DECA: A new model for assessing the foliar uptake of atmospheric lead by vegetation, using Lactuca sativa as an example

Abstract

Keywords:Lead Foliar uptake Modelling Atmospheric particulate matter Lettuce Health risk assessment a b s t r a c tIn the context of peri-urban atmospheric pollution by industrial lead recycling emissions, metal can transfer to plant shoots. Home gardeners consuming their produce can therefore be exposed to metal pollution.The Human Health Risk Assessment Protocol (HHRAP) model from the United States Environmental Protection Agency (US EPA) classically used in risk assessment provides foliar metal uptake predictions for large farms but is not adapted to cultures in kitchen gardens. Thus, this study developed a new model, entitled "DECA", which includes individually measured parameters and the washing of vegetables before human consumption.Results given by DECA and HHRAP models were compared with experimental measurements of lettuce. The data calculated by the DECA model were highly correlated with the measured values; the HHRAP model overestimates foliar lead uptake. Moreover, strong influences of factor of washing and time-dependent variations of loss coefficient were highlighted. Finally, the DECA model provided important risk assessment data regarding consumption of vegetables from kitchen gardens.

Lead and Cadmium Phytoavailability and Human Bioaccessibility for Vegetables Exposed to Soil or Atmospheric Pollution by Process Ultrafine Particles

“…The maximum allowable concentrations of Pb and Cd in commercial vegetables are 3 and 2 mg Pb kg −1 dry weight, respectively (Honour et al, 2009; Morman and Plumlee, 2012). The washing procedure removed a maximum 30% of total Pb, in accordance to previous studies on lettuce exposed to similar conditions (Schreck et al, 2012a,b). The metal concentrations measured in vegetables significantly differ as a function of exposure type (foliar or root), metal nature (Pb or Cd), plant type (lettuce, radish, or parsley), and plant part type (roots or leaves).…”

“…The exposure of the plants was restricted to atmospheric fallout by placing a geotextile membrane on the top of the unpolluted soil (25.5 ± 1.6 mg Pb and 0.45 ± 0.05 mg Cd kg −1 of dried soil) to avoid soil contamination and metal transfer via root uptake, as described by Uzu et al (2010) and Schreck et al (2012a,b).…”

“…The physicochemical properties of the soil were: pH water of 8.5, cation exchange capacity of 6.9 cmol (+) kg −1 , and soil organic matter and carbonates (CaCO 3 ) content of 6 and 4 g kg −1 , respectively. Light, temperature, humidity, and pluviometry were controlled during the experiment as reported by Schreck et al (2012b).…”

“…Plants were grown in pots to ensure that the soil used was uniform and relatively free of metal contamination. The annual emission of PM from the smelter is 328 kg (Schreck et al, 2012b). The emitted PM was previously characterized by Uzu et al (2011b).…”

“…During the vegetable exposure experiments, Pb concentration in industrial atmospheric fallout was characterized in the smelter courtyard by collecting bulk depositions in Owen gauges (Taylor and Witherspoon, 1972) following the procedure described by Schreck et al (2012b) and Gandois et al (2010). Metal concentrations of Pb and Cd in atmospheric fallout were 450 ± 7 and 0.8 ± 0.1 mg m -2 mo -1 , respectively.…”