Final Exam Set

Coliforms

Bacteria present in the environment and in the feces of all warm-blooded animals and humans. They will not likely cause illness. However, their presence in drinking water indicates that disease-causing organisms (pathogens) could be in the water system.

Bromate

BrO₃⁻ is a disinfection by-product formed in water during ozonation when bromide ion is present and may also be formed in concentrated hypochlorite solutions used to disinfect drinking-water. The current maximum contaminant level (MCL) of bromate in the US national primary drinking water standard is set at 10 micrograms/L. Bromate is a powerful oxidant, oxidation state of (+V). Its conjugate acid is strong with a pKa reported between -2 and 0.5.

Ferric Ion

Fe(III) is the more oxidized form of iron It has multi-protic acid base behavior where Fe³⁺ is the most acidic form and Fe(OH)²⁺ is its conjugate base. Other bases include Fe(OH)₂⁺, Fe(OH)₃⁰ and Fe(OH)₄

Ferric Hydroxide

Fe(OH)₃ or Fe₂O₃ forms during the process of corrosion of iron metal such as in cars. Iron metal acts as the anode in a galvanic cell and is oxidized to Fe²⁺; oxygen is reduced to water at the cathode. In the atmosphere Fe²⁺ is further oxidized to Fe³⁺ and then precipitates as Fe₂O₃.

Hydrogen Peroxide

H₂O₂ - strong oxidant, used in advanced oxidation processes to degrade complex organic contaminants oxygen has an oxidation state of -I

Cupric ion

It has multi-protic acid base behavior where Cu²⁺ is the most acidic form and Cu(OH)⁺ is its conjugate base. Other bases include Cu(OH)₂⁰ and Cu(OH)₄⁻ Harmful to health in high concentrations, metal is commonly used in industry for piping and wires. It is toxic to salmon, and an indicator of corrosion.

Bacteria

unicellular microorganisms which have cell walls but lack organelles and an organized nucleus 0.2 to 2.0 micrometer diameter

Amoeba

A single-celled organism that catches food and moves about by extending fingerlike projections of protoplasm. Amoebas are either free-living in damp environments or parasitic. Some amoeba have an association with human disease: Acanthamoeba spp., Balamuthia mandrillaris, Naegleria fowleri and Sappinia diploidea. Acanthamoeba spp. and B. mandrillaris are opportunistic pathogens causing infections of the central nervous system, lungs, sinuses and skin, mostly in immunocompromised humans. Naegleria fowleri usually infects people when contaminated water enters the nose and travels to the brain, where a rare and deadly infection called primary amebic meningoencephalitis, or PAM, can occur, according to the Centers for Disease Control. The ameoba is most common in soil and warm freshwaters, such as lakes, rivers and hot springs. https://cbsaustin.com/news/local/doctors-explain-rarity-of-brain-eating-amoebas

Silver Chloride

AgCl can dissociate to form Ag⁺ ions which are toxic to many organisms When silver nanoparticles are released into the enviornment they can be oxidized and release Ag⁺ Ag nanoparticles can be placed in ceramic water filters for disinfection, often used in rural areas

Bromide

Br⁻ Bromide is an anion found in seawater, desalinated water and drinking water. It forms salts with sodium, potassium and other cations, which are usually very soluble in water. In seawater, Br⁻ concentrations range from 65 to 165 mg/L where as freshwater concentraitons typically range from trace amounts to about 0.5 mg/l. Concentrations of bromide in desalinated waters may approach 1 mg/l. This is a problem because removing the bromide ion prior to disinfection will have a profound effect in the lowering of the potential formation of trihalomethanes and other disinfection by-products (DBPs).

Bromine

Br₂ are disinfectants and can be used as an alternative for chlorine. In swimming pools, bromine is used against the formation and growth of algae, bacteria and odors in swimming water. ... At the pH value that is usually found in swimming pools, bromine is mainly present as hypobromous acid (HOBr). Brominated disinfection by-products are considered more toxic/carcinogenic than chlorinated counterparts

Methyl merucury

CH₃Hg⁺ an organometallic cation formed from inorganic mercury by the action of microbes that live in aquatic systems including lakes, rivers, wetlands, sediments, soils and the open ocean. Its derivatives are the major source of organic mercury for humans. It bioaccumulates within the food chain (e.g. fish) Ingested methylmercury is readily and completely absorbed by the gastrointestinal tract and crosses blood-brain barrier and placenta, where it is absorbed by the developing fetus. Toxic to the central and peripheral nervous systems.

Monochloramine

Chloramines (monochloramine NH₂Cl) are disinfectants that provides longer-lasting disinfection compared to other more powerful oxidants as the water moves through pipes to consumers Used in Austin for secondary disinfection in the distribution system

Chlorine

Cl₂ is a disinfectant commonly used in water treatment protozoa such as giardia and cryptosporidium are often resistant to this disinfectant because they form oocysts

Chromium Hydroxide(s)

Cr(OH)₃(s) is the hydroxide precipitate of Cr(III). It has low solubility. Upon dissolution it undergoes acid base reactions to form Cr³⁺, Cr(OH)²⁺, Cr(OH)₂⁺, Cr(OH)₃⁰ and Cr(OH)₄⁻

Chromate

CrO₄²⁻ Cr(VI) base of HCrO₄⁻ H₂CrO₄ is the diprotic acid for this syste, corrosive oxidixing agent, toxic and carcinogenic. Chromium is in the VI oxidation state in this compound which is more toxic than the III oxidation state - it is carcinogenic Cr(VI) is used in metal plating, cleaning glassware, and corrosion prevention (PG&E, Hinkley, CA, Erin Brokovich). Also used as photographic chemical and as a wood preservative.

