SARS-CoV-2 surveillance in indoor and outdoor size-segregated aerosol samples.

We aimed to determine the presence of SARS-CoV-2 RNA in indoor and outdoor size-segregated aerosol samples (PM10-2.5, PM2.5). Five outdoor daily samples were collected between November and December 2020 in an urban/industrial area with relatively high PM10 levels (Maliaño, Santander, Spain) by using a PM impactor (air flowrate of 30 L/min). In a non-hospital indoor sampling surveillance context, 8 samples in classrooms and 6 samples in the central library-Paraninfo of the University of Cantabria (UC) were collected between April and June 2021 by using personal PM samplers (air flowrate of 3 L/min). Lastly, 8 samples in the pediatric nasopharyngeal testing room at Liencres Hospital, 6 samples from different single occupancy rooms of positive patients, and 2 samples in clinical areas of the COVID plant of the University Hospital Marqués de Valdecilla (HUMV) were collected between January and May 2021. N1, N2 genes were used to test the presence of SARS-CoV-2 RNA by RT-qPCR. SARS-CoV-2 positive detection was only obtained from one fine fraction (PM2.5) sample, corresponding to one occupancy room, where a patient with positive PCR and cough was present. Negative results found in other sampling areas such as the pediatric nasopharyngeal testing rooms should be interpreted in terms of air sampling volume limitation and good ventilation.

Estimating changes in air pollutant levels due to COVID-19 lockdown measures based on a business-as-usual prediction scenario using data mining models: A case-study for urban traffic sites in Spain.

In response to the COVID-19 pandemic, governments declared severe restrictions throughout 2020, presenting an unprecedented scenario of reduced anthropogenic emissions of air pollutants derived mainly from traffic sources. To analyze the effect of these restrictions derived from COVID-19 pandemic on air quality levels, relative changes in NO, NO2, O3, PM10 and PM2.5 concentrations were calculated at urban traffic sites in the most populated Spanish cities over different periods with distinct restrictions in 2020. In addition to the changes calculated with respect to the observed air pollutant levels of previous years (2013-2019), relative changes were also calculated using predicted pollutant levels for the different periods over 2020 on a business-as-usual scenario using Multiple Linear Regression (MLR) models with meteorological and seasonal predictors. MLR models were selected among different data mining techniques (MLR, Random Forest (RF), K-Nearest Neighbors (KNN)), based on their higher performance and accuracy obtained from a leave-one-year-out cross-validation scheme using 2013-2019 data. A q-q mapping post-correction was also applied in all cases in order to improve the reliability of the predictions to reproduce the observed distributions and extreme events. This approach allows us to estimate the relative changes in the studied air pollutants only due to COVID-19 restrictions. The results obtained from this approach show a decreasing pattern for NOx, with the largest reduction in the lockdown period above -50%, whereas the increase observed for O3 contrasts with the NOx patterns with a maximum increase of 23.9%. The slight reduction in PM10 (-4.1%) and PM2.5 levels (-2.3%) during lockdown indicates a lower relationship with traffic sources. The developed methodology represents a simple but robust framework for exploratory analysis and intervention detection in air quality studies.

Poorer cognitive function and environmental airborne Mn exposure determined by biomonitoring and personal environmental monitors in a healthy adult population.

BACKGROUND/AIM: In the Santander Bay (Cantabria, northern Spain), a ferromanganese alloy plant is located. Our objective was to characterize the Mn personal exposure of adult healthy volunteers living in this highly Mn exposed region, and to determine its association with a poorer cognitive function. METHODS: Cross-sectional study analyzing 130 consecutive participants. Cognitive function was assessed by Stroop Color Word, Verbal Fluency tests, Trail Making Test (TMT), Digit Span (WAIS III) and Rey Osterrieth Complex Figure (ROCF) tests and crude scores were standardized according to NEURONORMA norms. Exposure to Mn was assessed in terms of source distance, by Personal Environmental Monitors (PEMs) allowing the separation of fine (PM2.5) and coarse (PM10-2.5) particles (obtaining the bioaccessible fraction by in-vitro bioaccessibility tests), and by biomarkers (blood, hair and fingernails). Age, sex, study level and number of years of residence were predefined as confounding variables and adjusted Mean Differences (MDs) were obtained. RESULTS: Statistically significant lower scores (negative MDs) in all test were observed when living near the industrial emission source, after adjusting for the predefined variables. Regarding PEMs results, statistically significant lower scores in all Stroop parts were obtained in participants with higher levels of Total Mn in All fractions (PM10). For Verbal Fluency tests, negative MDs were obtained for both bioaccessible fractions. Digit Span Backward scores were lower for those with higher levels in the bioaccessible coarse fraction, and negative MDs were also observed for the ROCF Delayed part and the non-bioaccessible fine fraction. As regards to Mn in fingernails, adjusted MDs of -1.60; 95%CI (-2.57 to -0.64) and -1.45; 95%CI (-2.29 to -0.61) for Digit Span Forward and Backward parts were observed. CONCLUSIONS: Our results support an association between poorer cognitive function and environmental airborne Mn exposure.

