Publications

We investigated the scale and causes of Pb contamination in Chinese tea. Lead concentrations in 1225 tea samples collected nationally between 1999 and 2001 varied from <0.2 to 97.9mg kg−1 dry weight (DW), with 32% of the samples exceeding the national maximum permissible concentration (MPC) of 2.0mg kg−1 DW and a significant difference between tea types. There was an increasing trend in tea Pb concentration from 1989 to 2000. Proximity to highway and surface dust contamination were found to cause elevated Pb concentrations in tea leaves. Furthermore, Pb concentration in tea leaves correlated significantly and positively with soil extractable Pb, and negatively with soil pH, suggesting that root uptake of Pb from soils also contributed to Pb accumulation in tea. Potential contributions to human Pb intake from drinking tea were small at the median or national MPC Pb values, but considerable at the highest concentration found in the study.

. At Woburn Experimental Farm (SE central England) sulphur (S) deficiency symptoms occurred in a winter oilseed rape crop grown in Lansome field on soil of the Cottenham series, but not on the Blithe series soil in the adjacent Mill Dam Close field. At maturity, the two crops produced a similar amount of dry matter but seed yield and harvest index were significantly less in Lansome. Total S uptake of the crop in Lansome was less than half of that in Mill Dam Close, which was similar to the amount normally found in a S sufficient crop. Both soils are of light texture (loamy sand and sandy clay loam for the Cottenham and Blithe series, respectively), and there was little difference in the extractable S concentration in the topsoils between the two fields. However, more extractable S was found in the subsoil of Blithe series, because it contains more free Fe and Al oxides and has a lower pH. These results show that any evaluation of the soil S supply needs to take into account the pool of available S in the subsoil.

No abstract is provided for this article.

Nanomaterial-based delivery systems can deliver functional genes or siRNA into intact plant cells and create transgene-free genetically engineered plants. This system allows highly efficient and organelle-specific delivery that can overcome host-range limitations. This approach will have a diverse range of applications in plant biotechnology and plant biology.

Halogenated polycyclic aromatic hydrocarbons (H-PAHs), including chlorinated polycyclic aromatic hydrocarbons (Cl-PAHs) and brominated polycyclic aromatic hydrocarbons (Br-PAHs), are compounds in which one or more hydrogen atoms replaced by chlorine or bromine atoms. These compounds are not only difficult to degrade but also highly fat soluble and toxic. They are a new type of high-risk organic pollutants with structures similar to those of dioxins, and their toxicity is even higher than that of the parent polycyclic aromatic hydrocarbons (PAHs). The bioaccumulation of H-PAHs can be predicted by their octanol-water partition coefficient (Kow); in general, higher bioaccumulation capacity and Kow values indicate greater fat solubility. Therefore, animal-derived foods with higher fat contents, such as animal meat, milk, aquatic products, and their processed forms, are more likely to be contaminated with higher contents of H-PAHs than those with lower fat contents. In this work, a gas chromatography-triple quadrupole mass spectrometry (GC-MS/MS) method coupled with stable isotope dilution was established to determine 15 H-PAHs in aquatic products. The instrument and pretreatment methods were systematically optimized. The GC-MS/MS used in this method can effectively eliminate matrix interferences and features high sensitivity and low analytical cost; thus, it has good application prospects. The samples were added with an isotope internal standard before extraction to calibrate the loss of the tested substance during the pretreatment process, extracted by accelerated solvent extraction, purified using gel permeation chromatography and PRiME HLB columns, and then analyzed by GC-MS/MS. The use of two DB-5MS chromatographic columns (30 m×0.25 mm×0.25 μm) and microplate fluidics technology to connect chromatographic columns 1 and 2 in series led to better separation effects, good peak shapes, and high target compound responses. The 15 H-PAHs demonstrated good linearities in the range of 1-50 μg/L, with correlation coefficients (r) greater than or equal to 0.993. The relative standard deviation (RSD) values of the relative response factor (RRF) of the H-PAHs were less than 9%, the method detection limit (MDL) was 0.009-0.072 μg/kg, and the method quantification limit (MQL) was 0.031-0.240 μg/kg. Three spiked levels of 0.25, 1.0, 2.5 μg/kg were added to the blank samples to determine the recovery and precision. The recoveries for these spiked levels were 74.6%-116.8%, 77.8%-123.2%, and 71.9%-124.8%, respectively, and the corresponding RSDs were 0.6%-8.2%, 0.6%-9.0%, and 0.4%-10.6%, respectively. The total actual content of H-PAHs in aquatic product samples was 0.60-3.54 μg/kg. Among the H-PAHs investigated, 9-chlorophenanthrene (9-ClPhe) showed the greatest detection rate (100%) and highest content (1.15 μg/kg), indicating that H-PAHs widely exist in aquatic products. Thus, further assessment of the dietary exposure risk of these compounds is necessary. The developed method simplifies the pretreatment step, and has the advantages of simplicity, rapid analysis, high recoveries, and good stability. It is suitable for the qualitative and quantitative analysis of H-PAHs in actual aquatic product samples and provides reliable technical support for the residue status and risk assessment of H-PAHs in aquatic products.

