05_01_Intro_Hidroquimica.pdf

Ingeniería Ambiental 2019 HIDROGEOLOGÍA MSc. Jorge Zafra Cordova Profesor del Curso de Hidrogeología [email protected]  Hidrogeología MSc.MInSgc.IJnog.rgJoergZeaZfarafraCCoorrddoovvaa  Hidrogeología Hydrochemistry Fundamentals of Aquati...

Ingeniería Ambiental 2019 HIDROGEOLOGÍA MSc. Jorge Zafra Cordova Profesor del Curso de Hidrogeología [email protected]  Hidrogeología MSc.MInSgc.IJnog.rgJoergZeaZfarafraCCoorrddoovvaa  Hidrogeología Hydrochemistry Fundamentals of Aquatic Chemistry Importance of water for humans Water withdrawal Important properties of water Anomalies of water Molecule of water Hydrogen bonds The hydrologic cycle Aquatic life Main aquatic chemical processes MSc. Ing. Jorge Zafra Cordova  Hidrogeología MAJOR AQUATIC CHEMICAL PROCESSES MSc. Ing. Jorge Zafra Cordova  Hidrogeología CHEMICAL COMPOSITION OF NATURAL WATERS Dissolved gases – O2, CO2, H2S, CH4, etc Main ions – HCO 3-, CO 32-, Cl-, SO 2- 4 , Na , K , + + Mg2+, Ca2+. Biogenic elements – N, P, Si, Fe Microelements – Mn, Cu, Zn, Co, Mo (biometals), Ni, Cr, Cd, Pb, Hg, F- and others (inorganical industrial pollutants) Organical compounds - Organic carbon, amines, aminoacids, proteins, humic and fulvoacids, oils, carbonyl compounds, organic acids, pesticides, synthetic detergents, etc. MSc. Ing. Jorge Zafra Cordova  Hidrogeología OXYGEN IN WATER Oxygen: Comes from the atmosphere Is produced by photosynthetic action of algae Oxygen is consumed: At night when the algae consume oxygen as part of their metabolic processes Metabolic processes of other organisms Degradation of biomass Biodegradation of pollutants MSc. Ing. Jorge Zafra Cordova  Hidrogeología CARBON DIOXIDE IN WATER Carbon dioxide (CO2) is the most important weak acid in water. Algae in water utilize dissolved CO2 in the synthesis of biomass. High concentrations of free carbon dioxide in water may adversely affect respiration and gas exchange of aquatic animals. It may even cause death and should not exceed levels of 25 mg/L in water. Carbon Dioxide comes to water: From the atmosphere CO2(water)  CO2(atmosphere) From solid carbonate minerals MCO3(slightly soluble carbonate salt)  M2+ + CO 32- As a product of metabolic processes. When water seeps through layers of decaying organic matter. When water infiltrates the ground, it may dissolve a great deal of CO2 produced by the respiration of organisms in the soil. MSc. Ing. Jorge Zafra Cordova  Hidrogeología METALS IN WATER Metal ions in water solution are present in forms such as the hydrated metal cation M(H2O)x n+. Metal ions in aqueous solution seek to reach a state of maximum stability through chemical reactions including acid-base: Fe(H2O)63+ ↔ FeOH(H2O)52+ + H+ Precipitation: Fe(H2O)63+ ↔ Fe(OH)3 (s) + 3H2O + 3H + And oxidation - reduction reactions: Fe(H2O)6 ↔ Fe(OH)3 (s) + 3H2O + e- +3H 2+ + MSc. Ing. Jorge Zafra Cordova  Hidrogeología MSc. Ing. Jorge Zafra Cordova  Hidrogeología MSc. Ing. Jorge Zafra Cordova  Hidrogeología MSc. Ing. Jorge Zafra Cordova  Hidrogeología MSc. Ing. Jorge Zafra Cordova  Hidrogeología CHEMICAL CONTENT OF SURFACE WATERS Ingredient Content Dissolved Oxigen 0 – 15 mg/l H2S - pH 6.8 – 8.5 pH (swamps) 4.5 – 5 Main ions Mg2+ 0.5 – 50 mg/l Na+ + K+ 1 – 75 mg/l Ca2+ 10 – 120 mg/l Cl- 5 – 80 mg/l SO42- 2 – 120 mg/l HCO3- 10 – 250 mg/l MSc. Ing. Jorge Zafra Cordova  Hidrogeología CHEMICAL CONTENT OF SURFACE WATERS Ingredient Content, mg/l Biogenic elements Total Fe 0.01 – 2 Total Si 1 – 10 Organic phosphorus 0.01 – 0.2 Inorganic phosphorus 0.01 – 0.5 Organic nitrogen 0.2 – 2 NO3- 0–2 NO2- 0 – 0.5 NH4+ +NH3 0.02 – 1.5 MSc. Ing. Jorge Zafra Cordova  Hidrogeología CHEMICAL CONTENT OF SURFACE WATERS Ingredient Content, mg/l Microelements – industrial pollutants Cd ≤ 0.0001 Pb 0.0001 – 0.005 Cr 0.0001 – 0.005 0.0005 – 0.01 Ni Microelements - biometals Co 0.0001 – 0.005 