Aquifer Contamination Research Articles

An assessment of total coliforms and associated thresholds as water quality indicators using a large Ontario private drinking water well dataset

A spatiotemporally static total coliform (TC) concentration threshold of five colony-forming units (CFU) per 100 mL is used in Ontario to determine whether well water is of acceptable quality for drinking. The current study sought to assess the role of TC and associated thresholds as microbial water quality parameters as the authors hypothesized that, since static TC thresholds are not evidence-based, they may not be appropriate for all well water consumers. A dataset containing the microbial water quality information of 795,023 samples (including TC and Escherichia coli (E. coli) counts) collected from 253,136 private wells in Ontario between 2010 and 2017 was used. To accurately assess the relationship between E. coli and non-E. coli TC, “non-E. coli coliform” (NEC) counts were calculated from microbial water quality data and replaced TC throughout analyses. This study analysed NEC and E. coli detection rates to determine differences between the two, and NEC:E. coli concentration ratios to assess links, if any, between NEC and E. coli contamination. Study findings suggest that spatiotemporally static NEC thresholds are not appropriate because seasonal, spatial, and well-specific susceptibility factors are associated with distinct contamination trends. For example, NEC detection rates exhibited bimodality, with summer (29.4 %) and autumn (30.2 %) detection rates being significantly higher (p < 0.05) than winter (21.9 %) and spring (19.9 %). E. coli detection rates also varied seasonally, but peaked in summer rather than autumn. As such, it is recommended that these factors be considered during the development of private well water guidelines and that static thresholds be avoided. Furthermore, the authors propose that, because NEC:E. coli concentration ratios change in the context of the aforementioned factors, they may have a role in inferring groundwater contamination mechanisms, with high ratios being associated with generalized aquifer contamination mechanisms and low ratios with localized contamination mechanisms.

Extraction and Characterization of Microplastics from Portuguese Industrial Effluents.

Microplastics (MPs) are contaminants present in the environment. The current study evaluates the contribution of different well-established industrial sectors in Portugal regarding their release of MPs and potential contamination of the aquifers. For each type of industry, samples were collected from wastewater treatment plants (WWTP), and different parameters were evaluated, such as the potential contamination sources, the concentration, and the composition of the MPs, in both the incoming and outcoming effluents. The procedures to extract and identify MPs in the streams entering or leaving the WWTPs were optimized. All industrial effluents analysed were found to contribute to the increase of MPs in the environment. However, the paint and pharmaceutical activities were the ones showing higher impact. Contrary to many reports, the textile industry contribution to aquifers contamination was not found to be particularly relevant. Its main impact is suggested to come from the numerous washing cycles that textiles suffer during their lifetime, which is expected to strongly contribute to a continuous release of MPs. The predominant chemical composition of the isolated MPs was found to be polyethylene terephthalate (PET). In 2020, the global need for PET was 27 million tons and by 2030, global PET demand is expected to be 42 million tons. Awareness campaigns are recommended to mitigate MPs release to the environment and its potential negative impact on ecosystems and biodiversity.

The Influence of Seasonal Recharge and Groundwater Pumping on the Seawater Intrusion in a Coastal Karst Aquifer

