Hydrochemical study of Rain Water In Baghdad city-Iraq

:- The chemical substance dissolved in rain water are generally considered to have two atmospheric sources, dry fallout and/or soluble salts. The present study deals with the rain water year 1995-1996 at Baghdad city were expressed in term of monthly averages of the collected samples . The concentrations values of cations (Ca, Mg, K and Na) and anions (Cl, SO 4 and HCO 3 ),were expressed as average annual. All ions concentration, are found to be within the excepted range of fresh water. These results were compared with rain water year 1985-1986. Appreciable reduction in concentrations of both cations and anions have been recorded, and the percentages of reduction are ranging between 28% to 84%. Moreover, by adopting fractionation factor, the results revealed that the sea water have less contribution of all ions concentration than other sources (local activities). The results of the chemical analysis were dealt with statistically by using cluster and factor analysis .

The aim of this paper is to find out the variation of ions concentrations between the tow different water years ( 1985 -1986 to 1995 -1996 ), and revealed the causes of these variations by using the fractionation factor and statistical analysis.

Analysis of the Results :-
The Hydrochemical analysis results of the water year 1995-1996 were expressed in term of monthly averages of the collected samples (Table -2 and K as cations , Cl , SO 4 , HCO 3 as anions.
Due to the fact that early events brings down the long existed dust and chemicals in the air prior to the rainfall events (Al-Jabbari et al. ,1989 ), it can be seen from The concentrations of HCO 3 were ranging between 0.44-1.73meq/l and its average value 0.599 meq/l .The main source of this anions is the CaCO 3 dust which is dominated within the top dry soil, as well as, the agricultural activities ( plantation regions ).Also this anion is reduced within the last ten years, and its percent reduction was 59% .

Concentration Analysis
The composition of rainwater is determined by the source of the water vapor and by the ions which are acquired by water (or lost from it) during transport through atmosphere.Near the sea coast the composition of rainwater strongly resembles the dilution of seawater.As the distance increase towards the urban areas , the concentrations of ions that are directly derived from seawater decreases (Plummer,1996).In industrialized areas additional sources are burning of wastes , power plants and other industry factories will be another contribution during rain events especially for Cl ion.
However , Na in aerosols may also originate from soil dust particles in arid climates in addition to sea salt (Plummer,1996).
Accordingly the distribution of depletion or addition of ions must be non for both rain water and sea water.This situation can be get it by adopting fractionation factor.This reflects the changes of ionic concentrations ratio in rain water with respect to the ionic concentration in sea water, where : In this formula, the Cl and Na concentrations in rain or seawater can be expressed as mol/l , mg/l or any other units, also the above feature of factor means that the concentration is calculated relative to Na.It can be calculate this factor relatively to any cations or anions.if that group of variables have similar behavior.The value (r = ± 0.4) for 99% confidence level was taken as a minimum limit for measuring the degree of correlation between clusters of variables.The cluster analysis R-mode for rain water resulted in the appearance of tree major groups A , B and C (Fig. 1 ).

Statistical analysis of
This analysis has revialed wih three magior groups.Group -A , consisits of the anions which included in the rain water , group -B , consists the cations and trace elements, as well as total hardness (T.H.).
Trace elements in rain water assossiated with the cations, but with less correlations.Total the main source of these ions is plant (Hem,1985).
The third factor, affect with 12.1 % from the total effects, it is consists sulfate ion and lead with less contribution of iron in this factor, it can be attributed this factor to the effect of fuel and manufacturing factor on the rain water, due to fuel components of SO 4 ,pb and Fe .

Counclusions
The results of the study of rain water ,generally, all ions are located within an excepted range of fresh water.
The results of the chemical analysis were dealt with statistically by using cluster and factor analysis.Cluster analysis, R -mode showed 3 major groups, the first group (group -A), consists of the anions (with good correlations), while the major groups (group -B ) included cations, trace elements, and total hardness, it could be explained by association of trace elements with cations in rain water.
Cluster analysis, Q-mode , also, conduct three