Exposure to particulate matter: Direct and indirect role in the COVID-19 pandemic.

Knowing the transmission factors and the natural environment that favor the spread of a viral infection is crucial to stop outbreaks and develop effective preventive strategies. This work aims to evaluate the role of Particulate Matter (PM) in the COVID-19 pandemic, focusing especially on that of PM as a vector for SARS-CoV-2. Exposure to PM has been related to new cases and to the clinical severity of people infected by SARS-CoV-2, which can be explained by the oxidative stress and the inflammatory response generated by these particles when entering the respiratory system, as well as by the role of PM in the expression of ACE-2 in respiratory cells in human hosts. In addition, different authors have detected SARS-CoV-2 RNA in PM sampled both in outdoor and indoor environments. The results of various studies lead to the hypothesis that the aerosols emitted by an infected person could be deposited in other suspended particles, sometimes of natural but especially of anthropogenic origin, that form the basal PM. However, the viability of the virus in PM has not yet been demonstrated. Should PM be confirmed as a vector of transmission, prevention strategies ought to be adapted, and PM sampling in outdoor environments could become an indicator of viral load in a specific area.

Meteorological Normalisation Using Boosted Regression Trees to Estimate the Impact of COVID-19 Restrictions on Air Quality Levels.

The global COVID-19 pandemic that began in late December 2019 led to unprecedented lockdowns worldwide, providing a unique opportunity to investigate in detail the impacts of restricted anthropogenic emissions on air quality. A wide range of strategies and approaches exist to achieve this. In this paper, we use the "deweather" R package, based on Boosted Regression Tree (BRT) models, first to remove the influences of meteorology and emission trend patterns from NO, NO2, PM10 and O3 data series, and then to calculate the relative changes in air pollutant levels in 2020 with respect to the previous seven years (2013-2019). Data from a northern Spanish region, Cantabria, with all types of monitoring stations (traffic, urban background, industrial and rural) were used, dividing the calendar year into eight periods according to the intensity of government restrictions. The results showed mean reductions in the lockdown period above -50% for NOx, around -10% for PM10 and below -5% for O3. Small differences were found between the relative changes obtained from normalised data with respect to those from observations. These results highlight the importance of developing an integrated policy to reduce anthropogenic emissions and the need to move towards sustainable mobility to ensure safer air quality levels, as pre-existing concentrations in some cases exceed the safe threshold.

Biomonitoring and bioaccessibility of environmental airborne manganese in relation to motor function in a healthy adult population.

BACKGROUND/AIM: Santander, the capital of Cantabria, Spain (172,000 inhabitants) is 7 km from an industrial emission source (IES) of Mn located in a 10,000 inhabitants town (Maliaño) (annual air Mn arithmetic mean = 231.8 ng/m3; reference WHO guideline = 150 ng/m3). Our objective was to compare the motor function of adult healthy volunteers living in both places. METHODS: Cross-sectional study analyzing 130 consecutive participants. Exposure to Mn was assessed in terms of source distance from the IES, by Personal Environmental Monitors (PEMs) carried for 24 h by participants consisting of a portable impactor connected to a personal pump, and by biomarkers (blood, hair and fingernails). The impactor allowed the separation of fine (PM2.5) and coarse (PM10-2.5) particles and for each particle size in-vitro bioaccessibility tests with biologically active fluids were performed to separate the soluble (bioaccessible) from the insoluble (non-bioaccessible) fraction. Mean Differences (MDs) adjusted for age, sex, and study level, were obtained for motor function tests results. RESULTS: Regarding Grooved Pegboard, overall mean time to complete the test was 59.31 and 65.27 seconds (Standard Deviation = 10.11 and 11.69) for dominant and nondominant hands respectively. Statistically significant higher times (indicating worse function) were observed when living near the IES in both hands but MDs of only 1.22 and 2.05 seconds were obtained after adjusting for the predefined confounders (p = 0.373 and 0.221 respectively). Regarding Mn levels in their PEMs (in both bioaccessible and non-bioaccessible coarse&fine fractions) higher times were computed in participants with higher levels for the bioaccessible-fine fraction, with a MD that diminished but still yielded statistical significance after controlling for confounding: adjusted MD = 3.01 more seconds; 95%CI (0.44-5.38), p = 0.022. Poorer results were also observed for fingernails levels. Regarding Finger Tapping Test, no statistically significant differences were found with the exception of Mn fingernails levels. CONCLUSIONS: Our results suggest poorer motor function as assessed by Grooved Pegboard test in relation to "proximity to IES", "bioaccessible-fine fraction as determined by PEMs and "Mn fingernails levels". However, our findings were affected by confounding, and only the adjusted MD for the Mn bioaccessible-fine fraction remained of sufficient magnitude to maintain statistical significance.