Wu, X.; Xu, Z.; Xu, Z.; Hu, B.X.; Chang, Q., and Hu, Y., 2022. The influence of seasonal recharge and groundwater pumping on the seawater intrusion in a coastal karst aquifer. Journal of Coastal Research, 38(4), 785–794. Coconut Creek (Florida), ISSN 0749-0208. Groundwater resources in the coastal karst aquifers are threatened by long-distance seawater intrusion. The severity of groundwater contamination can be affected by hydrologic and anthropogenic factors, including rainfall conditions and pumping situations. A better understanding of these factors' control on the seawater intrusion is critical for their vulnerability estimation and aquifer management. The aquifer salinization, pumping safety, and the vulnerability of inland springs were examined by a synthetic-modeling work in this study. Different pumping locations, pumping rates, the comparison of dynamic seasonal recharge (DSR), and steady-state recharge (SSR) were considered in this study. Several time-based metrics were developed to estimate the aquifer vulnerability and water quality. The results show that the distance of pumping location to the shoreline significantly impacts seawater intrusion. The near-shore pumping leads to lower aquifer contamination while higher salinity in pumped water, and the inland pumping causes more aquifer salinization with cleaner pumped water. In addition, aquifer, pumping water quality, and inland spring are more vulnerable to seawater intrusion under the DSR condition than SSR condition. The difference of aquifer salinization between DSR and SSR condition increases with pumping rate from 50 to 150 m3/day and then decreases from 150 to 200 m3/day, which shows a threshold pumping rate in comparing DSR and SSR conditions. The insights from this work provide essential suggestions for groundwater simulations and related management decisions.

Predicting the risk of saltwater contamination of freshwater aquifers during aquifer thermal energy storage

Predicting the risk of saltwater contamination of freshwater aquifers during aquifer thermal energy storage

The elimination of lead(II) ions in a solution by bio-adsorption: Kinetics, equilibrium, and thermodynamics

In the present study, the removal capacity of Pb(II) ions was investigated using the biomass of dried cattle manure in an aqueous solution. The biomaterials were characterized using Scanning Electron Microscopy (SEM) and Energy-Dispersive X-ray Spectroscopy (EDS) techniques. The results reveal that the adsorption mechanism may be associated with the interaction between Pb(II) ions and functional groups through aggregation, coordination, ion exchange, microprecipitation, oxidation, and hydrophobicity. The bio-adsorption of the metal was analysed in discontinuous tests; the effect of temperature, pH, agitation, and adsorbent dose was evaluated. The maximum adsorption capacity was determined at pH 7.5, 18°C and 200 rpm. The bio-adsorption of Pb(II) was best fitted to the pseudo-second order model. The experimental data of the isotherm were adjusted to the models of Langmuir, Freundlich and Dubinin–Radushkevich; while Langmuir’s model related better to the experimental data forming a single layer at saturation. The rate of adsorption was rapid, reaching equilibrium after 25 min and removal of 96.8%. Thermodynamic parameters determined that the process was viable, spontaneous, and exothermic. The present study contributes mainly to demonstrating that a biomaterial prepared from bovine manure is a promising adsorbent for heavy metals such as Pb(II). It also reduces the environmental impact of this waste through the generation of greenhouse gases in countries that maintain intensive livestock. Another important aspect is the reduction of the micro- and macronutrients accumulation in soil and contamination of surface waters and aquifers by runoff and seepage during rainy periods.

Geogenic controls on the high levels of uranium in alluvial aquifers of the Ganga Basin

The Indo-Gangetic Basin (IGB) alluvial aquifer system provides a reliable drinking water supply to over half a billion people. Understanding the groundwater quality, aquifer processes, groundwater storage, and depletion trends in the IGB alluvial aquifer system— one of the world's most important freshwater resources has been the focus of many previous studies. However, understanding what governs uranium variability in the IGB alluvial aquifer system— for example, whether uranium is released from natural deposits or anthropogenic sources such as mill tailing, emissions from the nuclear industry, combustion of fossil fuels, and phosphate fertilizers— are under-explored but critically important for constraining the environmental fate of uranium. Here, we present surface and groundwater uranium concentration data in the central parts of the IGB alluvial aquifer system. We find a high concentration of groundwater uranium above the World Health Organization provisional guideline value of 30 μg/L in 17% (n = 29) of collected groundwater samples, whereas other heavy metals, namely Cr, Ni, Pb, and Cd were within the recommended range. Trace element systematic demonstrates that anomalous uranium enrichment is primarily derived from geogenic sources, while uranium mobility is predominantly controlled by the alkalinity (a proxy for bicarbonate), hence by soluble uranyl carbonate complexes. As in the year 2020, the Bureau of Indian Standard incorporated uranium as a possible drinking water contaminant, our dataset calls for additional assessments of groundwater uranium concentrations in Indian groundwater resources because uranium concentration data are scarce compared to other geogenic contaminants such as arsenic and fluoride. We conclude that uranium, like arsenic and fluoride, is also critical geogenic contaminant in the alluvial aquifers that needs to be better monitored as higher levels of uranium in drinking water have adverse health effects.

