Assessment of heavy metal accumulations and health risk potentials in tomatoes grown in the discharge area of a municipal wastewater treatment plant

Electrochemical and Colorimetric Nanosensors for Detection of Heavy Metal Ions: A Review

Human exposure to acute and chronic levels of heavy metal ions are linked with various health issues, including reduced children's intelligence quotients, developmental challenges, cancers, hypertension, immune system compromises, cytotoxicity, oxidative cellular damage, and neurological disorders, among other health challenges. The potential environmental HMI contaminations, the biomagnification of heavy metal ions along food chains, and the associated risk factors of heavy metal ions on public health safety are a global concern of top priority. Hence, developing low-cost analytical protocols capable of rapid, selective, sensitive, and accurate detection of heavy metal ions in environmental samples and consumable products is of global public health interest. Conventional flame atomic absorption spectroscopy, graphite furnace atomic absorption spectroscopy, atomic emission spectroscopy, inductively coupled plasma-optical emission spectroscopy, inductively coupled plasma-mass spectroscopy, X-ray diffractometry, and X-ray fluorescence have been well-developed for HMIs and trace element analysis with excellent but varying degrees of sensitivity, selectivity, and accuracy. In addition to high instrumental running and maintenance costs and specialized personnel training, these instruments are not portable, limiting their practicality for on-demand, in situ, field study, or point-of-need HMI detection. Increases in the use of electrochemical and colorimetric techniques for heavy metal ion detections arise because of portable instrumentation, high sensitivity and selectivity, cost-effectiveness, small size requirements, rapidity, and visual detection of colorimetric nanosensors that facilitate on-demand, in situ, and field heavy metal ion detections. This review highlights the new approach to low-cost, rapid, selective, sensitive, and accurate detection of heavy metal ions in ecosystems (soil, water, air) and consumable products. Specifically, the review highlights low-cost, portable, and recent advances in smartphone-operated screen-printed electrodes (SPEs), plastic chip SPES, and carbon fiber paper-based nanosensors for environmental heavy metal ion detection. In addition, the review highlights recent advances in colorimetric nanosensors for heavy metal ion detection requirements. The review provides the advantages of electrochemical and optical nanosensors over the conventional methods of HMI analyses. The review further provides in-depth coverage of the detection of arsenic (As), cadmium (Cd), chromium (Cr), copper (Cu), mercury (Hg), manganese (Mn), nickel (Ni), lead (Pb), and zinc (Zn) ions in the ecosystem, with emphasis on environmental and biological samples. In addition, the review discusses the advantages and challenges of the current electrochemical and colorimetric nanosensors protocol for heavy metal ion detection. It provides insight into the future directions in the use of the electrochemical and colorimetric nanosensors protocol for heavy metal ion detection.

Amino-terminated SiO2-Al2O3 composite aerogels from fly ash for improved removal of Cu2+ and Pb2+ ions in wastewater: one-pot synthesis, excellent adsorption capacity and mechanism

In this study, by using a sol-gel grafting-atmospheric drying method, amino-terminated SiO₂-Al₂O₃ composite aerogels, namely 3-aminopropyltriethoxysilane (APTES) or 3-(2-amino-ethoxy) propylmethyldimethoxysilane (AEAPMDS) modified SiO₂-Al₂O₃ aerogels (AMSAAs), were synthesized from the fly ash and characterized by field-emission scanning electron microscopy, X-ray diffraction and X-ray photoelectron spectroscopy etc.. And the AMSAAs were verified as excellent adsorbents for removing heavy metal ions (Cu²⁺ and Pb²⁺ ions) from wastewater. The effects of modification conditions and testing parameters including pH value, adsorbent dose, initial ions concentration, adsorption time and temperature were systematically investigated. Results demonstrated that 0.2 mol/L APTES modified aerogels (0.2APTES-SAAs) possessed the best adsorption properties. Under the optimal pH value of 4.0-6.0 and the adsorbent dose of 0.4-0.6 g/L, the equilibrium adsorption capacities of Cu²⁺ and Pb²⁺ ions were as high as 195 mg/g and 500 mg/g within 20-30 min, respectively. The adsorption processes were agreed fairly well with Freundlich isotherm adsorption model and the pseudo-second-order kinetic model, which indicated that the adsorption processes were heterogeneous multilayer adsorption and controlled by the chemical reaction between AMSAAs and heavy metal ions. The obtained adsorption thermodynamic parameters (ΔH°, ΔS° and ΔG°) revealed that the adsorption processes were exothermic and spontaneous with decreased randomness at the solid-liquid interface. The excellent recyclability of as-prepared AMSAAs proved as economically promising adsorbents for practical applications.

