Average Bioaccumulation Factors Research Articles

Assessment of heavy metals bioaccumulation in Silver Birch (Betula pendula Roth) from an AMD active, abandoned gold mine waste.

Acid mine drainage (AMD) is generally outlined as one of the largest environmental concerns, characterized by very low pH value of mine waste, heavy metals and high sulphate content. This extremely hostile environment reduces plant ability to develop and grow. Present study focuses on a silver birch (Betula pendula Roth), a pioneer species that grows on an extremely hostile gold mine waste, to investigate the bioaccumulation of rare metals (thallium (Tl) and indium (In)), as well as nine other more common heavy metals (bismuth (Bi), cadmium (Cd), cobalt (Co), copper (Cu), lead (Pb), manganese (Mn), nickel (Ni), silver (Ag) and zinc (Zn)), and to asses phytoextraction and phytostabilization potential of silver birch. Additionally, parameters determining AMD process and overall contamination (pH, electrical conductivity (EC), sulphates (SO42-), arsenic (As), iron (Fe), oxidation-reduction potential (ORP), turbidity, dissolved oxygen (DO), total dissolved solids (TDS), acidity, hardness, X-ray diffraction (XRD) and radioactivity) were determined in mine waste and drainage water samples. To assess the heavy metals bioaccumulation and mine waste status, statistical geochemical indices were determined: bioaccumulation factor (BCF), pollution load index (PLI), geochemical abundance index (GAI) and exposure index (EI). The results show that silver birch bioaccumulates the essential elements Cu, Ni, Mn and Zn, and the nonessential elements Tl (average BCF = 24.99), In (average BC = 23.01) and Pb (average BCF = 0.84). Investigated mine waste was enriched by Bi, Ag and Cd according to positive values of GAI index. Present research provides a novel insight into bioaccumulation of nonessential heavy metals in silver birches who grow on the extremely hostile mine waste, and they exhibit significant phytoremediation potential.

Heavy metals in five commonly consumed fish species from River Swat, Pakistan, and their implications for human health using multiple risk assessment approaches

This study analyzed the levels of heavy metals bioaccumulation in commonly consumed riverine fish species, including G. cavia, T. macrolepis, G. gotyla, S. plagiostomus, and M. armatus from River Swat in Pakistan, and quantify their potential risk to children and adults in general and fisherfolk communities using multiple pollution and risk assessment approaches. The highest metal detected by inductive coupled plasma mass spectrometry (ICP-MS) was Zn, which ranged from 49.61 to 116.83 mg/kg, followed by Fe (19.25–101.33 mg/kg) > Mn (5.25–40.35 mg/kg) > Cr (3.05–14.59 mg/kg) > Ni (4.26–11.80 mg/kg) > Al (1.59–12.25 mg/kg) > Cu (1.24–8.59 mg/kg) > Pb (0.29–1.95 mg/kg) > Co (0.08–0.46 mg/kg) > Cd (0.01–0.29 mg/kg), demonstrating consistent fluctuation with the safe recommendations of global regulatory bodies. The average bioaccumulation factor (BAF) values in the examined fish species were high (BAF > 5000) for Pb, Zn, Mn, Cu, Cr, Ni, and Cd, bioaccumulate (1000 > BAF < 5000) for Co, and probable accumulative (BAF <1000) for Fe, and Al, while the overall ∑heavy metals pollution index (MPI) values were greater than one (MPI > 1) indicating sever heavy metals toxicity in G. cavia, followed by S. plagiostomus, M. armatus, G. gotyla, and T. macrolepis. The multivariate Pearson's correlation analysis identified the correlation coefficients between heavy metal pairs (NiCr, CuCr, PbCr, AlCo, CuNi, and PbNi), the hierarchical cluster analysis (CA) determined the origin by categorizing heavy metal accumulation into Cluster-A, Cluster-B, and Cluster-C, and the principal component analysis (PCA) discerned nearby weathering, mining, industrial, municipal, and agricultural activities as the potential sources of heavy metals bioaccumulation in riverine fish. As per human risk perspective, S.plagiostomus contributed significantly to the estimated daily intake (EDI) of heavy metals, followed by G.cavia > M.armatus > G.gotyla > T.macrolepis in dependent children and adults of the fisherfolk followed by the general population. The non-carcinogenic target hazard quotient (THQ) and hazard index (HI) values for heavy metal intake through fish exposure were < 1, while the carcinogenic risk (CR) for individual metal intake and the total carcinogenic risk (TCR) for cumulative Cr, Cd, and Pb intake were within the risk threshold of 10−6–10−4, suggesting an acceptable to high non-carcinogenic and carcinogenic risk for both children and adults in the fisherfolk, followed by the general population.

