Human health risk assessment of heavy metals in the soil–Panax notoginseng system in Yunnan province,China

In this study, a total of 69 topsoil samples and 10 Panax notoginseng samples from Yunnan Province were collected and the concentrations of As, Cd, Cu, Hg, Ni, Pb and Zn in all the samples were determined. The hazard index (HI), total carcinogenic risk (TCR) and estimated daily intake (EDI) of heavy metals were calculated to assess the health risk of P. notoginseng growers and consumers. The average concentrations of As, Cd, Cu, Hg, Ni, Pb and Zn in P. notoginseng planting soils are 43.6, 0.55, 50.8, 0.30, 73.4, 58.2, and 161 mg/kg, respectively. The average Nemerow integrated pollution index of heavy metals in soils is 1.8, indicating that the P. notoginseng planting soils are slightly polluted by those heavy metals. The average HI value is 1.29 and the TCR value of As is above the threshold value, suggesting that As pollution in soil has adverse impact on local growers' health. P. notoginseng is polluted by Cd, As and Pb. 39.1% of estimated daily intakes of As for P. notoginseng consumers through leaf consumption exceeding its permitted daily exposure dosages, suggesting that there is a potential health risk for P. notoginseng consumers to consume P. notoginseng leaves.     

Distribution features and internal relations of heavy metals in soil–maize system of mining area,Anhui Province,Eastern China

A total of 59 topsoil and corresponding maize plants were collected from this study area. The spatial distribution, correlation analysis, and multiple linear regression of heavy metals were researched detailedly in this article. The results showed that distribution characteristics of heavy metals (Pb, Cd, and Ni) in different parts of maize plants (immature stage) accumulated mostly in stems, with Pb mainly accumulated in roots (mature period), and Cd and Ni mostly in leaves. Except for the southeastern local region of this mining area, Mn and Cu possessed roughly similar spatial distribution characteristics. The results of partial correlation analysis indicated that Cu, Cd in the roots of the tested maize plants and Ni in soil may have antagonistic effects, Cu (soil)–Cu (stem) and Ni (soil)–Pb (stem) had a certain promoting effect. Besides, Cu, Pb, and Ni in soil promoted the absorption of Cu, Pb, and Ni in the leaves, whereas Cr and Pb in soil can promote the enrichment of Mn in maize grains. Our findings suggested that the concentrations of heavy metals in maize organs could be predicted accurately using the established models.     

The difference of potassium dynamics between yellowish red soil and yellow cinnamon soil under rapeseed (Brassica napus L.)–rice (Oryza sativa L.) rotation

To increase the use efficiency of potassium (K) fertilizer, special attention was paid to the dynamics of soil K in the root zone and non-root zone. Difference in K dynamics between yellowish red soil and yellow cinnamon soil under rapeseed (Brassica napus L.)rice (Oryza sativa L.) rotation was studied using a rhizobox system. Results showed that soil water soluble K (Sol-K) and exchangeable K (Ex-K) in the root zone of both soils were reduced in the early stage of rapeseed growth. Along with plant growth and K uptake, soil Sol-K in the inner (0–20 mm to root zone), middle (20–40 mm) and outer (40–60 mm) compartments of the non-root zone of yellowish red soil migrated towards the root zone. As a result, soil Ex-K was transformed into Sol-K. The changes in soil Sol-K and Ex-K in the non-root zone of yellow cinnamon soil were similar to yellowish red soil, and soil non-exchangeable K (Nonex-K) in the root zone also decreased significantly. In the early stage of rice growth, waterlogging promoted diffusion of soil Sol-K from non-root zone to root zone and transformation of Ex-K into Sol-K. Along with the growth of rice and K uptake, soil Ex-K in each compartment of yellowish red soil decreased significantly. Soil Sol-K and Ex-K in the yellow cinnamon soil declined to a certain extent, and then remained unchanged, while soil Nonex-K kept on decreasing. It revealed that the plants first absorbed K in the root zone, of which K reserve was replenished by a gradual diffusion of K from the non-root zone. The closer to the root zone, the greater the contribution to K uptake by plants. Within one rotation cycle, Ex-K and Sol-K in yellowish red soil were the main forms of K available to the plants, and little Nonex-K could be absorbed. However, in the yellow cinnamon soil, Nonex-K was the main form of K available to the plants, followed by Ex-K and Sol-K.     

