As one of the most popular beverages around world, factors influencing transfer of heavy metals from soil to tea leaves is crucial to investigate and assess health risk through tea drinking. Parent material (PM), soil and tea samples from Anhui province, typical tea producing area in China were collected in this study. To find out distribution characteristics of heavy metals in tea and soil, and influencing factors for transfer process, variables of plantation factors, soil properties and geological background were taken into account. The results showed that weathering pedogenic process could be the main release source of heavy metals in soil under the acid environment for tea growth. More than 75% of soil Cd, Hg, Pb and Zn exceeded background. However heavy metals in tea samples were below the limits of China, WHO and EU standards. Soil organic matter and redox process influenced the distribution and transfer of As, Pb, Cd and Hg in soil and tea. While geochemical behaviours of Cr, Cu, Ni and Zn were mainly related to soil pH and iron oxides in tea garden. The method of classification and regression trees (CART) showed clones of tea type, bedrock type, soil texture, soil organic and fertilizer application were identified as the main factors influencing transfer factors of heavy metals from soil to tea. The specific types of tea grown in the soil with sandy clay and bedrock of granite/granodiorite and shale should be given more monitoring. The non-carcinogenic hazard quotients (HQ) and cancer risk (Risk) through tea drinking were primarily caused by Pb and Cd respectively. To reduce the potential health risk from tea, application of organic and/or compound fertilizer were thought to be the effective management strategy for tea plantation.

Geological load and health risk of heavy metals uptake by tea from soil: What are the significant influencing factors?

Cadmium (Cd) toxicity is highly detrimental for the human and largely originated from faulty industrial and agricultural practices. Cadmium toxicity can be observed in minute concentration and highly mobile in the soil–plant system and availability in soil is mainly governed by various physio-chemical properties of the soil. Cereals and vegetables cultivated in peri-urban areas, former mining and industrial areas accumulate Cd in toxic limit as they receive Cd from multiple ways. In general, when the total cadmium (Cd) concentration in soil exceeds 8 mg kg−1, or the bioavailable Cd concentration becomes >0.001 mg kg−1, or the Cd concentration in plant tissue reaches 3–30 mg kg−1 most plants exhibit visible Cd toxicity symptoms. The impacts of Cd toxicity are seed germination, growth, photosynthesis, stomata conductance, enzyme activities and alteration in mineral nutrition. The major source of Cd in human is food chain cycle and causes disorders like “itai-itai” disease, cancer, and nephrotoxicity. Cadmium harms kidney, liver, bone and reproductive body parts and may be fatal in serious condition. WHO recommended the tolerable monthly Cd intake are 25 μg kg−1 body weights and in drinking water Cd concentration should not exceed 3 μg L−1. It is hard to remove these potent and hazardous metals from the environment as they have long mean residence time but, can be converted into less toxic form through bioremediation. This chapter focuses on the effect of Cd toxicity in soil–plant-human continuum and its bioremediation techniques to mitigate the Cdtoxicity.

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Toxicity of Cadmium in Soil-Plant-Human Continuum and Its Bioremediation Techniques

Mine waste can constitute an environmental hazard, especially when poorly managed. Environmental assessment is essential for estimating potential threats and optimizing mine waste management. This study evaluated the potential environmental risk of sulfidic mine waste samples originating from the Neves Corvo Mine, Portugal, and the closed Freiberg mining district, Germany. Metal(loid)s in the waste samples were partitioned into seven operationally defined fractions using the Zeien and Brummer sequential extraction scheme. The results showed similar partitioning patterns for the elements in the waste rock and tailing samples from Neves Corvo Mine; most metal(loid)s showed lower mobility, as they were mainly residual-bound. On the contrary, the Freiberg tailing sample had considerably elevated (24–37%) mobile fractions of Zn, Co, Cd, and Mn. The majority of Fe (83–96%) in all samples was retained in the residual fractions, while Ca was highly mobile. Overall, Pb was the most mobile toxic element in the three samples. A large portion of Pb (32–57%) was predominantly found in the most mobilizable fractions of the studied waste samples. This study revealed that the three mine wastes have contamination potential for Pb and Zn, which can be easily released into the environment from these waste sources.

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Fractionation of Metal(loid)s in Three European Mine Wastes by Sequential Extraction

Plant species sustaining under a polluted environment for a long time are considered as potentially resistant species. Those plant species can be considered as an eco-sustainable tool used to bio-monitor and mitigate pollution. This study was carried out on a total of ten commonly available plant species to assess their anticipated performance index (API), dust capturing capacity (DCC), and metal accumulation index (MAI) in chromite mine and control areas. According to the anticipated performance index (API), Macaranga peltata (Roxb.) Müll.Arg., Holarrhena pubescens Wall. ex G.Don and Ficus hispida Roxb. ex Wall. are highly tolerant species while Terminalia arjuna (Roxb. ex DC.) Wight & Arn. and Trema orientalis (L.) Blume are intermediate tolerant species. F. hispida was also shown to have the highest dust capturing capacity (5.94 ± 0.43 mg/cm2) whereas that of Woodfordia fruticosa Kurz (1.03 ± 0.11 mg/cm2) was found to be lowest. The metal accumulation index ranged from 17.29 to 4.5 and 6.38 to 1.94 at the mine and control areas, respectively. Two-way ANOVA analysis revealed area-wise significant differences between biochemical and physiological parameters. Also, results showed that the pollution level and heavy metal affected different biochemical and physiological parameters of plant species at the mining area. The plant species with the highest API, DCC, and MAI value could be recommended for greenbelt development in different polluted areas. 

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Pollution resistance assessment of plants around chromite mine based on anticipated performance index, dust capturing capacity and metal accumulation index

Geochemical fractionation, bioavailability, ecological and human health risk assessment of metals in topsoils of an emerging industrial cluster near New Delhi

An attempt has been made to assess the geoavailability of heavy metals in polluted soils using short sequential fractionation schemes. For this purpose, 25 composite soil samples were collected fro...

V.K. Trivedi

Papers

Assessing Geoavailability of Zinc, Copper, Nickel, Lead and Cadmium in Polluted Soils Using Short Sequential Extraction Scheme