Mo 0.0005 – 0.01 Cu 0.002 – 0.05 Zn 0.003 – 0.10 Mn 0.002 - 1 MSc. Ing. Jorge Zafra Cordova  Hidrogeología CHEMICAL CONTENT OF SURFACE WATERS Ingredient Content, mg/l Organic compounds Carbonyl compounds 0.02 – 2 Esters 0.05 – 8 Organic acids 0.5 – 15 Carbohydrates 0.01 – 2 Saccharides 0.05 – 2 Amines 0.03 – 3 Aminoacids 0.004 – 5 Proteins 0.02 – 5 Fulvic acids 0.5 – 10 Humic acids 0.02 - 2 MSc. Ing. Jorge Zafra Cordova  Hidrogeología MAXIMUM PERMISSIBLE CONCENTRATIONS (MPC) FOR SURFACE WATER, LOW 296/2005 SK MSc. Ing. Jorge Zafra Cordova  Hidrogeología WATER FROM PRECIPITATION In the composition of the precipitation in natural conditions the hydrocarbonic ions predominate and the interrelation between the basic ions is: HCO - > SO 2- > NO - > Cl- > NH + > Na+ > Ca2+ > Mg2+ 3 4 3 4 Precipitation that falls through forest vegetation changes their chemical composition and pH, and then directly affects river water. On the other hand a great amount of precipitation forms high waters, which reduce the total number of the contained hydrochemical elements. MSc. Ing. Jorge Zafra Cordova  Hidrogeología Hydrochemistry Groundwater and seawater Groundwater Mineral water, its classification Artesian water Connate water Geothermal water Seawater MSc. Ing. Jorge Zafra Cordova  Hidrogeología GROUNDWATER Groundwater is the water found in the spaces between soil particles and cracks in rocks underground. Ground water is an important part of the water cycle. Ground water is the part of precipitation that seeps down through the soil until it reaches rock material that is saturated with water. Groundwater represents the largest single source of freshwater in the hydrological cycle (about 95% globally) MSc. Ing. Jorge Zafra Cordova  Hidrogeología GROUNDWATER The term groundwater includes: Mineral Water Artesian Water Connate Water Geothermal Water MSc. Ing. Jorge Zafra Cordova  Hidrogeología MINERAL WATER Must contain no less than 250 parts per million (ppm) total dissolved solids (TDS) with the solids being the minerals in the water Must come from a geologically and physically protected underground water source Is distinguished from other types of water by the regular mineral and trace elements present No minerals may be added to this water MSc. Ing. Jorge Zafra Cordova  Hidrogeología MINERAL WATER CLASSIFICATIONS CO2 concentration – 0.5 – 1.4 g/l – low-carbon water 1.4 – 2.5 g/l – carbonated water > 2.5 g/l – high-carbon water H2S concentration – 10 – 50 mg/l – low sulphide 50 – 100 mg/l – Moderately sulphide 100 – 250 mg/l – high sulphide > 250 mg/l very high sulphide MSc. Ing. Jorge Zafra Cordova  Hidrogeología MINERAL WATER CLASSIFICATIONS pH – 3 – 3.5 – high acid water 3.5 – 5.5 – acid water 5.5 – 6.8 – low acid water 6.8 – 7.2 – neutral water 7.2 – 8.5 – low alkaline water > 8.5 – alkaline water Temperature – ≤ 20 °C – cold 20 – 35°C – warm 35 – 42°C – hot, thermal > 42°C very hot MSc. Ing. Jorge Zafra Cordova  Hidrogeología ARTESIAN WATER Artesian water is groundwater that flows freely upwards out of an artesian bore or well. From a well in a confined aquifer. Water level in well must be at a higher elevation than the top of the aquifer. May also be known as "artesian well water“. Artesian water may also be relatively highly mineralized, owing to the long travel time, and contain gases and dissolved iron, which may precipitate on the surface. MSc. Ing. Jorge Zafra Cordova  Hidrogeología CONNATE WATER Because of its long contact with rock material, connate water can change chemical composition throughout the history of the rock and become highly mineralized. Connate water can be more dense and saline compared with seawater; connate water salinities can range from 20 to more than 300 grams per liter. MSc. Ing. Jorge Zafra Cordova  Hidrogeología GEOCHEMICAL COMPOSITION OF CONNATE WATER MSc. Ing. Jorge Zafra Cordova  