Assessment of metal leachability and toxicity from sediment potentially stored on land

Abstract

The aim of this study was to assess the toxicity and metal leachability from three dredged bottom sediments potentially stored on land. Washing out was conducted at a sediment dry mass to water mass ratio of 1:10. The method relies on washing out pollutants from the examined sample using water with third degree of purity in static/quasi-dynamic conditions. The investigations comprised three 27-h washing out cycles, including leaching in static conditions (19 h) and shaking (8 h). Bottom sediments are complex matrices; therefore laboratory tests cannot always reflect changes in physicochemical properties, which can potentially take place after a longer period of time. In spite of this, static-dynamic tests conducted under laboratory conditions provide information which enables a rough estimation of the potential threat posed by the studied sediment to the environment, at a given time. It was demonstrated that the leachability of metals during storage of polluted (Rybnik, Rzeszów) or unpolluted (Narożniki) bottom sediments does not pose a hazard to the environment. The Microtox test showed low toxicity of test water extracts. Considering their final destination, the potential and actual environmental hazards which the extracted bottom deposits pose should be assessed by determining the leachability of metals.

Concentration, sources and risk assessment of PAHs in bottom sediments

“…Moreover, the lowest PAH concentrations in the sediments from the Narożniki and Głuchów reservoirs could be associated with a low C OM content and dominant sandy fraction. Moreover, both reservoirs are located in rural areas, and these areas were characterized by low anthropopressure related to urbanization, industry and transport (Madeyski et al 2008 , Baran et al 2015 ). The highest PAH concentration in sediments from the Rybnik, Głuchów, Brzóza Królewska, Brzóza Stadnicka, Besko and Chechło reservoirs was found at station 3 near the dam, while in sediments from the Rzeszów and Narożniki reservoirs—at station 1 (inlet, backwater station).…”

“…Their common feature is the role they play in the flood protection system as well as the recreation opportunities they offer, particularly angling, thanks to which they are stocked with fish. The Rybnik reservoir was created as a facility of the conventional power plant’s technological line, and its main purpose is to supply water for cooling the power units (Kostecki 2004 ; Baran and Tarnawski 2015 ; Baran et al 2015 ; Baran et al 2016 ). Water is exchanged and cooled in the reservoir (which puts the reservoir under strong thermal pressure), and flow horizontal circulation is forced.…”

“…The facility built in the city of Rzeszów on the Wisłok River has been subjected to an intensive silting process since the very first years of operation. Currently, the loss of capacity is estimated to be more than 60% (Baran and Tarnawski 2012 ; Baran et al 2015 ; Koniarz et al 2015a ). The reservoir is very shallow, and silts form vast islands.…”

“…Its purpose is flood protection for towns, improvement of water-soil conditions and economic development of the surroundings through popularization of water sports and recreation. The measurements taken after 4 years of reservoir operation showed almost 0.6% silting ratio (Baran et al 2015 ; Michalec and Wałęga 2015 ). As a result of a failure of the lateral dam, the reservoir was out of service for 3 years.…”

Assessing bioavailability of complex chemical mixtures in contaminated soils: Progress made and research needs

“…The process of aging can enhance the amount of absorbed heavy metals in soil, where a redistribution from weakly bound fractions to more strongly bound fractions can be observed (Settimio et al 2014;Wang et al 2015). Recent metal contamination tends to be more reactive and prone to dissolution compared to older contamination where the elements might be in crystalline forms (Lynch et al 2014), which presents a lower environmental risk (Baran et al 2015; Environmental Agency 2008).…”