Genetic analyses of the host-pathogen system Turnip yellows virus (TuYV)—rapeseed (Brassica napus L.) and development of molecular markers for TuYV-resistance

The aphid transmitted Turnip yellows virus (TuYV) has become a serious pathogen in many rapeseed (Brassica napus L.) growing areas. Three-years’ field trials were carried out to get detailed information on the genetics of TuYV resistance derived from the resynthesised B. napus line ‘R54’ and to develop closely linked markers. F₁ plants and segregating doubled-haploid (DH) populations derived from crosses to susceptible cultivars were analysed using artificial inoculation with virus-bearing aphids, followed by DAS-ELISA. Assuming a threshold of E ₄₀₅ = 0.1 in ELISA carried out in December, the results led to the conclusion that pre-winter inhibition of TuYV is inherited in a monogenic dominant manner. However, the virus titre in most resistant lines increased during the growing period, indicating that the resistance is incomplete and that the level of the virus titre is influenced by environmental factors. Bulked-segregant marker analysis for this resistance locus identified two closely linked SSR markers along with six closely linked and three co-segregating AFLP markers. Two AFLP markers were converted into co-dominant STS markers, facilitating efficient marker-based selection for TuYV resistance. Effective markers are particularly valuable with respect to breeding for TuYV resistance, because artificial inoculation procedures using virus-bearing aphids are extremely difficult to integrate into practical rapeseed breeding programs.     

Does heavy metal hurt in the secondary battery production sites? The case study of occupational risk from Yangtze River Delta,China

The purpose of this study was to determine the occupational health risk to employees of lithium-ion battery factories in Yangtze River Delta, China. Soil samples were collected from materials synthesis workshop and battery assembly line workshop, which are named site A, site N1, site N2, and site Z according to different battery products. We analyzed the heavy metals for Co, Cd, Mn, Cu, and Ni. The soil heavy metal exposure model and the health risk characterization model were built to assess occupational health risk. Besides, uncertainty analysis with the aid of Monte Carlo simulation was used to perform error propagation for model parameters. The health risk assessment with uncertainty results indicated that all the four sites have relative low risk of carcinogens for employees, and N1, A, and Z sites also have relative low risk of non-carcinogen for employees, but N2 site has value of 6.94, which is heavily higher than the threshold value (defined as 1.0). It means that the employees in N2 site are facing threat of the heavy metals. These results provide basic information of heavy metal pollution control and environment management in lithium-ion battery factory. It also answered the question of the occupational risk in the sites.     

Genetic mapping of nuclear fertility restorer genes for the ‘Polima’ cytoplasmic male sterility in canola (Brassica napus L.) using DNA markers

 Co-segregation of male fertility with DNA markers selected by targeted mapping approaches as being potentially linked to the Rfp1 restorer gene for the pol cytoplasmic male sterility (CMS) was analyzed using two canola (Brassica napus L.) backcross populations. Eleven DNA markers (10 RFLP markers and one RAPD marker) directly linked to the Rfp1 locus were identified. The linkage group containing the Rfp1 locus was found to correspond to B. napus linkage group 18 of Landry et al. (1991). A similar pattern of co-segregation between DNA markers and male fertility was observed in a backcross population segregating for the pol restorer gene Rfp2 from line ‘UM2383’; one RFLP marker, cRF1b, showed perfect linkage with both Rfp1 and Rfp2 and detected identical polymorphic fragments in both the Rfp1 and Rfp2 restorer lines. Our findings indicate that restoration of pol CMS is controlled by a single nuclear genetic locus on linkage group 18 and that Rfp1 and Rfp2 are likely allelic. Received: 2 October 1996 / Accepted: 20 December 1996     

Photosynthetic characterization of three dominant plant species in the saline–alkaline soil of the Yellow River Delta,China

