Exposure to polychlorinated biphenyls in residents near a chemical factory in Italy: the food chain as main source of contamination

High levels of PCBs were recently found in soil, food and some farmers living close to a chemical factory which until the 1980s had produced polychlorinated biphenyls (PCBs) in Brescia, North Italy. We performed a survey on a random sample of subjects aged 20-79 years living in various areas of the town with different levels of soil pollution to investigate factors associated with increased levels of PCB in serum (24 congeners were tested). Total PCB values were closely related to age (Spearman r=0.68; p<0.0001). The 166 consumers of locally produced food had higher PCB levels than non-consumers (median=1143 versus 719; 95th centile=9301 versus 2635ng/g lipid) with the highest levels among consumers of food produced in the most contaminated area close to the factory (median=2551; 95th centile=33464ng/g lipid). A dose-effect relationship between consumption of food produced in this area and PCB blood levels was observed (Spearman r=0.52, p=0.0014). Consumers of only plant food produced in this area had higher levels of PCB than non-consumers (median=1100; 95th centile=10,800ng/g lipid). Three subjects who had worked at the factory in the past showed high PCB levels. Distribution of PCB congeners did not differ between consumers of locally produced food and non-consumers, apart from PCB 209 which was found at high levels in former factory workers and was more common among consumers of food produced in the polluted area. In conclusion, we found high serum PCB levels in humans living in a highly polluted area in an industrialized town in Italy, due mainly to consumption of food produced in polluted areas.     

A review of the PGM industry,deposit models and exploration practices: Implications for Australia's PGM potential

Australia is prospective for platinum group metal (PGM) mineralisation (in particular primary magmatic reef, primary magmatic by-product, late magmatic and hydrothermal, and alluvial placer type) but its known PGM endowment is negligible compared to that of South Africa, Russia, the USA and Canada. Most Australian PGM projects are operated by mid-cap or junior companies and form part of larger, more diverse project portfolios held by these explorers. Most projects were ‘hot’ while market conditions were favourable. However, as other metals became ‘fashionable’ and market conditions for PGM changed, so did the focus of these companies. Pure PGM companies are rare in Australia. The search for and development of PGM-only deposits in Australia are high risk business activities. No new primary PGM deposits have been discovered since the mid to late 1980s and none of the significant deposits that were discovered or evaluated in the 1980s have been mined. This review suggests that at least several A$10 million but more likely several A$100 million were sunk into PGM exploration and development projects but none advanced to the mining stage. The viability of Australian PGM projects is very sensitive to (1) metal prices, (2) the US$/A$ exchange rate, and (3) large capital expenditure requirements relative to the small size of Australian PGM-only deposits. Most PGM-only projects were initiated at times of high PGM prices. However, advanced exploration, feasibility studies and project development always lagged behind the price booms. South Africa, Russia and Canada contain approximately 98% of the known global PGM reserves. This situation has a very negative effect on the Australian PGM industry as the well-endowed nations continue to receive the lion's share of exploration spend and new projects.     

Reliability of groundwater vulnerability maps obtained through statistical methods

Statistical methods are widely used in environmental studies to evaluate natural hazards. Within groundwater vulnerability in particular, statistical methods are used to support decisions about environmental planning and management. The production of vulnerability maps obtained by statistical methods can greatly help decision making. One of the key points in all of these studies is the validation of the model outputs, which is performed through the application of various techniques to analyze the quality and reliability of the final results and to evaluate the model having the best performance. In this study, a groundwater vulnerability assessment to nitrate contamination was performed for the shallow aquifer located in the Province of Milan (Italy). The Weights of Evidence modeling technique was used to generate six model outputs, each one with a different number of input predictive factors. Considering that a vulnerability map is meaningful and useful only if it represents the study area through a limited number of classes with different degrees of vulnerability, the spatial agreement of different reclassified maps has been evaluated through the kappa statistics and a series of validation procedures has been proposed and applied to evaluate the reliability of the reclassified maps. Results show that performance is not directly related to the number of input predictor factors and that is possible to identify, among apparently similar maps, those best representing groundwater vulnerability in the study area. Thus, vulnerability maps generated using statistical modeling techniques have to be carefully handled before they are disseminated. Indeed, the results may appear to be excellent and final maps may perform quite well when, in fact, the depicted spatial distribution of vulnerability is greatly different from the actual one. For this reason, it is necessary to carefully evaluate the obtained results using multiple statistical techniques that are capable of providing quantitative insight into the analysis of the results. This evaluation should be done at least to reduce the questionability of the results and so to limit the number of potential choices.     