Occurrence, bioaccumulation and trophic transfer of organophosphate esters in marine food webs: Evidence from three bays in Bohai Sea, China

Due to the widespread use of organophosphate esters (OPEs), the occurrence and trophic transfer of OPEs have attracted attentions in ecosystems. However, as the final sink for these chemicals, the bioaccumulations and trophodynamics of OPEs in marine ecosystems are still not clear. In this study, seawater, sediment and marine organisms collected from Bohai Bay (BHB), Laizhou Bay (LZB), and Liaodong Bay (LDB) in Bohai Sea (BS), China were analyzed to investigate the occurrence, bioaccumulation and trophic transfer of typical OPEs. Total concentration of OPEs (∑9 OPEs) in surface water in LZB (255.8 ± 36.44 ng/L) and BHB (209.6 ± 35.61 ng/L) was higher than that in LDB (170.0 ± 63.73 ng/L). Marine organisms in LZB accumulated the highest concentrations of OPEs among the 3 bays (∑10OPEs, 70.56 ± 61.36 ng/g ww). Average bioaccumulation factor (BAF) of OPEs in marine organism in BHB, LZB, and LDB was ranged from −2.48 to 0.16, from −2.96 to 1.78, and from −2.59 to 0.59. We also found that trophic magnification factors (TMF) are generally <1, which suggested trophic dilutions of OPEs in BS, China. Nevertheless, the relatively high OPEs levels in BS still may bring potential risks to ecosystem and human health.

Impacts of Uptake and Accumulation of Cd on Double Rice-Paddy Soil by Silicon Fertilizer Continuous Application

The impacts of silicon (Si) fertilizers on cadmium (Cd) bioavailability in soil and Cd accumulation in paddy-rice plants were investigated in a field positioning test. The results indicated that the continuous application of 180 kg·hm-2 Si fertilizers improved soil bioavailable Si in paddy-rice fields by 108.1%-275.0% and improved pH values by 1.15-1.33 in soil. The difference in the contents of DTPA-Cd in soil by 12.3% and 15.9% was significant in early and late rice, respectively. The continuous application of silicon promoted the transformation of soil cadmium to a stable form and reduced the contents of exchangeable Cd and carbonate binding state Cd in the soil by 2.6%-5.1% and 8.6%-24.9%. The contents of ferric manganese oxide binding state Cd were increased significantly; meanwhile, the contents of organic binding state Cd and residue state Cd in soil were improved by 2.3%-12.8% and 2.3%-6.0%, respectively. The contents of Cd in the root, shoot, and rice were reduced by 38.4%, 49.7%, and 50.9% in early season rice and by 30.6%, 34.4%, and 39.2% in late season rice, respectively. The absorption factors and translocation factors were reduced significantly by 25.5%-49.6% and 13.5%-52.6%, and the average bioaccumulation factors were decreased by 6.0% and 8.0% in early and late season rice. The powder Si fertilizer had the best results overall. In conclusion, Si fertilizer could reduce the absorption and accumulation in rice; however, the continuous Cd reduction effect of continuous application Si fertilizer was not obvious.

Metal(loid)s Spatial Distribution, Accumulation, and Potential Health Risk Assessment in Soil-Wheat Systems near a Pb/Zn Smelter in Henan Province, Central China.

To understand the influence of Pb/Zn smelter on surrounding environment, 110 soil and 62 wheat grain samples (62 paired samples) were collected nearby a Pb/Zn smelter in Jiaozuo City, Henan Province, China. The content and spatial distribution of metal(loid)s in the soil-wheat system, and the potential health risk via consumption of wheat grains were determined. Results showed that the average content of Pb, Cd, As, Cu, Zn, and Ni in soil were 129.16, 4.28, 17.95, 20.43, 79.36, and 9.42 mg/kg, respectively. The content of Cd in almost all soil samples (99.1%) exceeded the national limitation of China (0.6 mg/kg). Spatial distribution analysis indicated that atmospheric deposition might be the main pollution source of Pb, Cd, As, and Zn in soil. In addition, the average content of Pb, Cd, As, Cu, Zn, and Ni in wheat grain were 0.62, 0.35, 0.10, 3.7, 35.77, and 0.15 mg/kg, respectively, with the average Pb and Cd content exceeding the national limitation of China. The average bioaccumulation factor of these metal(loid)s followed the following order: Zn (0.507) > Cu (0.239) > Cd (0.134) > Ni (0.024) > Pb (0.007) > As (0.006). Health risk assessment indicated that the average noncarcinogenic risk of children (6.78) was much higher than that of adults (2.83), and the carcinogenic risk of almost all wheat grain is higher than the acceptable range, with an average value of 2.43 × 10−2. These results indicated that humans who regularly consume these wheat grains might have a serious risk of noncarcinogenic and carcinogenic diseases.

