Hydrogeochemistry - Science topic

Software such as SOLVEQ-XPT, RTest and GeoT.

Application of machine learning or other free AI tools in hydrogeochemistry

Dears

I have some questions aboout Mineral Exploration using hydrogeochemistry, maybe..

How do you use physico-chemical parameters (Trace elements, TDS, pH, othes) of Surface and ground waters in Mineral Exploration?

What do you considerate when you use the statistical analysis of your data? Maybe, do you separate your data in different groups? What do you considerate to separate your data (lithology, location in the catchment area, parameters of contaminación, others)?

Thanks for your advices ando comments.

JC

The packed bed column (H = 2m) is filled with alternate soil (coarse) and sand samples. I want to study the residence time of my target compound but before that I require a tracer to monitor the flow for calculating the HRT. What are the suitable tracers available that are cost effective as well as inert (should not interact and adsorb on soil and sand)?

Many open source programs exist in the field of geology with all its specializa (Water resources , hydrology , Hydrogeology, Geostatistics ,Quality water .......etc) that many people are unaware of.

What software do you want to suggest to us ?

Thanks

Reghais Azzeddine

Please, can you suggest a high graphical resolution software for creating hydrogeochemical graphs, especially for Gibb's diagrams?

Dear all!

i am highly interested in contributing "book chapter section" for hydrogeochemistry or groundwater quality studies, particularly around upper Blue Nile or the whole Nile Basin. Can anyone tell me if there are such calls available?

thanks in advance !!!

I am currently working on quantitative data by applying standard indexes and models to evaluate the potential health risk. So, in that regard, your suggestions will be helpful to calculate the "groundwater threshold values".

I am currently working on my paper on hydrogeochemistry. I would like to ask for any reference material regarding the accepted charge balance error for groundwater chemistry (major ions). We conducted a groundwater study in 2019 and planning to publish a paper. However, I got confused about the Charge balance error. I have read that it should not be more than +-5%. These water samples were actually sent to the commercial laboratory available in our region. However, some of these data are more than 10% error. Out of 60 samples, 30 will be eliminated bcos of this. Can I consider samples with <10% error? Any available reference that I can use for this? Thank you so much! Your inputs will be of big help!

Hello,

Please, are you aware about any research that has used classical hydrologeochemical methods to delineate seawater intrusion in an area where halite dissolution is one of the most important processes affecting groundwater mineralization?

Based on the literature I read, generally we use some ions ratios such as Na and Cl, and generally researchers consider Cl to be conservative and originating from seawater intrusion. However, I guess this would not work, since chloride and sodium do not come only from seawater, but also from halite dissolution

Thank you in advance!

Sincerely,

Mohamed Ouarani

Is there free software that you can recommend for this?

I am using the chloro-alkaline indices, but I don’t know if it is the right way.

We have a hydrogeological setting of triassic layers, which are characterised by a ground water flow and mixing system. We tried to separate the sources of the groundwater flow and mixing system via hydrochemistry (ions), isotopes (deuterium, oxygen-18, tritium, carbon-14, strontium-isoptopes and sulphur isotopes), and still is not enough information to understand fully the hydrogeological regime. Which could be other approaches or tracers to separate the different aged components ?

I'm looking for good tips on high impact factor journals related to karst hydrogeology and its related topics, such as contamination, pumping tests, etc. Any good lists?

Hi all,

I'm gonna study the impacts of the rise of production wells numbers (for irrigation purpose), LU/LC changes on the groundwater in a flat area where  river branch, main canal and many irrigation and drainage canals run through. The main aquifer in this area is recharged from the surface water (i.e. river branch, main canals, and irrigation and drainage canals) and the infiltration of excess irrigation water. The aquifer is semi-confined to phreatic (leaky aquifer). In addition, it is highly conductive with hydraulic conductivity ranging from 80 to 100 m /day, that is because it consists mainly of sand and gravels with clay lenses. Unfortunately, there is no a systematic monitoring for the water level, water chemistry or actual management for this aquifer. There are too many research works in different ways (e.g. geologic, hydrogeology, hydrogeochemistry,..etc.) have been done. There is no actual estimation for recharge quantity, monitoring for the impact of the anthropogonic activities on this aquifer. I have studied some samples from  3 wells, 2 shallow wells (25 m deep and 2.5 inches diameter) and one deep (65 m deep and 8 inches diameter). One of the two shallows is hand pump tube well and located close to the urban area (in agricultural land) with peizometric level, 10.4 m  and nitrate concentration, 6 ppm. And the second shallow well is being pumping using pump machine and located in urban area, north east the first shallow well with approximately distance 1 km long, with peizometric level of 10.3 m and nitrate concentration, 100 ppm. The deep well (the third one) is located north the second shallow well with distance 1 km long, peizometric level is 10.3 m and nitrate concentration is 3 ppm, which located at agricultural land. The second shallow well and the deeper one are both located close to drain canal with its nitrate concentration not more than 40 ppm as literature's result . I believed that the highly pumping rate is the main factor that gives the high nitrate value for the second shallow well. I really need to study the large area with many urban areas surrounded by agricultural lands, and find out the pollutions anomalies. I will measure CFCs as indicator of the recent recharge, GMS model to simulate the nitrate transport and the future prediction of its concentration, main ions, N15  to find the source of the nitrate and total coliforms . I really interested to find a valuable solutions for such problem. So if some one interested to help me in such study or give me advises, ideas and recommendations to how can I study the nitrate pollution anomaly, estimate and quantify the groundwater recharge, and study the impacts of the high density of wells (for irrigation purpose) on the quality and quantity of the groundwater in this area, I will be greatly appreciate.

