Malodour and health risks in the surroundings of an animal rendering plant

Background and Aim. Volatile Organic Compounds (VOCs) emitted from animal rendering processes, may be hazardous and/or malodorous. This study was conducted in the vicinity of a rendering plant in Southwest Greece, during operation and after its compulsory cessation. The aim was to assess the odour annoyance and the possible carcinogenic and toxic risks, derived from VOCs in ambient air. Methods. VOCs were absorbed onto Tenax TA/Sulficarb sorbents via active sampling and analyzed by Thermal Desorption-Gas Chromatography-Mass Spectrometry. Odour Activity Values (OAVs) were calculated for odorants. Health risks were determined by probabilistic risk assessment. Past and present odour nuisance perceived by residents was assessed through a questionnaire. Results. A substantial reduction in ambient air concentrations of VOCs (47 %) was found after closure of the plant. Seventeen compounds totally disappeared, of which four (propanoic and butanoic acids, dimethyl trisulfide, 2-nonenal) were immensely malodorous. The total odour burden, as expressed by the sum of OAVs, decreased by 70 %. Residents reported a definite drop in the frequency, intensity, duration and annoyance of the odour. Non-specific health symptoms (nausea, respiratory problems, etc.) that participants were experiencing in the past, no longer occur. During the operation period, the cumulative Lifetime Cancer Risk (LCR) for the general population was calculated to be 10 times higher than the acceptable risk. The cumulative mean Hazard Quotient (HQ = 3.3), indicated a high risk of adverse health effects. After activity termination, LCR decreased by 3-fold, while HQ remained almost the same. Conclusions. Three major issues, odour disturbance, cancer and toxic risks were imposed on the surrounding population by a rendering plant, which was not operating under the Best Available Techniques framework. A significant amelioration of life quality was reported by residents after activity termination. Keywords Odorous compounds; Health risk assessment; Rendering; VOCs; Residents' perception