Soil contamination and persistence of pollutants following organophosphate sprays and explosions to control red-billed quelea (Quelea quelea).

Background: Red-billed quelea (Quelea quelea) are controlled at breeding colonies and roosts by organophosphate sprays or explosions. Contamination with organophosphates after sprays and with petroleum products and phthalates after explosions was assessed.

Results: Concentrations in soil of the organophosphate fenthion the day after sprays were uneven (0-29.

Effects of the organophosphate fenthion for control of the red-billed quelea Quelea quelea on cholinesterase and haemoglobin concentrations in the blood of target and non-target birds.

The red-billed quelea bird Quelea quelea is one of sub-Saharan Africa's most damaging pests, attacking small-grain crops throughout semi-arid zones. It is routinely controlled by spraying its breeding colonies and roosts with organophosphate pesticides, actions often associated with detrimental effects on non-target organisms. Attributions of mortality and morbidity of non-targets to the sprays are difficult to confirm unequivocally but can be achieved by assessing depressions in cholinesterase activities since these are reduced by exposure to organophosphates.