STUDENT TANYA PROKOPENKO TEACHER KAROL RIVERA COURSE SCH

STUDENT: TANYA PROKOPENKO TEACHER: KAROL RIVERA COURSE: SCH 4 U DATE: APRIL 7, 2015

ANALYSE HEALTH AND SAFETY ISSUES INVOLVING ELECTROCHEMISTRY CORROSION OF METAL PIPES IN DRINKING WATER SYSTEM

CORROSION IS A COMPLEX SERIES OF REACTIONS BETWEEN THE WATER AND METAL SURFACES AND MATERIALS IN WHICH THE WATER IS STORED OR TRANSPORTED. • THE CORROSION PROCESS IS AN OXIDATION/REDUCTION REACTION THAT RETURNS REFINED OR PROCESSED METAL TO THEIR MORE STABLE STATE. WITH RESPECT TO THE CORROSION POTENTIAL OF YOUR DRINKING WATER, THE PRIMARY CONCERNS INCLUDE THE POTENTIAL PRESENCE OF TOXIC METALS , SUCH AS LEAD AND COPPER; DETERIORATION AND DAMAGE TO THE HOUSEHOLD PLUMBING, AND AESTHETIC PROBLEM S SUCH AS: STAINED LAUNDRY, BITTER TASTE, AND GREENISH-BLUE STAINS AROUND BASINS AND DRAINS.

NEARLY ALL METALS WILL CORRODE TO SOME DEGREE. THE RATE AND EXTENT OF THE CORROSION DEPENDS ON THE DEGREE OF DISSIMILARITY OF THE METALS AND THE PHYSICAL AND CHEMICAL CHARACTERISTICS OF THE MEDIA, METAL, AND ENVIRONMENT. IN WATER THAT IS SOFT, CORROSION OCCURS BECAUSE OF THE LACK OF DISSOLVED CATIONS, SUCH AS CALCIUM AND MAGNESIUM IN THE WATER. IN SCALE FORMING WATER, A PRECIPITATE OR COATING OF CALCIUM OR MAGNESIUM CARBONATE FORMS ON THE INSIDE OF THE PIPING. THIS COATING CAN INHIBIT THE CORROSION OF THE PIPE, BECAUSE IT ACTS AS A BARRIER, BUT IT CAN ALSO CAUSE THE PIPE TO CLOG. WATER WITH HIGH LEVELS OF SODIUM, CHLORIDE, OR OTHER IONS WILL INCREASE THE CONDUCTIVITY OF THE WATER AND PROMOTING CORROSION.

SOME FACTORS • LOW PH (ACIDIC WATER) AND HIGH PH (ALKALINE WATER)- FOR HIGH ALKALINITY WATER - IT IS POSSIBLE THAT A CHEMICAL SCALE MAY FORM THAT WOULD HELP TO PROTECT AGAINST CORROSION, BUT IF A BACTERIA BECAUSE ESTABLISHED BENEATH THE SCALE, SUCH AS SRB ETC, YOU MAY EXPERIENCE A PROBLEM RELATED TO MICROBIOLOGICALLY INDUCED CORROSION OR MIC - THERE IS AN UPPER LIMIT TO THIS CONCERN BECAUSE ABOVE PH 12 WOULD PROVIDE FOR ADEQUATE DISINFECTION , • HIGH FLOW RATE WITHIN THE PIPING, • HIGH WATER TEMPERATURE, • OXYGEN AND DISSOLVED CO 2, • HIGH DISSOLVED SOLIDS, SUCH AS: SALTS, SULFATES, • CORROSION RELATED BACTERIA AND ELECTROCHEMICAL CORROSION, AND • PRESENCE OF SUSPENDED SOLIDS, SUCH AS SAND, SEDIMENT, CORROSION BY-PRODUCTS, AND RUST.

IMPACT AND POTENTIAL HEALTH CONCERNS WITH CORROSIVE WATER • DECREASE THE EFFICIENCY OF HOT WATER HEATERS AND MAY CAUSE PREMATURE FAILURE TO THE HEATER; • CORRODES AND CAUSES PREMATURE FAILURE OF HOUSEHOLD PLUMBING AND PLUMBING FIXTURES; • IMPARTING A BITTER TASTE TO YOUR WATER BECAUSE OF ELEVATED LEVELS OF METALS, WHICH CAUSES YOU IN PURCHASE BOTTLED WATER; • RESULTS IN THE FORMATION OF RED WATER OR GREENISH BLUE STAINS ON DRAINS; AND • CONSUMPTION OF WATER WITH ELEVATED LEVELS OF TOXIC METALS, SUCH AS: LEAD AND COPPER, HAVE BEEN SHOWN TO CAUSE BOTH ACUTE AND CHRONIC HEALTH PROBLEMS.