Impact of Environmental Airborne Manganese Exposure on Cognitive and Motor Functions in Adults: A Systematic Review and Meta-Analysis.

BACKGROUND/OBJECTIVE: Whether environmental exposure to Manganese (Mn) in adults is associated with poorer results in cognitive and motor function is unclear. We aimed to determine these associations through a meta-analysis of published studies. METHODS: A systematic review was conducted to identify epidemiological studies on a population ≥18 years old exposed to environmental airborne Mn, and in which results on specific tests to evaluate cognitive or motor functions were reported. We consulted Medline through PubMed, Web of Science and SCOPUS databases. We also performed a manual search within the list of bibliographic references of the retrieved studies and systematic reviews. To weight Mn effects, a random effects versus fixed effect model was chosen after studying the heterogeneity of each outcome. RESULTS: Eighteen studies met the inclusion criteria. Among them, eleven studies reported data susceptible for meta-analysis through a pooled correlation or a standardized means difference (SMD) approach between exposed and non-exposed groups. Regarding cognitive function, the results of the studies showed heterogeneity among them (I2 = 76.49%, p < 0.001). The overall effect was a statistically significant negative correlation in the random effects model (pooled r = -0.165; 95%CI: -0.214 to -0.116; p < 0.001). For SMD, the results showed a lower heterogeneity with a negative SMD that did not reach statistical significance under the fixed effects model (SMD = -0.052; 95%CI -0.108 to 0.004; p = 0.068). Regarding motor function, heterogeneity (I2 = 75%) was also observed in the correlation approach with a pooled r (random effect model) = -0.150; 95%CI: -0.219 to -0.079; p < 0.001. Moderate heterogeneity was observed according to the SMD approach (I2 = 52.28%), with a pooled SMD = -0.136; 95%CI: -0.188 to-0.084; p < 0.001, indicating worse motor function in those exposed. CONCLUSIONS: Correlation approach results support a negative effect on cognitive and motor functions (the higher the Mn levels, the poorer the scores). Regarding the SMD approach, results also support a worse cognitive and motor functions in those exposed, although only for motor function statistical significance was obtained.

A Review on the Environmental Exposure to Airborne Manganese, Biomonitoring, and Neurological/Neuropsychological Outcomes.

The occupational exposure to airborne manganese (Mn) has been linked for decades with neurological effects. With respect to its environmental exposure, the first reviews on this matter stated that the risk posed to human health by this kind of exposure was still unknown. Later, many studies have been developed to analyze the association between environmental Mn exposure and health effects, most of them including the measure of Mn in selected human biomarkers. This review aims at collecting and organizing the literature dealing with the environmental airborne Mn exposure (other routes of exposure were intentionally removed from this review), the biomonitoring of this metal in different body matrices (e.g., blood, urine, nails, hair), and the association between exposure and several adverse health effects, such as, e.g., neurocognitive, neurodevelopmental, or neurobehavioral outcomes. From the different exposure routes, inhalation was the only one considered in this review, to take into account the areas influenced by industrial activities closely related to the Mn industry (ferromanganese and silicomanganese plants, Mn ore mines, and their processing plants) and by traffic in countries where a fuel additive, methylcyclopentadienyl manganese tricarbonyl (MMT), has been used for years. In these areas, high air Mn levels have been reported in comparison with the annual Reference Concentration (RfC) given by the US EPA for Mn, 50 ng/m3. This review was performed using Scopus and MEDLINE databases with a keyword search strategy that took into account that each valid reference should include at least participants that were exposed to environmental airborne Mn and that were subjected to analysis of Mn in biomarkers or subjected to neurological/neuropsychological tests or both. Overall, 47 references matching these criteria were included in the discussion. Most of them report the measure of Mn in selected biomarkers (N = 43) and the assessment of different neurological outcomes (N = 31). A negative association is usually obtained between Mn levels in hair and some neurological outcomes, such as cognitive, motor, olfactory, and emotional functions, but not always significant. However, other biomarkers, such as blood and urine, do not seem to reflect the chronic environmental exposure to low/moderate levels of airborne Mn. Further studies combining the determination of the Mn exposure through environmental airborne sources and biomarkers of exposure and the evaluation of at least cognitive and motor functions are needed to better understand the effects of chronic non-occupational exposure to airborne Mn.