The diurnal variations of photosynthesis of three dominant species, including Glycine soja, Phragmites australis, and Cynanchum chinensis, in the Yellow River Delta in China have been studied under the same natural conditions using a Li-6400 portable photosynthesis system. The results showed that the curves of diurnal variations of net photosynthetic rate (P_N) of the three plants were different. The diurnal variation of P_N on C. chinensis was a midday depression pattern and had two peaks. However, P_N of G. soja and P. australis showed single-peak curves. The transpiration rate (E) of G. soja was significantly higher than that of P. australis and C. chinensis, both showed single-peak curves. In general, the diurnal course of stomatal conductance (g_s) followed the same pattern of P_N. A similar diurnal pattern of intercellular CO₂ concentration (C_i), vapor pressure deficit (VPD), and water use efficiency (WUE) was observed among different species. VPD showed single-peak curves, while WUE was characterized by double-peak curves, which was contrary to C_i. Linear correlations among photosynthetic variables and key environmental factors indicate high positive correlations between P_N and E, P_N and photosynthetic active radiation, P_N and leaf temperature (T_leaf), P_N and VPD, and between P_N and g_s except C. chinensis. Negative correlations among P_N and relative humidity, P_N and C_i were found. The irradiance response curves derived from the leaves were substantially affected by different species. C. chinensis showed highest apparent quantum efficiency, followed by P. australis and G. soja, while apparent dark respiration (R_d), convexity (k), light saturation point, and maximum gross CO₂ assimilation rate (P_max) of G. soja were higher than those of P. australis and C. chinensis. The irradiance response curve of P_N and WUE of different plant species followed the same order: G. soja>C. chinensis>P. australis. They were both higher than most of other species. It was concluded that plant species adapting to the saline–alkaline habitat showed higher photosynthesis. In addition, G. soja is also effective to improve saline–alkaline soil quality.     

Assessment of ecosystem health during the past 40 years for Lake Taihu in the Yangtze River Delta,China

An assessment of the ecosystem health of Lake Taihu in eastern China from 1960 to 2005 was conducted using separate and aggregated chemical and biological indicators. The chemical oxygen demand, the total nitrogen, total inorganic nitrogen and total phosphorus concentrations, and the molar ratio of TN to TP (N/P) have all significantly increased (P < 0.05) since 1980. The trophic state index increased from 35.0 in 1960 to >60.0 in 1990, confirming that Lake Taihu changed from being oligotrophic to being eutrophic. These changes in water quality have led to corresponding changes in species composition and in the densities and biomasses of many aquatic species. Algal blooms have occurred frequently since the late 1980s, leading to the dominance of small zooplankton and benthic invertebrates. About 41 fish, 65 zooplankton and 16 macrophyte species were estimated to have disappeared from the lake since the late 1980s. Buffer capacity increased for phytoplankton and zooplankton but decreased for zoobenthos. These results suggest that the Lake Taihu ecosystem was in better health in 1960, and has deteriorated since 1980.     

Pollen–pistil interaction in protogyny and self-incompatibility system of Indian mustard (Brassica juncea (L.) Coss.)

The pollen morphology of two species of Drosera has been investigated by means of both light and electron microscopy. The apertures are situated proximally, a state rarely found in the pollen of Angiospermous plants. The pollen morphology of Aldrovanda, Dionea and Drosophyllum is compared.     

Land use intensification affects soil microbial populations, functional diversity and related suppressiveness of cucumber Fusarium wilt in China’s Yangtze River Delta

