The entry of Cd into the food chain is of concern as it can cause chronic health problems. To investigate the relationship between soil properties and the concentration of Cd in wheat (Triticum aestivum L.) and harley (Hordeum vulgare L.) grain, we analyzed 162 wheat and 215 barley grain samples collected from paired soil and crop surveys in Britain, and wheat and barley samples from two long-term sewage sludge experiments. Cadmium concentrations were much lower in barley grain than in wheat grain under comparable soil conditions. Multiple regression analysis showed that soil total Cd and pH were the significant factors influencing grain Cd concentrations. Significant cultivar differences in Cd uptake were observed for both wheat and barley. Wheat grain Cd concentrations could be predicted reasonably well from soil total Cd and pH using the following model: log(grain Cd) = a + b log(soil Cd) - c(soil pH), with 53% of the variance being accounted for. The coefficients obtained from the data sets of the paired soil and crop surveys and from long-term sewage sludge experiments were similar, suggesting similar controlling factors of Cd bioavailability in sludge-amended or unamended soils. For barley, the model was less satisfactory for predicting grain Cd concentration (22% of variance accounted for). The model can be used to predict the likelihood of wheat grain Cd exceeding the new European Union (EU) foodstuff regulations on the maximum permissible concentration of Cd under different soil conditions, particularly in relation to the existing Directive and the proposed new Directive on land applications of sewage sludge.

The ATLAS experiment sensitivity to top quark Flavour Changing Neutral Current (FCNC) decays was studied at LHC using tt events. While one of the top quarks is expected to follow the dominant Standard Model decay t → bW , the other decays through a FCNC channel, i.e. t → Zu(c), t → γu(c) or t → gu(c). Different types of analyses, applied to each FCNC decay mode, were compared. The FCNC branching ratio sensitivity (assuming a 5σ signal significance) and 95% confidence level limits on the branching ratios (in the hypothesis of signal absence) were obtained.

The PAH content of soils from a long-term agricultural experiment that received 25 separate sewage sludge applications from 1942 to 1961 is presented along with data from an untreated control plot and a plot that received repeated applications of farmyard manure. Archived plough layer (0-23 cm) soil samples were collected, stored, and processed in the same manner between 1942 and 1984 (i.e., before, during, and after sludge amendments) and samples of the applied sludges were available for analysis. Soil concentrations increased between 1942 and 1960 on the sludge-amended plot and subsequently showed a steady decline. By 1984 the sludge-amended plot still contained over 3 times more £PAH than the corresponding control soil. By 1960 ~70% of the £PAH load added in the sludge was unaccounted for; this had increased to nearly 85% by 1984. Some compound-specific trends are apparent in the data; generally, the higher molecular weight PAHs have been more persistent. It is argued that biodegradation and transboundary transfers due to ploughing are the two main loss mechanisms.

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A new growth medium which closely approximates the composition of the soil solution is presented. This soil solution equivalent (SSE) medium contains the following components (millimolar):

sions and deposition in western Europe has led to increased S deficiency in many agricultural crops, which Archived wheat (Triticum aestivum L.) grain and straw, and soil remove substantial amounts of S from the soil annually samples from the control plot of the Rothamsted Broadbalk Experiment, located in southeastern England and established in 1843, were (McGrath and Zhao, 1995;. used to investigate the effects of dramatically changing SO 2 pollution

SUMMARYBoth Bromus erectus and Holcus lanatus grew better in NOg-N than in NH4-N. NH4-N inhibited Mn uptake and NO3-N enhanced it. The concentration of Mn found in both species was greater in NO3-N than NH4-N treated plants and increased severity of toxicity symptoms was observed in plants given NO3-N treatments. In general, uptake and concentration of Mn was greater in Holcus than in Bromus, although Holcus displayed less severe symptoms of toxicity. Root concentrations of Mn were greater than those of shoots in Holcus. As excess Mn generally affects plant tops more severely than roots it is possible that a mechanism reducing upward translocation of Mn conferred a degree of tolerance in Holcus. Growth of the population of Holcus used was affected to a lesser extent than Bromus by large concentrations of Mn in nutrient solution which may partially account for the markedly different frequency of occurrence of these species on soils which contain high concentrations of both NH4-N and Mn. In Bromus NH4-N and Mn interact to reduce their combined effects but in both species the adverse effects of NH4-N on growth for the most part masks that of Mn. Conversely with NO3-N, itself beneficial, Mn uptake is not depressed as it is with NH4-N and when Mn-toxicity occurs, it is more marked. In solution culture Bromus is very sensitive to NH4-N and also to Mn in the presence of NH4-N or NO3-N, whereas in the kind of habitat in which Bromus occurs N is present as NO3 and the adverse effect of any Mn present is neutralized by Ca.

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