الفهرس 
AcknowledgementOnly 14 pages are availabe for public view
 |  | from | 189 |  |  |
| | | from | 189 | | |
Abstract
The major objective of this study is to assess the toxicity and bioaccumulation of heavy metals associated with selected industrial emissions in Alexandria. Tanneries at Max Industrial Complex and Egyptian Copper Works at H~gar EI-Nawatya were c30sen for the study. Untreated wastes from these industries causing remarkable water poll ution in Alexandria. The program included the study of the lethal and sublethal effect of the raw and treated effluents of both industries using Tilapia zillii Gerv. Experimental studies were performed from October 1982 to November 1983. The results of tannery waste water analyses showed that, the main pollution constituent were putrefiable organic matter; chromium and high conoentration of salts. Dissol ved oxygen was not found. Examined effluents do not comply with the emission limitation of the Egyptian Law. The results of fish toxicity bioassay showed that, the 96-hr. TIm was very low (4 ). This means that, the effluent of tannery waste waters is highly toxic. The results of subl ethal assessment showed that Fe and Cu were the dominant metals in the waters. On the other hand, Cr was not detec ted for long-term exposure due to its rapid precipition. Also, after the first month of exposure, there were insig nificant variations in Pe and Cu in the waste water. The results of bioaccumulation showed that, the concentrations of heavy metals were most~ higher in the liver than in the gills and flesh of the fish. The influence of tannery wastes on feeding activity were insignificant for all r~ concentrations. In this study laboratory tests were conducted to assess the efficiency and design criteria for the following trea tment processes: Screening; Plain sedimentation; Sedimenta tion with chemical coagulants; Activated sludge process and Sand filtration. The following results of treatment show: 1- Screening achieved 4 and 8 reduction in BaD and S.R. respectively. 2- Plain sedimentation for 24 hrs. achieved removal of 48 S.S.; 28.9 BaD; 85.5 chromium. The significant reduction of chromium by this process was attributed to the coagulation capacity of chromium. )- Alum coagulation were proved to be effective in removals of 62.6 S.S.; 24.7 BaD. Insignificant removals of heavy metals were noted. . 4 Activated sludge study was conducted using detention time 18 hrs. with a feeding rate 2.0 L/h. stable foam was encountered and controlled. The effluent of activated sludge process resulted in appreciable reduction in BaD; COD; and V.S. (79.4 ; 75.’7 ; 53.5 ) respectively. 5 Significant removals efficiency were achieved by sand filtration, which removed 92.7 BOD; 91.4 COD; 86.5 ~ of NH3 and most of trace metals. The results of fish toxicity b10assay showed that, treatment of tannery waStes by plain sedimentation incr e~ed the 96-h. TL to 20 while chemical coagulation ID were ineffective. The best results were obtained by tertiary treatment (60 ) due to the reduction 0: most pollutants from the effluent. The results of sublethal assessment showed that, there were insignificant variations between the control and tertiary treatment in the bioaccumulation of Fe and Cu in the flesh of the fish. The influence of treated tanneries on feeding activity were insignificant for different methods of treatment. On the other hand) the results of copper effluent analyses . showed that, copper waste was characterized by high concen trations of heavey metals (Cu and Fe) and a moderate levels of organic matter as measured by BOD and COD. Dissolved oxygen was insufficient for aquatic life. The results of fish toxicity bioassay showed that, the 96-hr. TL were m 100 ) due to the reduction 0: most pollutants from the effluent. The results of sublethal assessment showed that, there were insignificant variations between the control and tertiary treatment in the bioaccumulation of Fe and Cu in the flesh of the fish. The influence of treated tanneries on feeding activity were insignificant for different methods of treatment. On the other hand) the results of copper effluent analyses . showed that, copper waste was characterized by high concen trations of heavey metals (Cu and Fe) and a moderate levels of organic matter as measured by BOD and COD. Dissolved oxygen was insufficient for aquatic life. The results of fish toxicity bioassay showed that, the 96-hr. TL were m 100 and 40 concentrations. At 60 and higher concentrations the response were signi ficant at 5 level. The condition of the fish flesh were decreased cQntinually. In this study, laboratory tests were conducted to assess the efficiency and design criteria for the following treatment processes: (1) Treated effluent’ using activated carbon. (2) Treated effluent using activated clay. Results of treated copper effluent showed that, most pollutants were appreciably reduced by adsorption. ~e 96-hr. TL were 100 for different methods of treatment. ID The results of sublethal assessment showed that, there were insignificant variations between the control and treated effluent. The heavy metals accumulation in different organs of the fish was significantly higher for fish exposed to raw waste in comparison with those exposed to treated efflu ent using either activated carbon or clay. The influence of treated copper effluent on feeding activity were insignificant.