Research on derivation of formaldehyde screening values for construction land soil
Formaldehyde is a quintessential pollutant in industries such as textiles,leather,furniture,chemical raw materials and chemical manufacturing,with improper disposal or leakage of formaldehyde wastewater leading to severe soil contamination.The guidelines for risk assessment technology in China have not yet provided toxicological parameters and screening values for formaldehyde,resulting in significant discrepancies in the toxicological parameters used by entities during the assessment process.This leads to considerable uncertainty in deriving the screening value for formaldehyde.Urgent need to systematically summarize the potential hazards and main exposure pathways of formaldehyde to human health,and establish the physicochemical toxicity parameters of formaldehyde.The findings indicated that the predominant exposure route of formaldehyde was through inhalation,primarily causing respiratory carcinogenicity and non-carcinogenic toxicity effects through oral intake.Based on scientific evidence and timeliness from both domestic and international sources,this conclusion demonstrated the inhalation unit risk factor(IUR)at 1.1 × 10-2 m3·mg-1,the inhalation reference concentration(RfC)at 7×10-3 mg·m-3,and the oral reference dose(RfDo)at 2×10-2 mg·kg-1·d-1 for formaldehyde;further,according to models recommended by the national guidelines,the screening values are derived for Category 1 land at 32.7 mg·kg-1 and Category 2 land at 59.5 mg·kg-1.The dominant exposure pathway for formaldehyde was inhalation of outdoor gaseous pollutants in the surface and lower soil layers,and factors such as the average time of cancer effect(ATca),the flow velocity of the mixed zone(Uair),the height of the mixed zone(δair),and the duration of gaseous pollutant intrusion(τ)significantly influenced the screening values obtained.
health risk assessmentformaldehydesoil screening valuetoxicity parametersexposure pathway
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