Monitoring of suspended particulate matter (SPM), heavy metals and other parameters in some workplaces
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This report presents results of measurements of sound levels, chemical analysis of air particulate matter and soil samples from two factories in Nairobi. A preliminary assessment of suspended particulate matter (SPM) in a residential site and its possible impacts on acute respiratory infections (ARI) of children under five years of age is also reported. Our investigations show that for Factory A, the Soil pH measurements within the Factory were more basic (pH=8.5) than those collected near a complainant's residence (pH=7.2). The sound level measurements showed that the maximum noise level recorded was 90 dB. This was at a distance of about 0.5 m from the main exhaust vent of the Factory (20 m above ground level). There was a strong ''detergent-perfume'' odour within and outside the Factory premises especially towards the complainant's side. However, the odour fluctuated. There was also no smoke emissions noticed during the site visits when the factory was operational. For Factory B, the major source of environmental degradation was drainage and management of the factory effluents. The BOD and COD levels for effluents samples analyzed (<350 mg/L, <450mg/L respectively) are considered high for direct disposal into the municipal sewer system. The wastewater was heavily loaded with particulate matter-total dissolved solids (TDS) (1240-1550) mg/L and the total suspended solids (TSS) (1170-3732) mg/L. All these levels are higher than the recommended Kenyan standards for BOD (<20mg/L), COD (<50mg/L), TDS (<1200mg/L) and TSS (<30mg/L). The soil and sediment samples analyzed contained heavy metals such as chromium, lead, copper, zinc and possible organic compounds. The sediment samples from the bottom of the disposal underground waste tank were contaminated with lead (250-300 μg/g), copper (3.56-4.04)%, total chromium (0.91-0.94)% and zinc (847-940 μg/g). The proposed remedy for cleaning up the soil at this site was to remove and stabilize the contaminants in order to reduce the potential for migration of contaminants from soil to ground water, public exposure to contamination and inhalation of dust, direct contact with, or ingestion of contaminated soil particles. The assessment of suspended particulate matter (SPM) in a residential site was done at Kibera. The SPM data collected over an eight-month period (May-December 1998) had the coarse particles (8.01 μm) ranging from 62.4-107.5 μm/m3 whereas the fine particles ranged from 16.2-24.4 μm/m3. The prevalence of ARI cases in 1998 ranged between 29.9% in January to the highest level of 59.6% in June. The total number of children who presented themselves throughout the study period, January-December 1998, was 146. A parallel study of dust sampling was also carried out from January to December 1998 in a typical office environment. Dust levels recorded from the working office environment at the Institute of Nuclear Science was found to range from 0. 44 -1.79 μg/cm2/day.