Development of Colorimetric Whole-Cell Biosensor for Detection of Heavy Metals in Environment for Public Health

Heavy metals cause various fetal diseases in humans. Heavy metals from factory wastewater can contaminate drinking water, fish, and crops. Inductively coupled plasma-mass spectrometry (ICP-MS) and atomic absorption spectrometry (AAS) are commonly used to analyze heavy metal contents; however, these methods require pre-treatment processes and are expensive and complex. To overcome these limitations, three metal-sensing materials using a whole-cell biosensor in Escherichia coli (E. coli) were developed. Strains were engineered to harbor three kinds of plasmids containing the copA, zntA, and mer promoters for sensing copper, cadmium, and mercury, respectively. The luciferase (lux) gene was inserted as a reporter into the plasmid, which was later replaced with a fused protein sequence containing OmpA (1–159) and mCherry for optical detection. The constructed strains could detect mercury, cadmium, and copper at 0.1–0.75 ppm, 0.2–0.75 ppm, and 2–7.5 ppm, respectively, with linearity values of 0.99030, 0.99676, and 0.95933, respectively. The immobilization linearity value was 0.99765. Notably, these three heavy metals could be detected by visual analysis of the strains. Overall, these findings establish this novel sensor as a potential approach for heavy metal detection in biological samples and foods.

Evaluation of Long-Term Leaching of Arsenic from Arsenic Contaminated and Stabilized Soil Using the Percolation Column Test

Arsenic in the soil can leach into groundwater and contaminate drinking water, posing a serious risk to human health. The stabilization of arsenic in contaminated soil is one of the immobilization technologies used to remediate contaminated lands. However, few studies have evaluated the long-term release of As and pH changes in stabilized soils. We compared different stabilization techniques in the field by mixing contaminated soil with 5% of either acid mine drainage sludge (AMDS), coal mine drainage sludge (CMDS), steel slag, or cement. We evaluated the results using an up-flow percolation column test to observe any pH changes and As releases from the stabilized soils up to a liquid–solid (L/S) ratio of 50 (approximately representing a 50 year period). At the initial stage of percolation (at an L/S ratio of 0.2 or 0.2 of a year of exposure), some alkaline components and any incompletely bound As in the soils washed out with the eluent. The pH of the cement-stabilized soil was approximately 12 throughout the experiment (up to 50 L/S). Adding stabilizers to the soil reduced As leaching by 54–81% (overall efficiency) compared to the control (contaminated soil only). The order of stabilization efficiency was: steel slag (55.0%) < AMDS (74.3%) < cement (78.1%) < CMDS (81.5%). This study suggests that the groundwater of the stabilized soil should be carefully monitored for the initial five years because the soluble ionic species can leach over this period.

Adversity of industrial water pollution on agriculture and livelihood: Experiences of rural population of Dindigul

Tannery pollution affected water and livelihood of people in Dindigul. Polluted water and soil reduced agricultural production; contaminate drinking water, and livelihood. The present study aims to study the adverse effects of industrial pollution on agriculture and livelihood in Dindigul. Twenty randomly villages drawn with equal number from the vicinity of tanneries and far. A survey was conducted using structured interview schedule among 400 men and women of 18 years and above from 20 villages. Details on Socio-Economic characteristics, water, agriculture and livelihood collected online using Kobo toolbox in Tamil language. In affected and non-affected villages 71 and 102 hold agricultural land only 53 and 87 have cultivated respectively. One third in affected villages and two thirds in non-affected villages cultivated throughout the year. Tanneries affected the livestock population, reduced agricultural production, polluted irrigation, polluted soil and made it infertile, deteriorated the quality of agricultural produce. Compared to economic benefits from tanneries the damage are exorbitant. Politicians and policy makers ignored pollution and turned blind eye to the problems caused to the rural population and livelihood.