Estimating suitability of groundwater for drinking and irrigation, in Odisha (India) by statistical and WQI methods.

Twelve major hydro-geochemical parameters derived from about 1134 water samples were studied to understand spatial variation of groundwater quality in the coastal state of Odisha. Multivariate statistical analysis techniques, i.e., cluster analysis and principal component analysis (PCA), and varimax rotation were used to classify various types of groundwater, and plausible sources that control the quality of water in the region. The concentration of major ions varies in the order of Na+ > Ca2+ > Mg2+ > K+ and HCO3- > Cl- > SO42- > F-. Out of the three clusters identified, the 2nd cluster is having more mineralization and relatively poor quality of groundwater as compared to the first and the third cluster. Furthermore, estimates of the Water Quality Index (WQI) indicate that the groundwater in the area can be classified from excellent to medium quality. Furthermore, the sodium absorption ratio (SAR) and Kelly's ratio (KR) suggest that about 70% of groundwatersamples are of low to medium salinity, whereas about 30% show higher salinity. The Wilcox diagram reveals that almost 90% of the groundwater is suitable for irrigation. The mining activity appears less likely to be affecting the quality of subsurface water. Water-rock interactions and evaporation-crystallization may be the two dominant factors that appear to control the groundwater away from the coastal areas. Results of this study may be useful to identify the suitable sites for groundwater extraction for drinking and irrigation purposes, besides being useful to the policy-makers in formulating effective plans for preventing further contamination of groundwater aquifers.

Identification of aquifer pollution’s point sources with the reciprocity principle

The principle of reciprocity, called Maxwell–Betti theorem, initially used in mechanics in an elastic structure, establishes a relation of equality between two distinct strains under different loads. In this paper, we extend and apply this principle to flow and solute transport equations in porous media, in order to perform the pollution sources identification in aquifers. We developed general 2D expressions of the reciprocity principle for transient transport problems. This model leads to a linear equations set, with point sources coordinates, concentrations and associated water fluxes as unknowns The proposed model is then applied to the Rocky Mountain Arsenal aquifer (Konikow in Modeling Chloride Movement in the Alluvial Aquifer at the Rocky Mountain Arsenal, Colorado. Technical Report Water-Supply Paper 2044, USGS, 1979), where polluted water is injected into a well in the domain. The used inverse technique successfully recovered the position and the pollutant concentration in addition to the associated water flux. In addition, we developed and implemented the inverse method for different knowledge levels of the degrees of the aquifer contamination, i.e. more or less data available in the field. Multiple pollution point sources and noisy data situations are also developed and tested with high efficiency. The proposed method would be easy and useful to be implemented in the modeling software now widely used by researchers and groundwater managers. It can thus be applied in real case studies, to help authorities and regulators to efficiently identify the polluters and the contamination process, i.e. its location, onset, duration and the associated mass and water fluxes.

VisU-HydRA: A Computational Toolbox for Groundwater Contaminant Transport to Support Risk-Based Decision Making

Obtaining accurate and deterministic predictions of the risks associated with the presence of contaminants in aquifers is an illusive goal given the presence of heterogeneity in hydrological properties and limited site characterization data. For such reasons, a probabilistic framework is needed to quantify the risks in groundwater systems. In this work, we present a computational toolbox VisU-HydRA that aims to statistically characterize and visualize metrics that are relevant in risk analysis with the ultimate goal of supporting decision making. The VisU-HydRA computational toolbox is an open-source Python package that can be linked to a series of existing codes such as MODFLOW and PAR2, a GPU-accelerated transport simulator. To illustrate the capabilities of the computational toolbox, we simulate flow and transport in a heterogeneous aquifer within a Monte Carlo framework. The computational toolbox allows to compute the probability of a contaminant’s concentration exceeding a safe threshold value as well as the uncertainty associated with the loss of resilience of the aquifer. To ensure consistency and a reproducible workflow, a step-by-step tutorial is provided and available on a GitHub repository.