If we assume that in the water (porewater) the 222Rn is coming only from the 226Ra in the sediment, how is the relation that can I use to calculate the quantity of 222Rn in water coming from the 226Ra in sediments?

I am sure that I can not simply assume that all the 226Ra in the measured sediments will become 222Rn in porewater, but I think there are many factors influencing the relation between them (maybe the salinity ? recoil effect?? )

Can you suggest me some papers or arguments for understand which formula use and which are the influencing parameters of this process?

Many thanks.

I measured 222Rn in groundwater and I found more Radon near vulcanic sediments and/or near areas with intense agriculture. So I suppose that the sources of Radon are some lithologies (flux diffusive from sediments), or could be discharging water coming from pollutted areas or not (in groundwater the Radon is always more than in surface water -because is a gas-) etc. Can you suggest me other sources of Radon in groundwater?

Thank you.

Researchers in hydrogeology, hydrogeochemistry, environmental geology

Multi-phase flows in subsurface media, how is it related to Reservoir Geochemistry?

Is it straining ? what will happen when Dp/Dg < 0.008 ? 

I'm looking for codes that can do this for saturated and/or unsaturated porous media. I expect there are a few that can handle the porosity changes easily, but predicting permeability changes seems much more complicated.

I wish to differentiate the contribution of evaporation and seawater intrusion in the groundwater salinity (coastal aquifer), arid/semi-arid region using groundwater quality data. I don't have isotope data. any good recommendation/suggestions?

Hydrogeochemistry

Groundwater pollution by nutrients is one of the problems in the world. A lot of research have been done about the influence of nitrates on water quality, but understanding how the chemistry phosphate in groundwater is influenced by lithology is important.

On the field, we measured pH and alkalinity. From these parameters, I back-calculated the concentration of dissolved CO₂ in my samples. They vary between 12 and 23 mg/l (10^-2 atm).

The lab also provides us with the concentrations of dissolved CO₂ 10 times higher than those calculated from field parameters (180-230 mg/l - 10^-1 atm. I was expecting to have my samples degassed.

The samples come from a shallow semi-confined to confined Quaternary aquifer (depth of sampling between 25 and 60 m).

I cannot make any sense of it. Any thoughts would be greatly appreciated. Thanks

Hi everyone, my question is for GIS expert. I am working on hydrogeochemistry of Sikkim Himalayas. Therefore I am trying to prepare the interpolation map of this area. Due to undulating topography, the normal interpolation will not be physible. Can I introduce the elevation information into it? How to introduce the elevation information into the interpolation?

Please help.

A year ago, I collected brackish and saline groundwater samples and measured main ions. Unfortunately, calcium and potassium gave wrong measurments. After a year, I repeated the measurments in the same groundwater samples. Variations in anion concentrations (Cl and SO4) and cations (Mg) are practically negligible (Cl and SO4) but Na+ varied significantlly, with 3 times the concentrations mesured a year ago, particularly in those sample whose salinities are the lowest. The calibration curves of the IC and the standards are corrected. I must comment that samples have been maipulated several times. I would greatly appreciate any explanation. Thanks in advance.

Hi, everyone.

I have a data matrix of 650 cases (sites of groundwater sampling) and 19 physicochemical variables. I'm trying to group the sites on the basis of their similarities and thereby being able to propose a monitoring network containing only the representative sites of each group. For what I've read in some articles, It would be good to perform a Cluster Analysis (CA) and a Principal Components Analysis (PCA), do you think so?