Use of CALPUFF to predict airborne Mn levels at schools in an urban area impacted by a nearby manganese alloy plant.

Children are susceptible to the health effects derived from elevated manganese (Mn) environmental exposure; residents living in urban areas where ferromanganese alloy plants are located are usually exposed to high Mn levels. In this work, a dispersion model developed by the USEPA, CALPUFF, has been used to estimate the airborne Mn levels near educational centers located in Santander bay, Northern Spain, an urban area where high Mn levels have been measured in the last decade. The CALPUFF model was validated in a previous work from a multi-site one-year observation dataset. Air manganese levels in 96 primary, secondary and high schools located in Santander bay were estimated using the CALPUFF model for two months corresponding to warm and cold periods using real meteorological data and Mn emission rates corresponding to different emission scenarios. Results show that when the emission scenario that best represented the observations dataset is used, the air Mn levels exceed the WHO guideline (i.e. 150 ng Mn/m3) in 24% and 11% of the studied schools in the cold and warm periods respectively. These exceedances depend on the distance from the FeMn alloy plant and the direction of the prevailing winds. Additional emission scenarios based on the implementation of preventive and corrective measures are simulated and analysed in terms of the number of exceedances of the WHO guideline. The age range of children has been also considered in the analysis.

Estimation of PM10-bound manganese concentration near a ferromanganese alloy plant by atmospheric dispersion modelling.

Numerous studies have associated air manganese (Mn) exposure with negative health effects, primarily neurotoxic disorders. This work presents a description of the emission and dispersion of PM10-bound Mn from industrial sources in the Santander bay area, Northern Spain. A detailed day-specific emission estimation was made and assessed for the main Mn source, a manganese alloy production plant under 8 different scenarios. Dispersion analysis of PM10-bound Mn was performed using the CALPUFF model. The model was validated from an observation dataset including 101 daily samples from four sites located in the vicinities of the manganese alloy plant. Model results were in reasonable agreement with observations (r = 0.37; NMSE = 2.08; Fractional Bias = 0.44 and Modelled/Observed ratio = 1.57). Simulated and observed Mn concentrations in the study area were much higher than the guidelines proposed by the World Health Organization (WHO) and the U.S. Environmental Protection Agency (USEPA), highlighting the need to reduce the Mn concentrations in the area. Based on the analysis of the Mn source contribution from the ferromanganese alloy plant, some preventive and corrective measures are discussed at the end of the paper. This work shows that CALPUFF dispersion model can be used to predict PM10-bound Mn concentrations with reasonable accuracy in the vicinities of industrial facilities allowing the exposure assessment of the nearby population, which can be used in future epidemiological studies.

Characterization of manganese-bearing particles in the vicinities of a manganese alloy plant.

Numerous studies have associated air manganese (Mn) exposure with negative health effects, primarily neurotoxic disorders. Despite there is not a specific European regulation, institutions such as the World Health Organization (WHO) have proposed an annual average guideline value of 150 ng/m3. Bioaccessibility and toxicity mechanisms of Mn remain unclear, however it is generally agreed that adverse health effects are strongly linked to particle size and morphology, chemical composition and oxidation state. This study aims to deepen the understanding of the physico-chemical characteristics of PM10 and deposition samples collected in an urban area in the proximities of a ferromanganese alloy plant. Total Mn content was determined by ICP-MS after a microwave-assisted acid digestion. The size, morphology and chemical composition of individual particles were studied by SEM-EDX. XRD was used to identify the major crystalline phases. Most of the particles observed by SEM-EDX contain Mn. 60% of Mn-PM10 particles were spheres of small size and were attributed to condensation processes at the smelting unit. Mn-bearing particles present in deposition were characterized by irregular shapes and bigger sizes, most of them consisting of SiMn slags and Mn ores and alloys, and attributed to diffuse emissions from raw material and product handling and processing. Due to the differences in the characteristics of Mn-bearing particles found in the different matrices, further studies on the potential toxicity and health effects of these particles should be done, especially in relation with the small and spherical particles present in PM10, which are expected to be more problematic.

