الفهرس 
chapter 1Only 14 pages are availabe for public view
 |  | from | 381 |  |  |
| | | from | 381 | | |
Abstract
Summary
Environmental pollution is one of the major problems of the world and it is increasing day by day due to urbanization and industrialization. In the last six decades Lake Manzala subjected to various threats among of them a high polluted as toxic heavy metals and pesticides due to progressive increase of industrial and agricultural drainage, as well as sewage out fall from the surrounding governorates. The released organic compounds and heavy metals are one of the key factors that exert negative influences on man and environment causing toxicity to water, fish and other forms of biotics and abiotics that are continually exposed to potentially toxic heavy metals. Thus, much attention has been paid to the investigation of heavy metal concentrations in different fish body parts because fish plays an essential role in the human diet; such information will help ensure that high levels of heavy metals are not being transferred to humans via fish consumption. In recent years, various methods for heavy metal treated from wastewater and fish have been extensively studied. This current study for was removal of heavy metal from wastewater and Oreochromis niloticus (Nile tilapia) by using 1-[2-Thiazolylazo]-2-naphthol (TAN) and 4-[2-Thiazolylazo] resorcinol (TAR), and also used antioxidants for protection of O. niloticus.
1. Chapter one: Introduction
Contains the introduction which included two parts:
Part 1:
General introduction: Which give a brief idea about problem of pollution and its reasons. Also, took on the definition of heavy metals, sources, classifications, dangerous and them effects on human. In addition, information given about fish and its importance, factors which effects on bioaccumulation of heavy metals, pathways of metals accumulation in fish, economic importance of O. niloticus and Lake Manzala. In the last give a brief idea about azo compound and its application.
Part 2:
Literature survey review: Gives a literature survey on heavy metals determination in aquatic environment and fish in Egypt and specially Lake Manzala in through last years. Also, the previous studied for spectrophotometric methods in determined some metal ions special Zn(II), Cd(II) and Pb(II) with azo compound. Survey took about metal complexes for schiff bases and azo compounds. Addition, gives a literature survey of some the previous studied about methods of removal of heavy metals from water and fish.
2. Chapter 2: Materials and Methods
The experimental part which includes information about instruments and chemicals were used for this study. Also, consist of synthesis procedures thiazolylazo compounds (TAN and TAR). This chapter comprises working procedures which performed for UV/VIS spectrophotometric to determine optimum reaction conditions and also validation protocol. In addition, preparation method of thiazolylazo complexes derived from TAN and TAR ligand with metals (Zn(II), Cd(II) and Pb(II)) for structural characterization, thermal and biological activity determined. Also, procedures for determination heavy metals in water and fish samples in Lake Manzala including; site description, sampling, digestion, analysis of heavy metals, and statistical analysis were performed. An experiment designed to investigate possibility of removal heavy metals from water and fish was done.
3. Chapter 3: Results and discussion
This chapter consists of the result and discussion and includes five parts.
Part (I):
Spectrophotometric studied of thiazolylazo ligands as 1-[2-Thiazolylazo]-2-naphthol (TAN) and 4-[2-Thiazolylazo] resorcinol (TAR) that form coordination compounds with metal ions (Zn(II), Cd(II) and Pb(II)) under optimum conditions (pH, buffer volume, ligand concentration, solvents, sequence of addition, reaction time, reaction temperature). The metal ligand ratio (M:L) in alcoholic aqueous solutions as determined by the “molar ratio” and by “continuous variation” methods, both indicate 1:2 for Zn (II) and Cd(II) and Pb(II) complexes. The molar absorptivity (L/mol.cm) for Zn (II), Cd(II) and Pb(II) with TAN were found to be 3.636 x 103 at λmax= 535 nm, 5.298 x 103 at λmax= 565 nm, and 1.381 x 104 at λmax= 485 nm, respectively, while with TAR found to be 2.753 x 103 at λmax= 500 nm 3.356 x 103 at λmax= 505 nm, and 3.909 x 103 at λmax= 530 nm, respectively. Beer’s law is obeyed in the range of (0.2 - 1.6) µg/mL and (0.1 - 1.4) µg/mL for TAN and TAR metal complexes respectively. This part contains the validation result of all metal ions complexes (Limit of detection (LOD), Limit of quantification (LOQ), Linearity test and Reproducibility). However, the results shown that, the proposed method is the advantageous over other methods due to wider range of determination, higher accuracy, increased stability and lower time consumption. Also, the proposed method has been successfully applied to determination of metal ion at trace level in different water types.
