Urban ecosystems

These peculiarities of urban area development led to the technogenic biogeochemical provinces, i.e., the areas with local increase of pollutants in different components of urban ecosystems such as soils, grounds, surface and ground waters, plants, atmosphere. These pollutants create ecological risk to human and ecosystem health by their accumulation in the biogeochemical food webs (food stuffs and water). 

Air pollution in cities can be considered to have three components sources, transport and transformations in the troposphere, and receptors. The sources are processes, devices, or activities that emits airborne substances. When the substances are released, they are transported through the atmosphere, and are transformed into different substances. Air pollutants that are emitted directly to the atmosphere are called primary pollutants. Pollutants that are formed in the atmosphere as a result of transformations are called secondary pollutants. The reactants that undergo the transformation are referred to as precursors. An example of a secondary pollutant is troposphere ozone, O3, and its precursors are nitrogen oxides (NO = NO + NO2) and non-methane hydrocarbons, NMHC. The receptors are the person, animal, plant, material, or urban ecosystems affected by the emissions (Wolff, 1999). 

McDonnell, M.J., Pickett, S.T.A., et al (1997) Ecosystem processes along an urban-to-rural gradient. Urban Ecosystems, 1 21. 

Pataki, D.E., et al., An integrated approach to improving fossil fuel emissions scenarios with urban ecosystem studies, Ecological Complexity, 6(1) pp. 1 14,2009. 

It was found that the mid-resistant species Hypogymnia physodes h Parmelia sulcata exhibit the best indicator capability. There were essential changes in the spectra of these species. The changes in the chemical composition are accompanied by exterior alterations in the eoloration as well as in the thallus stmcture. There are good reasons for using these species in the monitoring of urban ecosystems. 

Rees WE. Urban ecosystems the human dimension. Urban Ecosystems 1997 1 63-75. 

Today, plant roots in urban areas have surfaces like flypaper for copper,... A. Manceau et al. Thlaspi arvense binds Cu(ll) as a bis-(L-histidinato) complex on root cell walls in an urban ecosystem. 2013. Metallomics 5(12), p. 1674. DOl 10.1039/c3mt00215b. 

Grimm NB, Foster D, Groffman P, Grove JM, Hopkinson CS, Nadelhoffer KJ, PataM DE (2008) Peters DPC (2008b) The changing landscape ecosystem responses to urbanization and pollution across climatic and societal gradients. Front Ecol Environ 6 264—272... 

Meyer JL, Paul MJ, Taulbee WK (2005) Stream ecosystem function in urbanizing landscapes. J N Am Benthol Soc 24 602-612... 

The main concern regarding tetraalkyl lead has been about human health hazards, a concern that has resulted in the progressive replacement of leaded petrol by unleaded petrol in most countries (Environmental Health Criteria 85). There has been particular concern about possible brain damage to children in polluted urban areas. Little work has been done on the effects of organolead compounds on wildlife or ecosystems, so the following account will be brief. 

Ecosystem type Urban lake Forest lake Forest lake Forest lake... 

Sensitive sites would include sites that are receiving high inputs of atmospheric Hg deposition and sites with aquatic ecosystems where top end predators have high levels of Hg. We also recommend that urban sites with elevated atmospheric Hg deposition and forest sites with shallow hydrologic flowpaths, wetlands, and unproductive aquatic ecosystems should strongly be considered as candidate sites. 

In marine ecosystems, the high copper levels measured in heavily contaminated coastal areas sometimes approach the incipient lethal concentrations for some organisms (Neff and Anderson 1977). Elevated copper concentrations in marine and estuarine environments may result from atmospheric deposition, industrial and municipal wastes, urban runoff, rivers, and shoreline erosion. Chesapeake Bay, for example, receives more than 1800 kg of copper daily from these sources (Hall et al. 1988). Copper concentrations in abiotic marine materials are generally higher near shore than... 

Haque, A., H. Gruttke, W. Kratz, U. Kielhom, G. Weigmann, G. Meyer, R. Bomkamm, I. Schuphan, and W. Ebing. 1988. Environmental fate and distribution of sodium [14C]pentachlorophenate in a section of urban wasteland ecosystem. Sci. Total Environ. 68 127-139. 

In addition to large oil spills, petroleum hydrocarbons are released into the aquatic environments from natural seeps as well as non-point-source urban runoffs. Acute impacts from massive one-time spills are obvious and substantial. The impacts from small spills and chronic releases are the subject of much speculation and continued research. Clearly, these inputs of petroleum hydrocarbons have the potential for significant environmental impacts, but the effects of chronic low-level discharges can be minimized by the net assimilative capacities of many ecosystems, resulting in little detectable environmental harm. 

---