Pollutants riverine

POCs proportions and content of POCs in river waters compared with maximum permissible concentration (MPC, for DDT, HCH and PCB, are equal to 100,20 and 1 ppb correspondingly for water and 100,100 and 100 for bottom sediments) behavior of toxic compounds in the water body factors promoting an increase of the ecological risk of polluted riverine input into the Caspian Sea (Figure 4). 

Meybeck, M. 1993. Riverine transport of atmospheric carbon sources, global typology and budget. Water, Air, and Soil Pollution, 70, 443-463. 

During the wastewater treatment, an oxidative conversion of the surfactant molecules leads predominantly to the formation of polar compounds. They display a particularly high solubility and mobility in the aqueous medium and, therefore, transportation over relatively long distances can occur if they are not further degraded, resulting in the wide dissemination of these pollutants in riverine systems and thus also to estuaries, coastal regions and ultimately the marine environment (see Chapters 6.2 and 6.3). In the latter, the final levels will mainly be influenced by dilution effects and physical removal by precipitation or adsorption [63] because of relatively low microbial activity in this ecosystem compared with fresh water environments [64]. 

The impact of anthropogenic nutrient emissions in the coastal zone is heightened by its chemical speciation. Pollutant nitrogen and phosphorus are delivered to the coastal waters primarily in inorganic form, whereas most of the natural riverine dissolved nitrogen and phosphorus are components of organic compounds, i.e., DON and DOE Thus, the pollutant nutrients are delivered to the coastal waters in a chemical form that can be directly assimilated by coastal plankton, whereas the organically bound (natural) forms must first be remineralized. 

Consider the case of a pollution cloud in the river passing by the infiltration location during time At, which shall be very short compared to the time tw needed for the ground-water to travel from the river to the wells. During the event, the concentration in the river is Cin before and after the event, the riverine concentration is approximately zero. 

To evaluate the net riverine influx of dissolved species to the ocean, the river load has to be corrected for sea salts transported via the atmosphere from the ocean to the continents and rained out mainly in coastal precipitation. Table 9.7 shows the average concentration of selected dissolved and particulate elements in rivers from Martin and Meybeck (1979), and the corresponding net fluxes corrected for sea-salt cycling from Martin and Meybeck (1979). The corrections of fluxes for cyclic salts and pollution are still debatable estimates (e.g., Holland, 1978 Maynard, 1981), and affect mainly the evaluation of the net flux of Na+ by perhaps as much as 20%. 

The high degree of urbanization of the coastal zone of the Black Sea represents a permanent menace of marine environment pollution. The principal pollution sources include industrial wastes of large cities and their sanitary condition. Rivers also influence the pollution of marine environment. This is especially manifested in shelf regions such as the northwestern part of the Black Sea. Here, the principal manifestations of the influence of the riverine runoff are represented by eutrophication and formation of a near-bottom hypoxy over vast areas. 

Meanwhile, the pollution of riverine and sea waters by different hazardous chemicals such as pesticides, phenols, and, at selected places, oil products also increased. The highest pollution degree is observed in the near-mouth regions of the Don and Kuban rivers and in the areas adjacent to major ports. These ecological changes resulted in a sharp drop in the biological productivity of the sea. The trophic base for fish multifold reduced and the total fish hauls, especially those of valuable fish species, also decreased. 

Umezawa, Y., Miyajima, T., Kayanne, H., and Koike, I. (2002). Significance of groundwater nitrogen discharge into coral reefs at Ishigaki Island, southwest of Japan. Coral Reefs 21, 346—356. UNEP/MAP/MED POL. (2003). Riverine transport of water, sediments and pollutants to the Mediterranean Sea. MAP Technical Reports Series. United Nations Environment Programme— Mediterranean Action Plan, Athens. 141,. pp. 1—111. 

A calculation of maximum/minimum ratio from the atmospheric input data in Figure 3 yields the following results Pb = 33, Zn = 9, Cd = 17, Cr=1.5, Cu = 5, Ni = 4. We know that the burning of leaded gasoline is responsible for the large increase of Pb. Enormous metal production of Zn and Cd ores as well as refuse incineration are responsible for the increases of these metals. In addition, marine aerosols are an important source of Cd (Li, 1981). Obviously, Cu-Ni production from ores increased during this period but not nearly as much as for Zn-Cd. Also, combustion of fossil fuels contributed somewhat to the increase of Cu and Ni. The main source of Cr is steel and iron manufacturing which appears to not be as important an impact on the atmospheric environment as sources for the other metals. The pollution sources of Cr are minimal as reflected in the balance between riverine input and marine sediment output (Li, 1981). 

The activities of humans have had some impacts on both the major and minor element chemistry of the modem oceans. For example, seawater major ion budgets mostly assume the estimated riverwater input to seawater is that of the pristine (pre-human) system. However, anthropogenic processes have altered some of these fluxes. For example, the riverine CF flux may have increased by more than 40% as a result of human activity and the SOj flux may have doubled, due mainly to fossil fuel combustion and oxidation of pollution-derived H2S. 

Using empirical orthogonal functions (Dippner and Pohl, 2004) for a monitoring data set for the period 1993-2000 a positive trend in the order of one-third standard deviation appeared for dissolved Cd and Cu concentrations in surface waters of the B altic Proper. It was discussed that these trends were a result of a new stagnation period when the exchange with North Sea water was limited and the trace metal input via atmospheric and riverine sources resulted in the enrichment of trace metals in surface waters. This assumption was supported by the pollution loads entering the Baltic via rivers, industries, urban areas, and from the atmosphere (Table 13.2). 

Besides the particle-reactive character of this element, which leads to a rapid export and a short residence time of 0.5-1.3 years (Section 13.5), these findings are consistent with the worldwide decrease in the use of leaded gasoline, but they are in contrast to elevated riverine and atmospheric Pb inputs, according to the HELCOM pollution load compilation as shown in Table 13.2. Below the halocline, a negative Pbdiss trend of 15%/year ( 0.0142 nmol/(kg year)) was estimated for the period between 1995 and 2000. 

Figure 3 presents the reconstructed mass spectrum of the first discriminant function which separated the river and marine stations in the DiD2-map of Figure 1. The positive D-function describes the covariant mass peaks with higher intensities with respect to the zero point spectrum. All sample spectra with such characteristics will have positive score values. This spectrum is a representation of the characteristics of riverine material. The negative D-function spectrum in Figure 3 is indicative of the marine characteristics. The D spectrum shows a number of mass peaks indicative for carbohydrates, lignin and proteinaceous material (12). The mass peak m/z=86 and 100 are uncommon and a special characteristic of these fluvial samples. It can be speculated to be the molecular ion of (alkyl)thiadiazole (a metal binding pollutant), however a cyclic ketone, short chain alcohol or unsaturated acid are also possibilities. These mass peaks were chosen for further study because of their rare occurrence and their high discriminating power in the factor-discriminant analysis.

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