Migration of heavy metals in the soil-grape system and potential health risk assessment

The accumulation of heavy metals in soil may introduce them to the food chain and cause health risks for humans. In the present study, 43 pairs of soil and grape samples (leaf and fruit) were collected form vineyards in the suburbs of Kaifeng city (wastewater-irrigated area in Henan Province, China) to assess the heavy metal (Pb, Cd, Cu, Zn and Ni) pollution level in soil, heavy metal accumulation in different grape tissues and the potential health risk via consumption of grapes. The results showed that the average contents of Pb, Cd, Cu, Zn and Ni in vineyard soil were 42.27, 3.08, 62.33, 262.54 and 26.60 mg/kg, respectively. Some of these soil samples were severely contaminated with Cd and Zn, with an average pollution index (Pi) of 5.14 and 0.88, respectively. Most of these soil samples were severely polluted by heavy metals, with an average Nemerow integrated pollution index (PN) of 3.77. The bioavailable heavy metals were negatively correlated with soil pH and positively correlated with soil organic matter (OM). In addition, heavy metals were more likely to accumulate in grape leaves, and their contents in grape pulp were all within the maximum permissible limit set by China (GB 2762-2017). The average bioaccumulation factors (BFs) of Pb, Cd, Cu, Zn and Ni in grape pulp were 0.007, 0.096, 0.160, 0.078 and 0.023, respectively. Health risk assessment indicated that there was no noncarcinogenic risk for grape consumers (adults and children). However, the carcinogenic risk (CR) ranged from 4.95 × 10−7 to 2.17 × 10−4, and the CR value of three grape samples was higher than 10−4, indicating that a probability of carcinogenic disease existed for humans who regularly consumed the grapes from this region.

Seasonal variation in tissue-borne heavy Metal(loid)s in herbaceous plants growing in contaminated soils developed from industrial wastes of industrial revolution age

• 1-year field monitoring of plant uptake of metal(loid)s from contaminated soils. • Different seasonal variation patterns for different metal(loid)s in shoot tissue. • Shoot-borne heavy metal(loid)s were below permissible levels except for Cd. • Phytoextraction had negligible effects on metal(loid)s except for Cd, Mn and Zn. • Creeping bentgrass ecotype has the potential for clean-up of Cd-contaminated soils. A 1-year monitoring program was performed to examine the seasonal variation in shoot-borne heavy metal(loid)s in a dominant herbaceous plant species (creeping bentgrass) growing in contaminated soils developed from industrial wastes of Industrial Revolution age in Greater Manchester, UK. Heavy metal(loid)s in soil and plant tissues were quantified by inductively coupled plasma optical emission spectrometry (ICP-OES) after microwave-assisted acid digestion. The results show that different heavy metal(loid)s in the shoot tissue had different seasonal variation patterns. Seasonal shoot cutting-regrowth did not markedly affect the accumulation of various heavy metal(loid)s in the shoots. The concentration of shoot-borne heavy metal(loid)s was below the maximum tolerable level set for cattle except for Cd during spring-summer. The seasonal variation pattern for removal rate of Cd, Cr, Cu, Pb and Zn was strongly controlled by seasonal variation in biomass yield. The heavy metal(loid) removal from the soils via seasonal shoot harvest was 0.11, 0.56, 0.57, 3.56, 60.4, 0.34, 0.27 and 12.3 mg/m 2 for As, Cd, Cr, Cu, Mn, Ni, Pb and Zn, respectively. It is estimated that during the 1-year monitoring period, only 0.0002, 0.4014, 0.0142, 0.0423, 0.1627, 0.0154, 0.0008 and 0.1840% of the total metal(loid)s were removed from the soil by the plant shoots for As, Cd, Cr, Cu, Mn, Ni, Pb and Zn, respectively. Phytoextraction literally had negligible effects on removing the investigated heavy metal(loid)s from the contaminated soils except for Cd, Mn and Zn. The average bioaccumulation factor for the investigated heavy metal(loid)s was in the following decreasing order: Zn > Mn > Cu > Cr > Ni > Cd > Pb > As. The translocation factor for Cd was over 10 under either non-regrowth or cutting-regrowth conditions although the bioaccumulation factor was smaller than 0.5. The research findings obtained from this study have implications for risk assessment and management of the industrial waste-turned contaminated soils.

Influencing Factors of Cadmium Bioaccumulation Factor in Crops

The Cd bioaccumulation factor (BCF) of crops is affected by many aspects. In order to clarify the differences in the Cd bioaccumulation factor characteristics of different crops under field conditions and the influence of soil properties, point-to-point samples of soil and crop grains were collected during crop harvesting on plots with varying pollution levels in the primary production areas of rice, wheat, and maize in China. The characteristics of the Cd bioaccumulation factors of rice, wheat, summer maize, and spring maize and the effects of soil properties on the Cd bioaccumulation factors of different crops were studied, and the quantitative relationship between the Cd bioaccumulation factors and soil properties was established through multiple regression equations. The results revealed that the average BCF values of Cd in rice, wheat, summer maize, and spring maize were 0.915, 0.155, 0.113, and 0.102, respectively, with the Cd content in the field soil of 0.15-2.66 mg·kg-1. Rice is significantly higher than wheat and maize, and spring maize has the lowest Cd bioaccumulation factor. The Cd content in the soil is extremely negatively correlated with the BCF of wheat, summer maize, and spring maize. The relationship between soil organic matter (SOM) and the BCF of wheat and summer maize demonstrated a significant negative correlation. The soil pH and cation exchange capacity (CEC) also affect the BCF of crops. Introducing the soil Cd content, pH, SOM, CEC, and other factors, the Cd bioaccumulation factor prediction equations of rice, wheat, summer maize, and spring maize were established. The correlation coefficients of the BCF prediction equations for rice, wheat, summer maize, and spring maize are 0.423*, 0.796**, 0.826**, and 0.551**, respectively. The above models reached significant or extremely significant levels, which can better predict the BCF value of different crops under varying soil conditions.

