The relationships between content of heavy metals in soil and in strawberries

Fractionation of metals in soil for strawberry cultivation: Effect on metal migration in food chain and application in risk assessment

Although trace metals in strawberry production system have attracted growing attention, little is known about metal fractionation in soil for strawberry cultivation. We hypothesized that the metal fractions in soil influenced by strawberry production had significant effect on food chain transport of metals and their risk in soil. Here, samples of strawberries and soil were gathered in the Yangtze River Delta, China to verify the hypothesis. Results showed that the acid-soluble Cr, Cd, and Ni in soil for strawberry cultivation were 21.5%-88.3% higher than those in open field soil, which enhanced uptake and bioaccessible levels of these metals in strawberries. Overall, the ecological, mobility, and health risks of Pb, Zn, Ni, and Cu in soil were at a low level. However, the ecological risk of bioavailable Cd, mobility risk of Cd, and cancer risk of bioavailable Cr in over 70% of the soil samples were at moderate, high, and acceptable levels, respectively. Since the increased acid-soluble Cr and Ni in soil were related to soil acidification induced by strawberry production, nitrogen fertilizer application should be optimized to prevent soil acidification and reduce transfer of Cr and Ni. Additionally, as Cd and organic matter accumulated in soil, the acid-soluble Cd and the ecological and mobility risks of Cd in soil were enhanced. To decrease transfer and risk of Cd in soil, organic fertilizer application should be optimized to mitigate Cd accumulation, alter organic matter composition, and subsequently promote the transformation of bioavailable Cd into residual Cd in soil.

Accumulation, migration and health risk of trace metals in a soil-strawberry-human system of the Yangtze River Delta region, China

Growing concern has been paid to metals in soil-strawberry system. In contrast, few attempts have been made to investigate bioaccessible metals in strawberries and further assess health risk based on bioaccessible metals. Moreover, the connections between soil parameters (e.g. soil pH, organic matter (OM), total and bioavailable metals) and metal transfer in soil-strawberry-human system still need to be systematically investigated as well. Considering that strawberries are extensively grown under plastic-shed conditions in China, a total of 18 paired plastic-shed soil (PSS) and strawberry samples were taken from the strawberry bases located in the Yangtze River Delta of China as a case study to assess accumulation status, migration and health risk of Cd, Cr, Cu, Ni, Pb, and Zn in the PSS-strawberry-human system. Overall, heavy application of organic fertilizers induced accumulation and contamination of Cd and Zn in PSS. In particular, 55.6% and 44.4% of PSS samples had considerable and moderate ecological risk caused by Cd, respectively. Despite no metal pollution in strawberry, PSS acidification mainly caused by high nitrogen input promoted Cd and Zn uptake by strawberry and enhanced bioaccessible concentrations of Cd, Cu, and Ni. In contrast, the increased soil OM caused by organic fertilizer application decreased Zn migration in PSS-strawberry-human system. Additionally, bioaccessible metals in strawberries induced limited non-cancer and cancer risk. To mitigate accumulation of Cd and Zn in PSS and metal transfer in the food chain, feasible fertilization strategies should be developed and carried out.

Chemometric Valorization of Strawberry (Fragaria x ananassa Duch.) cv. 'Albion' for the Production of Functional Juice: The Impact of Physicochemical, Toxicological, Sensory, and Bioactive Value

Strawberries (Fragaria x ananassa Duch. cv. 'Albion') were harvested at two stages of ripeness (75% vs. 100%) and their physicochemical, sensory, toxicological, and bioactive properties were evaluated before and after processing into juice. The fresh fruits and their by-products were also evaluated. During processing into juice, the color change was higher in the fully ripe fruits, confirming the encouraging prospects for using the less ripe strawberries for processing. The analysis of heavy metals (Cu, Zn, Ni, As, Cd, Pb) was carried out, and in juice and by-product samples of 100% maturity, only Pb was higher than the MDK. Of the 566 pesticides analyzed, only cyprodinil was found in the by-products of the strawberries at 75% maturity, while pyrimethanil was detected in all samples. Fresh strawberries of both ripeness levels were rated similarly to the corresponding juices for all sensory attributes studied, indicating that sensory perception was not affected by processing. However, ripeness was found to be an important factor influencing most sensory attributes. The by-products were the materials with the highest levels of all bioactive compounds. Considering all quality parameters evaluated, the chemometric evaluation confirms the suitability of 75% ripe strawberries for processing into functional juice, which could be important for the juice industry.