The influence of land use on the concentration and vertical distribution of PBDEs in soils of an e-waste recycling region of South China

Distributions and compositions of old and emerging flame retardants in the rhizosphere and non-rhizosphere soil in an e-waste contaminated area of South China

“…The geometric mean concentrations of the total PBDEs in RS and NRS samples were 50.6 and 35.4 ng g À1 , respectively. These values were similar to those reported for farmland soils in Qingyuan (2.9e207 ng g À1 ) in South China ) and for soils in the proximity of e-waste recycling areas (28.8e468 ng g À1 ) (Cheng et al, 2014). However, they are much higher than in agricultural soils associated with e-waste dismantling activities in Hong Kong (0.60e8.07 ng g À1 ) (Lopez et al, 2011).…”

Isomer-specific investigation of PCDD/F mobility and other fate processes in deep soil cores

“…Rapidly decreasing concentrations with soil depth, albeit typically within the top 10-20 cm, have been reported elsewhere for a range of HOCs. These include PCBs (Moeckel et al, 2008;Bergknut et al, 2010Bergknut et al, , 2011, DDT (Moeckel et al, 2008), PBDEs (Yang et al, 2010;Cheng et al, 2014), PCDD/Fs (Brzuzy and Hites, 1995;Bergknut et al, 2011) and PAHs (Guggenburger et al, 1996;Wang et al, 2004) released or deposited to agricultural, forest and background soils. This characteristic subsurface concentration gradient has generally been attributed to vertical transport of surface deposits via leaching in the dissolved phase for water soluble compounds (Moeckel et al, 2008) or transport with DOC, POM or other facilitators for more hydrophobic compounds (Guggenburger et al, 1996;Krauss et al, 2000).…”

“…These include hydrology, climate, soil properties, as well as the type and ubiquity of facilitators present (de Jonge et al, 2004;Paria, 2008). The majority of field evidence from remote (Brzuzy and Hites, 1995;Krauss et al, 2000;Moeckel et al, 2008;Bergknut et al, 2010Bergknut et al, , 2011, agricultural (Prange, 2003;Wang et al, 2004;Cheng et al, 2014) or contaminated (Persson, 2007;Yang et al, 2010;Grant et al, 2011) soils report HOC migration typically to depths only up to 0.5-1 m. At most sites, DOC or particulate organic matter (POM) has been proposed as the responsible facilitators. Although scarce, more extensive migration has also been attributed to facilitated processes with surfactants (Grant et al, 2011).…”

Spatial distribution and temporal trends of farmland soil PBDEs: processes and crop rotation effects

“…Wang analyzed the PBDE concentration in Longtang Town and got the total concentration of PBDEs in soil ranged from 4.8 to 533.0 ng/g dry weight (Wang et al 2011). In 2014, Cheng et al (2014) compared PBDEs in soils from paddy field, peanut field, e-waste recycling site, and reference site and found significant correlation between PBDEs with total organic carbon content in soils. The authors found that the total concentration of PBDEs in this region was at a high level and had resulted in substantial human exposure (Wang et al 2014a, b).…”

“…When the crop rotated to autumn peanut in August and the land is turning dry, the PBDEs concentration in farmland soil reached the lowest level which was 8.1 ± 1.2 ng/g dry weight. Many studies showed that PBDEs in water field may be much lower than that in dry field (Cheng et al 2014;Wang et al 2011), and most PBDEs in agricultural soil are accumulated in the rhizosphere area (Wang et al 2014b). But the results of this study showed a trend that the total PBDEs concentration in farmland soil decreased from rice transplanting in April to rice harvesting in August, but increased to a higher level at fallow land period and returned to the highest level in early paddy period when the soil was totally wet at the beginning of the next year.…”