Part (II):
Solid complexes of thiazolylazo ligands as 1-[2-Thiazolylazo]-2-naphthol (TAN) and 4-[2-Thiazolylazo] resorcinol (TAR) with Zn (II) and Cd(II) and Pb(II) were studied and identified with the structure by elemental analysis, (IR and 1H NMR spectra) and also thermal analysis (TG and DTG) techniques. Therefore, from CHN analysis, IR, 1H-NMR spectra and thermal decomposition confirmed that TAN behaves as mono negative tridentate chelating agent, coordinating through the phenolic ring atom oxygen, the azo group nitrogen and thiazole ring nitrogen, for complexes of Zn(II) and Cd(II). While TAN ligand with Pb(II) and also TAR ligand with Zn(II), Cd(II) and Pb(II) behaves as tridentate chelating agent where the ligand complex with two metal ions in the same time, it coordinates to first via thiazole ring nitrogen and azo group nitrogen, in the same time it coordinates to the other ion through thiazole ring sulfur. The solid complexes had the general formula [M(L1)2].nH2O; M=Zn(II), (n=2) and M=Cd(II), (n=4), [M2(L1)(NO3)4.H2O].nH2O; M=Pb(II) (n=1) where L1=TAN, while [M2(L2)(NO3)4.H2O].nH2O; M=Zn(II) (n=1) and M= Pb(II) (n=2), [M2(L2)(Cl)4.H2O].nH2O; M= Cd(II) (n=3) where L2= TAR.
In addition, the thermal analysis studies indicated that final decomposition product corresponds to respective metal oxides. The kinetic thermodynamic parameters such as: E∗, ΔH∗, ΔS∗ and ΔG∗ are calculated from the DTG curves, all complexes are more ordered activated complexes than the reactants, and decomposition processes are endothermic. Molecular docking was used to predict the binding between azo compounds with the receptor of prostate cancer 2q7k-Hormone. The biological activity of the two ligands and their metal complexes was evaluated against some kinds of Gram positive Gram negative bacteria and Fungi.
Part (III):
The present work evaluated the concentrations of Zn(II), Cd(II) and Pb(II) in water of Lake Manzala. The same metals were measured in muscles, gills and liver of O. niloticus fish that were collected from the same study area. Also, the physical and chemical properties of the water were determined. The sampling were collected from three sites from El Manzala Lake, including El-Genka (I), EL-serw (II) and Lagan (III( and where their choice due to their relation with pollution. The samples were taken from three sites at every season from January until October 2014.
The study results showed that the mean concentrations heavy metals (Zn(II), Cd(II) and Pb(II)) were 2.12, 0.07 and 0.53 ppm, respectively in lake water. from results of this study, El-Genka site generally showed the highest heavy metals concentrations in water, while Lagan site appeared to be the lowest polluted region of the lake. In addition, the highest metal levels in the water were found during summer, while the lowest levels occurred during winter and autumn. Concentrations of these metals in water of Lake Manzala showed seasonal variations during the study period and generally were high comparing to the permissible limit recommended.
In fish muscles, the mean concentrations of heavy metals as (Zn(II), Cd(II) and Pb(II)) were 4.65, 0.09 and 0.47 ppm, respectively. The mean of Zn(II), Cd(II) and Pb(II) in the gills of fish were 16.47, 0.3 and 1.91 ppm, respectively. The mean concentrations of same heavy metals in the liver were 20.87, 0.14 and 0.58 ppm, respectively. from the results of this study indicated that generally O. niloticus samples from El-Genka and El-Serw sites the highest metal concentrations in their tissues, while Lagan site was the lowest polluted region in fish tissue. Also, metal accumulation in O. niloticus samples during summer, spring and autumn (hot and warm) seasons were showed higher than winter season. In addition, the order of metals accumulation in fish organs in this study were as the following gills> liver> muscle. Our results indicated that, the highest concentrations of elements were found in gills and liver while the lowest concentrations of metals in muscle. Thus, the gills and liver of fish are more often recommended as environmental indicator organs of water pollution than other organs. In this study, the average concentrations of metals in fish organs were found in the order Zn(II)> Pb(II)> Cd(II).