In the other hand, I've done the CA with the software Statistica, but I encounter the problem that I have so many cases (650) to interpret the dendogram and also the amalgamation matrix. So I could not group my data by this way.

Does anyone know how could I deal with the issue of the great number of cases to perform these multivariate analyzes? (articles, tutorials, software) 

Thank you very much.

Kind regards.

To qualify the contribution of three end-members (seawater, groundwater and treated wastewater, whose concentrations are known) in the aquifer system, I used Cl and Br as tracers in a mass-balance equation.To confirm the end-members, I applied eigenanalysis (PCA) and the plot between the two tracers. From the plot, half of the samples fell within the mixing “envelope” defined by the end-members. The other half were forced based on some calculations.

Questions:

1. Is the mixing ratio of these two chemical species enough? I am aware it can be several end-members, but I have particular interest to estimate the fraction of these end-members. 

2. Shall I exclude the outliers?

Thank you in advance for your help

The pH would not be a good indicator as the bog water first flows along a 5 km mineral bedded stream and becomes more alkaline (from pH ~3 to ~ 5-6) before point-infiltrating into the karst system.

The method should be affordable to be carried out on monthly basis for few to tens of samples in the framework of a low-budget phd project.

My purpose is to adjust the pH of DI-water (after it gets acidic because of CO2-equilibrium) and then use it as a solvent for a salt solution. It is important that this solution's conductivity is mainly determined by the salt i solve into it and not by the buffer.

Any precious hints? (desired pH is around 7 at the time, but real goal is to be able to move it "freely" in the 5-to-9 range).

Thanks a lot in advance!

When it come to batch dissolution experiment (for water-rock interaction study), most authors have selected igneous rocks, sedimentary rocks and minerals formed under igneous conditions. Is there any special reason for that? Is there any article for the same experiment where metamorphic rocks were used?

Thank you

 When I want to analysis the recharge rate  between groundwater and surface water, I found that the  river has a  very irregular stream bank,  how to calculate it ? 

I'm interested in knowing the main compostitional and chemical features (e.g. organic matter content, main oxides and heavy metals, etc) of the Quaternary sequences which host the GW resources in Po Plain sector

I want to apply univariate and bivariate spectral analysis in order to study the hydrogeological system (springs).

I am looking at the availability of Principal Component Analysis for hydrogeochemical data sets displayed as time series and I would like to know your opinions .

In the isotope hydrogeology the critical depth of soil is reached if the isotope variability in the recharge waters is below the analytical precision (2 sigma). Is there any fixed value assigned to the anylytical precision (e.g. 2 per mille or 0.5 per mille)?

My field is groundwater hydrogeochemisty. I know the protocol for ground water sampling. But I have doubt about Uranium analysis in groundwater samples. Is there any special (specified) protocol we want follow for U analysis in groundwater? 

I would like to have opinions about the dominant geochemical factors that control NO3 mobility in the unsaturated zone (soil, subsoil and unsaturated bedrock). Relative literature refers only to anion adsorption in positively charged mineral surfaces (pH dependent) and/or reduction under anoxic saturated soil conditions with ample organic matter. Are there any other geochemical (and not biologically mediated) processes that control NO3 fate and transport within the vadose zone?

The oxygen and hydrogen isotope analysis and the value of DELTA O18 and delta H2 and other significant isotopes. Moreover comparison with other gulf countries.

Based on my experiences, there are three essential

conditions for the reliability of measurement results for naturally occurring water

samples:

1. Sampling: Water samples should be free from suspended matter/sediments. They

should be filtered before collection and their preservation. For preservation of

water samples, they should be acidified with AR nitric acid to pH-1.

2. For un-acidified water samples, the time interval between water collection and

analysis should occur on the same day.

3. Regarding the methodology adopted for uranium analysis, a choice of an appropriate fluorescence-enhancing reagent for different types of sample matrices is essential. Moreover, there are different methods of uranium analysis by laser induced fluorimetry depending on the sample matrix.

Moreover, there are other important parameters also, such as uranium/conductance ratio,

pH, total alkalinity/salinity values, the major, minor and trace elements present in hydro-geochemical samples play a major role in characterizing the strata given below the water table.The presence of fluoride may significantly affect the changes in uranium content.

The reliability/quality of measurement results of water samples depends on strict adherence to each step of sampling, preservation of samples, time-interval between sampling and analysis for filtered but un-acidified water samples, and on the methodology adopted, and not simply analyzed by any person or lab or any technique.

Especially, biogeochemistry or hydrogeochemistry in pore water of marine core deposite!

For my Master´s degree course in sedimentology the Dakar Canyon is my topic and I would like to read some interesting papers about this issue.