Hidrogeología GEOTHERMAL WATER Geothermal water has a temperature appreciably higher than that of the local average annual air temperature. In general, a spring is considered hot when its temperature is about 12.2 °C higher than mean annual ambient temperature. The relative terms geothermal water, warm springs, and hot springs are common. MSc. Ing. Jorge Zafra Cordova  Hidrogeología OCEAN AND SEAWATER Earth’s Water The ocean holds 98% of the 1.4 billion cubic 3.5 % kilometers of water on the planet Seawater ranges in salinity, but a useful 96.5 % approximation is 35 Oceans Other g/kg; or 35 parts per thousand or 3.5% MSc. Ing. Jorge Zafra Cordova  Hidrogeología MSc. Ing. Jorge Zafra Cordova  Hidrogeología CHEMICAL CONTENT OF SEAWATER Ingredient Content, gr/kg Main ions Cl- 19.353 SO42- 2.712 HCO3- 0.142 Br- 0.067 Mg2+ 1.294 Ca2+ 0.413 K+ 0.387 Na+ 10.76 Sr2+ 0.008 MSc. Ing. Jorge Zafra Cordova  Hidrogeología MICROELEMENTS IN SEAWATER MSc. Ing. Jorge Zafra Cordova  Hidrogeología Hydrochemistry Water pollutions and wastewater Sources of water pollution Wastewater Content and properties of waste water Chemical pollutant limitations Wastewater treatment MSc. Ing. Jorge Zafra Cordova  Hidrogeología SOURCES OF WATER POLLUTION Industrial Municipal Agricultural Natural (animal, vegetable, soil) Stormwater (garbage, soil runoff, spills) Landfill Underground storage tank MSc. Ing. Jorge Zafra Cordova  Hidrogeología WASTEWATER The wastewater can contain physical, chemical and biological pollutants in any form or quantity and cannot adequately be estimated without actual measuring and testing. The wastewater will either be discharged directly into a receiving body of water or into the sewerage system of a municipality, or it will be reused or recycled. MSc. Ing. Jorge Zafra Cordova  Hidrogeología THE COMMONLY DETERMINED PHYSICAL PROPERTIES OF WATER Colour Residue (solids) Temperature Turbidity Density Transparency Taste Odour Specific conductance Redox potential MSc. Ing. Jorge Zafra Cordova  Hidrogeología DETERMINATION OF PHYSICAL PROPERTIES OF WATER Temperature is measured during sampling because solubility of different substances, especially gases, depends on it. For measurement accurate thermometer is used. Density depends on concentration of dissolved compounds and dredges as well as temperature. Density is determined by gravimetric method using densimeter (g/cm3) at 20.0 ± 0.5°C Transparency depends on colour and turbidity. For determination visual method is used. Natural waters are usually colourless. Colour of water is caused by colourful humic compounds and iron (III) compounds. For determination visual method or comparison with standard are used. MSc. Ing. Jorge Zafra Cordova  Hidrogeología DETERMINATION OF PHYSICAL PROPERTIES OF WATER Turbidity in water is measured by the effect of the fine suspended particles on a light beam. Light-interference analytical methods are classified as nephelometric, and one system of turbidity measurement uses nephelometric turbidity units. Taste depends on presence of natural substances or pollutants in water. Taste is determined only in drinking waters. Odour of water is caused by volatile organic matters. Drinking and industrial waters should have no smell. Firstly character of smell is determined and then intensity of smell. Method for determination is organoleptic. MSc. Ing. Jorge Zafra Cordova  Hidrogeología CONTENT OF SOLUBLE AND INSOLUBLE COMPOUNDS Solid matter occurs in most waters as suspended solids and colloidal matter. The concentration of suspended solids is determined by filtration, the collected solids on the filter membrane being dried and weighed. Those suspended solids which are large and heavy are called settleable solids, and these may be determined volumetrically in a settling cone as a simple control test or weighed. The solids remaining