On-road vehicle particulate matter and gaseous emission distributions in Las Vegas, Nevada, compared with other areas

During the spring and summer of 2000, 2001, and 2002, gaseous and particulate matter (PM) fuel-based emission factors for approximately 150,000 low-tailpipe, individual vehicles in the Las Vegas, NV, area were measured via on-road remote sensing. For the gaseous pollutants (carbon monoxide, hydrocarbons, and nitrogen oxide), a commercial vehicle emissions remote sensing system (VERSS) was used. The PM emissions were determined using a Lidar-based VERSS. Emission distributions and their shapes were analyzed and compared with previous studies. The large skewness of the distributions is evident for both gaseous pollutants and PM and has important implications for emission reduction policies, because the majority of emissions are attributed to a small fraction of vehicles. Results of this Las Vegas study and studies at other geographical locations were compared. The gaseous pollutants were found to be close to those measured by VERSS in other U.S. cities. The PM emission factors for spark ignition and diesel vehicles are in the range of previous tunnel and dynamometer studies.     

Environmental risk assessment of human pharmaceuticals in Denmark after normal therapeutic use

An environmental risk assessment is presented for the 25 most used pharmaceuticals in the primary health sector in Denmark. Predicted environmental concentrations (PECs) for the aquatic environment were calculated using conservative assumptions and all PECs exceeded 1 ng/l. Measured concentrations were in general within a factor of 2-5 of PECs and ranged from approximately 0.5 ng/l to 3 micrograms/l for nine of the pharmaceuticals reported in literature. The calculation of predicted no-effect concentration (PNEC) based on aquatic ecotoxicity data was possible for six of the pharmaceuticals. PEC/PNEC ratio exceeded one for ibuprofen, acetylsalicylic acid, and paracetamol. For estrogens the PEC/PNEC ratio approached one when non-standard test was used. The ratio was below one for estrogens (standard test), diazepam and digoxin. For the terrestrial compartment, toxicity data were not available, and no assessment was carried out. Comparisons of predicted concentrations of furosemide, ibuprofen, oxytetracycline and ciprofloxacin in sludge based on either preliminary experimental sludge-water partition coefficients (Kd), octanol-water coefficients (Kow) or acid-base constants (pKa) revealed large variations.     

Effects of point-source PCB contamination on breeding performance and post-fledging survival in the dipper Cinclus cinclus

Despite widespread information on the incidence and biochemical effects of polychlorinated biphenyls (PCBs) in birds, field studies of effects on population processes are still scarce. This is particularly so in passerines. We therefore assessed breeding performance and post-fledging survival in dippers, Cinclus cinclus, breeding along the Afon Mule, a Welsh river where previous work indicated locally elevated PCB concentrations. We hypothesised that marked toxicological effects, including endocrine disruption, would be detectable as altered clutch-size, hatching success, nest success, brood-size, post-fledging survival or recruitment to the breeding population. Congener-specific analysis of PCBs in failed and deserted dipper eggs during 1990-93 revealed that geometric mean concentrations were four to 20 times higher along the Mule than elsewhere in Wales, UK. PCB signatures also varied highly significantly from other locations, with congeners 138, 153 and 180 dominant at the contaminated site, but 118 or 170 more frequent in eggs elsewhere. Subsequent analysis of surface runoff confirmed a small breaker's yard as a point source. Neither laying dates, clutch-sizes, brood-sizes, nest failure nor hatching failure along the contaminated Mule (n=46 breeding attempts and 218 eggs) differed significantly from dippers along adjacent reference rivers (n=82 breeding attempts and 315 eggs) or Welsh rivers as a whole (n=332 breeding attempts and 1534 eggs). Subsequent recaptures of breeding dippers ringed initially as nestlings were nearly identical between the Mule (7.7% of 182 nestlings), the reference set (7.5% of 323 nestlings) and all other Welsh rivers (7.3% of 2821 nestlings). These data illustrate the value of congener-specific analysis of bird's eggs in indicating local PCB sources. The data show also that PCBs can occur in dipper eggs at total concentrations of 0.49 (geometric mean)-1.29 (upper quartile) microg g(-1) wet mass without effects on breeding performance and survival. These values are below those at which biochemical or reproductive effects on other passerines have been detected, but above current concentrations in any other population of European dippers for which PCB data are available. Population effects by PCBs on European dippers are therefore unlikely. Survivors from locally contaminated sites like that in our study might allow field assessments of second-generation effects on breeding performance in wild birds that have developed under PCB exposure.     

PLATIN (plant-atmosphere interaction) I: A model of plant-atmosphere interaction for estimating absorbed doses of gaseous air pollutants

A PLant-ATmosphere INteraction model (PLATIN) was developed for estimating air pollutant absorbed doses under ambient conditions. PLATIN is based on the canopy energy balance combined with a gas transport submodel. The model has three major resistance components: (1) a turbulent atmospheric resistance Rah(zm) that describes the atmospheric transport properties between a measurement height above the canopy and the conceptual height z=d+z0m which represents the sink for momentum according to the big-leaf concept; (2) a quasilaminar layer resistance R(b,A) that quantifies the way in which the transfer of sensible heat and matter (e.g. latent heat, ozone) differs from momentum transfer; (3) a canopy or surface resistance R(c,A) that describes the influences of the plant/soil system on the exchange processes. Soil water content is simulated by a Force-Restore model. By a simple interception submodel precipitation and dew are partitioned into intercepted water and water reaching the soil surface. PLATIN can be run in a prognostic or a diagnostic mode. It is also intended for on-line use in air quality monitoring networks.     

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