Ecological and toxicological effects of inorganic nitrogen pollution in aquatic ecosystems: A global assessment.

Departamento de Ecología, Edificio de Ciencias, Universidad de Alcalá, 28871 Alcalá de Henares (Madrid), Spain.
Environment International (Impact Factor: 5.66). 09/2006; 32(6):831-49. DOI: 10.1016/j.envint.2006.05.002
Source: PubMed

ABSTRACT We provide a global assessment, with detailed multi-scale data, of the ecological and toxicological effects generated by inorganic nitrogen pollution in aquatic ecosystems. Our synthesis of the published scientific literature shows three major environmental problems: (1) it can increase the concentration of hydrogen ions in freshwater ecosystems without much acid-neutralizing capacity, resulting in acidification of those systems; (2) it can stimulate or enhance the development, maintenance and proliferation of primary producers, resulting in eutrophication of aquatic ecosystems; (3) it can reach toxic levels that impair the ability of aquatic animals to survive, grow and reproduce. Inorganic nitrogen pollution of ground and surface waters can also induce adverse effects on human health and economy. Because reductions in SO2 emissions have reduced the atmospheric deposition of H2SO4 across large portions of North America and Europe, while emissions of NOx have gone unchecked, HNO3 is now playing an increasing role in the acidification of freshwater ecosystems. This acidification process has caused several adverse effects on primary and secondary producers, with significant biotic impoverishments, particularly concerning invertebrates and fishes, in many atmospherically acidified lakes and streams. The cultural eutrophication of freshwater, estuarine, and coastal marine ecosystems can cause ecological and toxicological effects that are either directly or indirectly related to the proliferation of primary producers. Extensive kills of both invertebrates and fishes are probably the most dramatic manifestation of hypoxia (or anoxia) in eutrophic and hypereutrophic aquatic ecosystems with low water turnover rates. The decline in dissolved oxygen concentrations can also promote the formation of reduced compounds, such as hydrogen sulphide, resulting in higher adverse (toxic) effects on aquatic animals. Additionally, the occurrence of toxic algae can significantly contribute to the extensive kills of aquatic animals. Cyanobacteria, dinoflagellates and diatoms appear to be major responsible that may be stimulated by inorganic nitrogen pollution. Among the different inorganic nitrogenous compounds (NH4+, NH3, NO2-, HNO2NO3-) that aquatic animals can take up directly from the ambient water, unionized ammonia is the most toxic, while ammonium and nitrate ions are the least toxic. In general, seawater animals seem to be more tolerant to the toxicity of inorganic nitrogenous compounds than freshwater animals, probably because of the ameliorating effect of water salinity (sodium, chloride, calcium and other ions) on the tolerance of aquatic animals. Ingested nitrites and nitrates from polluted drinking waters can induce methemoglobinemia in humans, particularly in young infants, by blocking the oxygen-carrying capacity of hemoglobin. Ingested nitrites and nitrates also have a potential role in developing cancers of the digestive tract through their contribution to the formation of nitrosamines. In addition, some scientific evidences suggest that ingested nitrites and nitrates might result in mutagenicity, teratogenicity and birth defects, contribute to the risks of non-Hodgkin's lymphoma and bladder and ovarian cancers, play a role in the etiology of insulin-dependent diabetes mellitus and in the development of thyroid hypertrophy, or cause spontaneous abortions and respiratory tract infections. Indirect health hazards can occur as a consequence of algal toxins, causing nausea, vomiting, diarrhoea, pneumonia, gastroenteritis, hepatoenteritis, muscular cramps, and several poisoning syndromes (paralytic shellfish poisoning, neurotoxic shellfish poisoning, amnesic shellfish poisoning). Other indirect health hazards can also come from the potential relationship between inorganic nitrogen pollution and human infectious diseases (malaria, cholera). Human sickness and death, extensive kills of aquatic animals, and other negative effects, can have elevated costs on human economy, with the recreation and tourism industry suffering the most important economic impacts, at least locally. It is concluded that levels of total nitrogen lower than 0.5-1.0 mg TN/L could prevent aquatic ecosystems (excluding those ecosystems with naturally high N levels) from developing acidification and eutrophication, at least by inorganic nitrogen pollution. Those relatively low TN levels could also protect aquatic animals against the toxicity of inorganic nitrogenous compounds since, in the absence of eutrophication, surface waters usually present relatively high concentrations of dissolved oxygen, most inorganic reactive nitrogen being in the form of nitrate. Additionally, human health and economy would be safer from the adverse effects of inorganic nitrogen pollution.

