Učënye Zapiski Kazanskogo Universiteta. Seriâ Estestvennye Nauki (Sep 2016)
Comparison of Toxicity of Sediments from Rivers with Different Levels of Anthropogenic Load (Middle Volga Region, Russia) Based on Elutriate and Whole Sediment Tests
Abstract
Description of chemical characteristics and toxicity testing of whole sediment and elutri-ate have been performed with 35 samples taken during the monitoring of rivers in the Middle Volga region (Tatarstan, Russia) in 2013. The locations analyzed are sites associated with agriculture, forestry, and petroleum hydrocarbons (oil) production. The toxicity tests include: (1) Chlorella vulgaris (algal) elutriate test, (2) Paramecium caudatum (ciliate) elutriate test, (3) Daphnia magna (cladoceran) whole sediment toxicity test, and (4) Heterocypris incongruens (ostracod) whole sediment toxicity test. The concentrations of metals in 43% of sediment samples have been found to exceed probable effect concentration sediment quality guidelines (SQGs). However, the concentrations of polycyclic aromatic hydrocarbons (PAHs) and organochlorine pesticides have turned out to be below SQGs in most sites. The correlation analysis has shown metal toxicity to daphnid reproduction and ostracod growth (R2 = 0.34–0.64) and ammonia (R2 = 0.49–0.54). A higher percentage of samples have shown toxicity in the whole sediment tests (86%) compared to the elutriate tests (54%). A total of 91% of samples have demonstrated toxicity for at least one species. Toxicity has been most frequently observed for daphnid reproduction (83% of samples) and ostracod growth (56% of samples) compared to daphnid (23%) survival, ostracod (11%) survival, and ciliate reproduction (54%) or algal growth (54%). The most polluted sediments have been registered in the area of oil production. The comparison of toxicity of the samples from different types of areas has indicated that 100% of samples from the oil production area, 94% of samples from the agricultural area, and 50% of samples from the forest area were toxic to at least one test organism.
