RESUMO
The rapid urbanization and industrialization of Warri and environs between 1968 and 1990 have some adverse consequences due to accumulation of diverse categories of pollutants from drilling, production, and refining of crude oil and production of petrochemicals, especially black carbon. Persistent itching, foreign body sensation, and specified areas of conjunctival/limbal discoloration were used as markers for pollution keratoconjunctivitis (PKC). Children attending eye clinics in Delta State government hospitals located at Warri, Ekpan, and Aladja were sampled. Warri and Ekpan, both oil-producing areas, were used as the experimental group. Aladja, also within the same location but a nonoil-producing area (steel industries), was used as the control. The levels of black carbon and tetraethyl lead (TEL) were measured in the tear film of 100 children selected by a simple random technique from each location. Biochemical assays showed that the tear samples contained some levels of TEL among the sample population, and the TEL content was 0.01 microg/mL for all the tear samples. Stereomicroscopy gave the following estimated values of black carbon content washed off the external adnexia of the sample population: Ekpan 2%/mL, Warri 1.5%/mL, and Aladja 0.6%/mL. The results also show that occurrence of the three major clinical signs and symptoms of PKC (persistent itching, foreign body sensation, specified limbal/conjunctival discoloration, respectively) were as follow: Ekpan, 79, 68, and 65%; Warri, 55, 53, and 50%; Aladja, 26, 22, and 16%. This indicates that higher particulate concentrations of black carbon correlated with increased prevalence of the markers for manifestation of PKC. This implies that the markers for PKC in this experiment are more pronounced in oil-producing areas.