.

Hi, 

I am looking for an expert(s) in the application of machine learning methods to geoscientific issues and especially aquifer vulnerability. The purpose of this, is collaboration in a pdoc research i am conducting, co-authoring in papers and potential partnership in proposal submissions for project calls relevant to this field.

I want to simulate the interaction of an aquifer and Urmia salt lake in Iran. What type of software may be appropriate for these purposes? SEAWAT, SUTRA, HYDRUS, etc? I would like to hear all your suggestions.

Hydro-geochemical exploration of hidden uranium bodies is often based on redox conditions and speciation to determine U mobility. We propose here a pure multi-variate analysis model to identify water types and the corresponding mixing model. I am currently working on coupling the two approaches as redox fronts can be identified from factor maps. Any opinion, experience or work welcome to foster discussion, what would be your suggestions to help me move forward ?

I need to generate thermodynamic stability diagrams (log (aMg/aH) vs. log H4SiO4, log (aCa/aH) vs. H4SiO4 etc.) based on groundwater chemical samples to find out the stability fields of dissolution.

I am referring to an old work, but I guess most of the multivariate analysis techniques implemented and software systems developed could be usefully be re-adapted to modern software environments. Does anyone have knowledge of such work being performed ? Does anyone know of such techniques being in used in the mining / prospecting industry today ?

To help foster the discussion, I have added a paper in English published In book: Use of Microcomputers in Geology, Edition: Print ISBN 978-1-4899-2337-0, Chapter: 3, Publisher: Plenum Publishing Corporation - Springer Science+Business Media New York 1992, Editors: Hans-Kürzl and Daniel F. Merriam, pp.25-71

No DIS File specified is the error that appears when I attempt to run MODFLOW2000, I would like to know if this is an error that would be specific to a model because I have used MODFLOW2000 on other models and have not had this issue.

I am planing to study water-rock interaction in order to observe the element dissolution and weathering rate as a laboratory experiment. However, it won't be a flow system. So, are there any specific guidelines to set up this experiment? Should I use ground rock or as lumps (block). Most authors have mentioned their methods where ground rocks had been used. Please suggest me some more articles as well.

I am trying to do dissolution calculations for these polymorphs.

I am building a MODFLOW model in Groundwater VIstas and I have yet to find an efficient way of importing the rivers and streams into the model. I would like to directly extract the elevation from a DEM along the riverds in order to import into GWV.

Which parameters of soil, water or sediment will give clear indication of source of chromium in water?

I have problems with DOC TOC measurments with EPS. I follow the standard method to prepare the samples and use a DOC analyser. But results vary with a very high SD. Can someone help here or suggest alternate method to measure the same?

Many people I talk to would agree that the "quality" of carbon decreases with depth/age/distance from the surface. Quality here means essentially "ease of (bio)degradation". However, I find it hard to come up with references supporting this impression/concept/belief, apart from e.g. Pedersen et al. (2008) or Pabich et al. (2001; but only down to 40 m), DOC with depth:

McMahon, P.B., Böhlke, J.K., and Lehman, T.M., 2004, Vertical Gradients in Water Chemistry and Age in the Southern High Plains Aquifer, Texas, 2002: U.S. Geological Survey Scientific Investigations Report 2004-5053, 53 p.http://pubs.usgs.gov/sir/2004/5053/pdf/McMahon508.book.pdf. Is anyone aware of data linking e.g. BDOC (biodegradable dissolved organic carbon), or AOC (assimilable organic carbon), or proportion of high molecular weight humics with depth/groundwater age? It's one of these concepts that seems so obvious that you can claim it without even having to provide a reference, but is it actually true?

I have measured values of ORP (mv), pH and arsenic from groundwater samples.

Could anyone help me with the calculation of Si for groundwater?

Values of free molecular diffusion coefficients in water needed. Necessary for the calculation of the retardation factor Rf of the arsenic anions in the soil.

High temperature (upto 30 to 37 degree centigrade) is being observed in pumped groundwater from the aquifer under the city of Lahore (Pakistan). According to test drilling in the area in 1960s, alluvium was found till depths of about 1000 ft except at two of the places where hard materials were touched. No other geological reference with evidence leading to possibility of any geo-thermal activity has been observed or found in literature. What are the possible reasons for this high temperature groundwater?

SUGISAKI R. and TAKI K. (1987) Simplified analyses of He, Ne and Ar dissolved in natural water. Chemical J. 21, 21-23

I am trying to find out if the iron that is coloring my calcite is divalent or trivalent in order to asses the likelihood of it precipitating in anoxic conditions.