Metal uptake by spontaneously grown Typha domingensis and introduced Chrysopogon zizanioides in a constructed wetland treating gold mine tailing storage facility seepage

This study analyzed the capability of two species to take up metals from gold mine tailing storage facility seepage in a constructed wetland with horizontal subsurface flow. Naturally populated Typha domingensis (cattail) and introduced Chrysopogon zizanioides (vetiver) were sampled on a regular basis in two experimentation cycles; a monoculture of T. domingensis in the first cycle and a mixed culture of T. domingensis and C. zizanioides in the second. Corresponding water samples were taken from the inlet and outlet sections of the system. Metals were analyzed in both sets of samples. Seepage water from the tailing storage facility had a high content of metals, characterized by large fluctuations depending on the ore type being processed at a particular time and hence no clear removal patterns could be discerned. After 75 days' growth, T. domingensis exhibited an above-ground biomass production of 12.30 to 14.18 g per plant, higher than C. zizanioides which was only 6.65 g per plant. T. domingensis revealed an average bioaccumulation factor of 7, 5, 293, 1997, 413, 225 and 583 for As, Co, Cu, Mn, Ni, Pb and Zn, respectively, whilst C. zizanioides exhibited bioaccumulation factors of 6, 2, 278, 503, 228 and 1184 for As, Co, Cu, Mn, Pb and Zn respectively. However, the translocation factor found in C. zizanioides was higher compared to T. domingensis. Due to the higher biomass production, standing stocks of As, Co, Cr, Cu, Mn, Ni, Pb and Zn were 3, 7, 4, 7, 14, 7, 5, times higher in T. domingensis than in C. zizanioides. Therefore, T. domingensis could be considered as a promising alternative for gold mine tailing seepage phytoremediation, whilst C. zizanioides revealed very low growth rates and showed adaptation difficulties.

Accumulation of potentially harmful elements in edible parts of vegetables grown on two different geological substrates in Zimbabwe

This study investigated the bioaccumulation of potentially harmful elements (PHEs) in common, locally grown vegetables in Zimbabwean farmlands. The aim of the study was to compare PHE accumulation in vegetables grown on greenstone substrate to those grown on granitic substrate. The greenstone terrain in Zimbabwe hosts some of the most economically viable gold and base metal deposits in the country, an endowment that triggered the establishment and growth of many of Zimbabwe's main cities. Vegetable samples (n = 44) and soil samples (n = 102) were collected over 4 seasons and analysed by Inductively Coupled Plasma-Mass Spectrometer (ICP-MS). The results indicate that the trend of PHE concentration was the same in vegetables from both substrates, as follows: Cr > Pb > Zn > Cu > Ni > As > Co > Sb > Cd. A comparison of the PHE levels in the vegetables against the FAO/WHO Codex maximum permissible levels (MPL), revealed Pb levels above the limit in all samples from both substrates. Tomatoes revealed a concentration of Pb in the order of 1400 times and 360 times above the MPL in greenstone and granitic substrates, respectively. Arsenic concentrations were also well above the MPL in all vegetable samples from the greenstone substrate, as well as in the tomatoes, pumpkin leaves, cabbage and okra in the granitic substrate. Concentration levels of Cd, a known carcinogen, exceeded the MPL in tomatoes from both substrates. Root vegetables were found to accumulate lesser amounts of PHEs than leafy vegetables. The vegetables grown on the granitic substrate revealed average bioaccumulation factor (BAF) values that were higher than values obtained for vegetables grown on greenstone substrates, in the range of multiples of 16, 15, 5, and 4.5 for Sb, As, Cu, and Cd, respectively. The results of a Kruskal-Wallis test revealed that although there was a significant difference (p < 0.05), between the concentration of PHEs in soils in the greenstone and the granitic substrates, the PHE accumulation in vegetables was significantly different (p < 0.05) only for As, Ni, and Pb; but there was no significant difference in the accumulation of the rest of the PHEs studied. The study indicates potential human health risks due to ingestion of vegetables having As, Cd and Pb levels above safe limits (MPLs). The study recommends careful selection of vegetables for cultivation in different substrates based on type of geological substrate, type of plant species and the bioaccumulation factor as key in controlling bioaccumulation of PHEs. The results from this study can be applied in human health risk analysis and monitoring of PHE accumulation in food crops.