Introduction
The chemical substance dissolved in rain water are generally considered to have two atmospheric sources.They may be derived from fairly unreactive dust particles in which case they are deposited as dry fallout, or it may be present as gases or soluble salts which dissolved in rain water itself .The fallout deposited in amount independent of the quantity of precipitation , where as the substance dissolved in precipitation should have concentration that vary with rainfall amount .It has been demonstrated that much of the total dissolved and ionic load of many streams has been contributed by rainfall (Juang and Johnson,1967;Al-Jabbori,1989).Thus the magnitude of the atmospheric contribution must be known .The composition of rainwater is determined by the source of the water vapor and by the ions which are acquired by water (or lost from it) during transport through the atmosphere.Near the coast, the composition of rainwater strongly resembles diluted seawater .As the distance from the coast increases the concentrations of ions that are directly derived from seawater decreases .The study area (Baghdad city) is located in the Mesopotamian alluvial plain between latitudes 33°14' 33°25' N and longitudes 44°31'-44°17'E.The area is characterized by arid to semi arid climate with dry hot summers and cold winters, however, the source of the rain at Baghdad city is from the aerosols blowing from the Mediterranean sea west of the study area.The mean annual rainfall is about 151.8 mm (Al-Adili and Ali,2005).Table-1, showed the hydrochemical results of rain water components analysis at the rain year period 1995 -1996 at Baghdad city.The sampling and chemical analysis were carried out at by the University laboratories .
). Different ions exist within the atmosphere around the year.Their existence are characterized by different rates and they are controlled by many factors, partly climatologically, wind systems in the region and partly local conditions.The main components of rain water are: Ca , Mg , Na Eng.&Tech.Vol26,No4,2008 Hydrochemical study of Rain Water In Baghdad city-Iraq * Asst.Prof./ University of Technology /Building and Construction Department / Dams and Water Engineering branch .** Lecturer / University of Technology / Building and Construction /Dams and Water Engineering branch .408 The results of the chemical analysis were dealt with statistically by using cluster analysis.This analysis is depended on counting several variables of different samples, as well as, finding out the ratio of similarity among variables after comparison with each other ,and arrangements in the form of clusters or dendograms depending on the extent of their presence in the different samples.This is called (R -mode) where pairs of variables were compared with each other for all samples.When comparing these samples with each other depending on variables presence and the arrangement of their correlations in the form of clusters(Qmode) and by explaining these correlations ,the relationship between all the samples and classification could be defined.Pyramid (WARD) method was used in the two types of cluster analysis as it was considered the most modern and best method in such sort of studies.While, the factor analysis was used to minimize the big number of bilateral correlations at developed form and to classify into simple clusters.It was also, considered as one of the branches of multivariable aiming at putting new variables to replace those in the original findings.As with regard to hydrochemical and hydrological studies, the theoretical factors derived and physical operations affecting the rain water during flowing from source till preciptate, as wall as, the new operation (altering operations) such as the ionic exchange, concentration increase and decrease, reaction between water and dusts.In order to find out the similarity matrix bilateral correlations were used in (R-mode) among variables (Al-Adili,1995; Davis,1973).(I) Cluster analysis (R-mode):-The R-mode depended completely on bilateral correlation coefficients among different variables (elements) which disclosed the similarity in hydrochemical behavior of the variables.Likewise the bilateral correlation coefficients would't show clearly Eng.&Tech.Vol26,No4,2008 Hydrochemical study of Rain Water In Baghdad city-Iraq * Asst.Prof./ University of Technology /Building and Construction Department / Dams and Water Engineering branch .** Lecturer / University of Technology / Building and Construction /Dams and Water Engineering branch .408 soluble solids (TSS) correlate with all these in low relation, it could be interpreta and referring that the toatal soluble solids is sum of cations and inions .(II)Clusteranalysis ( Q-mode) :-The purpose of conducting this mode of analysis was finding out the similarity between samples one or all cases depending on measuring the Euclidean distance.The rate of resemblance among samples increased when the distance became closer and vice versa(Al-Gieali, 1989  ).This was done by comparing samples with each other depending upon their variables.It was provided in applying this mode, that the number of these samples was greater than the calculated variables for each sample or at least be equal in number ( Aqrawi and Al -Basree 1988 ).The number of samples in this analysis was amounted to 20 ones of 12 variables (12 elements ).Due to numerous number of samples ,Q-mode analysis results were classified rain water cases (event samples) into three main groups A ,B and C, (fig.-2)thus, this mode assisted us to find out several groups representing the rain water samples.This analysis mode (Q -mode ) showed that group -A , consists of 5 cases (samples) from the analyzied cases,wich represents the moderate concentrations of the analyzied components.That is mean, the meduim events of contribution to rain water sources.While,group -B, consists with 12 samples ( with different deegree of corrolations ).These samples have the lowset concentration of rain water components , and it could be explained as the fresh rain water type with the aerosols origins from the sea water.Nevertheless, the highest salinity and ions concentration are corrolated in a group -C, this relashionship represents the highest polluted cases (samples) due to different sources such as manufacturing process, fuel gaseos and human activties.Eng.&Tech.Vol26,No4,2008 Hydrochemical study of Rain Water In Baghdad city-Iraq * Asst.Prof./ University of Technology /Building and Construction Department / Dams and Water Engineering branch .** Lecturer / University of Technology / Building and Construction /Dams and Water Engineering branch .408This type of analysis, concluded the realtionships of the analyzied samples depending on their components concentration and their origions at aerosoles .(III) Factor Analysis (R-Mode) :-The factor analysis was employed to minimized the great number of correlations among variables and classify them into simple groups finding out new variables in the original findings.There are several types of factor analysis, but the present study focused on R-Mode for it was employed to find out the different correlations among variables (chemical analysis), it also contributed in understanding the nature of rain water origin and water quality.The values less than ( ± 0.4)were considered ineffective whether positive or negative on resulting factors.By using this analysis, three principal and important factors were appeared in explaining the results (Table -8) and they were of eigen values higher than (1) as the eigen value showed the contribution ratio of explaining the variable responding factor (apparent) .The selected factor should have an eigen value for more than (1).These factors had covered 70.15 % of the total variables of the rain water 1995-1996 year, as the first factor formed 37.81 % of the total effects.It had been positively affected by TSS -Na -HCO 3 -Cl -Mg -T.H. -K, which showed the quality of rain water present in the study area reflected by the variables above.This factor indicated the source for these ions by the contributions of agricultural and human activties.While, the seconed factor, represent the total hardness and quality of rain water by covering the T.H. which is measuring of Ca and Mg ions,with effect = 20.24%from the total effects.Howevere, Factor -2 consists Zn ione due to it's origen, Ritter and Rinefierd(1983), mentioned that the high value of Zn is conduct from air born pollution, that's why assosiated with Mg and Ca because year 1995-1996 at Baghdad city showed, by comparison with rain water year 1985-1986, appreciable reduction in concentration of both Eng.&Tech.Vol26,No4,2008 Hydrochemical study of Rain Water In Baghdad city-Iraq * Asst.Prof./ University of Technology /Building and Construction Department / Dams and Water Engineering branch .** Lecturer / University of Technology / Building and Construction /Dams and Water Engineering branch .408 cations and anions, and the percent reduction ranging between 28% to 84%.The composition of rain water is determined by the sources of the water vapor, as well as, by ions which are acquired by water (or lost from it ) adopting fractionation factor in this study, to conduct the distribution and contribution of the depletion or addition of ions in rain water and seawater, the results revealed that the sea water have less contribution of all ions concentration than the other sources in the study area ,due to the far distance between Baghdad city and the costal (Mediterranean sea ), also, the contribution of local activities such as, existed dust and chemicals in air as a gaseous which believed are the main sources of ions in rain water.and anions with those in unpolluted fresh water indicate, that major groups of cases (group of samples), each group representing samples (rain water) with low , moderate, and high concentration of analyzed variables.Factor analysis, R -mode , revealed three major factors affecting with 70.15% of the total variables.The highest effected Factor (with 37.81% ) representing the quality of rain water at the study area and sources of ions.While, the second factor effected with 20.24%, and can be interpreted as the plant contribution as a major source for the rain water.The last factor (with less effect = 12.1 %) attributed this factor to fuel and manufacturing processing as consists of SO 4 , pb , and Fe variables, which means the contribution of those ions at rain water in urban areas .