No abstract is provided for this article.

No abstract is provided for this article.

From 1998 to the end of October, 2012, the European Journal of Soil Science and Soil Use and Management published 94 papers authored by Chinese researchers. The number of papers has increased from two per year between 1998 and 2000 to 17 per year in 2011, and citations have also risen from two in 1998 to 120 in 2011 (Figure 1). The increasing research attention by Chinese scientists to soil science can be explained for the following reasons: (i) the vast territory and large climatic variation within China have resulted in diverse soil types, which provide considerable research opportunities, (ii) agriculture has a very long history in China, and this has had a dramatic impact on the environment, particularly on soil because a better understanding of soil productivity and sustainability is urgently required and (iii) with the fast development of the Chinese economy, the central government has increased greatly investment in scientific research, thus providing the resources needed to support fundamental and applied research. This virtual issue is a dual publication in both the European Journal of Soil Science and Soil Use and Management, and can be accessed without cost online (www.wileyonlinelibrary.com/journal/sum and www.wileyonlinelibrary.com/journal/ejss). The virtual issue provides a collation of research papers authored by Chinese soil scientists which have been published in the European Journal of Soil Science or Soil Use and Management and which give a flavour of the breadth and types of the research. Twenty papers are included covering the following five topics: (1) carbon and organic matter; (2) physical and chemical processes, functions and management; (3) biological interactions; (4) nutrient management and (5) soil degradation and impact of land management. These five research areas overlap to some extent and classification of some papers is difficult, but some important research themes can be recognized. Carbon cycling has a major influence on global climate change and is much influenced by the effects of this phenomenon. There are very important processes involved with carbon cycling in terrestrial systems including the effects of human activities. Chinese soil scientists have studied carbon stability as well as the properties of humic substances as affected by tillage (He et al., 2009; Wu, 2011) and soil amendment (Dou et al., 2008). Organo-mineral complexes play a significant role in stabilizing organic carbon. Studies on carbon stability require both microscopic and macroscopic approaches. Chemical and biological techniques are combined in order to understand the mechanisms of carbon sequestration, while regional and global carbon distribution and transformation are the basis for indentifying carbon sinks and sources. Chinese soil scientists have an advantage given the diversity of soils in their country (Zhang et al., 2007; Ye et al., 2008). A great challenge to studies on carbon stability in China is that different processes have varying roles in different regions, and thus it is important to identify region-specific processes that govern carbon cycling and which will have relevance in other parts of the world. An individual paper can be categorized as one focusing on physical, chemical or biological processes, however, there is usually a large degree of inter-dependence between such processes. The input of various chemicals, or change in physical conditions such as temperature and soil water alters the environment for soil organisms, while biological processes determine the uptake of soil nutrients, preservation of soil carbon and the release of greenhouse gases. Soil is the largest sink for various contaminants and thus is of major importance in maintaining a sustainable environment in which, physical, chemical and biological processes interact. Studies on soil physical properties such as soil temperature (Gao et al., 2008), chemical and biological behaviour which influence greenhouse gas emission (Xu & Inubushi, 2009; Min et al., 2012) and microbial activities (Guo et al., 2007) are included as examples in this virtual issue. Chinese soil scientists have studied the speciation, distribution and removal, mostly by biological methods, of heavy metals in contaminated soils (Wang & Staunton, 2006). Recent research has centred on emerging anthropogenic chemicals, such as manufactured nanoparticles, pharmaceuticals (especially antibiotics) and personal care products. These chemicals occur only after industrial development, and thus their behaviour and risks are unknown; as a result, risk assessment studies are urgently needed. In the last few decades, along with the rapid development of large-scale livestock and poultry industries in China, there has been an increase in contaminants in manures from livestock and poultry (such as heavy metals, residues of animal medicine, salts, and harmful bacteria) which have entered the environment through manure application as soil amendments. More research attention has been given to the fate of these contaminants including sorption, leaching, bonding and