Distribution, pollution, bioaccumulation, and ecological risks of trace elements in soils of the northeastern Qinghai-Tibet Plateau

Environmental quality of the northeastern Qinghai-Tibet Plateau has attracted more attention due to increasing anthropogenic disturbance. Therefore, this study investigated the distribution, pollution, ecological risks, and bioaccumulation of 12 target heavy metals and 16 rare earth elements (REEs) in soils of this area. The average concentrations of target trace elements in soils ranged from 0.16 (Hg) to 500.46 (Cr) mg/kg. Pb caused more serious pollution than the other elements based on geo-accumulation index evaluation. Hg exhibited the strongest enrichment feature with the average enrichment factor of 8.41. Compare with modified contamination degree and pollution load index, Nemerow pollution index method obtained the most serious evaluation results that 45.67% and 16.54% of sampling sites possessed high and moderate pollution. Evaluation results of potential ecological risk index showed that trace elements in soils posed very high and considerable ecological risks in 34.65% and 7.09% of sampling sites, respectively. Mining area was the region with the most serious pollution and ecological risks. Average bioaccumulation factor (BCF) values of target trace elements ranged from 0.05 (REEs) to 2.67 (Cr). Cr was the element that was easier to bio-accumulate in plants of the study area than the other target elements. It is in urgent need to take effective measures for controlling current pollution and potential ecological risks of trace elements in soils of the northeastern Qinghai-Tibet Plateau.

Comparison of mercury and methylmercury bioaccumulation in earthworms (Bimastus parvus) native to landfill-leachate-contaminated forest soil.

Total mercury (THg) and methylmercury (MeHg) bioaccumulation was explored in the Bimastus parvus species of earthworm (B. parvus) native to the leachate-contaminated forest soils around a Hg-polluted traditional landfill in Japan. General soil properties and concentrations of THg and MeHg in forest soils and in B. parvus were determined. The results indicated that the average THg concentrations in B. parvus and in forest soils in the leachate-contaminated sites were 10.21 and 14.90 times higher than those in the reference sites, respectively, whereas similar average MeHg concentrations were observed in forest soils (< 0.01 mg kg-1) and in B. parvus (0.100-0.114 mg kg-1) across all sampled sites. The average bioaccumulation factors of THg in B. parvus (BAFTHg) in forest soil were similar between the leachate-contaminated sites and the reference sites. Cluster and regression analyses demonstrated that the B. parvus Hg (THg and MeHg) and soil THg were positively correlated with each other and with soil organic matter (SOM) and clays, but were negatively correlated with sand and hardly correlated with silts and pH in leachate-contaminated forest soils. From these results, it was proposed that Hg exposure to food chains is possible through B. parvus, because B. parvus showed a high ability to accumulate THg and MeHg in both leachate-contaminated and reference forest soils. Together, these findings indicated that the role of B. parvus in MeHg production is not clear, and it is possible that the MeHg in B. parvus was firstly formed within forest soils and then accumulated in their tissues.

Heavy metal accumulation in rice (Oryza sativa) near electronic waste dumps and related human health risk assessment

ABSTRACTThis research was conducted to assess heavy metal contamination in the environment and within Oryza sativa. The translocation factors (TFs) and bioaccumulation factors (BAFs) for heavy metals in O. sativa and estimated daily intake (EDI) and health risk index (HRI) were measured. The samples were analyzed for heavy metals using inductively coupled plasma optical emission spectrometry (ICP-OES). Pb and Cr concentrations in water samples within and near the electronic-waste dumping area exceeded water quality standards for surface water sources from the Pollution Control Department in the Ministry of Natural Resources and Environment of Thailand (PCD). The Pb concentration in soil samples within the area also exceeded soil quality standards for habitat and agriculture from PCD. Most of the metals were highly concentrated in roots, except for Mn which has the highest concentration in leaves. Pb concentrations in rice grains exceeded the FAO/WHO standard (0.2 mg/kg). The average TF values for heavy metals from the soil to roots, roots to stems, stems to leaves, and stems to grains were Mn > Pb > Ni > Cr, Mn > Cr > Ni > Pb, Ni > Pb > Mn > Cr, and Pb > Ni > Cr > Mn, respectively. The average BAF values in O. sativa were Mn > Ni > Pb > Cr. The EDI for Cr, Pb, Mn, and Ni via O. sativa consumption were 6.19, 6.02, 370.57, and 3.80 µg/kg/day, respectively. The HRI for Cr, Pb, Mn, and Ni via O. sativa consumption were 0.30, 1.50, 2.60, and 0.002, respectively.