The extent of soil microbial diversity in agricultural soils is critical to the maintenance of soil health and quality. The aim of this study was to investigate the influence of land use intensification on soil microbial diversity and thus the level of soil suppressiveness of cucumber Fusarium wilt. We examined three typical microbial populations, Bacillus spp., Pseudomonas spp. and Fuasarium oxysporum, and bacterial functional diversity in soils from three different land use types in China’s Yangtze River Delta, and related those to suppressiveness of cucumber Fusarium wilt. The land use types were a traditional rice wheat (or rape) rotation land, an open field vegetable land, and a polytunnel greenhouse vegetable land that had been transformed from the above two land use types since 1995. Results generated from the field soils showed similar counts for Bacillus spp. (log 5.87–6.01 CFU g⁻¹ dw soil) among the three soils of different land use types, significantly lower counts for Pseudomonas spp. (log 5.44 CFU g⁻¹ dw soil) in the polytunnel greenhouse vegetable land whilst significantly lower counts for Fusarium oxysporum (log 3.21 CFU g⁻¹ dw soil) in the traditional rice wheat (or rape) rotation land. A significant lower dehydrogenase activity (33.56 mg TPF kg⁻¹ dw day⁻¹) was observed in the polytunnel greenhouse vegetable land. Community level physiological profiles (CLPP) of the bacterial communities in soils showed that the average well color development (AWCD) and three functional diversity indices of Shannon index (H′), Simpson index (D) and McIntosh index (U) at 96 h incubation in BIOLOG Eco Micro plates were significantly lower in the polytunnel greenhouse vegetable land than in both the traditional rice wheat (or rape) rotation land and the open field vegetable land. A further greenhouse experiment with the air-dried and sieved soils displayed significantly lower plant growth parameters of 10-old cucumber seedlings as well as significantly lower biomass and total fresh fruit yield at the end of harvesting at day 70 in the polytunnel greenhouse vegetable soil sources. The percentages of Fusarium wilt plant death were greatly increased in the polytunnel greenhouse vegetable plants, irrespective of being inoculated with or without Fusarium oxysporum f. sp. cucumerinum. Our results could provide a better understanding of the effects of land use intensification on soil microbial population and functional diversity as well as the level of soil suppressiveness of cucumber Fusarium wilt.     

Distribution of heavy metals in the geochemical phases of sediments from the Tietê River,Brazil

Abstract

The fractionation of heavy metals in riverbed sediments along the Tietê River basin, a highly polluted river in southeast region of Brazil, was investigated using a four-step sequential extraction procedure, in order to determine the concentration and distribution of Cu, Co, Cr, Cd, Zn, Ni and Pb, in the river bottom sediments, related to the potential mobility of geochemical phases. Around the metropolitan area of the City of São Paulo, which has 25 million people, the pollution is associated with municipal wastes and industrial effluents. Potentials of high mobility were observed for Cu and Zn along the entire river basin, associated mainly to the organic fraction, while at the Pirapora and Anhembi stations (upper and middle parts of the basin, respectively) the reactive forms of Ni and Pb were more associated to the Fe and Mn oxides. Near the mouth of the Tietê River, no significant contaminations caused by Cr and Ni in riverbed sediments was verified confirming the presence of these metals in the residual or lithogenous phase.     

Concentrations and chemical forms of heavy metals in agricultural soil near the world’s largest and oldest tungsten mine located in China

Abstract

Tungsten (W) mining has taken place in Ganzhou in China for about 100 years. Such long-term W mining may release large amount of metals to soils and waters around these mines. Twenty soil samples were taken from the area around the W mines and 10 soil samples from an area much farther away. These soil samples were analysed for physicochemical properties, heavy metal content and their chemical forms. Results show that long-term W mining significantly increased both total and labile contents of Cd, Cu, Pb and Zn, but did not, or only slightly, increased the total content of Co, Cr and Ni in the soil near the mine. Average enrichment factor (EF) in the agricultural soils was 4.0, 2.4, 2.2, and 2.0 for Cd, Cu, Pb and Zn, respectively. The labile fraction was dominated by the carbonate-bound fraction for Cd (54.5%) and organic matter-bound fraction for Cu (37.9%), while the major labile fractions for Pb and Zn were associated with carbonates (30.2% and 6.4%), oxides (17.9% and 10.6%) and organic matter (9.2% and 18.8%). Consequently, there is a need to be cautious about Cd in the soils contaminated by W mining.     

Trace metals in the common mussel,Mytilus edulis (L.), and in the alga Fucus vesiculosus (L.) from the region of the sound (Öresund)