WATER TESTING FOR CORROSION TO DETERMINE THE CORROSION IT IS RECOMMEND TO HAVE THE WATER CHECKED FOR EVIDENCE OF TESTING THE WATER FOR LEAD AND COPPER. THIS IS CONDUCTED BY DETERMINING THE LEAD AND COPPER CONTENT OF THE WATER AFTER THE WATER HAS BEEN LEFT IN THE PIPING OVERNIGHT. THE FIRST DRAW IS COLLECTED AND THEN A SECOND SAMPLE IS COLLECTED AFTER THE LINE HAS BEEN FLUSHED, TYPICALLY THREE TO FIVE MINUTES. THE FIRST DRAW SAMPLE IS THE FIRST ONE LITER OF WATER COLLECTED FROM A COLD WATER TAP WHICH HAS BEEN SHUT OFF FOR AT LEAST SIX HOURS. THIS IS THE SAMPLING PROCEDURE EPA IS REQUIRING COMMUNITY WATER SYSTEMS TO USE TO DETERMINE COMPLIANCE WITH THE NEW ACTION LEVELS. SAMPLES ARE THEN ANALYZED BY ATOMIC ABSORPTION SPECTROPHOTOMETRY FOR LEAD AND COPPER.

CORROSION TREATMENT • CORROSION CONTROL IS A COMPLEX SCIENCE, REQUIRING CONSIDERABLE KNOWLEDGE OF CORROSION CHEMISTRY AND OF THE SYSTEM BEING EVALUATED. CORROSIVE WATER CAN BE MANAGED BY INSTALLING PRETREATMENT SYSTEMS, INSTALLATION OF NON-CONDUCTIVE UNIONS, REDUCING HOT WATER TEMPERATURE, AND REPLACING COPPER PIPING WITH PVC OR CPVC. THE PRETREATMENT PROCESS TREATS THE CORROSIVITY OF THE WATER BY CHANGING THE SATURATION INDEX THROUGH AN INCREASE OR DECREASE IN THE PH, HARDNESS, AND/OR ALKALINITY. THE RESULTANT SATURATION INDEX IS TYPICALLY MORE POSITIVE AND PREFERABLY THE SI IS BETWEEN -0. 5 TO +0. 5.

FILTERS • THE NEUTRALIZING FILTER IS MORE COMMONLY USED. THE NEUTRALIZING FILTER USES CRUSHED LIMESTONE, MAGNESIA OR SOME OTHER MIXTURE AND AS THE WATER PASSES THROUGH THE FILTER, THE FILTER NEUTRALIZES THE EXCESS “ACID” AND RESULTS IN THE PARTIAL DISSOLUTION OF THE MEDIA. THEREFORE, THE NEUTRALIZING FILTER ACTUALLY INCREASES THE HARDNESS OF THE WATER AND RAISES THE PH. THE FOLLOWING ARE THE CHEMICAL EQUATIONS FOR THE FILTER REACTIONS. • H 2 CO 3 + CACO 3 -----> CA(HCO)3 2 (H 2 CO 3) + MGO -----> MG(HCO 3)2 + H 20

CORROSION CONTROL IN GENERAL, TREATMENT OF GROUNDWATER CAN BE ACCOMPLISHED BY ADDING SOME HARDNESS OR ALKALINITY, OR BOTH, AND ADJUSTING THE PH TO SLIGHTLY INCREASE THE SCALE-FORMING TENDENCY, THUS CREATING A FILM OR BARRIER TO THE CORROSION. INSTALLATION OF DIELECTRIC (NONCONDUCTIVE) UNIONS BETWEEN DISSIMILAR METALS SUCH AS COPPER PIPE AND STEEL HOT WATER HEATERS CAN LIMIT CORROSION BY BREAKING THE GALVANIC CIRCUIT. ONE OF THE MORE EFFECTIVE METHODS OF CONTROLLING CORROSION AND LEACHING OF TOXIC METALS INTO THE WATER IS PREVENTIVE, SUCH AS USING DIELECTRIC COUPLINGS, INSTALLING CPVC PIPING, AND STAINLESS STEEL EQUIPMENT. IF COPPER PLUMBING IS USED, NON-LEAD SOLDER SUCH AS 95/5 TIN/ANTIMONY SOLDER SHOULD BE USED.

CONCLUSION • OVER THE NEXT FEW YEARS, ALL REGULATED COMMUNITY WATER SYSTEMS WILL BE REQUIRED TO MONITOR THEIR LEVELS OF LEAD AND COPPER, WITH SAMPLES BEING TAKEN FROM COLD WATER TAPS IN CONSUMERS' HOMES. WATER SYSTEMS WITH LEVELS OF LEAD OR COPPER IN EXCESS OF THE ACTION LEVELS WILL BE REQUIRED TO IMPLEMENT CORROSION CONTROL PROCEDURES. THEREFORE, IT IS UP TO YOU TO CHECK AND MONITOR THE SAFETY OF YOUR OWN PRIVATE WATER SUPPLY.

THANK YOU FOR YOUR ATTANTION! LOVE CHEMISTRY AND CHEMISTRY WILL LOVE YOU BACK