USEPA Method Research Articles

Characterization, source and risk assessments of sediment contaminants (PCDD/Fs, DL-PCBs, PAHs, PCBs, OCPs, metals) in the urban water supply area

Water resources are becoming more valuable day by day. They need to evaluate the pollution and risk situations of the sources that supply water in detail. It is aimed to determine the level of POPs (PCDD/Fs, DL-PCBs, PAHs, PCBs, and OCPs) and metals, which are persistent pollutants, in the surface sediments taken from Yuvacık lake to reveal their possible sources, and to make toxicological and ecological risk assessments of sediment quality. It is one of the most comprehensive studies on the sediment scale for a drinking water source and is a first for the study area. Seventeen 2,3,7,8-substituted PCDD/Fs were analyzed with US EPA method (M.1613). The concentrations of all POPs were determined by GC-MS/MS. The range of ∑PCDD/F is 3.171 (Y8) to 28.42 (Y10) pg/g, with the highest concentrations of OCDD and 1234678-HpCDF compounds. Total DL-PCB concentrations 6.369 (Y8) to 37.41 (Y9) pg/g Total PAH concentrations in the samples ranged from 36.97 ng/g (Y1) to 81.38 ng/g (Y10). The PAH compounds with the highest concentrations at all sampled points were Phenanthrene 3141 (Y7) - 21,636 (Y10) and Naphthalene (11.40–19.41) ng/g. Total OCP concentrations ranged from 1.045 ng/g (Y8) to 4.179 ng/g (Y2), while total PCB concentrations ranged from 0.308 (Y1) to 1.55029 (Y9) ng/g. DDT p,p (0.4078–3.2544 ng/g) has the highest concentration among OCPs. PCB 101, 153, 138, and 180 are the highest detected PCB congeners. As a result of the source analysis, three different main sources were determined for all pollutant groups. They show accumulation in the sediment as a result of long-distance atmospheric transport. Toxicological values were found below acceptable limits. The main metals posing ecological risk were Ag, Cu, and Cd. Monitoring of POPs and assessing their toxicological and ecological risks are important for planning water resources and should be applied especially for critical basins.

Determination of Cr(VI) in Natural and Waste Waters Using Differential Pulse Polarography According to U.S. Epa (SW-846 Method 7198)

The accurate determination of hexavalent chromium in environmental matrices such as natural and waste waters is crucial for the safety of both human and wildlife populations. The United States Environmental Protection Agency (U.S.EPA) has put forth SW-846, Method 7198, using differential pulse polarography for determination of Cr (VI) in both, the natural as well as waste waters. In Method 7198, the cathodic peak current resulting from the reduction of Cr (VI) to Cr (III) is measured and the concentration range for this method is listed as 10 ppb to 5 ppm Cr (VI). Using BASi Epsilon potentiostat that is specifically made for measuring ultra-low current resolutions and a controlled growth mercury electrode (CGME) set-up, the US EPA method 7198 has been successfully optimized in this work for higher detection limits. It is observed that a detection limit of up to 7 ppb can be easily obtained by efficiently managing the interference of iron and sulphur through a combination of various supporting electrolytes. This work may also become a valuable source of reference information on the behavior of wide variety of electrolytes and their control parameters needed to achieve extremely low detection limits. Figure 1

Derivatization-free multi-step extraction for trace haloacetic acids analysis with ion chromatography: Performance and mechanisms

Haloacetic acids (HAAs) are a type of disinfection byproducts commonly found in drinking water with carcinogenic, mutagenic, or teratogenic risks to humans. Currently, the analytical methods of trace HAAs are either labor-intensive or very expensive. We herein propose a facile multiple-step extraction strategy for HAAs analysis with common ion chromatography (IC). This study is based on a fundamental water chemistry principle that HAAs become protonated featuring positive logKow values (> 0.34) under pH < pKa but deprotonated featuring negative logKow values (< −2.37) under pH > pKa. By taking advantage of the species and property switches, HAAs can be extracted and enriched into methyl tert-butyl ether first at pH < 0.5 and then back-extracted into neutral water and enriched again. Equally important, interfering anions in IC chromatogram are eliminated because they have negative logKow values. Verification results show that HAAs were enriched by 11.4 times in average while interfering anions were almost eliminated (> 99%). Although similar to USEPA Method 552.3 in method detection limits (0.033–0.246 μg/L), recoveries (70%~110%), and relative standard deviations (< 9.91%), this method took ≤ 70 min to run a batch of samples without derivatization, which takes over 2 h. The methodology may be applicable to other pollutants that also have contrasting Kow values at different pH.

