Freshwater biota

Phenols. The first stable ozone oxidation product of phenol in water is ds ds-raucomc acid, which requires - 2 mol O /mol phenol. In practice, larger dosage levels of ozone are required because other ozone-reactive substances are present in most wastes. Ozone oxidation of phenoHc effluents is employed in paper mills, coke mills, oil refineries, and thermoplastic resin manufacture, producing effluents that are safe to freshwater biota (122,123) (see Lignin Pulp). 

The transfer of P from land to terrestrial biota (F23) represents the sum of terrestrial biological productivity. There is no significant gaseous form of P, nor is there a major transfer of living organisms between the freshwater-terrestrial system and the oceans. The terrestrial biota system is, therefore, essentially a closed system where the flux of P to the biota (p23) is balanced by the return of P to the land from the biota (F32) due to the decay of dead organic materials. 

Lerman et al. (1975) considered several cases in which mankind s activities perturbed the natural cycle. If we assume that all mined P is supplied to the land as fertilizer and that all of this P is incorporated into land biota, the mass of the land biota will increase by 20%. This amount is small relative to the P stored in the land reservoir. Since P incorporated into land biota must first decompose and be returned to the land reservoir before being transported further, there is essentially no change in the other reservoirs. Thus, although such inputs would significantly alter the freshwater-terrestrial ecosystem locally where the P release is concentrated, the global cycle would be essentially unaffected. 

Long-range atmospheric transport of Hg from fossil fuel combustion and solid waste incineration has increased Hg in freshwater and biota. In the United States, combustion of fossil fuels for power generation is estimated to generate about 30% of the total release of Hg into the atmosphere (Harriss and Hohenemser, 1978). One in every three lakes in the United States and nearly one-quarter of the nation s rivers contain various pollutants, including Hg (CNN, 2004). Forty States in the U.S. have issued advisories for methylmercury on selected water-bodies, and 13 states have statewide advisories for some or all sportfish from rivers or lakes (USGS, 2000). Fish consumption advisories for methylmercury account for more than three-quarters of all fish consumption advisories. 

During the last 5 years, a few studies have been published demonstrating that aquatic biota is able to accumulate BDE-209. Lepom et al. [43] first reported the occurrence of BDE-209 in freshwater fish in Europe, with concentrations up to 37 ng/g lw. Similar results were obtained by Burreau et al. [10], who detected BDE-209 in three different fish species from rural waters of the Lumpam estuary in the... 

Lethal concentrations (LC) of cadmium to freshwater biota during various exposure intervals... 

Table 1.3 Lethal Concentrations (LC) of Cadmium to Freshwater Biota during Various Exposure Intervals (Concentrations shown are in pg Cd/L (ppb) of medium fatal to 10% or 50% of test organisms)... 

For trivalent chromium and freshwater biota, toxicity was significantly increased in comparatively soft waters this pattern was especially pronounced for daphnids (Table 2.4). Among freshwater teleosts, survival was reduced at comparatively low pH (U.S. Environmental Protection... 

Stokes, P.M. 1979. Copper accumulations in freshwater biota. Pages 357-381 in J.O. Nriagu (ed.). Copper in the Environment. Part 1 Ecological Cycling. John Wiley, NY. 

Median BCF values in aquatic biota exposed to various concentrations of Pb+2 for 14 to 140 days varied from about 42 in fish to 2570 in mussels intermediate values were 536 for oysters, 500 for insects, 725 for algae, and 1700 for snails (USEPA 1985). There are several notable exceptions to this array significantly higher values have been reported in crustacean hepatopancreas (Heyraud and Cherry 1979), in various species of freshwater invertebrates (Spehar et al. 1978), in fish bone (Demayo et al. 1982) and liver (Haux and Larsson 1982), and in whole oysters (Zaroogian et al. 1979). In oysters, for example, BCF values varied from 3450 to 6600 after exposure to solutions... 

To protect important species of marine animals, the U.S. Environmental Protection Agency recommends that total recoverable zinc in seawater should average <58 pg/L and never exceed 170 pg/L for acid-soluble zinc, these values are <86 and 95 pg/L (Table 9.9). As was the case for freshwater biota, there is a growing body of evidence (Table 9.9) demonstrating that many species of marine plants, crustaceans, molluscs, echinoderms, and fish are adversely affected at ambient zinc concentrations between 9 and 50 pg/L, or significantly below the current proposed criteria for marine life protection. 

Proposed criteria for protection of aquatic life include mean zinc concentrations of <47 to <59 pg/L in freshwater, and <58 to <86 pg Zn/L in seawater. Results of recent studies, however, show significant adverse effects to a growing number of freshwater organisms in the range of 5 to 51 pg Zn/L, and to saltwater biota between 9 and 50 pg Zn/L, suggesting that some downward modification in the proposed criteria is necessary. 

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