Low bone density and renal dysfunction following environmental cadmium exposure in China

This paper presents the main findings of a study on health effects of environmental cadmium pollution in China, performed in 1998, i.e. approximately 25 years after the first warnings of such effects were published in Ambio. Forearm bone mineral density (BMD) and renal dysfunction were assessed in population groups exposed to cadmium via rice. Decreased BMD was found in postmenopausal women with elevated urinary cadmium (CdU) or cadmium in blood (CdB) and among men with elevated CdB. Also, clear and statistically significant dose-effect and dose-response relationships were found between CdB or CdU and renal dysfunction (increased excretion of retinol-binding protein). This is the first report of bone effects among Cd-exposed population groups in Asia outside Japan. The report is also of interest since it demonstrates that bone effects, a comparatively severe adverse health effect of Cd, in combination with renal dysfunction, still occurs in environmentally exposed population groups in Asia. Recent reports on bone effects in Cd-exposed population groups in Europe are discussed.     

Measuring the effect of photocatalytic purifiers on indoor air hydrocarbons and carbonyl pollutants

Laboratory tests of photocatalytic air purifiers are usually performed with a single pollutant, in the parts per million by volume domain and at airflow rates < or =0.1 m3/hr. Clearly, it is necessary to probe photocatalytic materials and apparatuses under real conditions or conditions closely mimicking reality. Photocatalytic prototypes were placed in an ordinary room. To collect hydrocarbons over a shorter period (15 min) than with adsorbent-containing cartridges, solid-phase microextraction (SPME) was used. Typically, concentrations in substituted benzene hydrocarbons and tetrachloroethene were decreased to 20-35% of initial values; toluene and m- + p-xylene concentrations dropped to 2-6 parts per billion by volume, and o-xylene and benzene concentrations were still lower. In the absence of appropriate, commercialized SPME fibers, carbonyl compounds (both formed and destroyed by photocatalysis) were extracted using cartridges containing 2,4- dinitrophenylhydrazine-coated silica. The concentration ranges (in parts per billion by volume) were shifted to higher values in treated air: from 9-15.5 to 12.5-18 for methanal, from 1.5-3 to 8-11.5 for ethanal, and from 4.5-19 to 8-26.5 for propanone with the prototype used; these unprecedented results do not exclude using photocatalysis to treat air, but they illustrate that improvement is needed. Because these tests are time-consuming, preliminary tests are useful; results obtained with a 225-L closed-loop, airtight, photocatalytic reactor with an external turbine enabling the ambient air inside the reactor to be circulated through the purifier device at 15-450 m3/hr flow rates are reported.     

Development of emission factors for polycarbonate processing

Emission factors for selected volatile organic compounds (VOCs) and particulate emissions were developed while processing eight commercial grades of polycarbonate (PC) and one grade of a PC/acrylonitrile-butadiene-styrene (ABS) blend. A small commercial-type extruder was used, and the extrusion temperature was held constant at 304 degrees C. An emission factor was calculated for each substance measured and is reported as pounds released to the atmosphere/million pounds of polymer resin processed [ppm (wt/wt)]. Scaled to production volumes, these emission factors can be used by processors to estimate emission quantities from similar PC processing operations.     

Bus fleet emissions: new strategies for mitigation by adopting natural gas

Energy consumption is related to local, regional and global impacts. Thus, by comparing different replacement scenarios of diesel vehicles with compressed natural gas, this article estimates pollutants and greenhouse gases emission in the city of São Paulo, Brazil. The calculation of fuel consumption is based on fleet characteristics, in terms of vehicle age, the average annual distance travelled by bus depending on the year and average fuel consumption. These values served as a basis to develop scenarios considering that a percentage of new vehicles that will be phased out and replaced with ones running on natural gas. Results show that the total avoided emissions can range from 579 thousand tons to 1.375 million tons of carbon dioxide (CO₂₎ over 20 years, depending on the scenario. For particulate matter, accumulated avoided emissions vary from 251 thousand to 584 tons over 20 years. The replacement of diesel buses with natural gas-fuelled buses presents favourable results, in comparison with the tendency scenario for CO₂ and particulate matter. Thus, a public policy for fuel replacement in largest cities, such as Sao Paulo, has an important global impact, especially when allowing the introduction of a renewable energy source, such as biogas. It will benefit from the natural gas previous infrastructure, which is largely available in Brazil. As recommendations, we explain the need to review the city of Sao Paulo Climate Change Law to allow the use of natural gas. Fuel replacement should be integrated with a public policy/public policies and operational strategies to promote citizens´ health as well as historical, cultural and heritage conservation for the city and its future generations.     

