Lecture 15

Lecture 15 - © E.Garcia 2010 FST 1 – Main topics –...

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Unformatted text preview: © E.Garcia 2010 FST 1 – Main topics – Lecture 15 Salt Water and Public Health issues Common Salt: Sodium Chloride (NaCl) is an inorganic compound. Relative weight of ‐ Microbial contamination ‐ Chemical contamination: pesticides, pharmaceuticals, industrial pollutants, etc sodium in common salt is 40% and the relative weight of chloride 60%. Lead contamination. Prior to 1986, most home plumbing systems were built of Salt has many functions, including: copper pipes soldered together with lead. Lead can leach into tap water (unless ‐ Source of essential nutrients: both elements are essential to our body. Sodium the water quality is carefully controlled). Lead is toxic; it may cause irreversible helps maintain the body’s fluid balance, among other functions. Chloride aids in nerve impulse transmission; it is a component of HCl produced in the stomach, etc neurological damage, renal disease, among other effects. ‐ Taste: saltiness Cryptosporidiosis is a diarrheal disease caused by microscopic parasites of the ‐ Food preservation, ex.: salting of meats, fish. genus Cryptosporidium. These organisms live in the intestine of infected humans and animals and pass in the stools. “Crypto” survives outside the body for long Dietary sources of sodium: about 75‐80% comes from processed foods; 15% from periods of time, and it is very resistant to chlorine‐based disinfectants. Boiling salt used in cooking and/or at the table and the remaining occurs naturally in foods. water is a very effective way of destroying Cryptosporidium. Some water filters also eliminate this organism; these are filters which remove particles ≤1 micrometer in Salt production Salt Purity diameter. “Crypto” is one of the most common causes of waterborne disease in ‐ salt mining (rock salt) Rock salt: 95% to 99% NaCl the U.S. ‐ solar evaporation Solar evaporation salt: ~ 99% NaCl ‐ solution mining Solution Mining: up to 99.99% (w/ purified brine) Water Fluoridation: considered one of the 10 great public health achievements of the 20th century (CDC – Centers for Disease Control and Prevention). Fluoridation Iodized salt prevents tooth decay safely. In many regions of the U.S., fluoride is added to water In the mid 1920s, iodide supplementation program took effect in the U.S. Iodide is supplies. Almost 2/3 of the population receives fluoridated water. an essential nutrient; it is a component of thyroid hormones. Iodide deficiency was common in America (Midwest). Today, iodized salt is the primary iodide source for Fluoride is an essential micronutrient. It makes teeth resistant to acid and bacterial many people. growth. It also enhances teeth remineralization. Common dietary sources of fluoride are water, tea, seafood. However, excessive fluoride in the diet during As salt is hygroscopic, an additive ‐ anti‐caking agent, such as calcium silicate ‐ is tooth development can cause dental fluorosis, or mottling (spotted teeth). frequently added to salt to prevent moisture retention. Bottled water consumption has more than doubled in the last decade. Consumers perceive bottled water as safer than tap water. Water Water covers about 70% of the Earth, however less than 1% is available as freshwater for human use. Of the freshwater available on Earth, ~2/3 is frozen in ice caps and glaciers. Worldwide, over 1 billion people lack access to safe drinking water. Our drinking water comes from ‐ Surface water: lakes, reservoirs, rivers, and streams. Our primary water source. ‐ Groundwater: underground in aquifers Water is a vital nutrient. Our body is made of ~60% water! Water has many functions in the body, such as carrying nutrients to cell and tissues, carrying waste out of the body; component of body fluids (saliva, joints, etc); participating in chemical reactions, body temperature regulation, etc. A recent report indicated that about 3/4 of the water bottles produced in the U.S. are not recycled. Readings 1. McGee p.639‐644 (Salt) 2. McGee p.172 (Preserved Meats; Dried Meats: Jerky) _____________ FYI (not for exam) 1.Sodium&Potassium (pdf file posted on the course web page) 2. Sodium (Salt or Sodium Chloride) http://www.americanheart.org/print_presenter.jhtml?identifier=4708 3. Evaporated salt http://www.saltinstitute.org/Production‐industry/Production‐ technologies/Evaporated‐salt‐refined‐salt ...
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  • Winter '10
  • CharlesF.Shoemaker
  • common salt, Salt production                                  Salt

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