Análise da potabilidade da água em poços rasos no município de Caiçara no Rio Grande do Sul

The objective of this work was to evaluate water quality and environmental impacts in shallow wells in rural properties of Caiçara - RS. The physicochemical and microbiological analyzes were performed between September 2017 and March 2018 in three rural properties, in addition to macroscopic evaluation. According to the results obtained, variables such as nitrate, total iron, pH, apparent color and turbidity are in disagreement with the water potability legislation, Consolidation Ordinance No. 5 (2007). In addition, all water samples showed total coliforms and Escherichia coli. The conservation of shallow wells was rated as reasonable or poor. From the monitoring carried out, environmental changes can be noticed, such as the lack of protection in the place and the degradation of the vegetation caused mainly by the inadequate use and occupation of the soil. This reflects the microbiological variables that contaminate drinking water, causing potential health problems for residents of the properties. These characteristics point to the importance of actions to protect and preserve water sources, not disrespecting the socioeconomic aspects of the region, based on incentives and instructions to landowners who have shallow wells for human consumption.

The Safety of Schools Based on Heavy Metal Concentrations in Classrooms’ Dust: A Systematic Review and Meta-Analysis

Background: Classroom is where children spend much of their time in; this study aimed to identify the concentration of heavy metals in the classroom dust based on the results of various studies in the world using the published data up to years 2018. Methods: Fifteen studies were selected for the study according to the inclusion and exclusion criteria. The mean concentration of 11 heavy metals including arsenic, barium, cadmium, cobalt, chromium, copper, iron, lead, manganese, nickel, and zinc was extracted. Results: The highest mean concentration of heavy metal (mg/kg) in classroom dust was related to iron (3904.7, 95%CI: 3657.1-8154.3), zinc (429.9, 95%CI: 182.8-677.1) and barium (419.2, 95%CI: 274.7-253.7), respectively. Subgroup analysis showed the maximum concentration (mg/kg) of iron in Iran (16945.5), zinc in Hong Kong (2293.5), barium in China (979.8), manganese in Iran (288.9), lead in Iran (258.8), chromium in Ghana (381.3), copper in Hong Kong (274.4), nickel in Iran (50.1), cobalt in China(43.4), arsenic in China(13.7) and cadmium in Hong Kong(8.7). Conclusion: Even safe and healthy classrooms can threaten children’s health by heavy metals. These metals are important since they are naturally found throughout the earth’s crust, accumulate in the food chain and contaminate drinking water as well as alloys in school equipment.

Exposure to Toxic Metals (As, Cd, Hg, Pb) in Two Artisanal and Small-scale Gold Mining (ASGM) Areas in Zimbabwe

Background: People living and working in ASGM areas are exposed to toxic metals such as arsenic (As), cadmium (Cd), mercury (Hg) and lead (Pb). Whereas Hg is purposely used to extract the gold from the ore, the other toxic metals can be liberated from the ore during the mining process. These metals can contaminate drinking water and food and are thus, a source of exposure for people living in these mining areas. However, there is limited to no data about the exposure to toxic metals of people living in ASGM areas. Therefore, the purpose of this study was to conduct biomonitoring of people identifying themselves as artisanal gold miners. Methods: Blood and urine were collected from 207 people living and working in two ASGM areas in Zimbabwe. Hg in whole blood and urine was analyzed by direct mercury analysis, Pb in blood as well as As and Cd in urine were analyzed by GF-AAS. The results were evaluated by descriptive analysis and correlated with the location, age, fish consumption, years living and working in the area. Results: Median As level in urine was 10.0 µg/l (range from below limit of detection to 460 µg/l). Median Cd level in urine was 0.3 µg/l (range from below limit of detection to 11.4 µg/l). Median Hg levels in blood / urine were 2.7 / 5.2 µg/l (range from 0.2 to 167 µg/l / 0.1 to 612 µg/l). Median Pb level in blood was 19.9 µg/l (range from 6.6 to 276 µg/l). As expected, the Hg levels were frequently above international reference values (e. g. NHANES, blood: 34%, urine: 69%). For Pb and Cd, a considerable number of participants (32% and 22% respectively) were above the reference values (NHANES / National Health and Nutrition Examination Survey) and for As 33% of the participants were above the reference value (UBA/ German Environment Agency). Conclusions: Hg levels were, as expected in ASGM areas, mainly above reference and threshold values. A high proportion of As, Cd and Pb levels were also above reference levels. Therefore, the exposure to toxic metals in the two ASGM areas in Zimbabwe is relevant for public health.

