Prevalence of heavy metals and antibiotic resistance of solid waste in a landfill

Antibiotics, heavy metals, and related antibiotic resistance bacteria (ARB) in municipal solid waste (MSW) landfills have aroused more attention due to their potential risk to the ecosystems and public healthcare. However, their contents and relationships have yet to be systematically understood in a landfill setting in Malaysia. Therefore, the prevalence of heavy metals and antibiotic resistance were observed in this study. This study selected solid waste samples of fresh or aged MSW from two representative garbage hills from Jabor- Jerangau landfills, Kuantan, Pahang. The samples were tested for ICP-MS for the concentration of heavy metals and diffusion discs for antibiotic resistance. The total content of measured heavy metals between new and aged garbage hills ranged from 0.2 mg/kg (Ni) to 108.19 mg/kg (Fe) and 0.01 mg/kg (Cu) to 31.92 mg/kg (Fe), respectively. No significant difference (p>0.05) between the new and aged MSW indicated time, and any treatments available for MSW did not affect its concentration. Fe was observed as the most concentrated heavy metal in these landfills. All isolates (100%) in fresh MSW were resistant to erythromycin, penicillins G, tetracyclines and sulfamethoxazole. However, 50% of the isolates in aged MSW were resistant to the tested antibiotics, whereas all isolates in aged MSW have susceptibility to sulfamethoxazole p<0.05. The data gained from this study can be used to plan appropriate treatment for both contaminants. This baseline information is critical for guiding future research, waste management policies, and public health interventions to address the growing concern of antibiotic resistance.