bio- and chemical-degradation. Because of limited farmland and population pressure, the application of fertilizers to farmland in China is intensive and there is a worrying trend in the decreasing efficiency of applied fertilizers in the last three decades as demonstrated by a number of papers in this virtual issue. China consumes currently about 30% of the global N-fertilizers, but only 30–35% is utilized by crops. Most of the N-fertilizers thus enter the environment with potential harmful effects. Agricultural-related non-point pollution has been a major environmental problem in China (Wang et al., 2004), as also indicated by the widespread eutrophication of inland lakes. Sustainable management of soil fertility is a very important challenge for Chinese soil scientists. Since the 1970s, long-term fertilizer experiments have been established in China and have produced valuable data. Chemical fertilizers as well as soil amendments, such as manures from livestock (Duan et al., 2011), organic matter and biomass as well as biochars have been applied. Powerful analytical techniques such as 13C cross-polarized magic angle spinning nuclear magnetic resonance (CPMAS NMR) (Zhang et al., 2009) and stable isotope tracing (Zhang et al., 2012) methods have been used to investigate the impact of fertilizer applications on nutrient cycling and the properties of soil organic matter. Multi-disciplinary approaches involving plant nutrition, soil science and agronomy are needed to ensure the optimal use of applied soil nutrients; with such approaches greater crop yield, and improved efficiency of nutrient uptake can be achieved. With the fast economic development of China, land-use has changed dramatically in the last two decades. Farmland and residential land use have both expanded with the increase in residential land use the greater. Population increase is the main driving force to land-use change, but state macroscopic agricultural policies also play an important role in structural changes. In many regions of China, soils are under-going rapid degradation (Liang et al., 2009). An important area of research for Chinese soil scientists is to assess soil degradation, erosion and fertility in different ecological systems (Liu et al., 2002; Huang et al., 2004) or different land-uses (Meng et al., 2001; Liu et al., 2007). This approach provides useful information for optimizing soil-use and management. For example, tillage can induce erosion and deposition of soils, while terracing is an effective method of soil conservation on steep slopes (Ni & Zhang, 2007), and has been used extensively to control water erosion in hilly areas of China. Modelling and prediction of soil properties are required for soil management and particular challenges are presented by spatial variability. Previous models mostly focus on soil horizon variablity in relation to geomorphology and/or landscape position. Recent research indicates that investigations into the spatial distribution of water and soil organic matter should also consider vertical redistribution resulting from the influence of soil organisms and plants. Otherwise, predictions concerning soil water budgets and carbon storage will be incorrect. Chinese scientists have analysed both temporal and spatial variation in relation to soil use and properties. Such models are extremely important for the development of numerical hydrological and atmospheric models as well as for multi-media transport models of contaminants. Thus, they not only provide basic information important to soil management, but also contribute to the understanding of soil development and pollution control. China has a considerable range of soil types and environmental conditions and as a result soil scientists have access to unique and diverse research resources. Because of the vast territory, the identification of region-specific processes that govern carbon cycling in different regions of China is essential for understanding the behaviour of carbon in terrestrial system. Physical, chemical and biological processes are inter-dependent in soils. With the development of the Chinese economy, many emerging anthropogenic chemicals are discharged into the environment and physical, chemical and biological concepts should be combined to understand their environmental behaviour and risks. Intensive farming in China requires optimal nutrient management. A multi-disciplinary approach will lead to greater crop yield and better use of nutrients. Modelling of soil property change and spatial variability in both horizontal and vertical directions has the potential to provide important information for soil sampling and land use management. It is clear that soil science in China has made major steps over recent decades in making important contributions to the understanding of soil processes and improved ways of optimizing the management of soils, not just with respect to China, but on a world-wide basis. Future global pressures on food production, the effects of climate change and demands for improved maintenance of environmental quality means that continued contributions from Chinese scientists will remain very important.

