Ultrafine Particle–Driven Toxicity from Plastic Waste Combustion: Haematological Disruption and Redox Imbalance in Experimental Rats

Open burning of plastic waste is a widespread disposal practice with potential systemic toxicological consequences. This study evaluated haematological and oxidative stress responses in albino rats exposed to smoke from burning plastics for 5, 10, 20, and 30 minutes daily over seven days. Air quality assessment revealed predominance of ultrafine particulates (PM₀.₃ = 293,156 N/L), elevated carbon monoxide (433 ppm), and hydrogen sulphide (39 ppm), indicating incomplete combustion and high inhalation risk. Haematological parameters showed duration-dependent alterations. Red blood cell count declined from 8.40×10⁶/µL in controls to 5.70×10⁶/µL in the 30-minute group, while haemoglobin decreased from 14.90 g/dL to 9.65 g/dL and packed cell volume from 44.50% to 28.50%. Total white blood cell count increased from 6.35×10³/µL to 11.35×10³/µL, with neutrophils rising from 59.5% to 73.5%. Platelet counts decreased from 645×10⁵/µL to 465×10⁵/µL. Oxidative stress markers demonstrated tissue-specific effects. Serum malondialdehyde increased from 0.62 µmol/L in controls to 1.76 µmol/L at 20 minutes, while hepatic MDA rose to 0.59 µmol/L at 30 minutes. Pulmonary MDA was significantly elevated at longer exposure durations. Reduced glutathione showed adaptive elevation in serum and lungs but declined in kidney tissue at 30 minutes. Catalase activity decreased significantly in serum at selected durations, whereas superoxide dismutase showed early elevation followed by attenuation with prolonged exposure. These findings demonstrate that repeated inhalation of burning plastic smoke induces systemic inflammation, erythrocytic suppression, and redox imbalance in a duration-dependent manner, underscoring significant public health implications.