Diverse impacts of a step and repeated BDE209-Pb exposures on accumulation and metabolism of BDE209 in earthworms

Decabromodiphenyl ether (BDE209) and lead (Pb) are the two common contaminants at e-waste recycling sites (EWRSs). A laboratory incubation study was conducted to explore the impacts of a step and repeated BDE209-Pb exposures on accumulation and metabolism of BDE209 in earthworms Eisenia fetida for the first time. The results indicated that BDE209 concentrations in repetitively-polluted soils were clearly higher. And the existence of high-level Pb could promote the bioaccumulation of BDE209 in earthworms along the exposure time. The post-clitellum contents of BDE209 were more than the pre-clitellum during the entire incubation. Additionally, GC/MS analysis results demonstrated that BDE206, BDE208, BDE153, BDE99, BDE47 and BDE28 could be detected in Eisenia fetida throughout 28-d experiment, and BDE206 and BDE208 were predominant metabolic products. A step exposure decreased the capability to metabolize BDE209 in the presence of Pb. Average bioaccumulation factor (BAF) for a step treatment was 0.525, as well as it was more than 1.1 times that of repeated exposure (BAF = 0.48). SEM observations suggested that a step exposure mode aggravated the damage in earthworms than repeated exposure. The results and related findings will establish a useful scientific basis for soil ecological risk assessment at EWRSs.

Investigating the phytoavailability of trace elements in contaminated agricultural soils and health risks via consumption of water spinach grown under field conditions in Zhuzhou, China

In this study, the phytoavailability of trace elements from contaminated agricultural soils to water spinach grown under field conditions in Zhuzhou, China was investigated using three single extraction methods: CaCl2, HAc, and acid ammonium acetate-EDTA (AEDTA) compared with a strong acid digestion method. The soils are primarily contaminated by Cd (4.16 ± 5.98 mg kg−1) and Pb (152 ± 160 mg kg−1), followed by Zn (403 ± 443 mg kg−1), Cu (60.5 ± 29.4 mg kg−1) and As (39.1 ± 36.0 mg kg−1). The main pollutants in water spinach grown in this area are Pb and Cd. The estimated dietary intakes of Cd, Pb and As in some sampling sites were higher than the tolerable limits, indicating that the potential health risks from exposure to these three elements through consumption of water spinach need more attention. Importantly, water spinach has an increased propensity for Cd phytoextraction in contaminated soils with an average bioaccumulation factor of higher than 1, whereas Pb in the edible parts of water spinach is probably present from atmospheric deposition. Statistical analysis indicated that more aggressive extraction procedures (HAc or AEDTA) were better able to predict the phytoavailability of trace elements. Moreover, the phytoavailability of Pb, Cd and Zn could also be well predicted by their total concentrations in soils. Although the trace elements content in water spinach could mostly be explained by total or extractable concentrations, the regression predictions were further improved by the incorporation of soil properties.

Trace metals and metalloids in forest soils and exotic earthworms in northern New England, USA

Trace metals and metalloids (TMM) in forest soils and invasive earthworms were studied at 9 sites in northern New England, USA. Essential (Cu, Mo, Ni, Zn, Se) and toxic (As, Cd, Pb, Hg, U) TMM concentrations (mg kg−1) and pools (mg m−2) were quantified for organic horizons (forest floor), mineral soils and earthworm tissues. Essential TMM tissue concentrations were greatest for mineral soil-feeding earthworm Octolasion cyaneum. Toxic TMM tissue concentrations were highest for organic horizon-feeding earthworms Dendobaena octaedra, Aporrectodea rosea and Amynthas agrestis. Most earthworm species had attained tissue concentrations of Pb, Hg and Se potentially hazardous to predators. Bioaccumulation factors were Cd > Se > Hg > Zn > Pb > U > 1.0 > Cu > As > Mo > Ni. Only Cd, Se, Hg and Zn were considered strongly bioaccumulated by earthworms because their average bioaccumulation factors were significantly greater than 1.0. Differences in bioaccumulation did not appear to be caused by soil concentrations as earthworm TMM tissue concentrations were poorly correlated with TMM soil concentrations. Instead, TMM bioaccumulation appears to be species and site dependent. The invasive A. agrestis had the greatest tissue TMM pools, due to its large body mass and high abundance at our stands. We observed that TMM tissue pools in earthworms were comparable or exceeded organic horizon TMM pools; earthworm tissue pools of Cd were up 12 times greater than in the organic horizon. Thus, exotic earthworms may represent an unaccounted portion and flux of TMM in forests of the northeastern US. Our results highlight the importance of earthworms in TMM cycling in northern forests and warrant more research into their impact across the region.