With the increasing use of engineered nanoparticles, these materials will inevitably be released into the environment with unknown consequences. The interactions between engineered nanoparticles and plants are of particular concern, and the uptake by plants may constitute one of the main routes of exposure for species at a higher trophic level, leading to possible biomagnification of nanoparticles in the food chain. A review of the current literature shows that nanoparticles can be taken up by plants and cause phytotoxicity. The mechanisms by which engineered nanoparticles penetrate plant cells are still not well understood. Most of the studies have been performed with a few plant species under non-natural conditions such as hydroponics, and have included only the germination or seedling growth stage. Nanoparticles may undergo biotransformation and subsequent translocation within plants, although the mechanisms are poorly understood. Phytotoxicity is an important aspect for assessing potential environmental impacts of nanoparticles, but the mode of toxicity remains to be investigated.

Cellular compartmentation of Zn in the leaves of the hyperaccumulator Thlaspi caerulescens was investigated using energy-dispersive x-ray microanalysis and single-cell sap extraction. Energy-dispersive x-ray microanalysis of frozen, hydrated leaf tissues showed greatly enhanced Zn accumulation in the epidermis compared with the mesophyll cells. The relative Zn concentration in the epidermal cells correlated linearly with cell length in both young and mature leaves, suggesting that vacuolation of epidermal cells may promote the preferential Zn accumulation. The results from single-cell sap sampling showed that the Zn concentrations in the epidermal vacuolar sap were 5 to 6.5 times higher than those in the mesophyll sap and reached an average of 385 mM in plants with 20,000 &mgr;g Zn g-1 dry weight of shoots. Even when the growth medium contained no elevated Zn, preferential Zn accumulation in the epidermal vacuoles was still evident. The concentrations of K, Cl, P, and Ca in the epidermal sap generally decreased with increasing Zn. There was no evidence of association of Zn with either P or S. The present study demonstrates that Zn is sequestered in a soluble form predominantly in the epidermal vacuoles in T. caerulescens leaves and that mesophyll cells are able to tolerate up to at least 60 mM Zn in their sap.

The incidence of sulphur (S) deficiency has increased in many crops in the U.K. and other European countries in the last 10 years. Apart from the effects on yield, the S nutrition of a crop often has a strong influence on the quality of the produce. We have shown that S fertilisation significantly improved breadmaking quality of field-grown wheat (Triticum aestivum L.) in the U.K. with the loaf volumes of the same variety grown at different sites correlating better with the concentrations of grain S than grain N. Sulphur also increased gel protein content of flour, but decreased its elastic strength. In contrast, application of S fertilisers to oilseed rape (Brassica napus L.) can lead to increased glucosinolate concentrations in the seed which exceed the limit for the meal to be used in animal feeds. Results from 29 field experiments showed that the glucosinolate concentration of rapeseed was usually higher when grown at the S-sufficient than the S-deficient sites. However, the addition of S fertiliser increased the glucosinolate concentration much more under S-deficient than under S-sufficient conditions. Furthermore, there was a strong interaction between N and S on seed glucosinolates. Increasing N decreased the glucosinolate concentration when S was deficient, but increased the glucosinolate concentration when S was applied. The need to maintain a balanced N and S supply for both yield and quality is stressed.