Concentrations of zinc, cadmium, lead and iron were determined in whole soft parts of mussels, Mytilus edulis (L.), and in growing tips of the alga Fucus vesiculosus (L.) from a total of 20 locations in the area of the Sound between Sweden and Denmark. Pollution profiles produced for each metal were similar in any one of the species studied but the profiles for metals in M. edulis were distinct from those for metals in F. vesiculosus. Results for mussels agreed broadly with those reported previously for this region, indicating a northward decrease in available metal concentrations. By contrast, results for algae showed few differences in metal availability throughout the study area, although some local effects were evident.The differences in the pollution profiles exhibited by these two organisms depend on their response to different portions of the total trace metal load of ambient waters. Results from the alga agree well with available data on the concentrations of trace metals in solution in waters of the Sound. The alga thus appears to be responding only to metals in solution, as suggested by previous authors. By contrast, the major proportion of the total body load of metals in mussels is derived from ingested phytoplankton. The pollution profiles exhibited by mussels may be explained if phytoplankton from the Baltic Sea contain higher concentrations of trace metals than do those from Kattegat. Possible mechanisms for the production of such differences in the metal contents of the two phytoplankton populations, and the ecological implications of these differences, are briefly discussed.     

Effects of Soil Properties on the Transfer of Cadmium from Soil to Wheat in the Yangtze River Delta Region, China—a Typical Industry–Agriculture Transition Area

In order to identify the effects of soil properties on the transfer of Cd from soil to wheat under actual field conditions, 126 pairs of topsoil and wheat samples were collected from the Yangtze River delta region, China. Relevant parameters (Cd, Ca, Mg, Fe, Mn, Zn, N, P, K, S, pH, total organic carbon, and speciation of soil Cd) in soil and wheat tissues were analyzed, and the results were treated by statistical methods. Soil samples (19.8%) and 14.3% of the wheat grain samples exceeded the relevant maximum permissible Cd concentrations in China for agricultural soil and wheat grain, respectively. The major speciations of Cd in soil were exchangeable, bound to carbonates and fulvic and humic acid fraction, and they were readily affected by soil pH, total Ca, Mg, S and P, DTPA-Fe, Ex-Ca, and Ex-Mg. Cadmium showed a strong correlation with Fe, S, and P present in the grain and the soil, whereas there was no significant correlation in the straw or root. Generally, soil pH, Ca, Mg, Mn, P, and slowly available K restricted Cd transfer from soil to wheat, whereas soil S, N, Zn, DTPA-Fe, and total organic carbon enhance Cd uptake by wheat.     

Did alder (Alnus) fires trigger rice cultivation in the lower reaches of the Yangtze River,East China?

It remains debatable as to how the prehistoric human communities managed the environment to enable the initial cultivation of rice during the early Neolithic in the coastal lower reaches of the Yangtze River, East China. Previous studies proposed an environmental context for the first rice cultivation at Kuahuqiao, Hangzhou, based on an archaeological sedimentary microfossil record that had been well-dated using radiocarbon methods. Those studies suggested that early humans began burning the predominantly alder scrub in a local swampy wetland, starting about 7750 cal. yr BP, which permitted the start of dedicated rice (Oryza) cultivation. Here we present a new, finer-detailed pollen-phytolith-microscopic charcoal record from the same locality. Our result reveals that local woods dominated by oak (Quercus) and pine (Pinus) were targeted for burning by early cultivators before the start of rice agriculture.     

Water sources of Populus euphratica and Tamarix ramosissima in Ejina Delta,the lower reaches of the Heihe River China北大核心CSCD

Aims: We aim to evaluate the water sources of typical riparian arbor species (Populus euphratica) and shrub species (Tamarix ramosissima), and analyze the spatial and temporal dynamics of plant water source in Ejina Delta, the lower reaches of the Heihe River. China. Methods: Eight sampling sites were selected in the riparian zones along the East River and West River in Ejina. The plant xylem water, soil moisture, rainwater, stream water and groundwater were taken and pretreated during the growing season in 2015-2016, and the stable oxygen isotope ratio (δ18O) for each water sample was measured. The δ18O of plant xylem water and soil moisture were compared to estimate the dominant depth of root water uptake, and the linear-mixed model called "IsoSource" were applied to determine plant water sources and quantify their proportions. Important findings: This study indicated that the main recharge sources for P. euphratica and T. ramosissima were stream water and groundwater. The contributions of rain water to them was negligible due to the limited amount and the shallow infiltration depth of local rainfall. As affected by groundwater level fluctuation, soil physical properties, as well as lateral and vertical recharge of stream water on soil moisture, the dominant depth of root water uptake spatially varied. However, the relative contributions of stream water or groundwater to plant water sources did not change significantly across space. Populus euphratica used more stream water (68%), while T. ramosissima used more groundwater (65%). Plant water sources were sensitive to environmental flow controls. The contributions of stream water to the water sources of the two species went up to 84% and 48% for P. euphratica and T. ramosissima respectively during the discharge period, but dropped to 63% and 30% during the non-discharge period. On the other hand, the contributions of groundwater decreased to 16% and 52% during the discharge period, but increased to 37% and 70% during non-discharge period. It is noteworthy that the high similarity of δ18O between stream water and groundwater due to extensive water exchange in the riparian zone made increase the uncertain in quantifying plant water sources.     