Effect of WESP on Emission Characteristics of Condensable Particulate Matter from Ultra-low Emission Coal-fired Power Plants

In order to study the effect of wet electrostatic precipitators(WESP) on emission characteristics of condensable particulate matter (CPM) from ultra-low emission coal-fired power plants that are under different capacity conditions, a set of CPM sampling devices was built based on US EPA Method 202, and an ultra-low emission coal-fired power plant was detected. This study evaluated the emission level of the CPM from the flue gas of coal-fired power plants, the effects of different unit capacity conditions on the CPM emission concentrations, and the removal efficiency of WESP for different components of the CPM. The results suggested that the emission concentrations of the CPM from ultra-low emission power plants were 27.27 mg·m-3 and 28.71 mg·m-3under the conditions of 75% and 100% capacity, respectively. The removal efficiencies of WESP for the CPM were 35.59% and 27.59%, respectively. SO42- was the main component of water-soluble ions of the CPM. The proportion of SO42- in inorganic components of the CPM reached more than 65% under different capacity conditions. In addition, the removal efficiency of WESP for Cl-, K+, Ca2+, Mg2+, Na+, and other inorganic ions reached 30%-50%, but the mass concentrations of SO42- and NO3- increased.

Central composite rotatable design for optimization of trihalomethane extraction and detection through gas chromatography: a case study

Central composite rotatable design (CCRD) was employed to optimize initial temperature (ºC), ramp function (ºC/min) and salt addition for trihalomethane extraction/quantification from the drinking water distribution network in Ratta Amral, Rawalpindi., Pakistan. Drinking water samples were collected from the treatment plant, overhead reservoir and consumer’s taps. The USEPA method for trihalomethane detection 551.1 via gas chromatography was applied using liquid–liquid extraction. The experiments with input variables for sample preparation and operational conditions were performed in a randomized order as per design of experiment by central composite rotatable design and responses were evaluated for model development. A significant (p = 0.005) two-factor interaction model was optimized. Initial temperature was observed to be insignificant (p = 0.64), while ramp function (p = 0.0043) and salt addition (p = 0.04) were significant. Product of salt addition and ramp was significant (p = 0.004), while product of initial temperature and salt addition was insignificant (p = 0.008). With a desirability function of 0.97, an initial temperature of 50 ºC, 6 ºC rise/min to 180 ºC and 0.5 g salt were optimized. It was found that development and optimization of the analytical methods for rapid trihalomethane detection would improve optimization of the current treatment practices in the country.

Effect of wet flue gas desulfurization on the concentrations and component profiles of condensable particulate matter from ultralow emission coal-fired power plants

This study investigated effect of wet flue gas desulfurization (WFGD) on the concentrations and component profiles of condensable particulate matter (CPM). This research was carried out in two ultralow emission coal-fired power plants (CFPPs), which were equipped with pulverized coal furnaces (PC), in Hunan province, China. The CPM concentrations were measured following the US EPA Method 202. The stack emissions of filterable particulate matter (FPM) met the Chinese ultralow emission standards, and the CPM concentrations from CFPP A and B were respectively 12.12 and 17.64 mg/Nm3. In the WFGD system, the removal efficiencies of the FPM and CPM were respectively 80% and 91% in CFPP A, 83% and 81% in CFPP B. SO42− accounted for the largest fraction of the total detected water-soluble ions in the CPM. Alkanes were the main component of the organic fraction in the CPM, which accounted for 95% in CFPP A and 92% in CFPP B. The removal efficiency of inorganic components from the CPM in CFPP A and B were 81% and 92%, respectively, possibly because the water-soluble ions could be dissolved and removed in the slurry; however, due to the limited solubility of alkanes and esters, the removal efficiency of organic components from the WFGD in CFPP A and B were only 17% and 31%, respectively. The emission factors (EFs) of the CPM for CFPP A and B range from 0.090 to 0.979 kg/(t of coal).

