Aliphatic hydrocarbons in urban runoff sediments: a case study from the megacity of Tehran, Iran

Source identification, accumulation and dispersion of heavy metals pollution into the surface sediments of urban runoff (case study, channels of Tehran City)

Heavy metals (HMs) pollution presents a significant challenge for both human health and natural ecosystems on a global scale. This study investigates the pollution of surface sediments resulting from urban runoff, identifies potential pollution sources, and examines the correlation between HMs and two factors: total organic carbon (TOC%) and particle size distribution (PSD). A total of 30 surface sediment samples were collected from three urban channels in the Tehran megacity. The concentrations of key elements, including strontium (Sr), lead (Pb), cadmium (Cd), nickel (Ni), and copper (Cu), were determined using Inductively Coupled Plasma-Optical Emission Spectrometry (ICP-OES). The mean concentrations of Cd, Ni, Cu, Pb, Sr, were 0.46, 39.80, 161.25, 261.75, 388.50 mg/litter, respectively, following the sequence Sr > Pb > Cu > Ni > Cd. To identify the HMs accumulation, factor analysis(FA) was employed. The HMs rank order based on FA was as follows: 37.7% > 24.4% > 24.1%. According to (FA), the possible accumulation source of Pb and Sr is as different as Cu, Ni, and Cd elements. A significant correlation between Sr with TOC% (r = 0.901, sig = 0.000), Pb with both TOC% and particles < 75µm (r = 0.77, r = 0.63, Sig = 0.000 respectively), while Cu, Ni and Cd with particles < 150µm (r = 0.68, r = 0.81, r = 0.87, Sig = 0.000 respectively) were observed). Overall, the concentration of heavy metals (HMs) demonstrated a significant negative correlation with the particle size of surface sediments.

Lipid Biomarkers in Urban Soils of the Alluvial Area near Sava River, Belgrade, Serbia

This study focused on the investigation of soil samples from the alluvial zone of the Sava River, located near the heating plant in New Belgrade, Serbia. Using gas chromatography with flame ionization detection (GC-FID), a broad range of alkanes, including linear n-alkanes (C10 to C33) and isoprenoids, was analyzed in all samples. The obtained datasets were effectively made simpler by applying multivariate statistical analysis. Various geochemical indices (CPI, ACL, AI, TAR, etc.) and ratios (S/L, Paq, Pwax, etc.) were calculated and used to distinguish between biogenic and anthropogenic contributions. This approach added a higher level of precision to the source identification of hydrocarbons and provided a detailed geochemical characterization of the investigated soil. The results showed that the topsoil had a high content of TPH (average value, 90.65 mg kg-1), potentially related to an accidental oil spill that occurred repeatedly over extended periods. The uncommon n-alkane profiles reported for the investigated soil samples are probably the result of inputs related to anthropogenic sources, emphasizing that petroleum was the main source of the short-chain n-alkanes. The methodology developed in this study was proven to be efficient for the assessment of the environmental quality of the soil in an urban part of New Belgrade, but it can also be a useful tool for soil monitoring and for a pollution assessment in other (sub)urban areas.

Unveiling the Compositional Analysis of Green Coffee Beans with and without Silver Skin

BACKGROUND

Green Coffee Bean (GCB) is covered with silver skin that is shed as a by-product of the roasting process. For the first time, a comparative study was conducted to differentiate the compositional analysis of green coffee beans with silver skin and without silver skin.

OBJECTIVE

The study aims comparatively assessing nutritional, anti-nutritional and fatty acids composition of green coffee beans with silver skin and without silver skin. The present study is also intended to find out various organic compounds of green coffee beans.

METHODS

The proximate analysis was used to study nutritional composition. Mineral analysis was assessed by atomic absorption spectroscopy. The antinutrients like phytic acid and tannin were assessed by UV-visible spectroscopy whereas volumetric and gravimetric analysis was used to determine oxalates and alkaloids. Gas chromatography and Fourier Transform Infra-Red spectroscopy were used for studying fatty acids and organic compounds, respectively.

RESULTS

Protein content was significantly (p<0.05) high in green coffee beans with silver skin, indicating 15% higher protein. Macro mineral content was also found significantly (p<0.05 and p<0.01) high in green coffee beans with silver skin, whereby 5.11% higher Phosphorus and 24.12% higher Calcium content was observed. However, iron content was 68.10% lower in green coffee beans with silver skin which might be due to its higher tannin content. Trace minerals zinc and copper were also found to contain 57.18% to 18.11% higher concentrations respectively in silver skin. Anti-nutritional analysis revealed the content of phytic acid and tannin as 161 and 77.29 mg/100g, respectively in green coffee beans with silver skin. The percentages of oxalates and alkaloids were found to be 0.64 and 14.30. These anti-nutritional compounds were significantly (p<0.05 and p<0.01) higher from green coffee beans without silver skin. Green coffee beans have been found with an utmost number of saturated fatty acids having palmitic acid as the most abundant. The unsaturated part is mainly composed of linoleic and oleic acid. Chlorogenic acid isomers and caffeine were the organic compounds detected through Fourier transform infrared spectroscopy.

