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: 5.56). 09/2006; 32(6):831-49. DOI: 10.1016/j.envint.2006.05.002
Source: PubMed


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.

230 Reads
  • Source
    • "The inorganic nitrogen pollution in aquatic ecos y s t e m s m a y s t i m u l a t e t h e d e v e l o p m e n t , maintenance, and proliferation of primary producers resulting in eutrophication of aquatic ecosystems. T h e C y a n o p h y c e a e , D i n o p h y c e a e , a n d Bacillariophyceae appeared to be the major groups that may be stimulated by inorganic nitrogen pollution (Camargo and Alonso 2006). "
    [Show abstract] [Hide abstract]
    ABSTRACT: Water samples were seasonally collected from 12 stations of the eastern coast of Suez Gulf during autumn of 2012 and winter, spring, and summer of 2013 in order to investigate phytoplankton community structure in relation to some physicochemical parameters. The study area harbored a diversified phytoplankton community (138 species), belonging to 67 genera. Four algal groups were represented and classified as Bacillariophyceae (90 species), Dinophyceae (28 species), Cyanophyceae (16 species), and Chlorophyceae (4 species). The results indicated a relative high occurrence of some species namely.; Pleurotaenium trabecula of green algae; Chaetoceros lorenzianus, Proboscia alata var. gracillima, Pseudosolenia calcar-avis, and Pseudonitzschia pungens of diatoms; Trichodesmium erythraeum and Pseudoanabaena limnetica of cyanophytes. Most of other algal species were fairly distributed at the selected stations of the study area. The total abundance of phytoplankton was relatively low (average of 2989 unit/L) in the eastern coast of Suez Gulf, as compared its western coast and the northern part of the Red Sea. The diversity of phytoplankton species was relatively high (2.35–3.82 nats) with an annual average of 3.22 nats in the present study. The results concluded that most of eastern coast of Suez Gulf is still healthy, relatively unpolluted, and oligotrophic area, which is clearly achieved by the low values of dissolved phosphate (0.025–0.3 μM), nitrate (0.18–1.26 μM), and dissolved ammonium (0.81–5.36 μM). Even if the occurrence of potentially harmful algae species was low, the study area should be monitored continuously. The dissolved oxygen ranged between 1.77 and 8.41 mg/L and pH values between 7.6 and 8.41. The multiple regression analysis showed that the dissolved nitrate and pH values were the most effective factors that controlled the seasonal fluctuations of phytoplankton along the eastern coast of Suez Gulf during 2012–2013.
    Environmental Monitoring and Assessment 10/2015; 187(10):1-18. · 1.68 Impact Factor
    • "Domestic wastewater discharge into water bodies without proper treatment is among the main sources of nitrogen release in the environment (Babu et al., 2011). Despite being an essential component of several biomolecules such as nucleotides and amino acids, its high availability in the inorganic forms of N-NH 4 + , N-NO 2 À and N-NO 3 À may result, among other consequences, in the intensification of the eutrophication process (Camargo and Alonso, 2006). "
    [Show abstract] [Hide abstract]
    ABSTRACT: The objective of this study was to assess the effect of different solar radiation intensities on nitrogen assimilation by a consortium of bacteria and microalgae grown in pilot scale high rate ponds (HRP) treating domestic wastewater. The HRPs received effluent from an anaerobic reactor. The experiment was carried out under tropical climate conditions. A total of five HRPs were used; four of them were covered with shading screens that blocked 9%, 18%, 30% and 60% of the incident solar radiation. Nitrification was the main process for nitrogen removal/transformation in all HRPs and the volatilization of ammonia nitrogen occurred in levels below the expected range due to low pH values. The organic nitrogen concentration followed the same trend of the biomass production, but no statistical difference was found between the 60% screen HRP and the uncovered one, which led to the conclusion that the intensity of the photosynthetically active radiation does not compromise nitrogen assimilation, since the bacterial biomass may develop in conditions that are unfavorable to the growth of microalgae. Moreover, other aspects, such as CO2 addition, may reduce nitrogen losses by volatilization and denitrification, as well as contribute to recover this nutrient through biomass assimilation.
    Ecological Engineering 08/2015; 81. DOI:10.1016/j.ecoleng.2015.04.040 · 2.58 Impact Factor
  • Source
    • "The benefits of using inputs like fertilizers in vegetable production cannot be over-emphasized, but inappropriate use and poor management can lead to environmental pollution and health complications (Smith et al., 1999; Camargo and Alonso, 2006; Obuobie et al., 2006). Fertilizer use and management with the dual purpose of securing crop production and limiting the adverse effects on health and environment have been understudied in Ghana. "
    [Show abstract] [Hide abstract]
    ABSTRACT: How to optimize fertilizer application (i.e. by choosing the best fertilizer types, dosage, time of application, and application methods) to sustain and increase crop production and quality in intensively cropped weathered soils in Ghana is understudied. The purpose of the study was to assess farmers' knowledge on fertilizer usage for intensive vegetable production in peri-urban areas in Ghana where production and marketing of vegetables cause significant export of nutrients from farms. Data were collected from 180 peri-urban vegetable growers in Abesim and Yawhima in the Sunyani Municipality using purposive and snowball sampling methods. The study showed that vegetable production constituted 65% and 70% of the total annual income of farmers in Abesim and Yawhima, respectively. Ninety-seven percent of the farmers used mineral fertilizers to improve soil fertility, but the use of organic manures such as poultry dung was very low even though it was available. Limited knowledge on fertilizer use and management among the farmers and high market prices of mineral fertilizers constrained their usage. Intensifying education on fertilizer use and management through agricultural extension services, the media, and at the point of sales are recommended to improve sustainable use of fertilizers for peri-urban vegetable production.
    Resources Conservation and Recycling 08/2015; 103:77-84. DOI:10.1016/j.resconrec.2015.07.018 · 2.56 Impact Factor
Show more