Potential human health risks of toxic/harmful elements by consumption of Pseudevernia furfuracea

The potential human health risks of some toxic/harmful elements related to the consumption of Pseudevernia furfuracea (L.) Zopf. were investigated. The toxic/harmful elements (cadmium (Cd), chromium (Cr), copper (Cu), lead (Pb), manganese (Mn), nickel (Ni), and zinc (Zn)) were determined in P. furfuracea. According to the analysis result, the maximum (max.) toxic/harmful element value was 62 ± 3.1 mg/kg for Mn and minimum (min.) value was 0.19 ± 0.01 mg/kg for Cd. The estimated daily exposure doses (EDEXDs) for men, women and children were dietary (bread) > dietary (tea) > dermal. For dietary (bread) and dietary (tea) non-carcinogenic (HQ) risk was children > women > men. For dermal, HQ risk was women > children > men. Hazard index (HI) value for men was >1 for Cr. HI value for men was 1.36 for Cr. HI value for women was >1 for Cr and Mn. HI values for women were 1.54 for Cr and 1.01 for Mn. Also, the HI value for children was >1 for Cr, Mn, and Pb. HI values for children were 3.44 for Cr, 2.24 for Mn, and 1.66 for Pb. This situation showed that there was a non-carcinogenic risk. Carcinogenic risk values were dietary (bread) > dietary (tea) > dermal. The total max. carcinogenic value was 1.97E-03 for Cr while the total min. carcinogenic value was 1.31E-05 for Pb. As a result, it has been determined that there may be a risk of cancer due to the consumption of lichen as bread and this situation may adversely affect human health.

Multidimensional Scaling of the Mineral Nutrient Status and Health Risk Assessment of Commonly Consumed Fruity Vegetables Marketed in Kyrgyzstan

Intensive production of fruits and vegetables causes heavy metal accumulation. Consumption of this kind of foodstuff is a growing concern of the modern world with the additional distress of the supply of enough foodstuffs. To contribute to this global purpose, this research aimed to find out the mineral nutrient and heavy metal concentrations of commonly consumed fruity vegetables in Kyrgyzstan. Totally, ten different fruity type vegetables were collected from five different large bazaars of Kyrgyzstan. From these, 20 samples, including washed/unwashed rinds of vegetables, were quantified in terms of their B, Ca, Cd, Cr, Cu, Fe, K, Mg, Mn, Na, Ni, Pb, and Zn contents by using inductively coupled plasma-optical emission spectrometry (ICP-OES). The concentrations of the fruity vegetables were found in the following range: B (1.392-25.816), Ca (92.814-4095.466), Cd (0.007-0.086), Cr (0.009-0.919), Cu (0.351-8.351), Fe (4.429-126.873), K (920.124-10,135.995), Mg (61.973-879.085), Mn (1.113-78.938), Na (36.132-266.475), Ni (0.039-1.215), Pb (0.081-2.906), and Zn (1.653-87.107) (mg kg^-1). It was determined that red capia pepper was the vegetable having the highest daily nutritional value according to evaluation done in our study. Taking into account of the HI values, all of the vegetables analyzed were determined to be lower than the limit value of 1 that falls into acceptable limits in terms of being safe. Peppers demonstrated the highest variation in terms of the elemental content. The high Cr content rendered hot pepper risky for consumption by both genders regarding with CR, and in terms of CR, it has been observed that nickel contents being found in vegetables including tomatoes pose a moderate risk for consumption. Quite lower risk was detected in red/Brandy-wine tomatoes, eggplants, and cucumber for both genders. As most striking result in our study, the Brandy-wine type tomato was found to be healthiest (as well as safest) and nutritious vegetable looking from the viewpoint of consumption in Kyrgyzstan.

