Imaging of Jurassic fossils from the Talbragar Fish Bed using fluorescence, photoluminescence, and elemental and mineralogical mapping.

The Talbragar Fish Bed is one of Australia's most important Jurassic deposits for freshwater fishes, land plants and aquatic and terrestrial insects. The site has yielded many well preserved fossils, which has led to the formal description of numerous new species and higher taxa. The excellent preservation of many fossils has allowed detailed anatomical studies, e.g. of the early teleost fish Cavenderichthys talbragarensis (Woodward, 1895). Here we report on the fluorescent characteristics and mineral composition of a range of Talbragar fossils. Most specimens fluoresce under ultraviolet, blue and green light. Elemental and mineralogical analyses revealed that the Talbragar fossils consist predominantly of quartz (SiO2), a mineral that is likely to account for the observed fluorescence, with trace kaolinite (Al2Si2O5(OH)4) in some of the fish fossils. Rock matrices are predominantly composed of quartz and goethite (FeO(OH)). Closer inspection of a plant leaf (Pentoxylon australicum White, 1981) establishes fluorescence as a useful tool for the visualisation of anatomical details that are difficult to see under normal light conditions.

Historical record of black carbon in urban soils and its environmental implications.

Energy use in urbanization has fundamentally changed the pattern and fluxes of carbon cycling, which has global and local environmental impacts. Here we have investigated organic carbon (OC) and black carbon (BC) in six soil profiles from two contrast zones in an ancient city (Nanjing) in China. BC in soils was widely variable, from 0.22 to 32.19 g kg(-1). Its average concentration in an ancient residential area (Zone 1) was, 0.91 g kg(-1), whereas in Zone 2, an industrial and commercial area, the figure was 8.62 g kg(-1). The ratio of BC/OC ranged from 0.06 to 1.29 in soil profiles, with an average of 0.29. The vertical distribution of BC in soil is suggested to reflect the history of BC formation from burning of biomass and/or fossil fuel. BC in the surface layer of soils was mainly from traffic emission (especially from diesel vehicles). In contrast, in cultural layers BC was formed from historical coal use. The contents of BC and the ratio of BC/OC may reflect different human activities and pollution sources in the contrasting urban zones. In addition, the significant correlation of heavy metals (Cu, Pb, and Zn) with BC contents in some culture layers suggests the sorption of the metals by BC or their coexistence resulted from the coal-involved smelting.

Atmospheric lead and heavy metal pollution records from a Belgian peat bog spanning the last two millenia: human impact on a regional to global scale.

Europe has been continuously polluted throughout the last two millennia. During the Roman Empire, these pollutions were mainly from ore extraction and smelting across Europe. Then, during the Middle Ages and the Early times of Industrial revolution (i.e. 1750), these pollutions extended to coal burning and combustion engine. Belgian ombrotrophic peat bogs have proved an effective archive of these pollutants and provide the opportunity to reconstruct the history of atmospheric deposition in NW Europe. The results of recent and past trace metal accumulation and Pb isotopes from a one-meter peat core (in the Misten peat bog) have been derived using XRF and Nu-plasma MC-ICP-MS. Combined with (14)C and (210)Pb dates these data have enabled us to trace fluxes in anthropogenic pollution back to original Roman times. Several periods of well-known Pb pollution events are clearly recorded including the Early and Late Roman Empire, the Middle Ages and the second industrial revolution. Also recorded is the introduction of leaded gasoline, and more recently the introduction of unleaded gasoline. Lead isotopes in this site have also enabled us to fingerprint several regional and global sources of anthropogenic particles.

Synthesizing bioaccumulation data from the German metals in mosses surveys and relating them to ecoregions.

The European Heavy Metals in Mosses Surveys measure and map environmental concentrations of metals at more than 7000 sites in Europe. In Germany, moss samples were taken at 592 sites in 1990, at 1026 sites in 1995, and at 1028 sites in 2000, where up to 40 metals were measured each time. This article is about how to calculate multi-metal indices from the site- and metal-specific monitoring data and how to link them with the natural regions (ecoregions) of Germany. The ecoregions were calculated with surface data on natural vegetation, elevation, soil texture and climate by means of Classification and Regression Trees (CART). The ecoregions were mapped by GIS and superimposed on a map of multi-metal bioaccumulation indices calculated by means of geostatistics and percentile statistics from the monitoring data. These indices integrate the concentrations of 8 metals measured in 1990, 1995, and 2000 or 12 metals from the 1995 and 2000 surveys, respectively, and the ecoregionalisation enables their geostatistical estimates to be grouped into 21 ecological land categories. This two-step aggregation revealed that, from 1990 to 2000, the multi-metal metal accumulation declined up to 80%, varying with the ecoregions. Based on the multi-metal accumulation index hot spots, the metal accumulation was mapped, ecoregionalised, and suggested for further ecotoxicological assessment. Thus, the approach helps to assess the metal bioaccumulation within ecoregions in a comprehensive and holistic manner over time, space, and metals. This data aggregation is of importance for the environmental reporting in Germany and within the framework of the international environmental information systems. Furthermore, ecoregions may help to plan and optimize monitoring networks. Because monitoring should measure and estimate not only the environmental concentrations of substances but also their impacts on ecoregions, the number of monitoring sites should be proportional to the areas covered by the ecoregions and located according to their spatial variation.

Comment on Martínez-García et al. "Heavy metals in human bones in different historical epochs".

Martínez-García et al. (Sci. Tot Env. 348:51-72) have examined heavy metal exposure of humans in the Cartagena region using analysis of archaeological bones. An analysis of the lead and iron levels they report shows that they are physiologically implausible and must therefore result from diagenesis. This, and analogy with the known diagenetic origin of certain other elements, suggests that the other metal analyses they report are also unlikely to be in vivo concentrations. Lifetime heavy metal exposure cannot be deduced from diagenetically altered concentrations.

