Determination Of Heavy Metals In Dust From Lecture Halls In A University In Nigeria: Assessment Of The Health Risks:- Njoku Johnpaul C

ABSTRACT This study determined the levels of 7 heavy metals Cr, Pb, Ni, Cd, Co, Fe and Cu in indoor dust collected in the lecture halls of six (6) colleges of Michael Okpara University of Agriculture, Umudike, Umuahia, Abia state, Nigeria. The dust samples were collected using foam and a plastic spatula in August, 2018 and analyzed for the levels of nickel, chromium, cobalt, copper, iron, lead and cadmium using Company Agilent Technologies (AAS280FS) Atomic Absorption Spectrophotometer. Based on the results it revealed wide range of concentrations ol the heavy metals; in the study area, Iron recorded a mean concentration ranging from 0.0012ppm to 202.271 ppm while Cadmium recorded a mean concentration level ranging from 0.0022ppm to 0.036ppm. Similar results in the study area showed that Nickel recorded a mean concentration level ranging from 0.107ppm to 0.426ppm. Lead recorded a mean concentration level ranging from 0.695ppm to 1.08ppm. Copper recorded a mean concentration level ranging from 0.06ppm to 0.146ppm. Cobalt and Chromium were not detected in the study area. According to the Hazard Quotients values by (Inhalation Exposure Pathway), Cd ranges from 1.65X10’9 to 3.00xl0's in samplesCPand CA respectively, Cu ranges from 1.67X1O*10 to 7.O4xlO'loin samples CN and CT respectively, Ni ranges from 3.14X1O’10 to 9.99X1O’10 in samples CA and CN respectively, Pb ranges from 2.33x1 O'7 to 4.53x1 O'7 in samples CT and CA respectively, Fe ranges from 1.12X10'8 to 6.70xl0’14in samples CN and CP respectively. Then by (Ingestion Exposure Pathway), Cd ranges from 3.36X10’6 to 5.54X10’5 in samples CP and CN respectively, Cu ranges from 1.36X10'6 to 3.81X10’6 in samples CT and CF respectively, Ni ranges from 0.35X10’6 to 1.79X10’5 in samples CA and CN respectively, Pb ranges from 1.62X10’4 to 2.52X10’4 in samples CT and CA respectively, Fe ranges from 1.20x1 O'9 to 2.43xl0’4in samples CP and CM respectively.The Values for the Hazard Index are as follows; Cd ranges from 5.01 xlO’13 to 8.26X10’13 in samples CP and CN respectively, Cu ranges from 4.49X10’17 to 8.40 X10’17 in samples CM and CT respectively, Ni ranges from 3.49X10’16 to 11.78 X10’15 in samples CA and CN respectively, Pb ranges from 3.95 X10’16 to 7.05x10’“ in samples CT and CA respectively, Fe ranges from 3.12X10’12 to 7.90 xlO’23 in samples CN and CP respectively. Also, comparison of the element levels in the lecture halls dust samples with the ambient air permissible limits established by the United Nations Environmental Protection Agency (UNEP’s) shows that the aveiage levels of I b and Fe were higher than the permissible limits.Due to average contents of elements in the dust samples, especially Pb and Fe were higher than the air permissible limits; the indoor dust can cause adverse effects on human health. Therefore, control of the anthropogenic sources that cause discharge of hazardous compounds particularly toxic heavy metals into the outdoor, indoor, and street dust, is recommended.