Ferrous iron

Fe²⁺ Ferrous form of Fe that occurs in waters with very low oxygen content. It is a reduced form of iron relative to Fe³⁺ Salts of ferrous ion such as FeCl₂ are often used in coagulation It has multi-protic acid base behavior where Fe²⁺ is the most acidic form and Fe(OH)⁺ is its conjugate base. Other bases include Fe(OH)₂⁰ and Fe(OH)₃⁻

Hypochlorous Acid

HOCl is an acid with a pKa of 7.6 A common form of chlorine based disinfectant used, forms from Cl₂ and is often added in in the basic form (OCl⁻) oxidation state of Cl is +1

Mercury(0)

Hg(0) is the most reduced form of Hg. It is volatile and when inhaled can pass the blood brain barrier and cause neurological damage. Only the volatile for of the elemental form of mercury passes the blood brain barrier. A naturally occurring heavy metal that is also the result of burning coal and other fossil fuels

Manganese (II)

Mn(II) The more reduced form of Mn found in water systems. Mn(III and IV) are more oxidized. Although manganese is an essential nutrient at low doses, chronic exposure to high doses may be harmful to the nervous system depending on the route of exposure. If consumed in high quantities, it can be detrimental to human health. Affects brain and respiratory tract. Released through burning of fossil fuels which can be toxic to plants and animals. Manganese present in water supplies at concentrations in excess of 0.05 mg/L can cause discoloration in laundered goods, "black" water, water main incrustation, deposits on industrial equipment such as paper machines, debris at water customers' taps and may negatively impact taste in drinking water and beverages.

Manganese Oxide

Mn⁴⁺(IV) is an oxidized form of Mn It precipitates as MnO₂(s) insoluble, affects aesthetic water quality, causes turbidity and brown-black water, can deposit in water pipes, oxidant. It is necessary for humans to survive, but is toxic when levels are too high.

Virus

Obligate Intracellular Parasites - metabolically inert, characteristics of life only when "inside" a host cell such as a bacteria, animal or plant 20-300 nm

pathogen

Organism that causes disease

Ozone

O₃ is a strong oxidant and disinfectant odorless or pale blue gas, slightly soluble in water ozone is capable of inactivating bacteria, viruses and protozoans

Lead Oxide

Pb(IV) A toxic, heavy metal that contaminates water when it passes through lined pipes, solder, brass fittings and paint and it damages the nervous system Under oxidizing condtions, lead(IV) can precipitate as PbO₂(s) which is platternite. This the preferred form of scale in water distribution systems with lead pipes. However, it can dissolve if the water utilities switch to disinfectants with lower oxidation potential.

Radium ion

Ra²⁺ a naturally occurring radionuclide. All isotopes of radium are highly radioactive, Radium-226 is the most common followed by Ra-228. Drinking concentrations of 5pCi/L and higher can lead to bone cancer Radium-226 is formed by the decay of uranium and thorium in the environment. has a half-life of 1600 years and decays into radon gas (specifically the isotope radon-222). Only radioactive alkaline earth metal; extremely volitile silvery-white metal.

Radon

Rn-222 is a naturally occurring gas that is tasteless, odorless, and radioactive. It releases alpha, beta, and gamma radiation, the latter of which can penetrate through the human body. Radon has caused an estimated 20,000 lung cancer cases per year in the US alone. Many homes, 1 in 3accumulates in high densities in low areas of buildings such as basements based on data, had radon levels exceeding safe limits, posing a significant risk to children and adults alike. Radon accumulates in high densities in low areas of buildings such as basements as well as in groundwater from bedrock. - the primary health effect of radon is lung cancer

Uranium (IV)

U(IV) - toxic, radioactive In nature, uranium is found predominantly as uranium 238 and uranium 235. more insoluble than the more oxidized form Common solid form of U(IV) is UO₂(s). U(IV) can be generated through biologically mediated U(VI) reduction. Weakly radioactive because all of its isotopes are unstable. Occurs naturally in low concentrations of a few ppm in soil, rock and water.

Giardia

a protozoa pathogen that causes diarrheal illness. It is found on surfaces or in soil, food, or water that has been contaminated with feces from infected humans or animals. It forms oocysts so is resistant to chlorine disinfection.

Escherichia coli

if you eat contaminated food or drink fouled water The natural habitat is the gastrointestinal tract of warm-blooded animals, and in humans, this species is the most common facultative anaerobe in the gut. Certain strains of E. coli, such as O157:H7, O104:H4, O121, O26, O103, O111, O145, and O104:H21, produce potentially lethal toxins.