Water Quality Monitoring of Five Karst Springs within a Pastureland in Southwest Polk County, Missouri

ABSTRACT The fractured nature of karst terrain makes these areas highly susceptible to contamination. Besides aquifer contamination, impaired karst springs can negatively impact the aquatic habitat of their receiving streams. Five springs of a shallow karst aquifer in southwest Polk County, Missouri, and their receiving stream were selected to construct a baseline of water quality data, using nitrate (NO3) as indicator. The main land use in the study area is cattle farming. Water samples were collected during a 12-month period and analyzed for pH, turbidity, Ca, Mg, HCO3, Cl, SO4, and NO3. Results show that each spring had its own range of values. NO3 and Cl values were below contamination levels and only in a few instances exceeded threshold levels reported for karst areas (NO3-N &amp;lt;3 mg/L; Cl &amp;lt;13 mg/L), implying that the number of cattle per acre is maintained at a sustainable level and leaking from the Springfield Plateau aquifer to the underlying Ozark aquifer poses a minor threat. Interestingly, NO3 and Cl did not correlate despite their common source, suggesting that they undergo different chemical and microbiological processes along their path. The yearly nitrate export from the Little Sac River was estimated as 286.8 Mg, and the maximum N load was observed in March. Monitoring of springs and streams is recommended for this environmentally fragile area.

Experimental Analysis of Mass Exchange Across a Heterogeneity Interface: Role of Counter‐Current Transport and Non‐Linear Diffusion

AbstractSolute transport in heterogeneous and fractured systems is a complex process given the permeability contrasts and the time scales discrepancies of transport in high‐permeability versus low‐permeability regions. We studied this phenomenon by injecting a solute (dyed water) in a micromodel comprising a single channel in contact with a porous medium and evaluated the mass exchange across the interface between the channel and porous medium (resembling the interface between free flow and porous media regions). Two sets of transport experiments were performed at three injection rates of 0.01, 0.1, and 1 ml/hr. Injection of dyed water into a clean‐water‐filled micromodel (referred to as the loading process hereafter) and injection of clean water into a dyed‐water‐filled micromodel (referred to as the unloading process hereafter). The dynamics of solute transport was recorded using time‐lapse optical imaging. Our experimental results demonstrated the change of the mass exchange rate coefficient with time and a much smaller transfer rate coefficient during the unloading compared to the loading process. It is proposed that concentration‐dependent counter‐current advection‐diffusion cause slow‐down and further delay in the transport. These results may provide further explanation for the observed slow release of contamination in aquifers.

Hydrogeochemical Data: A Tool for Mapping Aquifer Contamination from Landfill Dumpsites within Owerri Metropolis and Environs Southeastern Nigeria

Groundwater contamination near municipal garbage dumpsites was studied in Owerri, a city in southern Nigeria.The purpose of the study was to map aquifer contamination from landfill dumpsites within the Owerri metropolis and its environment using hydrogeochemical data. Groundwater samples were collected and examined at eight locations near landfill dumpsites. The result of the analysis shows that groundwater from the aquifers of all sampled locations is slightly acidic with an average pH value of 6.25. Bicarbonate, calcium and chloride have average concentrations of 26.19 mg/l, 4.25 mg/l and 0.26 mg/l, respectively. The results also show conductivity and total dissolved solids having an average value of 89.13 mg/l and 53.67 mg/l, respectively. These values fall within the maximum permissible Nigerian standards for drinking water quality and the World Health Standard for Drinking Water Quality. All the parameters did not exceed the NSDWQ (2007) standards except magnesium, which had a mean concentration of 1.16mg/l as opposed to the 0.20mg/l proposed by the Nigerian Standard of Drinking Water Quality. Also, future examination of the water resources within Owerri Metropolis should be done at least every two to three years by the government and relevant agencies to protect the health of people living within this environment.