A proposed methodology for the assessment of arsenic, nickel, cadmium and lead levels in ambient air.

Air quality assessment, required by the European Union (EU) Air Quality Directive, Directive 2008/50/EC, is part of the functions attributed to Environmental Management authorities. Based on the cost and time consumption associated with the experimental works required for the air quality assessment in relation to the EU-regulated metal and metalloids, other methods such as modelling or objective estimation arise as competitive alternatives when, in accordance with the Air Quality Directive, the levels of pollutants permit their use at a specific location. This work investigates the possibility of using statistical models based on Partial Least Squares Regression (PLSR) and Artificial Neural Networks (ANNs) to estimate the levels of arsenic (As), cadmium (Cd), nickel (Ni) and lead (Pb) in ambient air and their application for policy purposes. A methodology comprising the main steps that should be taken into consideration to prepare the input database, develop the model and evaluate their performance is proposed and applied to a case of study in Santander (Spain). It was observed that even though these approaches present some difficulties in estimating the individual sample concentrations, having an equivalent performance they can be considered valid for the estimation of the mean values - those to be compared with the limit/target values - fulfilling the uncertainty requirements in the context of the Air Quality Directive. Additionally, the influence of the consideration of input variables related to atmospheric stability on the performance of the studied statistical models has been determined. Although the consideration of these variables as additional inputs had no effect on As and Cd models, they did yield an improvement for Pb and Ni, especially with regard to ANN models.

PAHs in the urban air of Sarajevo: levels, sources, day/night variation, and human inhalation risk.

Polycyclic aromatic hydrocarbons (PAHs) are organic pollutants derived from pyrolysis and pyrosynthesis processes. Industrial activity, motor vehicle emission, and domestic combustion are the main sources of PAHs in the urban atmosphere. In this work, samples collected during the day and night in the urban area of Sarajevo are analyzed separately for gaseous and particle-bound PAHs; the possible origin of PAHs at the receptor site was suggested using different methods applied to the solid phase and to the total PAHs (gaseous + particulate phase). Finally, the risk level in Sarajevo associated to the carcinogenic character of the studied PAHs has been assessed. The result of this study suggests that (a) the total PAH concentrations were higher than those reported in other European cities; (b) the PAH daytime concentrations are higher than nocturnal concentrations: the sum of the PAH day/night ratios is 1.52 (gas) and 1.45 (particle phase); (c) stationary combustion and traffic were suggested to be the main sources of PAHs; (d) the average particle-bound benzo(a)pyrene (BaP) concentration (5.4 ng/m(3)) is higher than EU target annual value (1 ng/m(3)); and (e) PAH cancer risk exceeds the carcinogenic benchmark level recommended by the EPA mainly due to BaP during both the day and night periods.

Chemical profile identification of fugitive and confined particle emissions from an integrated iron and steelmaking plant.

The aim of this study is to obtain the characteristic inorganic chemical profile of important particle sources identified in the integrated iron and steel process: sintering, blast furnace, steelmaking and desulfurization slag processing. A complete chemical and physical characterization program was developed: particle size distribution, chemical analysis, XRD, SEM-EDX and TGA/DTA. The sample collected from the sinter stack showed high levels of K and Cl(-), followed by Fe, NH4(+), Ca, Na and Pb. The profile of the dust samples taken from the sinter cake discharge zone was quite different, showing higher amounts of Fe, Ca and Al, and lower amounts of K, Cl(-), Na and Pb. Dust samples collected from the blast furnace (BF) and steelmaking cast house may be distinguished from each other based on the higher levels of Fe (hematite and magnetite) and lower levels of Ca, Zn and C (graphite) found in BF dust. High levels of Ca and Fe were found in samples taken from the desulfurization slag processing area. Such information can be useful for source apportionment studies at receptor sites that could be influenced by iron and steelmaking plant emissions.

Evaluation of the urban/rural particle-bound PAH and PCB levels in the northern Spain (Cantabria region).