Preliminary assessment of health risks associated with consumption of grapevines contaminated with mining effluents in Turkey: Persistent trace elements and critical raw materials

In this study, some persistent trace elements and critical raw materials were investigated in grapevines contaminated with Pb-Zn mining effluents. The persistent trace elements under certain conditions remain without any change in form in the environment over long periods. The critical raw materials are the ones that have economic importance and have the risks associated with their supply. The health risks of persistent trace elements and critical raw materials in the leaves of grapevine that are consumed by humans were determined. The highest persistent trace elements concentrations followed the order of root > stem > leaf for Mn, Cu, Cd, Ni, and Cr while root > leaf > stem for Zn and leaf > root > stem for Pb. The maximum critical raw material concentrations for Co and V followed the order of root > stem > leaf. For Sb and La, these were leaf > root > stem and root > stem > leaf, respectively. The maximum critical raw materials concentrations for W was leaf > stem = root. The total maximum carcinogenic value was 0.146 for Cd while the total minimum carcinogenic value was 0.0054 for Pb. In this study, potential carcinogenic risk values in terms of ingestion of contaminated soil (Cr, Cd, and Ni) and dietary take of grapevine leaves (Ni, Cr, Cd, and Pb) are higher than acceptable levels (1 × 10^-4  - 1 × 10^-6 ). Maximum cancer risk on human health was determined as dietary intake of grapevine leaves. When hazard quotient for dietary (HQ_die ), hazard quotient for ingestion (HQ_ing ), and hazard quotient for inhalation (HQ_inh ) values ​​of critical raw materials were examined, the maximum values ​​were observed for children. Also, the highest hazard quotient for dermal (HQ_der ) value was determined for men. The hazard index and total hazard index values were >1 for critical raw materials. As a result, values >1 indicated potential non-carcinogenic human health risk associated with the consumption of grapevines contaminated with mining effluents. Actual region-specific exposure estimates for consumption of grapevines, however, were not evaluated. Integr Environ Assess Manag 2022;18:517-527. © 2021 SETAC.

A Comprehensive Review on the Heavy Metal Toxicity and Sequestration in Plants

Heavy metal (HM) toxicity has become a global concern in recent years and is imposing a severe threat to the environment and human health. In the case of plants, a higher concentration of HMs, above a threshold, adversely affects cellular metabolism because of the generation of reactive oxygen species (ROS) which target the key biological molecules. Moreover, some of the HMs such as mercury and arsenic, among others, can directly alter the protein/enzyme activities by targeting their -SH group to further impede the cellular metabolism. Particularly, inhibition of photosynthesis has been reported under HM toxicity because HMs trigger the degradation of chlorophyll molecules by enhancing the chlorophyllase activity and by replacing the central Mg ion in the porphyrin ring which affects overall plant growth and yield. Consequently, plants utilize various strategies to mitigate the negative impact of HM toxicity by limiting the uptake of these HMs and their sequestration into the vacuoles with the help of various molecules including proteins such as phytochelatins, metallothionein, compatible solutes, and secondary metabolites. In this comprehensive review, we provided insights towards a wider aspect of HM toxicity, ranging from their negative impact on plant growth to the mechanisms employed by the plants to alleviate the HM toxicity and presented the molecular mechanism of HMs toxicity and sequestration in plants.