic marker compounds indicate contribution from fossil fuels, plant materials and bacteria.