METHODOLOGY FOR WATER SAMPLING
AND PHYSICAL CHEMICAL ANALYSES
Any field work carried out in order to perform the physical chemical analyses must start by drawing up the objectives as these are the main factors to be considered for the identification of the sampling points, the periods, the ways of sampling, the handling of probes and the analytical requests.
The main objectives of the program for the water sampling and physical chemical analyses are:
· The characterization of the water quality from the interest areas, on long term - consisting in the measurement and integration of the data on long term
· The water quality control, on short term – with intensified sampling frequency when the values of the parameters are close to each other or exceed the critical values.
In order to achieve the main objectives the following specific objectives are foreseen:
1. To identify and monitor the parameters that put into evidence the variations of water quality on long term.
2. To statistically analyses the analytical results to identify the pollution sources of the water from the interested areas.
3. To characterize the water quality in order to make the appropriate corrections on long term.
4. To identify and monitor the physical chemical parameters needed for the quality control and appropriate corrections on short term.
5. To established the intervention methodology on short and long terms in order to improve the water quality and environmental protection.
The establishment of the water sampling programs and performance of physicochemical analysis for water quality control, and also the identification of its pollution sources and the preparation of the measurements set, suppose the following steps:
- The samples must be representative for the set and all precautions must be taken in order to preserve their status.
- The sampling point must be identified in order to obtain representative data.
- Before the sampling, the probe must be labeled in order to be easily identified.
- A program for samples quality must be tailored for physicochemical analyses that allow the water quality evaluation.
- A program must be set up to train the personnel for the sampling, manipulation and analysis of the water tests.
A plan for the analyses must be elaborated, as follows:
- Water quality control programs for the determination of the concentration of the parameters versus the admitted limits.
- Water quality characterization program to facilitate the assessment of the parameters for a certain period of time
- Programs for the identification of the pollutions sources necessary for the pollutants evaluation.
· Anions recognized as water pollutants that interfere in the ecosystems equilibrium
· Cations of heavy metals known as major pollutants according to the specificity of the industrial activities in the interested areas
· Organic compounds arising as results of human activities.
DETERMINATION OF EXTRACTABLE COMPOUNDS WITH SOLVENTS
Normative: SR 7587 QUALITY OF WATER
This method is a gravimetric one and is used to determine the content of substances that can be extracted with organic solvents from surface water and wastewater. Solvents used are: petroleum ether or hexane or carbon tetrachloride.
The extractable substances are: animal fat and vegetable oil (mineral oil, heavy oil), compounds with functional groups like hydroxyl, carbonyl, carboxyl, organic nitrogen compounds, insecticides, soaps, waxes, resins and tars that are extracted with solvents,
The method is applied if the content of extractable substances in analyzed water is between 20 and 500 mg /L. All the reagents are p.a. quality and water used as solvent is distillated water.
The final result represents the mean value of three determinations made in the same time.
Sampling is done in a perfectly clean glass container following the rules described in SR ISO 5667-10 or SR ISO 5667-6. If the sample must be preserved because the analysis is not immediately made, add 5 ml HCl with density 1.19 g/cm3, diluted 1:3 to 1L water sample.
Procedure: acidify sample to pH less than or equal to 2, extractable substances are extracted with organic solvent three or four time, the organic extract is evaporated to dryness and, is determined by weighing, the amount of extracted substances.
Method of calculation:
Extractable substances= (m2 – m1)/V – (m4 – m3)/V mg/L, where:
m2 - capsule mass without residue
m1 - capsule mass with residue from sample
m3 - capsule mass without residue, blank sample
m4 - capsule mass with residue from blank sample
V – volume of water sample, L
NITRATE ION CONTENT IN WATER
The objective of this analyze is to determine the nitrate ion content in surface water samples. Maximum error of the method is 5%.
Preparation of water samples
Water samples are taken in glass or plastic vessel, observing the prescriptions in force relating to water sampling. Before taking samples of water, dishes must be very well washed. To prevent some changes in the balance nitrate through biological activity, the nitrate determination must be done immediately after water samples harvesting .If the analyze cannot be done immediately, 4 cm3 chloroform must be add to 1000 cm3 water sample and then kept at low temperatures pending the determination.
Analyze is made using specific analytical kit. Analytical kits are analytical indicator strip, which shows specific color at one end area impregnated with an active identifying color reagent.
There are several types of kits, all but the base principle of colorimetric methods (color change caused by reaction between dye and reagent identification identified).
The main component of such a kit is represented by the active area of the analytical band, where the color reaction occurs.
A. RESEARCH ON REMEDIATION WITH BIOSORBENTS OF HEAVY METAL POLLUTED WATERS
Various toxic heavy metal ions discharged through different industrial activities, constitute one of the major causes of water pollution. Heavy metal residues in contaminated habitats may accumulate in microorganisms, aquatic flora and fauna, which in turn, may enter into the human food chain and result in health problems.
Common treatment processes for metal contaminated waste streams include chemical precipitation, membrane filtration, ion exchange, carbon adsorption, and co-precipitation/adsorption.Among these, adsorption process has been found as one of the most promising technologies in water pollution control in terms of cost, simplicity of design and operation.In the last years new methods based on biosorbtion were developed. Taking into account the copper-accented pollution in the region of Bor, Serbia, the research will consider the adsorption of this metal in the first laugh and then the removal of cadmium which is a highly toxic metal.Cadmium and cadmium compounds as compared to other heavy metals are relatively water soluble therefore mobile in soil and tends to bioaccumulations in tissues and bodies.
Our research has the following purposes:
- Finding a low cost sorbents;
- Experiments on removal of copper and cadmium, testing the adsorption capacity of selected material on water artificially polluted with copper and cadmium.
- Preparation of modified biosorbent (chemical reactions)
- Testing the adsorption capacity of modified biosorbent on water artificially polluted with copper and cadmium;
- Evaluation of treatment efficiency by the absorption curves comparatively with untreated biosorbent;
- Testing the adsorption capacity of modified biosorbent on sample of polluted water from Bor river;
- Proposal for a treatment technology of industrial water polluted with heavy metals (Cu and Cd).
B. LITERATURE STUDY ON PHYTOREMEDIATION OF SOILS CONTAMINATED WITH HEAVY METALS
Bioharvesting of metals from high biomass crops grown in soil substrates particularly those associated with sub-economic mineralization is termed phytomining. It is a recent more advanced technology of phytoremediation to produce low volume of biomaterial, which can either be safely disposed of or, if the target metal is of sufficient economic value, smelted, and recovered. This technology has potential application in the mineral industry to return an economic profit by commercial production of metals via cropping.
A successful phytomining process depends on adequate biomass yield and high metal contents in the harvestable parts of the plants. Many metals are largely immobile and their bioavailability to plant root is restricted. The bioavailability of metals for plant uptake and biomass can be increased by bringing modulation in both internal (plant associated) and external (soil associated) factors: plant associated factors, soil associated factors, fertilizers etc.
The literature study will conclude with a monographic work.