Nicotianamine: mediator of transport of iron and heavy metals in the phloem?

Recent work has demonstrated that minerals in plants are circulated between root and shoot. This occurs during the whole life time and renders possible response to changing environmental conditions. This mineral circulation occurs through intensive solute exchange between xylem and phloem in roots, stems, and leaves. The transport form of heavy metals such as iron, manganes, zinc and copper in the phloem, whether ionic or chelated, is unclear in most cases.
The unusual amino acid nicotianamine (NA) is ubiquitous throughout the plant kingdom. It is a chelator of several divalent transition metals. Its physiological role was investigated with the tomato mutant chloronerva, the only known NA-free multicellular plant. The mutant also exhibits disturbances of its iron metabolism and that of other heavy metals. This leads, among others, to a typical intercostal chlorosis and progressive iron accumulation in the leaves. From the heavy metal chelating properties of NA and from the phenotype of the mutant chloronerva it is concluded that NA is needed for normal distribution of heavy metals in young growing tissues fed via the phloem. This function could be fulfilled by mediating phloem loading or unloading of heavy metals as well as by preventing their precipitation in the alkaline phloem sap. An attempt is made to explain the chloronerva phenotype in the light of the phloem transport hypothesis of chelated iron.     

Seasonal and spatial variation in the diet of brown trout (Salmo trutta L.) in the subarctic River Laxá, north-east Iceland

This study examines seasonal and spatial patterns in the diet composition, stomach fullness and condition of a landlocked population of brown trout (2.5–61.3 cm) in the lake-fed River Laxá in NE-Iceland. The stomach contents consisted predominantly of benthic invertebrates, such as blackfly larvae Simulium vittatum (58%), chironomids (24%) and the freshwater snail Radix peregra (7%). The seasonal and spatial patterns of S. vittatum in the stomach contents were consistent with published studies on the life cycle and production of S. vittatum in the River Laxá. Close to the Lake Myvatn outlet (0–16 km), S. vittatum constituted 63% of the stomach content volume, and exhibited two peaks (i.e., generations) in its seasonal contribution to the stomach contents, whereas further downstream (16–35 km) S. vittatum constituted 45% of the volume and showed only clear evidence of one generation. Seasonal fluctuations in S. vittatum availability appear to affect the stomach fullness and the condition factor of the trout, especially close to the lake outlet where the fluctuations are pronounced.     

Length–weight relationships of seven fish species in the Yangtze River Estuary and its adjacent waters,Eastern China

The length–weight relationships (LWRs) for seven fish species belonging to five families in the Yangtze River Estuary and its adjacent waters are presented. Cynoglossus gracilis, Cynoglossus macrolepidotus, Ctenotrypauchen chinensis, Collichthys niveatus, Ophichthus apicalis and Erisphex potti were collected monthly in 2009 using trammel nets (the size of smaller mesh net was 1.5 m × 15 m × 4 panels with mesh sizes of 2.5, 3.4, 4.3 and 5.8 cm; the size of larger-mesh net was 2.4 m × 30 m × 4 panels with mesh sizes of 5.0, 6.0, 7.0 and 8.0 cm; soaking overnight). Lophiogobius ocellicauda were collected December in 2020 using shrimp trawl nets (mesh size 2.0 cm). The precision of measurement for the fish specimens is 0.1 cm total length and 0.1 g total weight. The estimated ranges of the parameters a and b for the seven fish species were from 0.0001 to 0.0289 and 2.718 to 3.541, respectively. Two new maximum total length were recorded for Ctenotrypauchen chinensis and Ophichthus apicalis.