The aim of the present study was to evaluate the polycyclic aromatic hydrocarbon (PAH) and polychlorinated biphenyl (PCB) levels in PM(10) and PM(2.5), at one rural and three urban sites in the Cantabria region (northern Spain). From all of these pollutants, benzo(a)pyrene is regulated by the EU air quality directives; its target value (1 ng/m(3)) was not exceeded. The concentration values of the studied organic pollutants at the studied sites are in the range of those obtained at other European sites. A comparison between the rural-urban stations was developed: (a) PAH concentration values were lower in the rural site (except for fluorene). Therefore, the contribution of local sources to the urban levels of PAHs seems relevant. Results from the coefficient of divergence show that the urban PAH levels are influenced by different local emission sources. (b) PCB rural concentration values were higher than those found at urban sites. Because no local sources of PCBs were identified in the rural site, the contribution of more distant emission sources (about 40 km) to the PCB levels is considered to be the most important; the long-range transport of PCBs does not seem to be significant. Additionally, local PAH tracers were identified by a triangular diagram: higher molecular weight PAHs in Reinosa, naphthalene in Santander and anthracene/pyrene in Castro Urdiales. A preliminary PAH source apportionment study in the urban sites was conducted by means of diagnostic ratios. The ratios are similar to those reported in areas affected by traffic emissions; they also suggest an industrial emission source at Reinosa.

Evaluation of the contribution of local sources to trace metals levels in urban PM2.5 and PM10 in the Cantabria region (Northern Spain).

The aim of this study was to evaluate the contribution of local emission sources to the selected trace metals levels (As, Ni, Cd, Pb, Ti, V, Mn, Cu, Mo and Hg) in urban particulate matter, PM10 and PM2.5, in the Cantabria region (Northern Spain) during the year 2008. PM10 and PM2.5 samples were collected and characterized in an urban sampling site at Santander (Cantabria); additional PM10 samples were collected at a rural site at Los Tojos (50 Km SW) to evaluate both the urban and rural environment. The particulate matter and the metals regulated by the EC air quality directives (Pb, As, Ni and Cd) did not exceed the EC limit or target values in the Cantabria region. The metal concentrations were much lower at the rural site except for Ni. Different techniques were used to analyse the possible sources of the studied metals: enrichment factor, urban impact, wind and pollutant roses and principal component analysis (PCA). A combination of these techniques allowed us to demonstrate that the local emission sources of metals in the particulate matter at Santander city were the most important. Ti, Ni, As and V were identified as the main urban background tracers while Mn and Pb were the main local industrial tracers. The urban background was found to be the major contributor to PM10. The relationship between the emission tracers and the major air pollutants (NO(2), NO, CO, SO(2),O(3) and PM(10)) was also studied by PCA; a significant relationship between tracers and the major air pollutants was not found, showing a decoupled relationship between major pollutants and metal species in particulate matter.

Modeling of zinc solubility in stabilized/solidified electric arc furnace dust.

Equilibrium models which attempt for the influence of pH on the solubility of metals can improve the dynamic leaching models developed to describe the long-term behavior of waste-derived forms. In addition, such models can be used to predict the concentration of metals in equilibrium leaching tests at a given pH. The aim of this work is to model the equilibrium concentration of Zn from untreated and stabilized/solidified (S/S) electric arc furnace dust (EAFD) using experimental data obtained from a pH-dependence leaching test (acid neutralization capacity, ANC). EAFD is a hazardous waste generated in electric arc furnace steel factories; it contains significant amounts of heavy metals such as Zn, Pb, Cr or Cd. EAFD from a local factory was characterized by X-ray fluorescence (XRF), acid digestion and X-ray diffraction (XRD). Zn and Fe were the main components while the XRD analysis revealed that zincite, zinc ferrite and hematite were the main crystalline phases. Different cement/EAFD formulations ranging from 7 to 20% dry weight of cement were prepared and subjected to the ANC leaching test. An amphoteric behavior of Zn was found from the pH dependence test. To model this behavior, the geochemical model Visual MINTEQ (VMINTEQ) was used. In addition to the geochemical model, an empirical model based on the dissolution of Zn in the acidic zone and the re-dissolution of zinc compounds in the alkaline zone was considered showing a similar prediction than that obtained with VMINTEQ. This empirical model seems to be more appropriate when the metal speciation is unknown, or when if known, the theoretical solid phases included in the database of VMINTEQ do not allow to describe the experimental data.