Algae and Macrophytes

Hexavalent chromium was associated with adverse effects in invertebrates of widely separated taxa reduced survival and fecundity of the cladoceran, Daphnia magna at a concentration of 10.0 xg/L and exposure for 32 days growth inhibition of the protozoan Chilomonas paramecium at 1100.0 3000.0 xg/L at temperatures of 10-30°C during exposures of 19-163 h abnormal movement patterns of larvae of the midge Chironomus tentans at 

0 xg/L in 48 h and a temporary decrease in hemolymph glucose levels in the freshwater prawn Macrobrachium lamarrei surviving 

Trivalent chromium was less effective than Cr+ in reducing fecundity of Daphnia magna 44.0 tig Cr+%. vs. 10.0 tJtg Cr+ /L. Annelid worms (Tubifex sp.) accumulated about 1.0 mg total chromium/kg whole body during exposure for 2 weeks in sediments containing 175.0 ttg Cr+ /kg, suggesting that benthic invertebrates have only a limited ability to accumulate chromium from sediments or clays. 

Among sensitive species of freshwater teleosts, Cr concentrations of 16.0-21.0 xg/L in the medium resulted in reduced growth of rainbow trout and Chinook salmon (Oncorhynchus tshawytscha) fingerlings during exposure of 14-16 weeks, and altered plasma cortisol metabolism in rainbow trout after 7 days. Rainbow trout avoid water containing 28.0 xg Cr+ /L however, avoidance thresholds increased linearly if pre-exposed to 

0 xg Cr+ /L for 7-20 weeks. Locomotor activity inbluegills Lepomis macrochirus) 

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Macrophytes are common in the lower river below the reservoirs. Floating algae and macrophytes in summer may cover >40% of the water surface in the lower river. The fast growth of macrophytes has relevant hydraulic effects that can lead to remarkable increases in the water level. These macrophytes also favor the massive development of blackflies (Simulidae erythrocephalum) [33]. 

Algae and macrophytes 11 species Brazil November 1989 whole Alga, Ascophyllum nodosum 2.4-6.9 DW 14... 

Algae and macrophytes nickel-contaminated areas vs. reference sites... 

ALGAE, MACROPHYTES, AND HIGHER PLANTS Marine algae and macrophytes, 24 species ... 

BACTERIA, ALGAE, AND MACROPHYTES Bacteria, freshwater Escherichia coli 1000-2000 (as Ag 3) All dead in 0.5-5.0 min 1... 

Freshwater algae and macrophytes, 13 species 30-7500 Adverse effects 4... 

Pentachlorophenol was most toxic and most rapidly metabolized in aquatic environments at elevated temperatures and reduced pH. Adverse effects on growth, survival, and reproduction of representative sensitive species of aquatic organisms occurred at PCP concentrations of about 8 to 80 pg/L for algae and macrophytes, about 3 to 100 pg/L for invertebrates (especially molluscs), and <1 to 68 pg/L for fishes, especially salmonids. Fatal PCP doses for birds were 380 to 504 mg/kg BW (acute oral), >3850 mg/kg in diets, and >285 mg/kg in nesting materials. Adverse sublethal effects were noted at dietary levels as low as 1.0 mg/kg ration. Residues (mg/kg fresh weight) in birds found dead from PCP poisoning were >11 in brain, >20 in kidney, >46 in liver, and 50 to 100 in egg. 

Photosynthetic inhibition of algae and macrophytes by anthracene, naphthalene, phenanthrene, pyrene (Neff 1985), and fluorene (Finger et al. 1985)... 

Marine algae transform arsenate into nonvolatile methylated arsenic compounds such as methanearsonic and dimethylarsinic acids (Tamaki and Frankenberger 1992). Freshwater algae and macrophytes, like marine algae, synthesize lipid-soluble arsenic compounds and do not produce volatile methylarsines. Terrestrial plants preferentially accumulate arsenate over arsenite by a factor of about 4. Phosphate inhibits arsenate uptake by plants, but not the reverse. The mode of toxicity of arsenate in plants is to partially block protein synthesis and interfere with protein phosphorylation — a process that is prevented by phosphate (Tamaki and Frankenberger 1992). 

The second difference between the laboratory tests and exposure under realistic environmental conditions is that in the laboratory exposure concentrations are maintained, or the ecotoxicological endpoints are adjusted to account for any decline. Under natural conditions a combination of the pyrethroids tendency to partition rapidly and extensively to organic matter, coupled with their susceptibility to degradation in aquatic systems where algae and macrophytes are present [13,14], means their overall dissipation rate from the water phase is generally relatively rapid. Water column dissipation half-lives tend to be around 1 day (see Sect. 5). This behavior means that it is unlikely that aquatic organisms will be exposed to pyrethroids in the water phase for prolonged periods in natural water bodies. 

Although the sediments in these systems accumulate Se over time, the small isotopic contrast suggests that dissimilatory reduction is not the dominant accumulation mechanism. If dissimilatory reduction of Se(VI) and/or Se(IV) to Se(0) by bacteria were the dominant mechanism, one would expect the accumulated Se(0) to be enriched in the lighter isotope. In the San Francisco Estuary case, this assumes that the isotopic fractionations measured by Ellis et al. (2003) can be extrapolated to much lower concentrations. Incorporation of Se into algae and macrophyte tissues, followed by decay of some material and conversion of its Se to Se(0), is more consistent with the observed Se isotope data. Notably, the mean Se isotope composition of the Se(0) in the sediments of the Herbel et al. (2002) study was identical to that of the macrophytes. 

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