CONCLUSION

These findings reveal the presence of both nutritional and anti-nutritional components in Coffee silver skin, with significantly higher levels of anti-nutritional factors in green coffee with silver skin, emphasizing the need for caution in the consumption of green coffee and utilization of coffee silver skin as a valuable bioresource.

Integrative assessment of urban dust polycyclic aromatic hydrocarbons using ground and satellite data in Iran

Recently, for quick urbanization and industrialization, pollutants, especially urban dust, have posed many threats to the human environment. Polycyclic aromatic hydrocarbons (PAHs) are regarded as the main dangerous pollutants that are widespread, persistent, and carcinogenic. The present work aimed to investigate the contamination and sources of PAHs, as well as to assess the risk of cancer for 16 priority PAHs, in urban dust samples in Ahvaz, Isfahan, and Shiraz cities in Iran. We measured PAH concentrations by gas chromatography-mass spectrometry (GC-MS). The average concentrations of the 16 PAHs in Ahvaz, Isfahan, and Shiraz were 6215.11, 7611.03, and 7810.37 μg kg-1, respectively. The domination of low-molecular-weight (LMW) PAHs was observed in Ahvaz, while maximum contribution was observed for high-molecular-weight (HMW) PAHs in Esfahan and Shiraz. For PAHs' source identification, diagnostic ratio, correlation analysis, clustering, and positive matrix factorization (PMF) model were used. PAHs had a combustion (coal and wood, oil, fossil fuels) and gasoline/diesel engine emissions in all cities. Comparative studies suggest that the PAH compounds' level is higher in the research area than in other countries, except for China and India. Also, the pollution of urban dust PAHs has increased over time compared to previous studies in the same cities. The cancer risk from exposure to dust contaminated with PAHs was assessed using the Incremental Lifetime Cancer Risk (ILCR) model. According to the findings, a high risk of exposure to cancer was observed in Ahvaz, Isfahan, and Shiraz. However, compared to adults, children are at higher risk of cancer in their daily lives via dermal contact and unconscious ingestion. Based on the ILCR values, the risk of cancer is in the order of Shiraz > Isfahan > Ahvaz. To assess air pollutants and their effects on urban dust, TROPOMI onboard the Sentinel-5P data were used in the studied cities during 2018-2021. The results show that Ahvaz has different high levels of CO compared to the other 2 cities. Also, Isfahan has different high levels of NO2 compared to the other 2 cities, but Shiraz has different low levels of O3. According to satellite time series data, the trend of the Aerosol Absorbing Index (AAI) has been increasing, while there was a decreasing trend in AAI from the beginning of the COVID-19 pandemic until 12 months later. Therefore, the natural and anthropogenic sources of urban dust PAHs have been increasing in all studied cities. Our findings show that PAH compounds in urban dust pose a significant threat to human health. Therefore, strategic management and planning are vital in reducing urban dust pollution.

Temporal-spatial variation, source forensics of PAHs and their derivatives in sediment from Songhua River, Northeastern China

The distribution patterns and health risk assessment of nitrated polycyclic aromatic hydrocarbons (NPAHs), hydroxy polycyclic aromatic hydrocarbons (OH-PAHs), and regular 16 priority polycyclic aromatic hydrocarbons (PAHs) in sediment from the Songhua River in northeastern China were investigated in this research. During dry seasons, concentrations of 16 USEPA priority PAHs, OH-PAHs, and NPAHs were extremely high, with average values of 1220 ± 288, 317 ± 641, 2.54 ± 3.98, and 12.2 ± 22.1 ng/g (dry weight, dw). The dry period level was confirmed to be 4 times greater than the wet period concentration. Modeling with positive matrix factorization (PMF) and estimation of diagnostic isomeric ratios were applied for identifying sources, according to the positive matrix factorization model: vehicle emissions (38.1%), biomass burning (25%), petroleum source (23.4%), and diesel engines source (13.5%) in wet season as well as wood combustion (44.1%), vehicle source (40.2%), coke oven (10.8%), and biomass burning (4.9%) in the dry season. The greatest seasonal variability was attributed to high molecular weight compounds (HMW PAHs). BaP was confirmed to be 81% carcinogenic in this study, which offers convincing proof of the escalating health issues.