A review of measured bioaccumulation data on terrestrial plants for organic chemicals: Metrics, variability, and the need for standardized measurement protocols

Abstract

Quantifying the transfer of organic chemicals from the environment into terrestrial plants is essential for assessing human and ecological risks, using plants as environmental contamination biomonitors, and predicting phytoremediation effectiveness. Experimental data describing chemical uptake by plants are often expressed as ratios of chemical concentrations in the plant compartments of interest (e.g., leaves, shoots, roots, xylem sap) to those in the exposure medium (e.g., soil, soil porewater, hydroponic solution, air). These ratios are generally referred to as "bioconcentration factors" but have also been named for the specific plant compartment sampled, such as "root concentration factors," "leaf concentration factors," or "transpiration stream (xylem sap) concentrations factors." We reviewed over 350 articles to develop a database with 7049 entries of measured bioaccumulation data for 310 organic chemicals and 112 terrestrial plant species. Various experimental approaches have been used; therefore, interstudy comparisons and data-quality evaluations are difficult. Key exposure and plant growth conditions were often missing, and units were often unclear or not reported. The lack of comparable high-confidence data also limits model evaluation and development. Standard test protocols or, at a minimum, standard reporting guidelines for the measurement of plant uptake data are recommended to generate comparable, high-quality data that will improve mechanistic understanding of organic chemical uptake by plants. Environ Toxicol Chem 2018;37:21-33. C 2017 SETAC

Improved prediction of the bioconcentration factors of organic contaminants from soils into plant/crop roots by related physicochemical parameters

“…As noticed, when log RCF (soil) is plotted against log K ow in Fig. 2(A), no distinct patterns emerge (R 2 < 0.16), as recognized in various reports (Cai et al, 2008; Doucette et al, 2018; Macherius et al, 2012; Mikes et al, 2009; Scheunert et al, 1994; Takaki et al, 2014; Tao et al, 2009; Trapp et al, 1990; Wu et al, 2012). Here the RCF (soil) at a given K ow varies by as high as 1400 -fold.…”

“…In addition, many observed RCF (soil) values are < 1, which is in contrast with the trend for organic chemicals concentrating from water into an organic phase. In analyzing a large set of chemical soil-plant data, Doucette et al (2018) and Takaki et al (2014) found a similar wide scatter in plots of log RCF (soil) versus log K ow . The lack of a specific relation between log RCF (soil) and log K ow comes with no surprise in view of C s = f om C om for relatively water-insoluble (high- K ow ) chemicals with a water-saturated soil, where the soil contamination intensity C om is independent of the value of f om (see more discussion in Hung et al, 2009).…”

Natural Purification Through Soils: Risks and Opportunities of Sewage Effluent Reuse in Sub-surface Irrigation

“…Crops contain enzymatic systems such as cytochrome P-450s and their (bio)transformation capacity may be compound as well as crop specific. Non-ionizable, polar, highly water-soluble organic compounds are most likely to be taken up by crops and translocated to shoot tissue (Doucette et al 2018).…”

Remediating Polluted Soils Using Nanotechnologies: Environmental Benefits and Risks

“…Soil is defined as the part of the solid earth that has been altered by the loosening of the earth, humus formation, and chemical decomposition, and by the transportation of humidification and chemical decomposition products [7,[10][11][12][13][14][15][16][17][18][19]. However, when it is examined in detail, soil is a complex structure and the biological and biochemical processes in it are the basis of the terrestrial ecosystems [7,8,[10][11][12][13][14][15][16][17][18][19]. In this respect, it is imperative to examine health changes of the soil and to determine its relationship with the plant.…”