  • [Show abstract] [Hide abstract]
    ABSTRACT: In this article, carbon dioxide deliming development in leather process was comprehensively reviewed. Based on carbon dioxide properties and its solubility in water, carbon dioxide deliming principle and mass transfer were analyzed, respectively. It was creative to propose reuse of carbon dioxide with available absorption and desorption technology which reduces occupational safety risk, regenerates new resource and leads to a cleaner production. Additionally this review provided the possible ways forwards of this technology. This review aims to give an overview of fundamentals, process optimization, occupational safety and possible ways forwards of carbon dioxide deliming in leather, and to provide useful information to researchers and engineers in this field.
    Journal of Cleaner Production 01/2015; 87:26-38. DOI:10.1016/j.jclepro.2014.09.066 · 3.59 Impact Factor
  • Source
    [Show abstract] [Hide abstract]
    ABSTRACT: Eutrophication is one of the key local stressors for coastal marine ecosystems, particularly in those locations with many estuaries, intense coastal development or agriculture, and a lack of coastal forests or mangroves. The land-derived import of not only inorganic nutrients, such as nitrate and phosphate, but also particulate and dissolved organic matter (POM and DOM) affects the physi-ology and growth of marine organisms with ensuing effects on pelagic and benthic community structures, as well as cascading effects on ecosystem functioning. Indicators for marine eutrophication are therefore not only key water quality parameters (inorganic and organic nutrient concentrations, oxygen and chlorophyll availability, and biological oxygen demand), but also benthic status and process parameters, such as relative cover and growth rates of indicator algae, invertebrate recruitment, sedimentary oxygen demand, and interactions between indicator organisms. The primary future challenge lies in understanding the interaction between marine eutrophication and the two main marine consequences of climate change, ocean warming, and acidification. Management action should focus on increasing the efficiency of nutrient usage in industry and agriculture, while at the same time minimizing the input of nutrients into marine ecosystems in order to mitigate the negative effects of eutrophication on the marine realm.
    Environmental Indicators, 1 edited by R. H. Armon, O. Hänninen, 01/2015: chapter Marine Eutrophication: pages 27; Springer., ISBN: 978-94-017-9498-5
  • [Show abstract] [Hide abstract]
    ABSTRACT: Trials were conducted to regenerate declining forests infested with lantana and psyllids near Mt Lindesay in northern New South Wales. Two years after treatment, trees in both controls and treated stands were significantly healthier. These changes were attributed mainly to drought-breaking rains. However, psyllid populations (as indicated by counts of bell miner, Manorina melanophrys) were higher in trees retained in treated areas than in control trees (in untreated areas), suggesting that treatments had not arrested chronic decline. Tree regeneration in treated areas was very variable and was dominated by brush box (Tristaniopsis confertus). Intense fire reduced lantana cover to a very low level in the year after treatment. Lantana cover doubled in the following year, but at 5% was still significantly less than before treatment (more than 80%). Declining eucalypt stands lack seed, and seedlings should be planted at high stockings (more than 1000 ha−1) to achieve canopy closure before lantana can recover to high levels. The cost of rehabilitating severely degraded stands, comprising 20% of the treated area, was AUD3500 ha−1. It appears unlikely that canopy closure will be achieved in the remainder of the treated area where recovery of shrubs and vines may make it difficult to reintroduce low-intensity fire. It is important to use low-intensity fire where possible to maintain essential ecological processes in dry to moist eucalypt forests so that they do not suffer canopy decline and shrub invasion.
    Australian Forestry 01/2010; 73(3):156-164. DOI:10.1080/00049158.2010.10676321 · 0.92 Impact Factor

Full-text (2 Sources)

Available from
Oct 16, 2014