Geological controls on fluoride contamination of unconfined aquifer in Mahoba district

Geological controls on fluoride contamination of unconfined aquifer in Mahoba district

A review on phyto-remediation by aquatic macrophytes: A natural promising tool for sustainable management of ecosystem

Heavy metal pollution is a significant source of pollution in the environment. Heavy metal contamination in aquifers endangers public health and the freshwater and marine ecosystems. Traditional wastewater treatment methods are mainly expensive, ecologically damaging, ineffective, and take much time. Phyto-remediation is a plant-based technique that gained popularity by discovering heavy metal accumulating plants that can accumulate, transport, and consolidate enormous quantities of certain hazardous contaminants. This is a low-cost sustainable evolving technique featuring long-term utility. Several terrestrial and aquatic vegetation have now been examined for their ability to repair polluted soils and streams. Several submerged plants have already been discovered to remove harmful pollutants such as Zn, As, Cu, Cd, Cr, Pb &amp; Hg. The most important part of effective phyto-remediation is selecting and choosing effective plant species. Aquatic macrophytes have high effectiveness for removing chemical contaminates. Watercress, hydrilla, alligator weed, pennywort, duckweed plants, water hyacinth are examples of aquatic macrophytes. Several macrophytes' metal absorption capability and procedures have now been explored or analyzed. Most of these research demonstrated that macrophytes had bioremediation capability. The bioremediation capability of macrophytes can be increased even more by employing novel bioremediation techniques. To demonstrate the extensive application of phyto-remediation, a comprehensive summary assessment of the usage of macrophytes for phyto-remediation is compiled.

Assessment of Hydrocarbon Pollution in Groundwater Using Electrical Resistivity Method

Hydrocarbon contamination of the groundwater system is a problem facing residents of Ejigbo, Lagos, Southwestern Nigeria. The area hosts the busiest satellite petroleum depots in Nigeria, and residents have attributed pollution of the groundwater system to hydrocarbon spills from possible pipeline leakages. This study aimed to identify and characterize the source and extent of the groundwater system contamination in the study area. The electrical resistivity method was adopted, comprising 2D Electrical resistivity imaging (ERI) and Vertical Electric Sounding (VES) techniques. Data acquired were processed and analyzed to obtain geoelectric sections, longitudinal conductance map and 2D ERI sections for the study area. Three distinct geoelectric zones were delineated, with the intermediate zone identified as the contaminated shallow aquiferous unit. This unit's resistivity values ranged from about 400 - 5000 ohm-m at a depth of 5 - 35 m. On the 2D ERI sections, possible locations of pipeline leakages were identified. On some ERI sections, a linear feature with resistivity value less than 300 ohm-m was observed from the surface down the depth of the entire section, truncating the horizontal flow of the contaminated unit. Generally, the results indicate that the contamination of the shallow aquifer in the area is widespread and mitigation measures should be urgently undertaken.

Denitrification in heterogeneous aquifers: Relevance of spatial variability and performance of homogenized parameters