Table -
meq/l respectively.Soil dust is the main possible source of these ions especially the Ca in rain water, due to Ca make the principle crystalline constituents of the urban dust which is easily eroded by wind action (Al-Jabbari et al.,1989, Gambell and Fisher, 1966).Comparison has been made with the results obtained by Al-Jabbari 1989 for the water year 1985-1986 .As can be seen from

Table -
Lecturer / University of Technology / Building and Construction /Dams and Water 4 demonstrate that the main enrichment ions of marine aerosols are Na and Cl, thus it can be adopted Na or Cl as a respective ions , here using the Na to finding F Na for all cations and anions and hence, reflects the depletion or addition of ions in rainwater with respect to seawater.As can be observed from fractionation factor that, generally, all cations and anions have a high values which indicating an enrichment of ions with respect to Na due to a presence of inland Eng.&Tech.Vol26,No4,2008 Hydrochemical study of Rain Water In Baghdad city-Iraq * Asst.Prof./ University of Technology /Building and Construction Department / Dams and Water Engineering branch .** Lecturer / University of Technology / Building and Construction /Dams and Water **

Table - 7: Correlation coeffecients for rain water at Baghdad city
Eng.&Tech.Vol26,No4,2008 Hydrochemical study of Rain Water In Baghdad city-Iraq * Asst.Prof./ University of Technology /Building and Construction Department / Dams and Water Engineering branch .Lecturer / University of Technology / Building and Construction /Dams and Water **