INTEGRATED RISK ASSESSMENT OF LABORATORY SAFETY COMPLIANCE: EVALUATING CHEMICAL AND MICROBIAL EXPOSURE IN INDOOR AIR QUALITY AT THE RUBBER RESEARCH INSTITUTE OF NIGERIA

Background: VOCs, heavy metals, and airborne microbial contaminants pose high occupational health risks in laboratory environments. Poor ventilation, improper chemical handling, and inadequate biosafety measures contribute to indoor air pollution, which may result in respiratory disorders, neurotoxicity, and cancer.

Objective: This study aimed to characterise chemical and microbial risks associated with airborne exposure in the laboratory environment by analysing VOCs, heavy metals, and airborne bacteria.

Method: Six laboratories at the Rubber Research Institute of Nigeria were sampled to determine air quality levels in the six laboratories at the institute. VOC analysis was carried out by Gas Chromatography-Mass Spectrometry (GC-MS), and heavy metal content was analysed by Inductively Coupled Plasma Mass Spectrometry (ICP-MS). The contamination with microbes was quantified and identified by culture-based methods. Statistical analysis assessed laboratory-type variations (ANOVA, t-tests, Pearson correlation).

Results:The study identified acetone (1.475 ppm), xylene (1.167 ppm), and toluene (0.825 ppm) as the most prevalent. Chronic exposure is a concern, even though benzene (0.115 ppm) and formaldehyde (0.588 ppm) were not above OSHA regulatory limits. These include heavy metals: mercury (0.148 ppm), cadmium (0.052 ppm) and nickel (0.193 ppm), which exceeded the recommended exposure limit and may exceed neurotoxicity and carcinogenicity. The analysis of airborne microbes proved high airborne bacterial loads Staphylococcus aureus (174.8 CFU/m³) and Escherichia coli (135.7 CFU/m³) exceeded WHO air quality guidelines. Although nickel (133.33 per million) and arsenic (112.89 per million) had cancer risk (CR) values above the USEPA solubility threshold, the CR values suggest a high probability of long-term cancer risk.

Conclusion: The results confirm that chemical and microbial pollutants vary across laboratory types, and pathology and agronomy laboratories are the most contaminated.

Recommendation: The study recommends increasing ventilation and air filter systems to reduce VOCs and microbial contaminants and running high-risk laboratories under BSL2/BSL3 protocols.