Relationship between Soil Properties, Content and Dynamics of Cadmium in Creole Cocoa Genotype Grown Organically in Bocas del Toro – Panama

Introduction: Quantifying Cadmium (Cd), helps to know the excess of this element harmful to human health.&#x0D; Objectives: Determine the concentrations of Cd and its relationship with the management and properties of the soil, leaf tissue, fruit and cocoa beans grown organically in small farms of producers in the district of Almirante, and to study the dynamics of this element in a Creole cocoa genotype AS-CP 26-61 (mulatto).&#x0D; Places and Duration of the Study: The research was carried out during the years 2019 to 2021, in 16 sites of farms of cocoa producers, organically grown, in Almirante, province of Bocas del Toro and the second, was in a house of vegetation, located in the facilities of the Institute of Agricultural Innovation of Panama, in the town of Divisa, corregimiento of Los Canelos, district of Santa María, province of Herrera, Republic of Panama.&#x0D; Methodologies: The samples were carried out in the16 farm sites in a systematic way selecting points at uniform distances in an area of 300 m2 with replicas (15 subsamples at depths of 0.30 m), within these areas the samples of leaves and fruits were taken. In the dynamics of the Cd, which was carried out in the creole cocoa genotype AS-CP 26-61 (mulatto), the soil was transferred from a representative area of the Almirante district to a depth of 0.30 m, filling pots with a capacity of 15 kg of dry soil. A completely random design was used, with six (6) treatments and three (3) repetitions. The treatments were (0, 4, 8, 12, 16 and 20 mgCdkg-1) inoculated the soils with cadmium sulfate. Soil samples were taken at two depths (0 to 0.15 m and 0.15 to 0.30 m); followed for plants (roots, stems and leaves), all extracted six (6) months after applying the treatments. Total and bioavailable Cd, Ca, Mg, soil texture, pH, soil organic matter, total foliar Cd, fruits and grains were measured. The analysis of the data was by the Infostat statistician. Soil organic matter was determined by Walkley and Black and total concentrations by USEPA method 3051 A; instead, the bioavailable Cd and K were determined by Mehlich 3; Ca and Mg per KCl; texture by Boyoucos.&#x0D; Results: As results in the 16 sites, the total and bioavailable Cd in the soil did not exceed the toxic levels for agricultural soils. On the other hand, the average levels of total Cd in the fruits and grains, did not present absorptions greater than 0.6 mgkg-1. While for the dynamics of Cd in the Creole cocoa genotype AS-CP 26-61 the maximum absorption form is presented by the leaves &gt; roots &gt; stem.&#x0D; Conclusion: By increasing the organic matter of the soil, it helps to block the concentrations of Cd in the leaves, fruits and grains; the levels of concentrations of Cd in the grain, do not exceed the maximum limits allowed according to the E.U. The use of the Creole genotype AS-CP 26-61 helped us to know in which part of the plant the concentrations of Cd are most concentrated.

Determination and human health risk assessment of polycyclic aromatic hydrocarbons (PAHs) in surface and ground waters from Ifite Ogwari, Anambra State, Nigeria

ABSTRACT Levels of Polycyclic Aromatic Hydrocarbons in surface and underground water sources from Ifite Ogwari, Ayamelum Local Government Area of Anambra State were investigated. Ecological and human health exposure risks were assessed following US EPA methods. The surface water sources are Isiachala, Iyiutu, Ube, Ahala Tabasi, Nabaloku, Atammele, Ogbu streams, and Omambala river. Underground water sources include Igbazine, Double, Ogba, Onowulugbe, Orator, and Commodore hand-dug wells. The water samples were collected using precleaned 500 cm3 glass bottles and were analysed for the presence of 16 US EPAPAHs using Gas Chromatography – Flame Ionisation Detector (GC- FID). The validated method showed that regression (R2) for all the PAHs ranged between 0.9622 and 0.9983. Limits of detection (LOD) ranged from 0.0033 to 0.1236 µg L−1 and limits of quantification (LOQ) from 0.0109 to 0.4115 µg L−1. Precision CV values ranged from 5.12 to 18.24%, and recovery values of the analytes in water varied between 83.94 and 99.99%. Naphthalene and chrysene were present in all the water samples while pyrene was absent in all except in Iyiutu. All the PAHs analysed were detected in Isiachala and Iyiutu except pyrene which was absent in Isiachala. All the samples contained at least three PAHs with concentrations ranging from 1.003 ng/µl of benzo[a] pyrene in Tabasi to 128.652 ng/µl of chrysene in Iyiutu. Ecological risk shows that the value was above US EPA background value. Human health risk assessment depicts that hazard index and total cancer risk ranges from 9.63E-05 to 1.93E-02. This study has shown that the inhabitants of Ifite Ogwari will experience adverse health and cancer illnesses over some time and therefore, a holistic approach by researchers and government agencies is needed to mitigate the ecological and health risk effects.