Bioaccumulation of decabromodiphenyl ether (BDE209) in earthworms in the presence of lead (Pb)

BDE209 (decabromodiphenyl ether) and lead (Pb) are the main contaminants at e-waste recycling sites, and their potential toxicological effects on terrestrial organisms have received extensive attention. However, the impact on earthworms of exposure to the two chemicals remains almost unknown. Therefore, indoor incubation tests were performed on control and contaminated soil samples to determine the uptake and transformation of BDE209 in the presence of Pb for the first time. The results have demonstrated that Pb addition can affect BDE209 bioaccumulation efficiency compared with exposure to BDE209 alone. For a low BDE209 concentration (1mgkg−1), Pb addition barely affected the uptake of BDE209, whereas for a high BDE209 concentration (100mgkg−1), Pb addition elicited a complex response. Scanning electron microscope (SEM) observation indicated that a higher level of Pb (250 and 500mgkg−1) facilitated the uptake of BDE209 through the skin. Gas chromatography/mass spectrometry (GC/MS) analysis showed that the peak of BDE209 accumulation usually appeared in the joint exposure groups involving 10 or 100mgkg−1 BDE209 and 250mgkg−1 Pb, and the average bioaccumulation factor (BAF) was 0.53, which is more than 1.2 times that of single exposure to BDE209 (average=0.44). Also, the earthworms eliminated more BDE209 after 21d, and the biodegradation products were mainly BDE206 and BDE208. Furthermore, Pb addition can affect the transformation efficiency of BDE209 in earthworms, and several lower bromodiphenyl ethers can be detected. The results of these observations have provided a basic understanding of the potential ecotoxicological effects of joint PBDE and heavy metal exposure on terrestrial invertebrates.

湘南某矿区蔬菜中Pb、Cd污染状况及健康风险评估

PDF HTML阅读 XML下载 导出引用 引用提醒 湘南某矿区蔬菜中Pb、Cd污染状况及健康风险评估 DOI: 10.5846/stxb201212251868 作者: 作者单位: 中南林业科技大学林学院环境科学与工程研究中心,中南林业科技大学环境科学与工程研究中心,中南林业科技大学环境科学与工程研究中心,长沙环境保护职业技术学院,中南林业科技大学环境科学与工程研究中心,中南林业科技大学环境科学与工程研究中心 作者简介: 通讯作者: 中图分类号: 基金项目: 环保部公益项目（201009047）；湖南省环境科学重点学科建设项目（2006180） Contamination status of Pb and Cd and health risk assessment on vegetables in a mining area in southern Hunan Author: Affiliation: Research Center for Environmental Science and Engineering, Central South University of Forestry and Technology,,,,,Research Center for Environmental Science and Engineering, Central South University of Forestry and Technology Fund Project: 摘要 | 图/表 | 访问统计 | 参考文献 | 相似文献 | 引证文献 | 资源附件 | 文章评论 摘要:通过采集湘南某矿区周边农田中种植的蔬菜和对应耕作层土壤样品，探究了农田蔬菜Pb、Cd的污染状况，蔬菜和土壤重金属含量之间的相关性，蔬菜中重金属对人体的健康风险。结果表明：（1）污染区土壤重金属污染非常严重，叶菜类蔬菜重金属超出了食品卫生标准限值，但是果菜类蔬菜中重金属没有超出食品卫生标准限值。（2）不同蔬菜不同器官所含Pb、Cd有明显差异；不同种类蔬菜Pb、Cd含量不同，一般是叶菜类 > 果菜类；同种蔬菜不同部位重金属含量的顺序也不同，一般为根 > 茎 > 叶 > 果，或根 > 叶 > 茎 > 果。（3）二类蔬菜中重金属Pb、Cd的富集系数顺序为叶菜类 > 果菜类。（4）蔬菜中Pb、Cd含量与土壤中相对应元素含量均无显著相关性。（5）就农产品安全性而言，果菜类蔬菜比叶菜类蔬菜更适合在此矿区栽培。 Abstract:Vegetables, including leafy vegetables and fruit, are of importance to human health. In order to evaluate the heavy metal contamination status and associated health risks of vegetables, 57 vegetables (34 spring vegetables and 23 winter vegetables) and 34 corresponding soil samples (sampled with the spring vegetables) were collected from farmland surrounding a mining area in southern Hunan, China. Analysis was carried out to determine the correlation between the heavy metal content of vegetables and soils, to enable assessment of the potential health risk to local inhabitants consuming the vegetables grown in the contaminated soils. The results showed that: (1) The measured maximum total Pb and Cd in the soils were up to 1251.9 mg/kg (the corresponding soil to the three-colored amaranth) and 13.2 mg/kg (the corresponding soil to the kidney bean), respectively. The average concentration of total Pb and Cd in all soils were 841.7 mg/kg and 6.5 mg/kg, respectively, which were 3.37 and 21.67 times the standard allowable concentration of Pb and Cd for vegetable soils in China (pH level < 6.5, Pb ≤ 250 mg/kg, Cd ≤ 0.3 mg/kg; Environment Quality Standard for Soil Heavy Metals GB15168-1995, Grade Ⅱ). It suggested that contamination from heavy metals in these soils was very serious. (2) Vegetables grown on the contaminated soils were rich in Pb and Cd in different plant organs. The highest levels of heavy metals were 5.03 mg/kg for total Pb and 2.92 mg/kg for total Cd in the edible parts of garlic and three-colored amaranth, respectively, which exceeded the maximum levels of the China National Food Sanitation Standards for total Pb (GB 14935-94, 0.2 mg/kg) and Cd (GB 15201-94, 0.05 mg/kg). The heavy metal content of leafy vegetables, not fruit, exceeded the China National Food Sanitation Standards for Heavy Metals. The contents of total Pb and Cd in different organs of the vegetables were quite different and generally followed a sequence of root > stem > leaf > fruit, or root > leaf > stem > fruit. Pb and Cd contents in leafy vegetables were generally higher than those in fruits. (3) The order of bioaccumulation factors (BFs) of heavy metals in the two vegetable types was leafy vegetables > fruits. Based on fresh weight, the average BFs of Pb varied within (0.7-8.4)×10-3 for leafy vegetables and (0-0.02)×10-3 for fruits, and those of Cd varied within (15.4-895.2)×10-3 for leafy vegetables and (0.04-38.1)×10-3 for fruits, which signified that the average BFs of Pb and Cd for leafy vegetables was greater than those for fruit vegetables. (4) The correlations were not significant between the heavy metal content in vegetables and those in soils; however, total Pb and Cd in the edible parts of vegetables presented a higher significant correlation level (R2 =0.821; n =18, R20.01 =0.590). (5) The results of the risk assessment on vegetables indicated that the hazard quotient (HQ) for total Pb and Cd in the edible parts of leafy vegetables were 1.70 and 3.73, respectively, 34.00 times and 53.28 times higher than those of the fruits (0.005 and 0.070). In relation to suitability of agricultural products in this mining area, fruits were more suitable for planting than leafy vegetables. 参考文献 相似文献 引证文献