The results of the present study showed that the metal concentrations in tissues of muscles, gills and liver were several times higher than water. So, the concentration of metals in various organs of O. niloticus reflects the degree water pollution in aquatic environments in which such fish are living.
Finally the muscle tissue of O. niloticus collected from the studied area in Lake Manzala may pose health risk to consumer, as concentration of Pb(II) and Cd(II) exceeded some those of permissible limits as (EC and EU).
Part (IV):
In this part, the effect of addition of TAN and TAR on the removal of heavy metals (Zn(II), Cd(II) and Pb(II)) from polluted water and O. niloticus tissues were tested. The results showed that the lowest concentrations of Zn(II), Cd(II) and Pb(II) in water were recorded in group exposed to TAR when compared to TAN group and control lake group. In addition, the order of heavy metals removal in water was; Zn(II)> Pb(II)> Cd(II) by exposure to TAN and TAR.
The results showed a significant decrease in concentration of Zn(II), Cd(II) and Pb(II) in all of the TAN and TAR treated groups in tissues of O. niloticus compared with control lake and tap water groups.
In all concentrations tested, the largest decline in levels of Zn(II) and Cd(II) were found in liver of O. niloticus exposed to TAN or TAR followed by gills then muscle, while Pb(II) levels was the largest eliminate in gills of O. niloticus treated with to TAN and TAR followed by liver then muscle. So, muscle tissue showed the lowest eliminated of all elements. In addition, the order of removal in heavy metals contents in different tissues of O. niloticus was: Zn(II)> Pb(II)> Cd(II) by exposure to TAN and TAR.
from results of this study, muscle, gills and liver of O. niloticus the Zn(II), Cd(II) and Pb(II) concentrations decreased with increased time exposure to TAR and TAN where elimination occurred high ratio in first month of removal period then simply increased until end of the experiment.
Present results indicated that TAR and TAN are effective in removal of Zn(II), Cd(II) and Pb(II) from polluted water and reducing bioaccumulation in fish, their effects were pronounced than control groups.
Part (V):
In this part, protection possibility of some O. niloticus tissues from Zn(II), Cd(II) and Pb(II) by using mixtures of vitamins (C and E) were studied. from the present results, when compared to the control lake group, it was found that both levels of Zn(II), Cd(II) and Pb(II) in tissues of O. niloticus treated with 0.25% and 0.5% vitamins had decrease levels. The concentrations of Zn(II), Cd(II) and Pb(II) decreased with the increase in vitamins ratio.
Also, the results showed that liver of O. niloticus treated to 0.25% and 0.5% vitamins was the highest elimination to Zn(II), Cd(II) and Pb(II) followed by gills then muscle. In addition, Zn(II), Cd(II) and Pb(II) accumulations in tissues of O. niloticus were decreased with increased protection period in all treatments, where reduction occurred from the first month of protection period then gradually increased until end of the experiment. Furthermore, the order of heavy metals reduction in muscle, gills and liver of O. niloticus after three months exposure to 0.25% and 0.5% vitamins have the order Zn(II)> Pb(II)> Cd(II), thus Cd(II) is released much more slowly from tissues. Therefore, it could be concluded that dietary ascorbic acid (vitamin C) and α-tocopherol (vitamin E) are efficient for reduction of Zn(II), Cd(II) and Pb(II) toxicity from fish tissues.
The current study clarified that using of TAN and TAR efficiently remove Zn(II), Cd(II) and Pb(II) from polluted water as chelating agents decreasing them in tissues of fish improving aquaculture ecosystem of fish, they are not toxic toward the aquatic environment. Also results indicated that using of vitamins especially vitamins (C and E) have the affinity to protect fish from heavy metals. from results, we concluded that using of TAN and TAR was more effective than using vitamins, as its results appeared from the first month. So TAN and TAR as synthetic materials are a promising tool for controlling Zn(II), Cd(II) and Pb(II) pollution in aquaculture. Thus, we give advice to use TAN and TAR as chelating agent for remove heavy metals from polluted water, after more experiments to know its effect on fish physiological processes.