| |
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) |