Interview with the mayor of Curitiba on habitat II

The objectives of Habitat II were (1) in the long term to arrest the deterioration of human settlements and create the conditions to achieve improvement in the environment on a sustainable basis, and (2) to adopt a general statement on principles and related Global Action Plan to guide national and international efforts in the next two decades. We have asked the Mayor of Curitiba, Brazil Rafael Greca de Macedo to comment on the conference results. Curitiba is one of the most known example of urban ecological planning.     

Identification of copper sources in urban surface waters using the principal component analysis based on aquatic parameters

The goal of this work was to identify the sources of copper loads in surface urban waters using principal component analysis under the aquatic parameters data evaluation approach. Water samples from the Irai and Iguacu rivers were collected monthly during a 12-month period at two points located upstream and downstream of a metropolitan region. pH, total alkalinity, dissolved chloride, total suspended solids, dissolved organic matter, total recoverable copper, temperature, and precipitation data provided some reliable information concerning the characteristics and water quality of both rivers. Principal component analysis indicated seasonal and spatial effects on copper concentration and loads in both environments. During the rainy season, non-point sources such as urban run-off are believed to be the major source of copper in both cases. In contrast, during the lower precipitation period, the discharge of raw sewage seems to be the primary source of copper to the Iguacu River, which also exhibited higher total metal concentrations.     

Euro Chlor Risk Assessment for the Marine Environment Osparcom Region: North Sea - Tetrachloroethylene

This risk assessment on tetrachloroethylene (PER) was carried out specifically for the marine environment, according to the methodology laid down in the EU risk assessment Regulation (1488/94) and the Guidance Document of the EU New and Existing Substances Regulation (TGD, 1997). The study consists of the collection and evaluation of data on effects and environmental concentrations from analytical monitoring programs in large rivers and estuaries in the North Sea area. The risk is indicated by the ratio of the "predicted environmental concentrations" (PEC) and the "predicted no effect concentrations" (PNEC) for the marine aquatic environment. In total, 18 studies for fish, 13 studies for invertebrates and 8 studies for algae have been evaluated. Both acute and chronic toxicity studies have been taken into account and the appropriate assessment factors have been used to define a PNEC value of 51 µg/l. Most of the available monitoring data apply to rivers and estuary waters and were used to calculate PECs. The most recent data (1991-1995) support a typical PEC of 0.2 µg PER/l water and a worst case PEC of 2.5 µg PER/l water. The calculated PEC/PNEC ratios give a safety margin of 20 to 250 between the predicted no effect concentration and the exposure concentration. Additional evaluation of environmental fate and bioaccumulation characteristics showed that no concern is expected for food chain accumulation.     

Aquatic humus from an unpolluted Brazilian dark-brown stream: general characterization and size fractionation of bound heavy metals

The main pool of dissolved organic carbon in tropical aquatic environments, notably in dark-coloured streams, is concentrated in humic substances (HS). Aquatic HS are large organic molecules formed by micro-biotic degradation of biopolymers and polymerization of smaller organic molecules. From an environmental point of view, the study of metal humic interactions is often aimed at predicting the effect of aquatic HS on the bioavailability of heavy metal ions in the environment. In the present work the aquatic humic substances (HS) isolated from a dark-brown stream (located in an environmental protection area near Cubat?o city in S?o Paulo-State, Brazil) by means of the collector XAD-8 were investigated. FTIR studies showed that the carboxylic carbons are probably the most important binding sites for Hg(II) ions within humic molecules. 13C-NMR and 1H-NMR studies of aquatic HS showed the presence of constituents with a high degree of aromaticity (40% of carbons) and small substitution. A special five-stage tangential-flow ultrafiltration device (UF) was used for size fractionation of the aquatic HS under study and for their metal species in the molecular size range 1-100 kDa (six fractions). The fractionation patterns showed that metal traces remaining in aquatic HS after their XAD-8 isolation have different distributions. Generally, the major percentage of traces of Mn, Cd and Ni (determined by ICP-AES) was preferably complexed by molecules with relatively high molecular size. Cu was bound by fractions with low molecular size and Co showed no preferential binding site in the various humic fractions. Moreover, the species formed between aquatic HS and Hg(II), prepared by spiking (determined by CVAAS), appeared to be concentrated in the relatively high molecular size fraction F1 (> 100 kDa).