By Shan-e-Haider Bukhari
Report
Difference between total analysis, Fractionation and
Speciation
Abstract:
Water sample from eight different site at VansjØ was analysed for chemical
analysis,fractionation and speciation.After the examination of important species,central
equlibriums,concentration and activity,pH,Alkalinity,Conductivity,UV/VIS absorbency a
data was calculated.some of the problem solved by using MINEQL.
Introduction:
We know that all life is dependent on water and that water exists in nature in many formsclouds, rain, snow, ice, and fog; however, strictly speaking, chemically pure water does not
exist for any appreciable length of time in nature. Even while falling as rain, water picks up
small amounts of gases, ions, dust, and particulate matter from the atmosphere. Then, as it
flows over or through the surface layers of the earth, it dissolves and carries with it some of
almost everything it touches, including that which is dumped into it by man.
These added substances may be arbitrarily classified as biological, chemical (both inorganic
and organic), physical, and radiological impurities. They include industrial and commercial
solvents, metal and acid salts, sediments, pesticides, herbicides, plant nutrients, radioactive
materials, road salts, decaying animal and vegetable matter, and living microorganisms, such
as algae, bacteria, and viruses. These impurities may give water a bad taste, color, odor, or
cloudy appearance (turbidity), and cause hardness, corrosiveness, staining, or frothing. They
may damage growing plants and transmit disease. Many of these impurities are removed or
rendered harmless, however, in municipal drinking water treatment plants.
The principal factors that are taken into consideration when determining water
Temperature
Temperature influences the amount of dissolved oxygen in water which in turn influences the
survival of aquatic organisms (raising the temperature of a freshwater stream from 20 to 30oC
will decrease the dissolved oxygen saturation level from about 9.2 ppm to 7.6 ppm.).
Increasing temperature also increases the rates of chemical reactions taking place in the
water. Increases in temperature are often associated with hot water discharge from power
stations and industries that use water as a coolant.
pH
pH measures the acidity or alkalinity of water. pH of rain water is about 5.5-6.0. Typically,
natural water has pH 6.5-8.5. A pH<5 (acidic water) is most damaging to eggs and larvae of
aquatic organisms. Most aquatic life (except for some bacteria and algae) cannot survive
pH<4.Natural alkalinity is due to CO2(g), HCO3-, CO32- and OH-, carbonate rocks such as
limestone and dolomite increase alkalinity. Alkalinity is increased by caustic substances from
industry (KOH, NaOH), soil additives in agriculture such as lime Ca(OH)2, superphosphate
which is mixture of Ca(H2PO4)2 and CaSO4, and soaps and detergents. Natural acidity is due
to CO2(g), HPO42-, H2PO4-, H2S, Fe3+, other acidic metal ions, proteins & organic acids.
Increases in acidity can be due to acids used in industry, acid mine drainage, acid rain.
Dissolved Oxygen (DO)
The Dissolved Oxygen test measures the current oxygen levels in the water. The Do level
varies with temperature. DO levels are highest in the afternoon due to photosynthesis and
lowest just before dawn. DO is lowered by an increase in temperature (as from a discharge of
hot water form a power station), increases in aerobic oxidation (due to increases in organic
matter from sewage or due to inorganic fertilisers such as phosphates and nitrate with
overstimulate algal growth). Water with DO<1ppm is dead.
Total Phosphate
Total Phosphate is used as an indicator of pollution from run-off in agricultural areas or
domestic sewage. Concentrations of 0.2mg/L are common. Concentrations of 0.05mg/L
indicate the possibility of eutrophication (increased nutrient concentrations) and algal blooms
are likely. Natural phosphate is due to decayed organic matter and phosphate minerals.
Total Nitrogen
Total Nitrogen is an important indicator of eutrophic waters, especially for those
contaminated by animal wastes, fertiliser run-off and domestic sewage. Aquatic nitrogen is
essential for the growth of organisms and is produced in natural processes including decay of
proteins, the action of lightning, and the action of nitrogen-fixing bacteria on ammonia.
Hardness
Calcium ions are a major contributor to water hardness and are due to water running through
rocks containing minerals such as gypsum (CaSO4.2H2O), calcite (CaCO3), dolomite
(CaMg(CO3)2). Hard water has a noticeable taste, produces precipitates with soaps which
inhibits lathering and forms precipitates (scale) in boilers, hot water systems and kettles.
Temporary hardness (or 'bicarbonate hardness') is due to Ca(HCO3)2 which deposits
CaCO3(s) as scale on boiling the water.
Magnesium ion levels are often high in irrigation water and can cause scouring in stock.
Ca2+ and Mg2+ can combine with Cl- and/or SO42- causing permanent hardness which can't be
removed by boiling. Water can be softened by an ion exchange process using a solid material
such as a resin or clay that is capable of exchanging Na+ or H+ for Ca2+ and Mg2+.
Microorganisms
Many protozoa, bacteria, viruses, algae and fungi are found in natural water systems. Some
are pathagenic (typhoid, cholera and amoebic dysentry can result from water-borne
pathogens). The excessive growth of algae (called 'algal bloom') can degrade water quality
because it lowers dissolved oxygen levels thereby killing other living things.
