|
Levels
likely to give rise to consumer complaintsa |
Reasons
for consumer complaints |
Physical
parameters |
colour |
15 TCUb |
appearance |
taste
and odour |
— |
should
be acceptable |
temperature |
— |
should
be acceptable |
turbidity |
5 NTUc |
appearance;
for effective terminal disinfection, median turbidity =1 NTU, single sample
=5 NTU |
Inorganic
constituents |
aluminium |
0.2 mg/l |
depositions,
discoloration |
ammonia |
1.5 mg/l |
odour
and taste |
chloride |
250 mg/l |
taste,
corrosion |
copper |
1 mg/l |
staining
of laundry and sanitary ware (health-based provisional guideline value
2 mg/litre) |
hardness |
— |
high
hardness: scale deposition, scum formation
low hardness: possible corrosion |
hydrogen
sulfide |
0.05
mg/l |
odour
and taste |
iron |
0.3 mg/l |
staining
of laundry and sanitary ware |
manganese |
0.1 mg/l |
staining
of laundry and sanitary ware (health-based guideline value 0.5 mg/litre) |
dissolved
oxygen |
— |
indirect
effects |
pH |
— |
low
pH: corrosion
high pH: taste,
soapy feel
preferably <8.0
for effective disinfection with chlorine |
sodium |
200 mg/l |
taste |
sulfate |
250 mg/l |
taste,
corrosion |
total
dissolved solids |
1000
mg/l |
taste |
zinc |
3 mg/l |
appearance,
taste |
Organic
constituents |
toluene |
24–170
µg/l |
odour,
taste (health-based guideline value 700 µg/l) |
xylene |
20–1800
µg/l |
odour,
taste (health-based guideline value 500 µg/l) |
ethylbenzene |
2–200
µg/l |
odour,
taste (health-based guideline value 300 µg/l) |
styrene |
4–2600
µg/l |
odour,
taste (health-based guideline value 20 µg/l) |
monochlorobenzene |
10–120
µg/l |
odour,
taste (health-based guideline value 300 µg/l) |
1,2-dichlorobenzene |
1–10
µg/l |
odour,
taste (health-based guideline value 1000 µg/l) |
1,4-dichlorobenzene |
0.3–30
µg/l |
odour,
taste (health-based guideline value 300 µg/l) |
trichlorobenzenes
(total) |
5–50
µg/l |
odour,
taste (health-based guideline value 20 µg/l) |
synthetic
detergents |
— |
foaming,
taste, odour |
Disinfectants
and disinfectant by-products |
chlorine |
600–1000
µg/l |
taste
and odour (health-based guideline value 5 µg/l) |
chlorophenols |
|
|
2-chlorophenol |
0.1–10
µg/l |
taste,
odour |
2,4-dichlorophenol |
0.3–40
µg/l |
taste,
odour |
2,4,6-trichlorophenol |
2–300
µg/l |
taste,
odour (health-based guideline value 200 µg/l) |