Nitrate contamination of aquifers is threatening the sustainability of water resource production around the globe. Denitrification is an ubiquitous process in groundwater systems and needs to be represented in managerial and predictive efforts. Yet, fully understanding the temporal and spatial dynamics of all biogeochemical and physical properties controlling nitrate reduction at the basin scale remains a challenging task. Conceptual simplifications such as homogenization are used, but their implications on model performance are often not well assessed. This paper (1) analyzes the importance of denitrification spatial variability on the fate of non-point source nitrate contamination, and (2) assesses the performance of upscaled denitrification rate coefficient values. Heterogeneity in the hydraulic conductivity of a typical unconsolidated alluvial aquifer system and its associated uncertainty is systematically represented in our 3D numerical simulations of flow and transport. The spatial variability in the nitrate reduction capacities of the aquifer is accounted for by 3 different conceptual models: a positive and a negative correlation with the aquifer hydraulic properties and a uniform random distribution. Our results indicate that heterogeneity in the denitrification rate coefficient – as well as the model describing spatial variability – has a significant impact on concentration statistics observed at a series of extraction wells. However, we also show that, under the modeling setting used in this study (e.g., stationarity of reactivity), upscaled values of denitrification rate coefficients allow a virtually perfect reproduction of nitrate concentration statistics, a promising outcome for employing parameter estimation (calibration) of effective rate coefficients of denitrification: A detailed description of the spatial variability of the nitrate reduction capacity of the alluvial aquifer is not necessary. Yet, these homogeneous, upscaled denitrification rate coefficients result from a complex interaction between the biochemistry and the physics of the aquifer, which makes their direct estimation a challenging task.

Direct aerobic oxidation (DAO) of chlorinated aliphatic hydrocarbons: A review of key DAO bacteria, biometabolic pathways and in-situ bioremediation potential.

Contamination of aquifers and vadose zones with chlorinated aliphatic hydrocarbons (CAH) is a world-wide issue. Unlike other reactions, direct aerobic oxidation (DAO) of CAHs does not require growth substrates and avoids the generation of toxic by-products. Here, we critically review the current understanding of chlorinated aliphatic hydrocarbons-DAO and its application in bioreactors and at the field scale. According to reports on chlorinated aliphatic hydrocarbons-DAO bacteria, isolates mainly consisted of Methylobacterium and Proteobacterium. Chlorinated aliphatic hydrocarbons-DAO bacteria are characterized by tolerance to a high concentration of CAHs and highly efficient removal of CAHs. Trans-1,2-dichloroethylene (t-DCE) is easily transformed biomass for bacteria, followed by 1,2-dichloroethane (1,2-DCA), dichloromethane (DCM), vinyl chloride (VC) and cis-1,2-dichloroethylene (c-DCE). Significant differences in the maximum specific growth rates were observed with different CAHs and biometabolic pathways for DCM, 1,2-DCA, VC and c-DCE degradation have been successfully parsed. Detection of the functional genes etnC and etnE is useful for the determination of active VC DAO bacteria. Additionally, DAO bacteria have been successfully applied to CAHs in new types of bioreactors with satisfactory results. To the best of the authors' knowledge, only one study on DAO-CAHs was conducted in-situ and resulted in 99% CAH removal. Lastly, we put forward future development prospect of chlorinated aliphatic hydrocarbons-DAO.

AquaCrop Simulation of Winter Wheat under Different N Management Practices

AquaCrop is a well-known water-oriented crop model. The model has been often used to simulate various crops and the water balance in the field under different irrigation treatments, but studies that relate AquaCrop to fertilization are rare. In this study, the ability of this model to simulate yield and the water balance parameters was investigated in a wheat field under different nitrogen management practices. During the 2015–2016 and 2016–2017 growing seasons, meteorological data were provided from a nearby meteorological station, and the evolution of soil water content and final yields were recorded. The model showed a very good performance at simulating the soil water content evolution in the root zone. Notwithstanding its simplicity, AquaCrop based on a semi-quantitative approach for fertility performed well at the field level for the final yield estimation under different nitrogen treatments and field topography variation. Although the correlation coefficient between simulated and measured final yields was high, increased values of variations were observed in the various zones of this experimental field (−50% to +140%). The model appears to be an efficient tool for evaluating and improving the management practices at the field level. The experiments were conducted in Thessaly, which is the largest plain and the main agricultural area of Greece. Thessaly, however, has a strong negative water balance, which has led to a strong decrease in the level of the aquifer and, at the same time, to sea intrusion. There is also a significant risk of contamination of the groundwater aquifer due to increased use of agrochemicals. This analysis is particularly important for Thessaly due to the need for improvement of agricultural practices in this area, to decrease the pressure of agricultural activities on natural resources (soil, water) and reverse the consequences of current management.

