Passaic river sediment interstitial water phase I toxicity identification evaluation

The Effects of Sediment Classification Pattern on a Water Column Organism, Ceriodaphnia dubia

The sediment compartment stands out because it functions as both a temporary sink of pollutants and a potential source of these elements that may become available to the water column.This study aimed to correlate the concentrations of total metals in the crude sediment and in the interstitial water with the ecotoxicity in the water column using an a modified sediment ecotoxicity test with Ceriodaphnia dubia. The results indicate that the sediment may contribute to the toxicity in the water column and that such toxicity is possibly not related to the metals present. Based on the chemical analysis of the metals, the Canadian Sediment Quality Guidelines (SQGs) would frame the sediment as non-toxic to benthic organisms, but the SQGs have no reference standards for possible effects on nektonic organisms. Due to the complexity of this compartment, it is fundamental to evaluate the interactions of the different pollutants in the system and possible effects on the nektonic organisms.

Toxicity identification evaluation of sediments in Liaohe River

Liaohe River has received significant attention in the northeast region and even in the entire country. As part of a recently completed water quality assessment, a series of water column and sediment toxicity tests was performed throughout the watershed. In the current study, we subjected sediments from the Liaohe River to toxicity identification evaluation manipulations and tests for chronic toxicity with midge (Chironomus riparius), with survival as the end point. In Phase I, the sediments were treated with zeolite, cation-exchange resin, and powdered coconut charcoal. Results confirmed that ammonia compounds were the major contaminants in terms of toxicity, although toxic effects from metals were also a concern in at least three sites. In Phase II identification, chemical analysis provided a strong evidence that the metals As and Cd are the probable causes of toxicity in the sediments, without the influence of ammonia. Temporally, ammonia is responsible for the toxicity of the selected sediments.

Testing of different plants to determine influence of physico-chemical properties and contaminants content on municipal sewage sludges phytotoxicity

This study attempts to evaluate the Phytotoxkit as a tool for measuring the toxicity of municipal sewage sludges using 10 common plants: mustard, turnip, cress, red clover, cucumber, tomato, radish, sorrel, and spinach. The results were used to determine a germination index (GI) and a median effective concentration (EC) value for each plant. The trace metal and polycyclic aromatic hydrocarbon (PAH) contaminant content and the physical-chemical properties were examined. Most sewage sludges were characterized by an unfavorable electrical conductivity value of about 5.2 mS/cm(-1). The most abundant trace metals were zinc (Zn) at 871-1680 mg kg(-1), manganese (Mn) at 245-661 mg kg(-1), and copper (Cu) at 88.2-161.0 mg kg(-1). The lowest values were determined for cobalt (Co) at 2.9-3.8 mg kg(-1) and cadmium (Cd) at 0.7-3.7 mg kg(-1). The PAH sum was based on 10 individual compounds (USE EPA), and the PAH content ranged from 4.76 to 27.95 mg kg(-1), most of the sewage sludges showing a predomination by carcinogenic PAHs. The GI values, based on seed germination and root growth inhibition bioassays, showed increasing plant sensitivity to the tested sewage sludges in the following order: cress > turnip > mustard > sorrel > tomato > sorgo > red clover > radish > cucumber > spinach. The EC50 sewage sludge values lay in the range 31-404 g/kg of soil, and significant relationships were found for most of the plants between EC50 and the magnesium content (Mg(2+): alpha = 0.888-0.924, P = 0.05), calcium content (Ca(2+): alpha = 0.813-0.911, P < or = 0.05), and pH (alpha = -0.913-0.948, P = 0.05). In the case of sewage sludge pollutants, significant relationships were found for trace metals such as: strontium (Sr: alpha = 0.851-0.948, P < or = 0.05), chromium (Cr: alpha = 0.858, P < or = 0.05), and nickel (Ni: alpha = 0.955, P = 0.05), as well as pyrene (PAHs).