with supernatant water above the settled matter are fine and called turbidity. For the removal of colloidal materials from water when they exceed acceptable concentration limits adsorbents are used. Many of the heavy metals are present in colloidal form and are removed from water by coagulation, filtration, adsorption, or a combination of these methods. MSc. Ing. Jorge Zafra Cordova  Hidrogeología REDOX POTENTIAL Eh a measure of the number of electrons in solution is the redox potential of an aqueous solution Redox potential of natural waters depends on dissolved gases and should be determined on the place of sampling For measurement platinum and silver chloride electrodes are used Calculated with the Nernst equation MSc. Ing. Jorge Zafra Cordova  Hidrogeología ELECTRICAL CONDUCTIVITY The concentration of total dissolved solids (TDS) is related to electrical conductivity (EC; mhos/cm) or specific conductance. The conductivity shows the capacity of water to transmit electrical current. TDS and conductivity affect the water sample and the solubility of slightly soluble compounds and gases in water (e.g. CaCO3, and O2). MSc. Ing. Jorge Zafra Cordova  Hidrogeología Hydrochemistry Individual indexes for determination of chemical content of water (Part I) pН and рОН Dissolved oxygen Hydrogen sulfide and sulfides Acidity and alkalinity Components of carbonate system Chlorides and sulphates Hardness of water Potassium and sodium Calcium and magnesium MSc. Ing. Jorge Zafra Cordova  Hidrogeología INDIVIDUAL INDEXES FOR DETERMINATION OF CHEMICAL CONTENT OF WATER MSc. Ing. Jorge Zafra Cordova  Hidrogeología рН and рОН Determination of pH is measurement of hydrogen ion activity in aqueous solution: The hydrogen ion concentration can be measured with a pH meter with glass electrode. It can also be titrated when the concentration becomes high enough to be detectable by chemical analysis. Since pH is a logarithmic function, the hydrogen ion concentration increases by a factor of 10 for each unit of pH reduction. Determination is performed right after sampling without preservation. MSc. Ing. Jorge Zafra Cordova  Hidrogeología WATER ALKALINITY The capacity of water to accept H+ ions (protons) is called alkalinity. Alkalinity is important in water treatment and in the chemistry and biology of natural waters. Frequently, the alkalinity of water must be known to calculate the quantities of chemicals to be added in treating the water. Highly alkaline water often has a high pH and generally contains elevated levels of dissolved solids. It is important to distinguish between high basicity, manifested by an elevated pH, and high alkalinity, the capacity to accept H+. Whereas pH is an intensity factor, alkalinity is a capacity factor In engineering terms, alkalinity frequently is expressed in units of mg/L of CaCO3, based upon the following acid- neutralizing reaction: CaCO3 + 2H+ →Ca2+ + CO2 + H2O MSc. Ing. Jorge Zafra Cordova  Hidrogeología DETERMINATION OF ALKALINITY Phenolphthalein alkalinity - titration with acid to the pH at which HCO 3- is the predominant carbonate species (pH 8.3) Total alkalinity - titration with acid to the methyl orange endpoint (pH 4.3), where both bicarbonate and carbonate species have been converted to CO2. Hydroxide alkalinity - precipitation of carbonate with BaCl2, titration with standard acid to phenolphthalein endpoint. BaCl2 + CO 2- 3 = BaCO3 + 2Cl - Preservation for determination of all kinds of alkalinity is keeping sample cool MSc. Ing. Jorge Zafra Cordova  Hidrogeología WATER ACIDITY Acidity as applied to natural water and wastewater is the capacity of the water to neutralize OH-. Acidity results from the presence of: Weak acids, particularly CO2 Sometimes , proteins, and fatty acids Acidic metal ions, particularly Fe3+ MSc. Ing. Jorge Zafra Cordova  Hidrogeología DETERMINATION OF