Effects of ozone, acid mist and soil characteristics on clonal Norway spruce (Picea abies (L.) Karst.)--an introduction to the joint 14 month tree exposure experiment in closed chambers

This paper introduces a series of publications referring to a single 14-month laboratory study testing the hypothesis that the recent decline of Norway spruce (Picea abies (L.) Karst.) at higher elevations of the Bavarian Forest and comparable forests in medium-range mountains and in the calcareous Alps is caused by an interaction of elevated ozone concentrations, acid mist and site-specific soil (nutritional) characteristics. The effect of climatic extremes, a further important factor, was not included as an experimental variable but was considered by testing of the frost resistance of the experimental plants. Results of these individual studies are presented and discussed in the following 14 papers. Plants from six pre-selected clones of 3-year-old Norway spruce (Picea abies (L.) Karst.) were planted in April 1985 in an acidic soil from the Bavarian Forest, or a calcareous soil from the Bavarian Alps. After a transition period, plants were transferred, in July 1986, into four large environmental chambers and exposed for 14 months to an artificial climate and air pollutant regime based on long-term monitoring in the Inner Bavarian Forest. The climatic exposure protocol followed realistic seasonal and diurnal cycles (summer maximum temperature, 26 degrees C; total mean temperature, 9.8 degrees C; winter minimum, -14 degrees C; mean relative humidity, 70%; maximum irradiance, 500 W m(-2); daylength summer maximum, 17 h; winter minimum, 8 h). Plants were fumigated with ozone, generated from pure oxygen (control: annual mean of 50 microg m(-3); pollution treatment: annual mean of 100 microg m(-3) with 68 episodes of 130-360 microg m(-3) lasting 4-24 h), and background concentrations of SO(2) (22 microg m(-3)) and NO(2) (20 microg m(-3)); windspeed was set at a constant 0.6 m s(-1). Plants were additionally exposed to prolonged episodes of misting at pH 5.6 (control) and pH 3.0 (treatment). Simulation of the target climatic and fumigation conditions was highly reliable and reproducible (temperature +/-0.5 degrees C; rh+/-10%; ozone+/-10 microg m(-3);SO(2) and NO(2)+/-15 microg m(-3)).     

Mineral and nutrient supply, content and leaching in Norway spruce exposed for 14 months to ozone and acid mist

The nutrient contents of an acid and a calcareous soil, as well as the foliar contents of four clones of Norway spruce grown on these soils, were evaluated during a 14-month exposure to low level ozone (100 microg m(-3) + peaks between 130 and 360 microg m(-3)) plus acid mist (pH 3.0). Whilst distinct differences could be established between and within clones depending on soil types and genotype, only few pollutant-related effects were observed. Leaching losses from foliage were generally low compared to field studies. The data obtained with young trees in an artificial environment do not support the hypothesis that enhanced leaching from foliage may contribute to nutrient deficiencies in mature stands of Norway spruce.     

Using Spatially Detailed Water‐Quality Data and Solute‐Transport Modeling to Support Total Maximum Daily Load Development1

Walton‐Day, Katherine, Robert L. Runkel, and Briant A. Kimball, 2012. Using Spatially Detailed Water‐Quality Data and Solute‐Transport Modeling to Support Total Maximum Daily Load Development. Journal of the American Water Resources Association (JAWRA) 48(5): 949‐969. DOI: 10.1111/j.1752‐1688.2012.00662.x Abstract: Spatially detailed mass‐loading studies and solute‐transport modeling using OTIS (One‐dimensional Transport with Inflow and Storage) demonstrate how natural attenuation and loading from distinct and diffuse sources control stream water quality and affect load reductions predicted in total maximum daily loads (TMDLs). Mass‐loading data collected during low‐flow from Cement Creek (a low‐pH, metal‐rich stream because of natural and mining sources, and subject to TMDL requirements) were used to calibrate OTIS and showed spatially variable effects of natural attenuation (instream reactions) and loading from diffuse (groundwater) and distinct sources. OTIS simulations of the possible effects of TMDL‐recommended remediation of mine sites showed less improvement to dissolved zinc load and concentration (14% decrease) than did the TMDL (53‐63% decrease). The TMDL (1) assumed conservative transport, (2) accounted for loads removed by remediation by subtracting them from total load at the stream mouth, and (3) did not include diffuse‐source loads. In OTIS, loads were reduced near their source; the resulting concentration was decreased by natural attenuation and increased by diffuse‐source loads during downstream transport. Thus, by not including natural attenuation and loading from diffuse sources, the TMDL overestimated remediation effects at low flow. Use of the techniques presented herein could improve TMDLs by incorporating these processes during TMDL development.     

Metabolism of DDT in Different Tissues of Young Rats

The bioconcentration and distribution pattern of p,p′-DDT 1,1,1-1trichloro-2,2-bis(2-chlorophenyl-4-chlorophenyl)-ethane] and its main metabolites (p,p′-DDD [1,1-dichloro-2,2-bis (4-chlorophenyl) ethane] and p,p′-DDE [1,1-dichloro-2,2-bis (4-chlorophenyl) in adipose tissue, liver, brain, kidney, thymus, and testis were examined in young rats after 10 days of intraperitoneal injection of 50 and 100 mg of p,p′-DDT/kg of body weight. Analyses were performed by high-resolution gas chromatography. p,p′-DDT was found to be accumulated in a dose-dependent manner with the highest concentration in adipose tissue. However, in brain, the accumulation of pesticide was low and remained unchanged at the higher dose. This difference may relate to the protective role of the blood-brain barrier, which limits the access of the xenobiotic in the cerebral compartment, and to the differential tissue lipid composition. Although tissues concentration of p,p′-DDE and p,p′-DDD correlated positively to total p,p′-DDT levels, the active role in detoxification of pollutants may explain why p,p′-DDD is more abundant in liver than in the rest of organs. On the contrary, in brain, the concentration of p,p′-DDE is higher than that of p,p′-DDD, suggesting that the metabolism of the parent insecticide proceeds via more than one pathway.