Baseline-contaminant metal concentrations in sediments from Lake Manzalah, Nile Delta, Egypt: Aquaculture at risk

Conference · Wed Jan 01 04:00:00 EST 1992 · Geological Society of America, Abstracts with Programs; (United States)

OSTI ID:6059547

Siegel, F R; Slaboda, M; Bagchi, S ^[1]; Stanley, D J ^[2]

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1. George Washington Univ., Washington, DC (United States). Dept. of Geology
2. Smithsonian Institution, Washington, DC (United States)

Cored sediments collected from Lake Manzalah, Egypt, December, 1990, were analyzed for 24 chemical elements. These include metals from industrial discharge that may be bioaccumulated by fish and humans. Lake Manzalah provides more than 50% of the total Egyptian food fish catch. Half of this catch is from the Ginka sub-basin which receives sewage (nutrient) and other discharge via the Bahr-El-Baqar drain. C-14 dated long cores give a sedimentation rate of 0.5 cm/yr for the study area. The 1 m cores studied may contain an environmental geochemistry log of about 200 years. Pre-industrial metal values, and rate and timing of any pollutant input to the lake can be estimated. Of seven cores analyzed, two have high concentrations for several potentially toxic metals in their upper 20 cm (Hg, 822 ppb; Pb, 110 ppm; Zn, 635 ppm; Cd, 1.3 ppm; Cu, 275 ppm; As 7 ppm; Sn, 18 ppm; Cr, 215 ppm; and others). These elements correlate among themselves and with C-org suggesting their bioavailability. This correlation level is not found between element contents and mineralogy. The discharge resulting in high metal concentrations in these lake sediments may be from between 1960 and 1970. This suggests an origin in discharge from major industries that developed after the emplacement of the High Dam at Aswan in 1964. The core with the highest metal contents is close to the outfall from the Bahr-El-Baqar drain in the Ginka aquaculture sub-basin. A second core with high metal values is 1.6 km from the outfall along the sub-basin current flow. There is potential for bioaccumulation of heavy metals to high concentrations in fish from the Gink sub-basin of Lake Manzalah. If these metals pass through the food web to humans, continuous ingestion presents a long-term health risk to consumers. Metal contents of fish from this area should be closely monitored.

• OSTI ID: 6059547
• Report Number(s): CONF-921058--
• Conference Information: Journal Name: Geological Society of America, Abstracts with Programs; (United States) Journal Volume: 24:7
• Country of Publication: United States
• Language: English

Related Subjects

54 ENVIRONMENTAL SCIENCES
540310* -- Environment
Aquatic-- Basic Studies-- (1990-)
AFRICA
AQUACULTURE
ARAB COUNTRIES
ARSENIC
BIOLOGICAL AVAILABILITY
CADMIUM
CHEMISTRY
CHROMIUM
CONTAMINATION
COPPER
DEVELOPING COUNTRIES
ECOLOGICAL CONCENTRATION
EGYPTIAN ARAB REPUBLIC
ELEMENTS
FISHERIES
FOOD CHAINS
INDUSTRIAL WASTES
LAKES
LEAD
MERCURY
METALS
MIDDLE EAST
SEDIMENTS
SEMIMETALS
SURFACE WATERS
TIN
TRANSITION ELEMENTS
WASTES
WATER CHEMISTRY
ZINC