ACIDITY Total acidity - titration with standard base to phenolphthalein endpoint Free mineral acidity - Titration with standard base to methyl orange endpoint, or potentiometric to pH 4.5 Preservation for determination of all kinds of acidity is keeping sample cool MSc. Ing. Jorge Zafra Cordova  Hidrogeología DISTRIBUTION OF SPECIES DIAGRAM FOR THE CO2 HCO-3 CO2- 3 SYSTEM MSc. Ing. Jorge Zafra Cordova  Hidrogeología HARDNESS OF WATER Hardness is correlated with TDS (Total dissolved solids). It represents total concentration of Ca2+ and Mg2+ ions, and is reported in equivalent CaCO3. Determination: calculated from the results of separate calcium and magnesium tests titration with ethylenediaminetetracetic acid (EDTA) MSc. Ing. Jorge Zafra Cordova  Hidrogeología RELATION BETWEEN HARDNESS CONCENTRATION AND CLASSIFICATION OF NATURAL WATER Hardness as mg/L CaCO3 Classification 0 – 60 Soft 61 – 120 Moderately hard 121 – 180 Hard >180 Very hard MSc. Ing. Jorge Zafra Cordova  Hidrogeología ORGANIC COMPOUNDS IN WATER Organic compounds are derived from: living organism domestic use agricultural applications industrial sources: ❖ chemical industrie ❖ petrochemical industrie Organic compounds in water also affect the water quality: cause disagreeable tastes and odours in drinking water. carcinogenic agents (Vinyl chloride, benzene and other) cancer-suspect agent (chloroform) MSc. Ing. Jorge Zafra Cordova  Hidrogeología NATURAL ORGANIC MATTER Naturally occurring organic compounds in terrestrial water include: carbohydrates (sugars and cellulose) lipids (neutral fats) proteins (the building blocks of proteins are amino acids) enzymes complexes of proteins with other organic compounds (for example, tannins) MSc. Ing. Jorge Zafra Cordova  Hidrogeología MAN - MADE ORGANICS Synthetic organic compounds include a broad variety of aliphatic and aromatic compounds. Many manufactured organic compounds may be found at very low concentrations in natural water. Isolation, identification and evaluation of health effects of these synthetic organics at low concentrations are lacking. MSc. Ing. Jorge Zafra Cordova  Hidrogeología MAN - MADE ORGANICS Chlorinated solvents Majority of pesticides, Petroleum components, Synthetic chemicals Petroleum products (including solvents, pharmaceuticals, plastics, dyes, and detergents) MSc. Ing. Jorge Zafra Cordova  Hidrogeología DISSOLVED ORGANIC CARBON (DOC) The parameter, dissolved organic carbon (DOC), is a commonly used measure for the concentration of organic compounds in aqueous solution. DOC is the fraction of total organic carbon (TOC is all carbon atoms covalently bonded in organic molecules) in water that passes through a 0.45 micron pore-diameter filter. Determination: (1) initial removal of inorganic carbon species, (2) oxidation of the organic material into carbon dioxide (micro dichromate oxidation procedure), (3) quantification of the carbon dioxide produced. MSc. Ing. Jorge Zafra Cordova  Hidrogeología DISSOLVED ORGANIC CARBON (DOC) Typical DOC concentrations for groundwater range from a few micrograms to several 10 mg per liter and more. DOC concentrations depend on: climate, soil and vegetation coverage, land use. MSc. Ing. Jorge Zafra Cordova  Hidrogeología AMINES Determination: Total amines – photometric determination with Bromocresol purple (4,4'-(1,1-Dioxido-3H-2,1-benzoxathiole-3,3-diyl) – bis (2-bromo – 6-methylphenol) ) and with previous separation by diffusion method, λ=410 nm (detection limit is 1 µg N/l) Gas chromatography (detection limit is 0.1 µg) Bromocresol purple Preservation: Right after sampling adding HCl (pH of sample 4 – 5). In lab – filtration through a 0.45 micron pore-diameter filter and adding HCl (pH of sample 1 – 2). MSc. Ing. Jorge Zafra Cordova  Hidrogeología PESTICIDES The term "pesticide" is a composite term that includes all chemicals that