Lead transfer into the vegetation layer growing naturally in a Pb-contaminated site

Novel metallomic profiling and non-carcinogenic risk assessment of botanical ingredients for use in herbal, phytopharmaceutical and dietary products using HR-ICP-SFMS

Knowledge of element concentrations in botanical extracts is relevant to assure consumer protection given the increased interest in plant-based ingredients. This study demonstrates successful multi-element investigations in order to address the lack of comprehensive profiling data for botanical extracts, while reporting for the first time the metallomic profile(s) of arnica, bush vetch, sweet cicely, yellow rattle, bogbean, rock-tea and tufted catchfly. Key element compositions were quantified using a validated HR-ICP-SFMS method (µg kg-1) and were found highly variable between the different plants: Lithium (18-3964); Beryllium (3-121); Molybdenum (75-4505); Cadmium (5-325); Tin (6-165); Barium (747-4646); Platinum (2-33); Mercury (5-30); Thallium (3-91); Lead (12-4248); Bismuth (2-30); Titanium (131-5827); Vanadium (15-1758); Chromium (100-4534); Cobalt (21-652); Nickel (230-6060) and Copper (1910-6340). Compendial permissible limits were not exceeded. Overall, no evidence of a health risk to consumers could be determined from consumption of the investigated plants at reasonable intake rates. Mathematical risk modelling (EDI, CDI, HQ, HI) estimated levels above safe oral thresholds only for Cd (16%) and Pb (8%) from higher intakes of the respective plant-derived material. Following high consumption of certain plants, 42% of the samples were categorised as potentially unsafe due to cumulative exposure to Cu, Cd, Hg and Pb. PCA suggested a potential influence of post-harvest processing on Cr, Ti and V levels in commercially-acquired plant material compared to wild-collected and farm-grown plants. Moreover, a strong correlation was observed between Pb-Bi, Be-V, Bi-Sn, and Tl-Mo occurrence. This study may support future research by providing both robust methodology and accompanying reference profile(s) suitable for the quality evaluation of essential elements and/or metal contaminants in botanical ingredients.

Effects of melatonin on growth and antioxidant capacity of naked oat (Avena nuda L) seedlings under lead stress

Melatonin (MT) plays an important role in plant response to abiotic stress. In recent years, lead (Pb) pollution has seriously affected the living environment of plants. In this study, we applied two different concentrations of MT to naked oat seedlings under Pb stress to explore the effect of MT on naked oat seedlings under Pb pollution. The results showed that Pb stress seriously inhibited the growth and development of naked oat seedlings, which was alleviated by MT. MT could increase the soluble protein content and decrease the proline content of naked oat seedlings to maintain the osmotic balance of naked oat seedlings. The application of MT could accelerate the removal of reactive oxygen species (ROS) and improve the activities of superoxide dismutase (SOD), peroxidase (POD) and catalase (CAT), so as to maintain the redox balance in naked oat seedlings. Exogenous melatonin could significantly increase the chlorophyll content of naked oat seedlings under Pb treatment, so as to improve the photosynthesis efficiency of naked oat seedlings. MT could also remarkably up regulate the expression of the genes of LOX, POX and Asmap1, and affect the expression of transcription factors NAC and WRKY1. It might regulate the expression of downstream genes through MAPKs pathways and TFs to improve the Pb tolerance of naked oat seedlings. These results proved that MT could significantly promote the growth and development of naked oats seedlings under Pb stress, which is expected to be applied in agricultural production practice.

Tolerance and Heavy Metal Accumulation Characteristics of Sasa argenteostriata (Regel) E.G. Camus under Zinc Single Stress and Combined Lead–Zinc Stress

Sasa argenteostriata (Regel) E.G. Camus is a gramineous plant with the potential for phytoremediation. In this study, we aimed to determine its tolerance to zinc stress and combined lead–zinc stress and the effect of zinc on its absorption and accumulation characteristics of lead. The results showed that S. argenteostriata had good tolerance to zinc stress, and S. argenteostriata was not significantly damaged when the zinc stress concentration was 600 mg/L. Under both zinc stress and combined lead–zinc stress, the root was the main organ that accumulated heavy metals in S. argenteostriata. The presence of zinc promoted the absorption of lead by the root of S. argenteostriata, and the lead content in the root under PZ1, PZ2, PZ3 and PZ4 treatments was 2.15, 4.31, 4.47 and 6.01 times that of PZ0 on the 20 days. In the combined lead–zinc stress treatments, the toxicity of heavy metals to S. argenteostriata was mainly caused by lead. Under high concentrations of combined lead–zinc stress (PZ4), the proportion of zinc in the leaf of S. argenteostriata on the 20 days increased, which was used as a tolerance strategy to alleviate the toxicity of lead.

Contamination, Spatial Distribution and Source Analysis of Heavy Metals in Surface Soil of Anhui Chaohu Economic Development Zone, China

Anthropogenic activities may result in the accumulation of heavy metals in the soil, especially in economic development zones with frequent industrial activities. Therefore, the investigation and assessment of soil heavy metal pollution in economic development zones is one of the important measures for soil environmental management and sustainable development. This study used Nemero evaluation, Kriging interpolation, cluster analysis, and principal component analysis to investigate the contamination degree, spatial distribution, and origin of heavy metal in Anhui Chaohu Economic Development Zone (ACED), Anhui, East China. The result showed that different land use types can cause different levels and types of soil heavy metal pollution. The maximum concentrations of heavy metals in the study area all exceeded their background value but did not exceed the guide values. The highest average concentrations were found in Zn, followed by Cr and Ni. The concentrations of As in soils have the largest coefficient of variation (CV) at 38%. The concentration of heavy metals in different functional areas was varied, the areas with higher Ni, As, Cd, Zn, and Cr concentrations were mainly distributed in Hot Springs Resort (HSR), the relatively higher concentrations of Pb, Hg, and Cu were mainly distributed in Integrated Zone (IZ), while all heavy metal (except for Ni) have relatively higher content in the surface soil of Huashan Industrial Zone (HIZ). Origin analysis showed that soil As, Cd, and Zn in HSR surface soil were predominantly influenced by agricultural activities, while Ni and Cr were mainly controlled by parent material. Pb and Hg in IZ surface soil were predominantly originated from the vehicle and domestic exhaust, and Cu was mainly controlled by industrial pollutants. Industrial activity was the main source of soil heavy metals in HIZ. Although heavy metal in ACED surface soil did not reach pollution levels, the concentration of Cd, Hg, Pb, and Cu was significantly affected by anthropogenic activities, especially in HIZ, which the necessary attention of heavy metals needs to be given.