Detection of lead in paint samples synthesized locally using-laser-induced breakdown spectroscopy

Heavy Metal Detection in Fritillaria thunbergii Using Laser-Induced Breakdown Spectroscopy Coupled with Variable Selection Algorithm and Chemometrics

Environmental and health risks associated with heavy metal pollution are serious. Human health can be adversely affected by the smallest amount of heavy metals. Modeling spectrum requires the careful selection of variables. Hence, simple variables that have a low level of interference and a high degree of precision are required for fast analysis and online detection. This study used laser-induced breakdown spectroscopy coupled with variable selection and chemometrics to simultaneously analyze heavy metals (Cd, Cu and Pb) in Fritillaria thunbergii. A total of three machine learning algorithms were utilized, including a gradient boosting machine (GBM), partial least squares regression (PLSR) and support vector regression (SVR). Three promising wavelength selection methods were evaluated for comparison, namely, a competitive adaptive reweighted sampling method (CARS), a random frog method (RF), and an uninformative variable elimination method (UVE). Compared to full wavelengths, the selected wavelengths produced excellent results. Overall, RC2, RV2, RP2, RSMEC, RSMEV and RSMEP for the selected variables are as follows: 0.9967, 0.8899, 0.9403, 1.9853 mg kg−1, 11.3934 mg kg−1, 8.5354 mg kg−1; 0.9933, 0.9316, 0.9665, 5.9332 mg kg−1, 18.3779 mg kg−1, 11.9356 mg kg−1; 0.9992, 0.9736, 0.9686, 1.6707 mg kg−1, 10.2323 mg kg−1, 10.1224 mg kg−1 were obtained for Cd Cu and Pb, respectively. Experimental results showed that all three methods could perform variable selection effectively, with GBM-UVE for Cd, SVR-RF for Pb, and GBM-CARS for Cu providing the best results. The results of the study suggest that LIBS coupled with wavelength selection can be used to detect heavy metals rapidly and accurately in Fritillaria by extracting only a few variables that contain useful information and eliminating non-informative variables.

Another casualty of the SARS-CoV-2 pandemic-the environmental impact

Cemetery leachate generated by the process of cadaveric decomposition is a significant contaminant of several matrices in the cemetery environment (soil, groundwater, and surface water). The biogenic amines cadaverine and putrescine stand out among the cemetery leachate contaminants, since they are potentially carcinogenic compounds. This review article presents a discussion of possible environmental impacts caused by the increase in deaths resulting from COVID-19 as its central theme. The study also aims to demonstrate the importance of considering, in this context, some climatic factors that can alter both the time of bodily decomposition and the longevity of the virus in the environment. Additionally, some evidence for the transmission of the virus to health professionals and family members after the patient's death and environmental contamination after the burial of the bodies will also be presented. Several sources were consulted, such as scientific electronic databases (NCBI), publications by government agencies (e.g., ARPEN, Brazil) and internationally recognized health and environmental agencies (e.g., WHO, OurWorldInData.org), as well as information published on reliable websites available for free (e.g., CNN) and scientific journals related to the topic. The data from this study sounds the alarm on the fact that an increase in the number of deaths from the complications of COVID-19 has generated serious environmental problems, resulting from Cemetery leachate.

Determination of heavy metals in cancerous and healthy colon tissues using laser induced breakdown spectroscopy and its cross-validation with ICP-AES method

Certain types of cancer deaths are widespread due to the diagnostic complexities at the early stages. Recent studies revealed that the bio-accumulated heavy metals (act as pro-carcinogens) in the human colon cause strong interactions with the nuclear proteins, leading to the DNA damages and repair processes inhibition, resulting in the cancers. Most of the conventional detection techniques suffer from the insensitiveness, cost-intensiveness, imprecision, slowness, cumbersomeness of sample preparation, and conflicting outcomes. To surmount these shortcomings an accurate, reliable, and rapid detection technique is essential for the early diagnostic and prevention of heavy metals accumulation induced colon cancers. This will enable not only to classify the malignant and non-malignant cells but can differentiate the proteins from abnormal cellular morphology. Using the indigenously developed fast and accurate (calibration-free) laser-induced breakdown spectroscopy (LIBS), we analyzed several cancerous and normal colon tissues collected from the colon cancer infected patients aged 40-60 years. The results showed the presence of carcinogenic heavy metals including lead (Pb), chromium (Cr), and mercury (Hg) in the malignant colon tissues, while the healthy tissues were devoid of these elements. The concentrations of Pb, Cr and Hg in the cancerous samples were discerned to be 3.1, 13.4 and 7.1 μg/L, respectively. Furthermore, the performance accuracy of the LIBS technique was validated by comparing the results obtained from the standard inductively coupled plasma atomic emission spectroscopy (ICP-OES). It was established that the LIBS analysis is useful for the speedy, precise and early detection of the heavy metals amassed malignant colon tissues, thereby saving millions of lives by promoting the chances for cancer cure.

Alkaline Extraction for Lead Determination in Different Types of Commercial Paints

In 2017, the World Health Organization and the United Nations Environment Programme formed the Global Alliance to Eliminate Lead Paint. All alliance member countries have pledged to develop control regulations that include lead threshold limits. To improve regulations and demonstrate compliance of paint industry products, it is necessary to have adequate, locally applicable methodologies. In this sense, the main objective of this research was to validate the methodology of alkaline extraction for the quantification of lead in ten different types of Ecuadorian commercial paints using flame atomic absorption spectrophotometry. Two hundred and fifty samples from different paint industry products were analyzed, and the results were used to evaluate the method’s performance and robustness. It was determined that the method could be applied for lead concentrations above 100 mg·kg⁻¹, and results showed relative standard deviation values lower than 14.8% and fortification recoveries between 80.3 and 119.4%, fulfilling the acceptance criteria established in the Environmental Protection Agency’s lead-based Paint Laboratory Operations Guidelines.