are used to kill or control pests. Classification: herbicides (weeds, plants), insecticides (insects), fungicides (fungi), nematocides (nematodes), rodenticides (rodents). molluscicides (snails and slugs), avicides (repel birds), piscicides (fish control), bactericides (bacteria), slimicides (slime-causing organisms in water), algicides (algae). MSc. Ing. Jorge Zafra Cordova  Hidrogeología THE PESTICIDE CYCLE MSc. Ing. Jorge Zafra Cordova  Hidrogeología THE IMPACT OF PESTICIDES ON WATER QUALITY The impact of pesticides on water quality is associated with the following factors: Active ingredient in the pesticide formulation. · Contaminants that exist as impurities in the active ingredient. Additives that are mixed with the active ingredient (wetting agents, diluents or solvents, extenders, adhesives, buffers, preservatives and emulsifiers). Degradates that is formed during chemical, microbial or photochemical degradation of the active ingredient. MSc. Ing. Jorge Zafra Cordova  Hidrogeología HOW DO PESTICIDES GET INTO WATER SUPPLIES? Pesticides that are not taken up by plants, adsorbed by soils or broken down by sunlight, soil organisms or chemical reactions may ultimately reach groundwater sources of drinking water. This will depend upon The nature of the soil, Depth to groundwater, Chemical properties of the pesticide, The amount and timing of precipitation or irrigation in the area. MSc. Ing. Jorge Zafra Cordova  Hidrogeología FACTORS AFFECTING PESTICIDES TOXICITY IN AQUATIC SYSTEMS The ecological impacts of pesticides in water are determined by the following criteria: toxicity persistence degradates environmental fate MSc. Ing. Jorge Zafra Cordova  Hidrogeología TOXICITY Mammalian and non-mammalian toxicity usually expressed as LD50 ("Lethal Dose": concentration of the pesticide which will kill half the test organisms over a specified test period). The lower the LD50, the greater the toxicity; values of 0-10 are extremely toxic (OMAF, 1991). Drinking water and food guidelines are determined using a risk-based assessment. Generally, Risk = Exposure (amount and/or duration) × Toxicity. Toxic response (effect) can be acute (death) or chronic (an effect that does not cause death over the test period but which causes observable effects in the test organism such as cancers and tumours, reproductive failure, growth inhibition, teratogenic effects, etc.). MSc. Ing. Jorge Zafra Cordova  Hidrogeología PERSISTENCE Measured as half-life (time required for the ambient concentration to decrease by 50%). Persistence is determined by biotic and abiotic degradational processes. Biotic processes are biodegradation and metabolism; abiotic processes are mainly hydrolysis, photolysis, and oxidation. Modern pesticides tend to have short half lives that reflect the period over which the pest needs to be controlled. MSc. Ing. Jorge Zafra Cordova  Hidrogeología DEGRADATES The degradational process may lead to formation of "degradates" which may have greater, equal or lesser toxicity than the parent compound. As an example, DDT degrades to DDD and DDE. DDE (dichlorodiphenyldichloroethylene) and DDD (dichlorodiphenyldichloroethane) are chemicals similar to DDT that contaminate commercial DDT preparations. DDE has no commercial use. DDD was also used to kill pests, but its use has also been banned. One form of DDD has been used medically to treat cancer of the adrenal gland. MSc. Ing. Jorge Zafra Cordova  Ingeniería Ambiental 2019 CONSULTAS? Hidrogeología Ingeniería Ambiental 67  Ingeniería Ambiental 2019 INFORMACION ADICIONAL - Assessing Water Quality for Human Consumption, Agriculture, and Aquatic Life Uses https://iopscience.iop.org/article/10.1088/1755- 1315/118/1/012019/pdf#:~:text=TDS%20has%20also%20bee n%20classified,mg%2FL%20%5B21%5D. Hidrogeología Ingeniería Ambiental 68  Hidrogeología MSc. Ing. Jorge Zafra Cordova