The level of bacterial contamination of water due to animal waste is measured by determining
the number of coliform organisms such as E. Coli
Heavy Metals
Heavy metals in concentrations above trace amounts are generally toxic to living things.
Trace amounts (<0.05 mg/L) of Zn, Cu and Mn are present in most natural waters. Zn and Cu
may be present in higher levels in irrigation areas due to the use of galvanised iron, copper
and brass in in plumbing fixtures and for water storage. In irrigation areas, acceptable levels
are 0.2 mg/L for Cu2+, and 2.0 mg/L for Zn2+ and Mn2+.
Experiments
Sampling
Eight different sample was taken from Morsa-Vansjø lakes. These eight different sites
contains different porpertities and indrigents because some of them are lakes and other are
rivers.
First site :
Grepperødfjorden (Lake)
Second site :
Bjørnerød bro
(River)
Third site :
Krosseng bru
(River)
Fouth site :
Holm/Kirkelva
(River)
Fifth site :
Nordby/Mørkelva
(River)
Sixth site:
Sperbund
(small river)
Seventh site :
Vanemfjoden
(Lake)
Eight site:
Storfjorden/Oksnøya
(lake)
On all these sites the sample were collected carefully then on the spot the temperature pH and
the Conductivity is calculated. During the calculation of pH the sample was not stirr due to
factor of degas.
Lab Experiment
The samples collected at different site analysed in the labortary.the analysis carried out by
making different fractionates.
Alkalinity
For the calculation of alkalinity 100ml of sample was taken in the flask and titrate with
0.0200 N H2SO4. The end point is obtained at the pH 4.5. when the end point is got all
samples repeated on the same patrens. Total alkalinity is calculated in the form of CaCO3
present in mg per liter
UV/VIS Absorbance
The absorbance of all samples was calculated at 254nm,400nm,600nm. There is difference
observed for both filter samples and non filtered sample this difference is due to the presence
of algae and Natural organic matters.
Measurment of absorbency at UV 254 is commonly used as proxy for dissolved natural
organic matters this is correlated with TOC due to conjugated double bond chromophores
Algae aborbe light at 254 but more than DNOM at vis 600 nm
Phosphate Fractionation
The P Fractionation is done by two different steps on the first step the raw samples of water
oxidaised by UV as photooxidation occures in lakes. The process is to put the wait amount of
samples from all sites put in the oxidation ovens and oxidaised for 20 min then after that the
P is calculated this is called fraction B then the sample samples but this time they first filtered
through 0.45 um filter then oxidaised by UV. From this oxidation the Organic bound P is
oxidaised.
Results and Conclusions
Tables of pH ,Alkalinity,conductivity measured at spot and in lab
Field Measurment
Sampling site
Sampling types
Sperbund
Krosseng bru
Holm/Kirkelva
Nordby/Mørkelva
Bjørnerød bro
Grepperødfjorden
Vanemfjoden
Storfjorden/Oksnøya
Small river
River
River
River
River
Lake
Lake
Lake
Date of sampling
9-Oct-08
9-Oct-08
9-Oct-08
9-Oct-08
9-Oct-08
9-Oct-08
9-Oct-08
9-Oct-08
Lab
measurment
Cond25C
pH
6.81
6.02
5.51
6.84
6.40
6.10
5.86
6.22
μS cm
92.7
85.0
47.3
86.8
89.6
80.0
86.6
79.8
-1
Temp.
ºC
22.8
22.9
22.2
22.8
22.4
22.0
23.3
23.2
time
14:30
13:25
13:50
14:10
13:05
12:40
14:50
15:20
Conductivity
at 25 c
77.9
86.5
56.0
65.2
75.0
78.5
68.0
65.1
conductivity
85.3
86.5
56.0
76.0
75.0
79.3
68.0
72.5
Temp.
10.3
12.2
10.4
13.4
11.8
13.4
14.1
13.6
pH
6.76
7.49
7.55
7.21
7.27
6.80
6.85
7.62
Absorbance
Raw water
Abs cm
filtered
-1
Abs cm-1
UV
VIS
VIS
UV
VIS
VIS
254
0.892
0.742
0.884
0.777
0.685
0.473
0.376
0.321
400
0.142
0.206
0.168
0.118
0.176
0.078
0.068
0.051
600
0.027
0.089
0.048
0.022
0.073
0.019
0.020
0.012
254
0.776
0.444
0.710
0.702
0.463
0.425
0.327
0.295
400
0.096
0.052
0.084
0.085
0.058
0.049
0.036
0.031
600
0.007
0.004
0.006
0.007
0.006
0.003
0.003
0.002
pH measured in lab and in field
8.00
pH measured in lab
7.00
6.00
5.00
4.00
3.00
2.00
1.00
0.00
0.00
2.00
4.00
6.00
8.00
pH measured in field
The changes i due to degases at different places and also the pH 7 is not easy in the fields