Detection of toxic elements using laser-induced breakdown spectroscopy in smokers' and nonsmokers' teeth and investigation of periodontal parameters

A laser-induced breakdown spectrometer (LIBS) was built and optimized to detect levels of toxic elements such as lead, cadmium, and arsenic present in the roots of extracted teeth of smokers and nonsmokers. Sixty extracted teeth from patients having a history of chronic periodontitis were divided into two groups of 30 teeth each for smoker and nonsmoker patients and, as controls, a third group of 30 patients who did not have a history of chronic periodontitis. The respective elemental concentration (Pb, Cd, and As) 23-29, 0.26-0. 31, and 0.64-11 ppm are for nonsmokers, 35-55, 0.33-0.51, and 0.91-1.5 ppm are for smokers, and lastly 0.17-0.31, 0.01-0.05, and 0.05-0.09 ppm are for control group. In order to test the validity of the results achieved using our LIBS system, a standard inductively coupled plasma (ICP) technique was also applied for the analysis of the same teeth samples, and ICP results were found to be in excellent agreement with our LIBS results. In addition to this, the gingival index, plaque index, clinical attachment loss (CAL) and probing pocket depth were also recorded. Our LIBS spectroscopic analysis showed high levels of lead, cadmium, and arsenic concentration on root surfaces of teeth, which may be due to CAL.

Assessment of lead and cadmium levels in frequently used cosmetic products in Iran

This study aims to investigate the content of lead and cadmium in most frequently used brands of cosmetic products (lipstick and eye shadow) in Iran. Fifty samples of lipstick (5 colors in 7 brands) and eye shadow (3 colors in 5 brands) were selected taken from large cosmetic stores in Isfahan (Iran) and lead and cadmium of them were analyzed. The results showed that the concentration of lead and cadmium in the lipsticks was within the range of 0.08–5.2 µg/g and 4.08–60.20 µg/g, respectively. The eye shadow samples had a lead level of 0.85–6.90 µg/g and a cadmium level of 1.54–55.59 µg/g. The content range of the heavy metals in the eye shadows was higher than that of the lipsticks. There was significant difference between the average of the lead content in the different brands of the lipsticks and eye shadows. Thus, the continuous use of these cosmetics can increase the absorption of heavy metals, especially Cd and Pb, in the body when swallowing lipsticks or through dermal cosmetic absorption. The effects of heavy metals such as lead can be harmful, especially for pregnant women and children. Therefore, effort must be made to inform the users and the general public about the harmful consequences of cosmetics.

Mineral contamination from cemetery soils: case study of Zandfontein Cemetery, South Africa

The burial of coffins may pose an environmental and health hazard since the metals that are used in coffin-making may corrode or degrade into harmful toxins. These may leach into the surrounding soils and groundwater. Very little research has been conducted world-wide on the mineral contamination potential of cemeteries, and virtually none in South Africa. The aim of the study is to determine whether burial practices affect the mineral content of soils in cemeteries. This was done by comparing the mineral concentrations of soils within the Zandfontein Cemetery in Tshwane (Gauteng, South Africa) to those off-site as well as those in zones with high burial loads with those zones with fewer burials. Twenty three soil samples were collected from various sites on- and off-site and analyzed for 31 minerals using ICP-AES. It was found that mineral concentrations of soils within the Zandfontein Cemetery were considerably higher than those off-site. Soil samples in multiple burials blocks also have elevated metal concentrations. These excess metals are probably of anthropogenic origin associated with burial practices and could pose an environmental and human health hazard. Strict monitoring of water quality in boreholes in the vicinity of the cemetery is recommended.

Development of a method for the determination of chromium and cadmium in tannery wastewater using laser-induced breakdown spectroscopy

This paper illustrates systematic development of a convenient analytical method for the determination of chromium and cadmium in tannery wastewater using laser-induced breakdown spectroscopy (LIBS). A new approach was developed by which liquid was converted into solid phase sample surface using absorption paper for subsequent LIBS analysis. The optimized values of LIBS parameters were 146.7 mJ for chromium and 89.5 mJ for cadmium (laser pulse energy), 4.5 μs (delay time), 70 mm (lens to sample surface distance), and 7 mm (light collection system to sample surface distance). Optimized values of LIBS parameters demonstrated strong spectrum lines for each metal keeping the background noise at minimum level. The new method of preparing metal standards on absorption papers exhibited calibration curves with good linearity with correlation coefficients, R(2) in the range of 0.992 to 0.998. The developed method was tested on real tannery wastewater samples for determination of chromium and cadmium.

Investigation of plasmas produced by laser ablation using single and double pulses for food analysis demonstrated by probing potato skins

We report on investigations of plasmas produced by laser ablation of fresh potatoes using infrared nanosecond laser radiation. A twin laser system consisting of two Nd:YAG oscillators was used to generate single or double pulses of adjustable interpulse delay. The potatoes were irradiated under ambient air with moderate pulse energies of about 10 mJ. The expansion dynamics of the ablation plume was characterized using fast imaging with a gated camera. In addition, time-resolved optical emission spectroscopy was applied to study the spectral line emission of the various plasma species. The electron density was deduced from Stark broadening, and the plasma temperature was inferred from the relative emission intensities of spectral lines. The relative concentrations of metals were estimated from the comparison of the measured emission spectra to the spectral radiance computed for a plasma in local thermal equilibrium. It is shown that the plasma produced by double pulses has a larger volume and a lower density. These properties lead to an increase of the signal-to-noise ratio by a factor of 2 and thus to an improved measurement sensitivity.