To evaluate plant and herbivore responses to nitrogen we conducted a fertilization study at a low and high pollution site in the mixed conifer forests surrounding Los Angeles, California. Contrary to expectations, discriminant function analysis of oak herbivore communities showed significant response to N fertilization when atmospheric deposition was high, but not when atmospheric deposition was low. We hypothesize that longer-term fertilization treatments are needed at the low pollution site before foliar N nutrition increases sufficiently to affect herbivore communities. At the high pollution site, fertilization was also associated with increased catkin production and higher densities of a byturid beetle that feeds on the catkins of oak. Leaf nitrogen and nitrate were significantly higher at the high pollution site compared to the low pollution site. Foliar nitrate concentrations were positively correlated with abundance of sucking insects, leafrollers and plutellids in all three years of the study.

A comprehensive study was conducted to determine the soil to plant transfer factor (TFS-P) of K-40, Cs-137, Th-232 and U-238 in perennial plants from accessible areas of Mumbai, using high-resolution γ spectrometry. A total of 50 soil and 150 plants samples were collected from all over the Mumbai region where lithology is dominated by basaltic rocks. The mean concentration values for K-40, Cs-137, Th-232 and U-238 in soil was 170.06 ± 65.36, 5.19 ± 1.20, 25.72 ± 6.262 and 10.21 ± 2.82 Bq kg⁻¹ respectively, whereas in case of plants the mean concentration values were determined to be 181.82 ± 18.50, 0.44 ± 0.14, 0.84 ± 0.19 and 0.79 ± 0.22 Bq kg⁻¹ respectively. The mean activity ratio of Th-232/U-238 in plants is 1.06 while in soil the ratio is 2.5. The soil to plant transfer factor (TFS-P) calculated for K-40, Cs-137, U-238 and Th-232 are 1.05, 0.076, 0.071 and 0.031 respectively. Higher value of TFS-P for K-40, which is an integral part of stable potassium clearly indicates the physiological need of stable potassium, for maintaining the different biological mechanisms of perennial plants under tropical conditions.

Communities of aquatic macroinvertebrates, fish density and biomass, and environmental variables were investigated in three Patagonian mountain rivers affected by urbanization. The rivers Las Minas, Esquel and Carbón that flow through the towns of Cholila, Esquel and Corcovado, respectively (northwest Chubut, Argentina) were selected to assess the degree of impairment. A reference site and an urban site were established on each river. Water quality variables including conductivity, major nutrients, total suspended solids (TSS) and dissolved oxygen, habitat conditions and quality of riparian ecosystems were investigated in autumn, winter, spring and summer 2005–2006. Macroinvertebrates were sampled concurrently in three riffles and three pools at each site. Invertebrate species richness, EPT richness, the Shannon–Weaver diversity index, % EPT density, and the BMPS index were lower at urban sites, whereas % collectors increased. The most impaired site was below Esquel, the largest town. Senzilloides panguipulli (Plecoptera), Polypedilum and Rheotanytarsus species (Diptera: Chironomidae), Nais communis (Oligochaeta) and Meridialaris chiloeensis (Ephemeroptera) dominated assemblages at reference and moderately impaired sites in summer, whereas the strongly polluted reach below Esquel had low flow in summer and a community dominated by Limnodrilus spp. (Oligochaeta), Helobdella spp. (Hirudinea), and two Hyallela species (Amphipoda). Canonical correspondence analysis indicated that ammonia, conductivity and TSS were important variables structuring invertebrate assemblages. In contrast, fish density and biomass varied in a non-systematic manner among sites. Overall, urbanization resulted in varying degrees of habitat degradation, sedimentation and nutrient enrichment that were reflected by the macroinvertebrate assemblages, which can be used effectively to monitor the effects of urban communities on Patagonian mountain streams.

Understanding and controlling air pollution in highly populated areas is very important, although interpreting the levels of gaseous pollutants and airborne particulate matter is complicated by dominant natural and anthropogenic emissions, micro-meteorological processes, and chemical reactions which take place directly in the atmosphere. For this reason, it is very difficult to relate the characteristics of air pollution to one or more specific emission sources. The aim of this paper is to detect associations among elements and organic compounds emitted from specific sources by means of chemical analyses, statistical processing of data, seasonal evolution study, and geochemical considerations to trace their origin. A detailed characterization of air quality during the period September 2000-September 2001 was carried out in three locations of the Venice region: A heavy traffic urban site, a public park, and the island centre of the city of Venice. Twenty-eight inorganic elements, four polycyclic aromatic hydrocarbons, CO and benzene were quantified and processed by a statistical procedure based on factor analysis considering variations on a seasonal basis. Results show the presence of associations between elements and compounds with the same behaviour in all sampling points. This indicates that several pollutants originate from a common source, and are then “diluted” throughout the study area, maintaining the imprint of their origin. Pt, polycyclic aromatic hydrocarbons, CO and benzene originating from the exhaust gas of vehicles are all linked in the traffic factor, whereas Cd is associated with Se, having a common source in industrial processes.

Water resources are threatened globally and declining water quality is primarily due to stormwater, agricultural, urban, and mining runoffs. Steamboat Creek in Nevada is the largest non point source (NPS) of pollution to the Truckee River. Treatment wetlands are a cost-effective and reliable technique to control NPS pollution, therefore, a large-scale wetland along Steamboat Creek has been proposed as a component of a regional watershed restoration plan. This study used ten parallel pilot-scale wetland mesocosms, and tested the effects of drying and rewetting, hydraulic retention time (HRT), and high nitrogen loading on the efficiency of nutrient and total suspended solids (TSS) removal. Drying and rewetting produced noticeable effects on nutrient retention, but the effect was short-lived. During longer HRT period nutrient removal in manipulated mesocosms with an 8 h HRT were higher than controls with a 4 h HRT. Reducing the HRT from 4 h to 30 min further decreased nutrient interception. During increased influent nitrogen loading (9.5 ± 2.4 mg l⁻¹), manipulated mesocosms functioned as sinks for total nitrogen (TN) with removal efficiency increasing from 45 ± 13% to 87 ± 9%. The average change in TN concentration was 9.1 ± 2.2 mg l⁻¹. Drying/rewetting and varying HRT influenced total phosphorus (TP) and TSS similarly, and TP removal was associated with TSS removal. Results can help make decisions regarding wetland construction, management, and operation more effective in order to reduce nutrient loads to the Truckee River.