Influence of layered heterogeneity on nitrate enrichment induced by cut-off walls in coastal aquifers

Cut-off walls have proven to be an effective countermeasure for mitigating seawater intrusion (SI). However, construction of cut-off walls may lead to upstream accumulation of nitrate contaminants in coastal aquifers. While stratified geological heterogeneities are widely present in coastal areas, how they may influence nitrate enrichment induced by cut-off walls remains poorly understood. In the present study, we employ variable-density coupling with reactive transport numerical models to understand and quantify the dynamic changes of salinity and NO3− in layered heterogeneous coastal aquifers in the presence of cut-off walls. Our comprehensive simulation results indicate that aquifer heterogeneities are a primary factor in regulating nitrate accumulation. For example, the presence of a middle low-permeability layer between two high-permeability layers reduces the influence of cut-off wall height on SI if the bottom of the wall is placed inside the low-permeability layer. While the thickness of the middle low-permeability layer has a minor impact on SI, a thicker middle low-permeability layer leads significantly aggravated nitrate contamination. Moreover, our simulations reveal that the degree of nitrate accumulation changes non-monotonically with changes in the hydraulic conductivity of low-permeability layer—the total nitrate mass (TNM) first increases and then decreases as the hydraulic conductivity of the low-permeability layer increases. We also found that the impact of heterogeneities is a function of the location and depth of the cut-off wall. With the increases of the distance between wall and the ocean, the nitrate enrichment degree of nitrate pollution in the upstream aquifer decreases while seawater intrudes further in layered aquifer (i.e. case HLH). TNM increases as the wall depth increases, but the growth rates of TNM becomes lower when the bottom of the wall is placed inside the low-permeability layer. These quantitative analyses have critical implications for the planning and design of cut-off walls to effectively control SI while at the same mitigating nitrate pollution.

Fertilizer potential of slurry from intensive dairy cattle farms in Intensive production forestry systems

Intensive dairy cattle breeding has a relevant social and economic impact in Portugal, particularly in the northern region. This activity generates a high flow of livestock effluents (slurry), rich in important nutrients for plant growth, which can be introduced into intensive production forestry systems. These effluents can provide a good alternative to mineral fertilizers, not only from an economic perspective but, particularly, from the point of view of environmental protection. In the present study, the effect of increasing doses of slurry on tree growth, either with or without mycorrhizal arbuscular fungi (AMF) and plant growth-promoting bacteria (PGPB) inoculation, was evaluated in clones of Paulownia CoT2 and Populus i214, as they are genotypes that have a high efficiency in the mobilization of soil nutrients (namely N) and in the capture of CO2 from the atmosphere, as well as high biomass calorific value. For this purpose, a demonstration field trial was installed, occupying an area of 14,607 m2, where the trees were planted with the compasses of: 2.5 x 1.5 m and 2.5 x 0.75 m, respectively for Paulownia and for Poplar. Prior to transplantation to the field, some plants were inoculated with AMF and PGPB. In the field, the following treatments were performed: T0 - no fertilization, either mineral or organic; T1 - amount of slurry equivalent to 85 kg of N ha-1; T2 - amount of slurry equivalent to 170 kg of N ha-1; T3 - amount of slurry equivalent to 340 kg of N ha-1, both with and without inoculation. Results revealed a significant and positive effect of the slurry application, both in the diameter at breast height (DBH) and total stand height (TH), showing its high fertilizing potential, and, on the other hand, there was no increased contamination by nitrates and by pathogenic microorganism in the leachates for the experimental doses of slurry. Therefore, we can conclude that, under the experimental conditions, the slurry resulting from the intensive exploitation of cattle constitutes an alternative to exclusively mineral fertilization in intensive production forestry systems, either by increasing the production of biomass or by the absence of contamination of aquifers by nitrates and pathogens.