A mathematical model for improving the ion chromatography method by applying external adjustment standards

Ion chromatography (IC) is included in the list of very efficient and fast methods for obtaining results without losses and with the minimization of the human factor.The aim of this paper is to demonstrate the mathematical model for adjusting anion concentrations (NO2– nitrite, NO3– nitrate, Cl- chloride and SO42- sulphate) for water samples by using external standards. The method uses an interpolation and requires a certain number of injections with an external standard (if a single calibration curve is used) or with several external standards (if many calibration curves are used for the same anion). The importance of interpolation is to obtain a theoretical value of the adjustment standard for any sample by reference to the real readings of this external standard.In this study, interpolation works by determining an equation of degree n, covering n interpolations, using the read values of some adjustment standards (eg. AR20-X and AR100-X). The obtained equation can be used later for any injection X , characteristic of a real sample NX, in order to obtain the adjusted areas AR20-X* and AR100-X*.Thus, it becomes possible to calculate the factor f that serves to adjust the areas of the real samples.This strategy demonstrates that the calibration curve can be done quite rarely, and that the results obtained should not be affected by the periodicity of the calibration curve, in compliance with the performance parameters of the method (eg according to Shewhart-type control diagrams and Proficiency Testing (PT) schemes).Even if the results obtained without interpolation follow the recommendations given by US EPA Method 300.0:1993 (the peak area of the adjustment standard does not exceed ± 10% of the area of the adjustment standard read on calibration) and by ISO 10304–1:2007 (the retention time for the anion peaks does not exceed ± 10% in a batch and the minimal resolution for any two investigated peaks of the recorded chromatograms (R) was>1.3), the method performs a continuous adjustment of the sample concentrations to the used calibration curves, providing more relevant results.

Evaluation of groundwater contamination for fluoride and nitrate in Nellore Urban Province, Southern India: a special emphasis on human health risk assessment (HHRA)

Groundwater pollution with fluoride and nitrate is one of the most serious issues in coastal regions. Thirty-nine groundwater samples were collected in the current research region and tested for PH, TDS, and EC. Thirty-nine groundwater samples were collected in the current research region and tested for PH, TDS, EC and cations, anions, and hardness. The elevated parameters are EC, PH, TDS, and nitrates. The fluoride fell in the permissible limit in Nellore urban area, nitrate and fluoride exposure heath risk calculated by using the US EPA method. From that, the total hazard index (THI) was calculated. The fluoride total hazard index value ranges from 0.15 to 0.95 and that of average 0.45, which fell below < 1, hence no significance on children, women, and men. The nitrate is falling in excess in groundwater. The ranges are 35 mg/l to 72 mg/l, and adverse value is 47.8 mg/l. The total hazard index (THI) of nitrates fell at > 1, which indicates a harmful for the human health. The computed THI affected percentage is the children (100%), women (95%), and men (30%). The nitrate was released in water due to the industrial discharge, septic tanks, manure pools, sewer system, and rock–water interaction. The abundance of the cations and anions is Ca2+ > Na+ > Mg2+ > K+ and HCO3− > Cl− > SO42 > NO3 > F. The Gibbs diagram explains the source of the chemistry; hence, all samples fell in the rock–water interaction area.

Automated SEM-EDS Analysis of Transition Metals and Other Metallic Compounds Emitted from Incinerating Agricultural Waste Plastic Film

Illegal open burning, which is criticized as a leading source of air pollutants among agricultural activities, currently requires constant effort and attention from countries around the world. A speciation analysis method is required to examine the harmful effects of particulate matter generated by incineration on the human body. In this study, to simulate open-air incineration, infrastructure for incineration tests complying with US EPA method 5G was built, and a large-area analysis was conducted on the particulate matter through automated SEM-EDS. For test specimens, waste mulching LDPE collected by Korea Environment Corporation Dangjin Office was used. To raise the identifiability of analyzed particles, the specimen was sampled on a plate made of Ag, which has a high atomic number, three times. Metal particulate matter showed a high reaction to C and C-O. The ratio of metal particulate matters that reacted to C and C-O was in the order of Cu (94.1%) &gt; Fe (83.3%) &gt; Al (79.7%). In this study, it was verified that waste mulching adsorbs metal chemicals originating from the soil due to its properties and deterioration, and that when it is incinerated, it emits particulate matter containing transition metals and other metals that contribute to excessive ROS production and reduction.