Risks associated with the transfer of toxic organo-metallic mercury from soils into the terrestrial feed chain

Although the transfer of organo-metallic mercury (OrgHg) in aquatic food webs has long been studied, it has only been recently recognized that there is also accumulation in terrestrial systems. There is still however little information about the exposure of grazing animals to OrgHg from soils and feed as well as on risks of exposure to animal and humans.In this study we collected 78 soil samples and 40 plant samples (Lolium perenne and Brassica juncea) from agricultural fields near a contaminated industrial area and evaluated the soil-to-plant transfer of Hg as well as subsequent trophic transfer. Inorganic Hg (IHg) concentrations ranged from 0.080 to 210mgkg−1 d.w. in soils, from 0.010 to 84mgkg−1 d.w. in roots and from 0.020 to 6.9mgkg−1 d.w. in shoots. OrgHg concentrations in soils varied between 0.20 and 130μgkg−1 d.w. representing on average 0.13% of the total Hg (THg). In root and shoot samples OrgHg comprised on average 0.58% (roots) and 0.66% (shoots) of THg. Average bioaccumulation factors (BAFs) for OrgHg in relation to soil concentrations were 3.3 (for roots) and 1.5 (for shoots).The daily intake (DI) of THg in 33 sampling sites exceeded the acceptable daily intake (ADI) of THg of both cows (ADI=1.4mgd−1) and sheep (ADI=0.28mgd−1), in view of food safety associated with THg in animal kidneys. Estimated DI of OrgHg for grazing animals were up to 220μgd−1 (for cows) and up to 33μgd−1 (for sheep).This study suggested that solely monitoring the levels of THg in soils and feed may not allow to adequately taking into account accumulation of OrgHg in feed crops and properly address risks associated with OrgHg exposure for animals and humans. Hence, the inclusion of limits for OrgHg in feed quality and food safety legislation is advised.

Phytoavailability and phytovariety codetermine the bioaccumulation risk of heavy metal from soils, focusing on Cd-contaminated vegetable farms around the Pearl River Delta, China

Five random vegetable farms were selected to investigate the bioaccumulation risk of heavy metals (HMs) by different type of vegetables around the Pearl River Delta (PRD), China. The concentration order of four major HMs in the surface soil samples was Cd<Cu<Pb<Zn, with only Cd concentrations (1.4–1.8mgkg−1) significantly higher than the permissible limit (≤0.3mgkg−1) for agricultural soils. Soil DTPA-extractable (phytoavailable) Cd concentrations differed markedly amongst the five farms, and varied within 0.017–0.17mgkg−1. Meanwhile, 28.0% of vegetable samples collected from these five farms were contaminated with Cd according to the permissible limit (≤0.05mgkg−1), and 71.4% of these polluted samples belonged to stem/leaf vegetables. The average bioaccumulation factors of Cd from cultivated soil to stem/leaf vegetables and melon/fruit/bean vegetables varied within 0.021–0.050 and 0.005–0.020 (soil total Cd basis), and 0.50–2.01 and 0.13–0.53 (soil DTPA-extractable Cd basis), respectively. Redundancy analysis (RDA) showed that DTPA-extractable Cd, which negatively but significantly correlated (P<0.05) to soil pH, was the key factor in influencing vegetable Cd accumulation, notably stem/leaf vegetables. The results show that Cd was the primary metal of risk in vegetable farms around the PRD region, and stem/leaf vegetables posed about 2.2 times higher health risks associated with exposure to Cd than melon/fruit/bean vegetables.