Potential human inhalation exposure to soil contaminants in urban gardens on brownfields sites: A breath of fresh air?

Abstract

Urban gardening has been experiencing increased popularity around the world. Many urban gardens are located on sites that may be contaminated by trace elements or organic compounds due to previous use. The three main exposure pathways to the human body for soil contaminants are (a) ingestion of soil directly, (b) consumption of produce containing or superficially contaminated with a contaminant, (c) and inhalation of soil dust. The first two modes have received much attention; however, the contribution of the inhalation route has not been investigated adequately. Two inhalation risk studies were carried out in urban gardens located in Kansas City, MO, by collecting dust while 25-m 2 plots were rototilled. Microclimatic variables were monitored, and total inhalable dust mass was determined using a personal sampling train including a small pump and air filter. Soil lead (Pb) concentration was assessed at both sites. For Study 1, particle size distribution of collected particles was estimated through analysis of scanning electron microscope images of filters. Little dust was collected at either site. Most particles captured, however, appeared to be <4 μm in diameter. The amount of dust emitted was correlated with soil moisture. Tilling reduced soil aggregate size and blended soil, resulting in a more homogeneous distribution of Pb. Dust inhalation while tilling is likely not a major Pb exposure risk for gardeners, but given the preponderance of very small particles in what was captured, care should be taken to prevent dust from entering the respiratory system.

Application and demonstration of meso-activity exposure factors to advance estimates of incidental soil ingestion among agricultural workers

“…Exposure to chemicals in soil may occur via dermal contact with soil, inhalation of soil particles that become airborne, and incidental ingestion of soil [20]. Of these pathways, the ingestion pathway is the most poorly understood.…”

Brownfield land and health: A systematic review of the literature

“…A large proportion of studies focused on the remediation process, economic impact, and risk assessment. Health impact assessments of brownfield land have been conducted in several locations [8][9][10][11][12], which focused on estimating potential population health effects due to proposed policy changes or intervention [13,14]. Yet, there is still a lack of epidemiological evidence that assesses the relationships between brownfield land and adverse health effects.…”