Release of heavy metals from conventional and reflective cool cement pavements

Cool cement blocks are used for pavement construction to mitigate the heat island effect. Cement block pavements in contact with water will produce leachates, which may affect soil, surface water and groundwater quality. Therefore, the objective of this work was to determine and compare the leaching behavior of heavy metals (Cd, Co, Cr, Fe, Mn, Ni, Pb, Zn) from conventional and reflective cool cement blocks using the mass transfer tank leaching test, according to USEPA method 1315 and the batch leaching test as a function of pH, according to method CEN/TS 14429. Comparison of the results of the two tests indicates that equilibrium was not reached during the mass transfer test. In all cases, the Leachability Index values are higher than 8, indicating limited mobility. Observed diffusivity values differ by several orders of magnitude (10−11 – 10−20 m2/s) and are very small, indicating very slow diffusion. Leaching curves as a function of pH were very consistent and close to each other, indicating that the leaching mechanisms were the same for all cement blocks. Α two-domain one-dimensional mathematical model describing heavy metal diffusion from the pavements to the underlying soil was developed and tested. Simulations with this model showed that emissions from reflective cool cement pavements to the underlying soil are not different from the conventional ones in the long run.

An online technology for effectively monitoring inorganic condensable particulate matter emitted from industrial plants

The concentration of condensable particulate matter (CPM) has gradually exceeded that of filterable particulate matter emitted from industrial plants equipped with advanced air pollution control systems. However, there is still no available online technology to measure CPM emissions. Based on the significant linear correlations (R2 > 0.87, p < 3 × 10‐3) between the electrical conductivity (EC) values and ionic mass concentrations of the CPM solutions when the interference of H+ was excluded. We developed an online inorganic CPM monitoring system, including a cooling and condensation unit, pH and EC meters, a self-cleaning unit, and an automatic control unit. The CPM mass concentrations obtained by the developed online monitoring system agree well (mean bias 3.8–20.7%) with those obtained by the offline system according to USEPA Method 202 when used in parallel during real-world studies. Furthermore, individual ion mass concentrations of CPMs can even be retrieved separately with a time resolution of one hour when industrial plants are under steady operating conditions. The newly developed system makes the online monitoring of CPM emissions available and lays a foundation for the control of CPM emitted from industrial sources to further improve air quality.

Risk assessment of heavy metals Cd, Hg and Pb in carp (Cyprinus carpio) from Jatiluhur Reservoir, West Java in rainy season

Jatiluhur Reservoir which dams up water from the Citarum River is used for aquaculture activities. The issue related to the water source of the Jatiluhur Reservoir originating from the Citarum River is the presence of heavy metal pollution that can pose a risk to humans who consume the fish. Carp (Cyprinus carpio) is one of the fishery products. This study aims to determine the relationship between chemical parameters of water quality and heavy metal content of Jatilhur Reservoir water, determine heavy metal content in carp (C. carpio), and risk assessment of carp consumption originating from Jatiluhur. Fish and water samples were taken from the farm during the rainy season in October, November 2020, and March 2021. The risk assessment was done based on USEPA (2000) method and used a risk ranger spreadsheet. The results showed that there was a relationship between BOD, COD, total phosphate and ammonia on the heavy metal content of Cd, Hg, and Pb. The risk assessment was based on the average level of fish consumption (0.04627 kg/day) and respondent body weight (63.5 kg), indicating that human health from consuming the fish is relatively safe, and based on the risk ranger the risk rating is 44 (medium).