29 % N2O emission reduction from a modelled low-greenhouse gas cropping system during 2009–2011

Atmospheric concentration of nitrous oxide (N₂O), a greenhouse gas (GHG), is rising largely due to agriculture. At the plot scale, N₂O emissions from crops are known to be controlled by local agricultural practices such as fertilisation, tillage and residue management. However, knowledge of greenhouse gas emissions at the scale of the cropping system is scarce, notably because N₂O monitoring is time consuming. Strategies to reduce impact of farming on climate should therefore be sought at the cropping system level. Agro-ecosystem models are simple alternative means to estimate N₂O emissions. Here, we combined ecosystem modelling and field measurements to assess the effect of agronomic management on N₂O emissions. The model was tested with series of daily to monthly N₂O emission data. It was then used to evaluate the N₂O abatement potential of a low-emission system designed to halve greenhouse gas emissions in comparison with a system with high productivity and environmental performance. We found a 29 % N₂O abatement potential for the low-emission system compared with the high-productivity system. Among N₂O abatement options, reduction in mineral fertiliser inputs was the most effective.     

Effects of female mating status on copulation behaviour and sperm expenditure in the freshwater crayfish <Emphasis Type="Italic">Austropotamobius italicus</Emphasis>

Sperm competition models predict that males should adjust their sperm expenditure according to the risk and/or intensity of sperm competition. In this paper, we analysed copulatory behaviour of both sexes and sperm expenditure in relation to female mating status (virgin or mated) in the freshwater crayfish Austropotamobius italicus, a species where males have been reported to feed on and remove sperm laid by other males. The same females were allowed to be inseminated sequentially by two males, and we compared the sexual behaviours of partners between the first (virgin females) and the second mating (mated females). We found that female resistance did not differ between the first and the second mating, nor males refused or took more time to mount a mated female. However, when mating with a mated female, males reached an effective copulation position significantly later. This occurred because second-mating males removed, by eating, all or most spermatophores previously deposited by first males. As removal was often incomplete, this resulted in a larger amount of sperm being deposited on female ventral parts after the second mating, although second males did not allocate more sperm to mated females than first males did. Thus, the peculiar mode of sperm competition, where males remove previously deposited sperm, and the consequent predictable strong last male prevalence in paternity likely led to the observed lack of adjustment of sperm expenditure to female mating status in this species.     

Assessment of reference values for polychlorinated biphenyl concentration in human blood

A chemical factory which produced polychlorinated biphenyls (PCBs) operated in Brescia, North Italy, (about 200000 inhabitants) from the 1930s to the 1980s. High levels of PCBs were recently found in soil, food and people living in an area close to the factory. We performed a survey among the general population living in non-polluted areas of the town in order to define the reference values (RVs) of the non-exposed population. A random sample of subjects aged 20-79 years (50% males) was selected. Participants underwent PCB determination and were interviewed on their residential and occupational history and current diet. For RV determination, subjects who had resided in the polluted area or consumed any food produced in the area in their lifetime were excluded. Eight hundred and ninety-two subjects were contacted, 579 (65%) of whom agreed to participate; 311 of them were considered for RV determination (53% male, mean age=48.7 years). Total PCB serum levels, computed as the sum of the 24 congeners determined, were: mean=5.15ng/ml (SD=8.83), median=4.11ng/ml, range=0.4-34.12ng/ml, 95th centile=14.38ng/ml. Lipid-adjusted mean and median were 897 and 705ng/g lipid, respectively. PCB values showed positive correlations with age (Spearman's r=0.76) and with serum concentration of total cholesterol (r=0.40) and triglycerides (r=0.36). No association was found with gender, cigarette smoking, alcohol or diet. Seven PCB congeners, (PCB 180, 153, 138, 170, 194, 118, and 156), including those at higher chlorination, were present in more than 30% of the subjects and contributed 99% of the total PCB levels, with a modest role of dioxin-like congeners.     

Dioxins in the Venice lagoon

Venice is famous around the world for its uniqueness and architectural splendours, arts and the history of the “Serenissima Repubblica”, as it was known in the past, but few are aware that Venice economy is strongly dependent on the industrial activities based mainly on the adjacent Porto Marghera area. For many years, the lagoon that physically separates the city from the dry land has avoided association between the concern connected with the pollution derived from these industrial activities and the public perception of Venice. Since 1995, dioxins have appeared as a lagoon contaminant, and their presence, at such a level requiring immediate “in depth” studies and interventions, has been fully realized for decades.     

Poly(lactic acid)/Cellulose Composites Obtained from Modified Cotton Fibers by Successive Acid Hydrolysis

This work is focused on the hydrolysis of cotton fibers from waste textiles to obtain micro and nanofibers to be used as reinforcements in polymer composites. To promote their compatibility with polymeric matrix, hydrolyzed cotton fibers were surface modified with various silane compounds. Thus, these fibers were mixed with commercial poly(lactic acid) (PLA) at 5% w/w loading by melt compounding. Acid treatments caused a decrease of the crystallinity index whereas the thermal stability was significantly improved, especially for cellulose fibers hydrolyzed in two steps. Morphological analysis revealed a reduction of the fibers diameter and a decrease of their length as a consequence of the hydrolysis. NMR analysis confirmed the silanization of the fibers by reaction with the silane agent. Tensile tests revealed that silanization treatments were able to increase the composite Young’s modulus and the stress at break with respect to the neat matrix, indicating that silanization improved the polymer/fiber compatibility interfacial adhesion. The overall results demonstrated that applying suitable surface modification strategies, waste cotton textiles can be effectively recycled as fillers in polymer based composites.