QUALITY

Guideline of drinking water quality WHO published- vol 1 1993

vol 2 1996

Acceptability aspectsAcceptability aspects Microbiological aspectsMicrobiological aspects Chemical aspectsChemical aspects Radiological aspectsRadiological aspects

Physical parameters

Turbidity- <5 NTU

Colour - upto 15 TCU

Taste & odour Temperature

Chlorides- std 200mg/l max 600mg/l

Hardness- calcium- 100-300 mg/l

Ammonia- NH3 & NH4+ upto 1.5mg/l pH - 6.5-8.5 <7 -corrosion & incrustation >8- compromise efficiency of

disinfection H2S - 0.05-0.1mg/l Fe - 0.3mg/l Na - 200mg/l

Total dissolved salts

TDS level <600mg/l [good] < 1000mg/l [acceptable]

Sulphate <250mg/l CaSO4 – 270mg/l MgSO4 – 90mg/l

Zn 3mg/l Mn 0.1mg/l

Dissolved O2 indirect effects

Cu 1mg/l

Al 0.2mg/l

Bacteriological indicators Coliforms- faecal groups -E coli Non faecal –klebsiella aerogens Faecal streptococci - recent faecal pollution Clostridium perfringes - remote infection

Virological aspects Cl2 - 0.5mg/l , 30min ,pH - 8 O3 - 0.2-0.4mg/l , 4min

Biological aspects Protozoa- E.histolytica ,giardia ,balantidium coli Helminths – Free living organisms – algae , fungi

inorganic constituents organic constituents

inorganic constituents

arsenic – 0.01mg/l dissolution of mineral ores ,industrial effluents cadmium – 0.003mg/l accumulate in kidney, long T1/2- 10-35y chromium -0.05mg/l cyanide – 0.07mg/l processed cassava ,thyroid and CNS effects fluoride – 1.5mg/l dental & skeletal flurosis production of Al ,manufacture of phosphate

fertilizers (4%)

Lead Pb – 0.01mg/l , plumbing systems

placental transfer -12th week and continues interfere with Ca2+ metabolism, renal tumors subencephalopathic neurological &behavioural

effects

Hg - 0.001mg/l ,target organ- kidney, methylHg- CNS effects

nitrate & nitrite – nitrate- 50mg/l nitrite – 3mg/l concent of nitrate + concent of nitrite

= < 1 G.value of nitrate G.value of nitrite

selenium Se- 0.01mg/l

ORGANIC CONSTITUENTS UPPER LIMIT OF CONCENT ( microgm/l )

Chlorinated alkanes

CCl4 2

dichloromethane 20

Chlorinated ethenes

Vinyl chloride 55

1.1-dichloroethene 30

1.2-dichloroethene 50

Aromatic hydrocarbons

benzene 10

toluene 700

xylene 500

Ethyl benzene 300

styrene 20

TDI- tolerable daily intake

NOAEL- no- observed –adverse- effect level

LOAEL- lowest- observed- adverse -effect level

UF - uncertainty factor

TDI = NOAEL/LOAEL UF GV =TDI x BW x P C P=Fract of TDI allocated

to drinking water C=daily drinking water

consumption BW= body wt

Somatic Hereditary

Stochastic effect - carcinogenesis Non-stochastic effect - severity Aim- prevent NSE &reduce probability of SE DW- safe limits + reasonably low Becquerel- 1 disintegration/sec

GV- gross alpha activity 0.1Bq/L gross beta activity 1Bq/L

Activities in surveillance function approval of new sources watershed protection approval-construction & operating procedures of WW

disinfection of plant & distribution

system periodic flushing programmes & cleaning

of water storage facilities certification of operators regulation of chemical substances Cross-connection control ,back flow control ,leaK detection control

Sanitary surveys Monitoring programmes

Development of codes of practice for well construction ,pump installation and plumbing

Inspection quality control in bottled water

Elements of surveillance programme SANITARY SURVEY SAMPLING BACTERIOLOGICAL SURVEILLANCE presumptive coliform test- MULTIPLE TUBE

METHOD MEMBRANE FILTER

TECHNIQUE Confirmatory tests DETECTION OF FAECAL STREP & Cl.PERFRINGES COLONY COUNT BIOLOGICAL EXAMINATION CHEMICAL SURVEILLANCE

THANK U