Analysis of research methodology on the content of heavy metals in sediments on the Indonesian coastal

Heavy metal pollution is one of the problems that often occurs in Indonesian coastal waters. Comparative methods of looking at heavy metal content in coastal sediments include a way to show similarities and differences between one or more articles by using certain criteria. Different comparison methods to see the heavy metal content in sediments include the AAS (Atomic Absorption Spectrophotometer) method, AAN (Netron Activation Analysis), Regression, and USEPA methods. Based on the comparison of 2 methods, namely: AAS and AAN methods, the most efficient in analyzing heavy metals in sediments in coastal areas is the Atomic Absorption Spectrophotometry (AAS) method compared to the Neutron Activation Analysis (AAS) method.Keywords:CoastalSedimentHeavy MetalSpectrophotometer

Implementation of initial emission mitigation measures for 1,4-dioxane in Germany: Are they taking effect?

Since our comprehensive investigation of finished drinking water in Germany obtained from managed aquifer recharge systems in the period 2015-2016, which revealed widespread contamination with 1,4-dioxane, mitigation measures (integration of AOP units, shutdown or alteration of production processes) have been implemented at some sites. In this study, we conducted follow-up tests on surface water concentrations and associated finished drinking water concentrations in 2017/2018, to evaluate the effectiveness of these measures. Our findings demonstrate that the emission mitigation measures had considerably reducing effects on the average 1,4-dioxane drinking water concentrations for some of the previously severely affected areas (Lower Franconia: -54%, Passau: -88%). Conversely, at notoriously contaminated sites where neither monitoring nor mitigation measures were introduced, the drinking water concentrations stagnated or even increased. Drinking water concentrations determined via a modified US EPA method 522 ranged from below LOQ (0.034 μg/L) up to 1.68 μg/L in all drinking water samples investigated. In river water samples, the maximum concentration exceeded 10 μg/L. Effluents of wastewater treatments plants containing 1,4-dioxane (5 μg/L–1.75 mg/L) were also analyzed for other similar cyclic ethers by suspected target screening. Thus, 1,3-dioxolane and three other derivatives were tentatively identified in effluents from the polyester processing or manufacturing industry. 1,3-Dioxolane was present in concentrations >1.2 mg/L at one site, exceeding up to sevenfold the 1,4-dioxane concentration found there. At another site 2-methyl-1,3-dioxolane was still found 13 km downstream of the discharge point, indicating that ethers analogous to 1,4-dioxane should be further considered regarding their occurrence and fate in wastewater treatment and the aquatic environment.

Interfering elements on determination of hexavalent chromium in paper materials with UV-vis spectrophotometry

Abstract Regulation of hexavalent chromium is based on Waste Framework Directive 1994/62/EC, European Commission and publication of the World Health Organization. Herein, detection of hexavalent chromium was performed by alkaline digestion and instrumental analysis which was demonstrated in USEPA methods. However, UV-vis detection method could be affected by some metal ions reacted with diphenylcarbizide. Actually, various interfering elements, such as Ni, Fe, Al, and Cu, were detected and selected by ED-XRF in paper materials. In order to improve accuracy of analysis results of hexavalent chromium in paper materials based on USEPA methods, the interfering elements was removed by liquid–liquid extraction with carbonate media using tricaprylmethylammonium chloride and chloroform after alkaline digestion. Consequently, the temperature for alkaline digestion was between 85 and 95 °C. Hydrochloric acid was proper complex tricaprylmethylammonium-Cr(VI) in the procedure of liquid extraction. After that hexavalent chromium was completely extracted using of 1 M sodium hydroxide solution. The technique for analyzing the hexavalent chromium used in liquid–liquid extraction significantly reduced the errors caused by the interfering elements, Fe and Cu. Thus, application of the extraction method was efficient in removing the interfering elements, which increased the recovery ratio of the hexavalent chromium from paper materials by 90 %.

The Utilization of Alkali-Activated Lead-Zinc Smelting Slag for Chromite Ore Processing Residue Solidification/Stabilization.