Photocatalytic oxidation of psychoactive drug Duloxetine: Degradation kinetics, inorganic ions and phytotoxicity evaluation

Pharmaceutically active compounds, emerging extensively in ecosystems as pollutants, have become an important environmental and public health issue, since they can contaminate drinking water and pose threat to wildlife and human health. Therefore, efforts should be made in order to establish proper methods for their inactivation or elimination in the environment. The photocatalytic oxidation of psychoactive drug Duloxetine (DLX) has been investigated. In the case of heterogeneous photocatalytic oxidation, the effect of TiO2 P25 concentration (0.1–1 g L-1), initial concentration of H2O2 (0.25–0.2 g L-1) and Fe3+ (0.00175–0.014 g L-1) and pH of the solution (3–10) on initial reaction rates were evaluated, while for homogeneous photocatalytic oxidation the effect of the amount of H2O2 (0.25–0.2 g L-1) and Fe3+ (0.00175–0.014 g L-1) were investigated. Additionally, the conversion of the heteroatoms in the molecule of DLX to inorganic ions (NO3-, NH4+, SO42-) during photocatalytic process has been observed, and phytotoxicity testing, using three plant species, was carried out in order to examine the effect of photocatalytic oxidation on the toxicity of DLX. According to the results presented in this study, both heterogeneous and homogeneous photocatalytic oxidation is an efficient methodology for DLX degradation.

The Occurrence of Potential Harmful Cyanobacteria and Cyanotoxins in the Obrzyca River (Poland), a Source of Drinking Water

Harmful cyanobacteria and their cyanotoxins may contaminate drinking water resources and their effective control remains challenging. The present study reports on cyanobacterial blooms and associated cyanotoxins in the Obrzyca River, a source of drinking water in Poland. The river was examined from July to October 2019 and concentrations of microcystins, anatoxin-a, and cylindrospermopsin were monitored. The toxicity of water samples was also tested using an ecotoxicological assay. All studied cyanotoxins were detected with microcystins revealing the highest levels. Maximal microcystin concentrations (3.97 μg/L) were determined in September at Uście point, exceeding the provisional guideline. Extracts from Uście point, where the dominant species were Dolichospermum flos-aquae (August), Microcystis aeruginosa (September), and Planktothrix agardhii (October), were toxic for Dugesia tigrina Girard. Microcystin concentrations (MC-LR and MC-RR) were positively correlated with cyanobacteria biovolume. Analysis of the chemical indicators of water quality has shown relationships between them and microcystins as well as cyanobacteria abundance.

Phosphorous runoff risk assessment and its potential management using wollastonite according to geochemical modeling

Loss of phosphorus from agricultural land through water runoff causes serious detrimental effects on the environment and on water quality. Phosphorous runoff from excessive use of fertilizers can cause algal blooms to grow in nearby water systems, producing toxins that contaminate drinking water sources and recreational water. In this study, a risk analysis of the algal toxin micro-cystin-LR and the mitigation of phosphorus from agriculture runoff is discussed. A risk analysis was performed on the algal bloom toxin microcystin-LR considering the Lake Erie algal bloom event of 2011 as a case study. Toxicity risk analysis results show that relatively low concentrations of microcystin-LR compared to recent case studies pose an acute health risk to both children and adults, and a significant increase in the risk of developing cancer is suggested but subject to further study given the assumptions made. This study investigated the potential of using wollastonite to mitigate phosphorus pollution, considering thermodynamic conditions of a constructed wetland receiving influent water from agriculture runoff, by using geochemical modelling. Geochemical modelling results show that wollastonite can react with phosphorus and capture it in the stable mineral form of hydroxyapatite, offering a possible strategy for risk mitigation of phosphorous runoff. A removal efficiency of 77% of phosphorus using wollastonite is calculated with the help of geochemical modelling.

Pathology in Ecological Research With Implications for One Health: Session Summary

This session explored the effects of pollutants on One Health at the ecosystem level that included microbes, insects, fish, and humans. The concept of One Health seeks to synergize medical, veterinary, and other health science disciplines to more effectively advance human and animal health. Presentations explored the interactions of pesticides, pathogens, phytochemicals, and xenobiotic biotransformation in bee colony losses critical for food security (bees have been recently listed under the 2017 US Food and Drug Administration (FDA) veterinary feed directive); the role of pathology in identifying the effects of pollutants on fish as sentinels for human health; the effects in rats of per- and polyfluoroalkyl substances (PFAS) that can persist in the environment and contaminate drinking water; harmful algal blooms and toxin production leading to animal and human disease; and the processing of environmental carcinogens by intestinal microbiota.