Residue levels of organochlorines and mercury in Cattle Egret, Bubulcus ibis, eggs from the Faiyum Oasis, Egypt
- Wageningen Agricultural Univ. (Netherlands) Foundation for Ornithological Research in Egypt, Belfort (Netherlands)
- Universita di Siena (Italy)
In Egypt, the Cattle Egret Bubulcus ibis is a common resident bird of the Nile Valley, the southern part of the Nile Delta, and the Suez Canal area. In the 1970s it disappeared as a breeding bird from the greater part of the Nile Delta, as did several other bird species, notably birds of prey. Only in recent years some of the species that had declined are markedly recovering, such as the Black-shouldered Kite Elanus caeruleus and the Cattle Egret. There is circumstancial evidence that these birds declined - at least partially - as a result of pesticide use in the main cotton growing areas, but this has never been substantiated. The recent recovery of some bird populations, commencing in the 1980s, coincides with a general shift from the use of organochlorines (except for endrin and HCH which are still in use) towards synthetic pyrethroids, organophosphates and carbamates in Egyptian agriculture: 30 million kg of formulated product annually, of which 70% are applied to cotton. The number of breeding pairs of Cattle Egrets in a well-known colony at Giza (30[degrees].01'N 31[degrees].13'E) steadily declined from 2500 in 1977 to 1100 in 1984. Therefore, it was decided to collect some eggs for residue analysis. Cattle Egrets are not piscivores, such as most other egrets, but mainly insectivores. They feed in agricultural areas and likely are good indicators for pesticide use in these habitats. Based on gizzard contents analysis, Kirkpatrick (1925) concluded that Cattle Egrets in Egypt only occasionally take (semi) aquatic prey, such as toads, and further predominantly Orthoptera and Diptera on arable land. Various studies have been published with respect to pesticides or heavy metals in the Egyptian environment but, surprisingly, birds have been almost completely ignored. The data presented are the first residue analyses of bird eggs from an agricultural area in Egypt, and as such they can be considered as baseline data for future research. 36 refs., 2 tabs.
- OSTI ID:
- 6524509
- Journal Information:
- Bulletin of Environmental Contamination and Toxicology; (United States), Vol. 48:5; ISSN 0007-4861
- Country of Publication:
- United States
- Language:
- English
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Related Subjects
63 RADIATION, THERMAL, AND OTHER ENVIRON. POLLUTANT EFFECTS ON LIVING ORGS. AND BIOL. MAT.
BIRDS
EGGS
EGYPTIAN ARAB REPUBLIC
RIVER DELTAS
MERCURY
BIOLOGICAL ACCUMULATION
ORGANIC CHLORINE COMPOUNDS
AFRICA
ANIMALS
ARAB COUNTRIES
COASTAL REGIONS
DEVELOPING COUNTRIES
ELEMENTS
METALS
MIDDLE EAST
ORGANIC COMPOUNDS
ORGANIC HALOGEN COMPOUNDS
VERTEBRATES
540320* - Environment
Aquatic- Chemicals Monitoring & Transport- (1990-)
560300 - Chemicals Metabolism & Toxicology