Lead–zinc smelting slag (LZSS) is regarded as a hazardous waste containing heavy metals that poses a significant threat to the environment. LZSS is rich in aluminosilicate, which has the potential to prepare alkali-activated materials and solidify hazardous waste, realizing hazardous waste cotreatment. In this study, the experiment included two parts; i.e., the preparation of alkali-activated LZSS (pure smelting slag) and chromite ore processing residue (COPR) solidification/stabilization. Single-factor and orthogonal experiments were carried out that aimed to explore the effects of various parameters (alkali solid content, water glass modulus, liquid–solid ratio, and initial curing temperature) for alkali-activated LZSS. Additionally, compressive strength and leaching toxicity were the indexes used to evaluate the performance of the solidified bodies containing COPR. As a result, the highest compressive strength of alkali-activated LZSS reached 84.49 MPa, and when 40% COPR was added, the strength decreased to 1.42 MPa. However, the leaching concentrations of Zn and Cr from all the solidified bodies were far below the critical limits (US EPA Method 1311 and China GB5085.3-2007). Heavy-metal ions in LZSS and COPR were immobilized successfully by chemical and physical means, which was detected by analyses including environmental scanning electron microscopy with energy-dispersive spectrometry, Fourier transform infrared spectrometry, and X-ray diffraction.

Agreement ℜ of Four Analytical Methods Applied to Pb in Soils from the Small City of St. John's, Newfoundland, Canada.

In the small city of St. John’s, NL (2020 population ~114,000), 100% of the soils of the pre-1926 properties exceeded the Canadian soil Pb standard, 140 mg/kg. The Pb was traced to high-Pb coal ash used for heating and disposed on the soils outside. Analytical instruments became available in the late 1960s and 1970s and were first used for blood Pb and clinical studies and repurposed for measuring environmental Pb. The environmental research part of this study compared four common soil Pb analysis methods on the same set (N = 96) of St. John’s soil samples. The methods: The US EPA method 3050B, portable X-ray fluorescence spectrometry (pXRF), The Chaney–Mielke leachate extraction (1 M nitric acid), and the relative bioaccessibility leaching procedure (US EPA method 1340). Correlation is not the same as agreement ℜ. There is strong agreement (Berry–Mielke’s Universal ℜ) among the four soil Pb analytical methods. Accordingly, precaution is normally advisable to protect children from the high-Pb garden soils and play areas. A public health reality check by Health Canada surveillance of St. John’s children (N = 257) noted remarkably low blood Pb. The low blood Pb of St. John’s’ children is contrary to the soil Pb results. Known urban processes causing the rise of environmental Pb and children’s Pb exposure includes particle size, aerosol emission by traffic congestion, and quantities of leaded petrol during the 20th century. Smaller cities had minor traffic congestion and limited combustion particles from leaded petrol. From the perspective of the 20th century era of urban Pb pollution, St. John’s, NL, children have blood Pb characteristics of a small city.

Heavy Metals in Water, Soils and Sediments of La Villa River Basin- Panama

Determine the concentration of heavy metals in water, sediments, and crops within the La Villa river basin, Herrera and Los Santos provinces, republic of Panama. La Villa river Basin, south central of Panama, in the rainy season of 2016 (May to November) and in the dry season of 2017 (December to April). Twenty two sediments and water samples were taken using the systematic method which consists of selecting sampling points at uniform distances and crops in upper, middle and lower basin. The selected sampling was confined to a preferably rectangular area of 10.0 m x 30.0 m, on which the sub-samples were taken with a number of 15 on each grid, at 0.20m depth. For collecting the water samples, a rod with a clean plastic bottle was introduced against the current of the river. The digestion of sediments and crops to determine the concentration of heavy metals (As, Pb, Cr, Ni, Cu, Mn, Zn and Cd) was carried out according to USEPA (25) method (3051A) (SW-846). In the sediments, in the rainy season, Cu (upper and lower basin) and Mn (all levels) values were found above the USEPA Standards. In the dry season, high values of Mn were found in the middle and lower basin, Cr in the upper and lower basin and As in all areas of the basin. In the rainy and dry seasons, high levels of Mn, Zn, Cr, Cd and Pb were found in the waters of the rivers that make up the basin. The main crops at each height of the basin were analyzed, determining high levels of As and Cr in the upper basin, in the middle and lower basin Cr and Cd. It is necessary to monitor the concentration of heavy metals in sediments of La Villa river basin because 90% of the agrochemicals that enter the country is destined for agriculture. Each Panamanian consumes (does not ingest) 3 kg of agrochemicals annually, exceeding six times the amount used in Central America. Due to their geological origin, these soils are rich in copper, manganese and arsenic, latter being associated with iron oxides and sulfides but there is also great influence of anthropogenic activities, agriculture and industries. Some metals such as lead and arsenic showed low solubility in water but showed high concentration in sediments. Chromium and cadmium present in crops come from water.