Heavy metals in human bones in different historical epochs.

The concentration of the metals lead, copper, zinc, cadmium and iron was determined in bone remains belonging to 30 individuals buried in the Region of Cartagena dating from different historical periods and in eight persons who had died in recent times. The metals content with respect to lead, cadmium and copper was determined either by anodic stripping voltammetry or by atomic absorption spectroscopy on the basis of the concentrations present in the bone remains. In all cases, zinc and iron were quantified by means of atomic absorption spectroscopy. The lead concentrations found in the bone remains in our city are greater than those reported in the literature for other locations. This led to the consideration of the sources of these metals in our area, both the contribution from atmospheric aerosols as well as that from the soil in the area. Correlation analysis leads us to consider the presence of the studied metals in the analysed bone samples to be the consequence of analogous inputs, namely the inhalation of atmospheric aerosols and diverse contributions in the diet. The lowest values found in the studied bone remains correspond to the Neolithic period, with similar contents to present-day samples with respect to lead, copper, cadmium and iron. As regards the evolution over time of the concentrations of the metals under study, a clear increase in these is observed between the Neolithic period and the grouping made up of the Bronze Age, Roman domination and the Byzantine period. The trend lines used to classify the samples into 7 periods show that the maximum values of lead correspond to the Roman and Byzantine periods. For copper, this peak is found in the Byzantine Period and for iron, in the Islamic Period. Zinc shows an increasing tendency over the periods under study and cadmium is the only metal whose trend lines shows a decreasing slope.

A review of the clinical and toxicological aspects of 'traditional' (herbal) medicines adulterated with heavy metals.

The popularity of traditional remedies has greatly increased in westernised countries over recent years. Although many of these remedies are used safely, there have recently been an increasing number of case reports being published of heavy metal poisoning after the use of traditional remedies, in particular, Indian Ayurvedic remedies. This study reviews the data on published cases, along with the history of Ayurvedic medicine in an attempt to provide an insight into why heavy metals, in particular lead, mercury and arsenic are added in such large concentrations to these remedies.

Historical change of heavy metals in urban soils of Nanjing, China during the past 20 centuries.

Two typical areas, including once commercial and residential quarters of Nanjing, China, were studied by investigating soil properties especially heavy metals of soils in various cultural layers formed in different Chinese Dynasties. The age of the soil profiles was dated by both archaeological and 14C chronological methods. The results showed that urban soils in the old commercial/workshop quarter of Nanjing were generally contaminated by heavy metals Cu, Zn, Pb, but their concentration levels varied significantly among the cultural layers formed in different dynasties. The substantial increase of heavy metals appeared in three historical periods, i.e., South Dynasty (222-589 AD), the earlier Ming (1368-1644 AD) and the late Qing (1644-1912 AD) in one area. The tremendous input and storage of heavy metals in soils was explained by the primitive smelting and the strengthened metal processing activities, which might be due to the requirement of weapon making or other industries, in the changing social conditions of the corresponding periods. Soils in the once noble political, cultural centers did not show significant increase of heavy metals. The difference in the distribution pattern of heavy metals revealed the contrasting history of the site uses. The change of contaminant level in soils is believed to be a reflection of various human activities in the city during the past 20 centuries.

Understanding human impact on the Baltic ecosystem: changing views in recent decades.

Grave environmental problems, including contamination of biota by organochlorines and heavy metals, and increasing deep-water oxygen deficiency, were discovered in the Baltic Sea in the late 1960s. Toxic pollutants, including the newly discovered PCB, were initially seen as the main threat to the Baltic ecosystem, and the impaired reproduction found in Baltic seals and white-tailed eagles implied a threat also to human fish eaters. Countermeasures gradually gave results, and today the struggle to limit toxic pollution of the Baltic is an international environmental success story. Calculations showed that Baltic deep-water oxygen consumption must have increased, and that the Baltic nutrient load had grown about fourfold for nitrogen and 8 times for phosphorus. Evidence of increased organic production at all trophic levels in the ecosystem gradually accumulated. Phosphorus was first thought to limit Baltic primary production, but measurements soon showed that nitrogen is generally limiting in the open Baltic proper, except for nitrogen-fixing cyanobacteria. Today, the debate is concerned with whether phosphorus, by limiting nitrogen-fixers, can control open-sea ecosystem production, even where phytoplankton is clearly nitrogen limited. The Baltic lesson teaches us that our views of newly discovered environmental problems undergo repeated changes, and that it may take decades for scientists to agree on their causes. Once society decides on countermeasures, it may take decades for them to become effective, and for nature to recover. Thus, environmental management decisions can hardly wait for scientific certainty. We should therefore view environmental management decisions as experiments, to be monitored, learned from, and then modified as needed.

From sewage water treatment to wastewater reuse. One century of Paris sewage farms history.

The irrigation fields of Paris have been used for 100 years. Their soils mainly contain heavy metals in the topmost layer. Metals come from raw sewage as well as from digested sludge of biological treatment plants which have been diluted for years in raw water. Vegetables that are cultivated in the irrigation fields concentrate metals but their average contents, however, are lower than the recommended limit values. Some vegetables concentrate more specifically one type of metal. Corn seeds accumulate less metal than green vegetables. The SIAAP keeps operating irrigation fields by delivering clariflocculated water with a low metal content from the new Seine Centre plant, with the purpose of keeping some 2,000 ha of green zone in an otherwise heavily constructed area and to prevent a metal release from the soil should irrigation be interrupted. Maintaining irrigation fields also relieves the biological treatment plant and then contributes to preserve the quality of the Seine river, especially in summer.