PAHs diagnostic ratios for the distinction of petrogenic and pirogenic sources: applicability in the Upper Iguassu Watershed - Parana, Brazil

ABSTRACT Polycyclic aromatic hydrocarbons (PAHs) are considered persistent organic pollutants and can cause serious damage in some organisms, including mutagenic and carcinogenic properties. The aim of this study was to evaluate the PAH concentrations in an urban basin and use diagnostic ratios to possible distinguish sources of contamination. The surface water analysis showed predominance of compounds containing 3 to 4 aromatic rings while in suspended particulate matter and sediment there was a predominance of compounds containing 4, 5 and 6 rings. Although present in low concentrations in the sediment, assessment of toxicity equivalent factor (TEF) showed values higher than 3 ng g–1 pellet to 50% of the samples with values of up to 125.35 ng g-1. The use of diagnostic ratios allowed verifying that the main source of PAHs in these aquatic environments, are pyrogenic sources. Still, the use of such relations should be done with caution, trying to assess possible interference of degradation factors

Phytoplankton Activities in Hypersaline, Anoxic Conditions. I—Dynamics of Phytoplankton Succession in the Solar Lake (Taba, Egypt)

The seasonal and vertical distribution of planktonic algae in the Solar Lake (Taba–Egypt) and their relation to some aquatic environmental factors were discussed through the period (Sep. 1996–Aug. 1997). Surface water analysis showed that no remarkable changes were observed in nitrate, silicate and iron, while turbidity, salinity and chloride were changed according to the season. In water column profile, H2S, temperature and salinity showed clear variations between stratification and holomixis. Maximum salinity (199‰) was recorded during stratification at 3-4 m depth. Stratification (Oct-June) appears clearly with changes in temperature (surface 16°C, thermocline up to 53.3°C and the bottom temperature around 47.7°C). Cyanobacterial mats of the Solar Lake are classified into two layers, the upper layer was dominated by coccoide forms while the lower was dominated by filamentous forms. During the period of study, 39 algal species were identified among which were 17 species of Cyanobacteria, 18 species of Bacillariophyta and 2 species of either Chlorophyta or Dinoflagellates.