Kimmo Mäenpää

Sewage sludge is an inevitable byproduct produced in wastewater treatment. Reusing nutrient-rich sludge will diminish the amount of waste ending in soil dumping areas and will promote circular economy. However, during sewage treatment process, several potentially harmful organic chemicals are retained in sludge, but proving the safety of processed...

Passive samplers are promising surrogates for organisms, mimicking bioaccumulation. However, several biological characteristics disturb the passive partitioning process in organisms by accelerating or restraining bioaccumulation, resulting in species-specific body residues of hydrophobic organic contaminants (HOCs). In addition to site-specific cha...

Activated carbon (AC) has been proven to be highly effective for the in-situ remediation of sediments contaminated with a wide range of hydrophobic organic contaminants (HOCs). However, adverse biological effects, especially to benthic organisms, can accompany this promising remediation potential. In this study, we compare both the remediation pote...

The increased use of silver nanoparticles (AgNP) in industrial and consumer products worldwide has resulted in their release to aquatic environments. Previous studies have mainly focused on the effects of AgNP on pelagic species, whereas few studies have assessed the risks to benthic invertebrates despite the fact that the sediments act as a large...

The biological effects of activated carbon (AC) amendments in sediments were studied with the midge Chironomus riparius. The effects on larvae growth were studied using three different AC particles sizes (PAC: 90% <63 μm, MAC: ø 63–200 μm and GAC: ø 420–1700 μm). The long- term effects of MAC were studied in an emergence experiment over two generat...

The nonbiting midge Chironomus riparius was used to study the remediation potential and secondary effects of activated carbon (AC, ø 63-200 μm) in PCB contaminated sediments. AC amendments efficiently reduced PCB bioavailability determined by C. riparius bioaccumulation tests and passive samplers. PCBs were shown to transfer from larvae to adults....

Hydrophobic organic contaminants (HOCs) reaching the aquatic environment are largely stored in sediments. The risk of contaminated sediments is challenging to assess since traditional exhaustive extraction methods yield total HOC concentrations, whereas freely dissolved concentrations (C_free) govern diffusive uptake and partitioning. Equilibrium s...

The sorption efficiency and possible secondary effects of activated carbon (AC) (ø 63-200 μm) was studied with Lumbriculus variegatus in three PCB contaminated sediments applying long AC-sediment contact time (3 years). AC amendment efficiently reduced PCB bioavailability as determined with both, L. variegatus bioaccumulation test and passive sampl...

Equilibrium sampling devices (ESDs) can be applied to study and monitor the exposure and fate of hydrophobic organic chemicals (HOCs) on a thermodynamic basis. ESDs can be used to determine freely dissolved concentrations and chemical activity ratios, and to predict equilibrium partitioning concentrations of HOCs in biota lipids. Our aim was to ass...

Lead (Pb) and mercury (Hg) have been used by humans for thousands of years, despite their known toxicity. Both of these metals enter the environment through human activities. Hg is converted to more bioavailable methylmercury (MeHg) by bacteria in aquatic sediments. Ecosystems are often subjected to pollution from numerous sources, exposing wildlif...

Knowledge on the internal distribution of halogenated organic chemicals (HOCs) would improve our understanding of dose–effect relationships and subsequently improve risk assessment of contaminated sites. Herein, we determine the concentrations of HOCs based on equilibrium partitioning in storage lipids, membrane lipids, and proteins in field-contam...

It has been well established that in many cases total concentration of a chemical in the environment is not the best indicator for the potential threats that the chemical may cause. The term bioavailability describes the fact that only a fraction of a chemical in the environment is available for uptake by organisms, which then determines possible b...

The equilibrium sampling in silicone is increasingly applied to measure freely dissolved concentrations and chemical activities within bioaccumulation research of hydrophobic organic chemicals. Two equilibrium methods were applied to PCB-contaminated soil and sediment, and directly calibrated with respect to equilibrium partitioning concentrations...

The aim of this work was to study the toxicity and biotransformation of polyaromatic hydrocarbon (PAH) pyrene in the oligochaete aquatic worm, Lumbriculus variegatus. PAHs are ubiquitous environmental pollutants that pose a hazard to aquatic organisms, and metabolizing capability is poorly known in the case of many invertebrate species. To study th...

The xenobiotics accumulated in sediments represent a hazard to organisms. In order to study the toxic effects of xenobiotics in organisms, body residue has been proposed as a more relevant dose-metric than the environmental concentration of the chemical. In this study, the benthic oligochaetes Lumbriculus variegatus were exposed to sediment-spiked...

The discharge of surfactants, such as 4-nonylphenol (4-NP) and linear alkylbenzene sulfonates (LAS), into water bodies leads to accumulation of the chemicals in the sediments and may thus pose a problem to benthic organisms. To study the bioaccumulation of surfactants, Oligochaeta worm Lumbriculus variegatus was exposed to sediment-spiked, [14C]-la...

In this study, pentachlorophenol (PCP) bioaccumulation and its effect on heat dissipation was studied in eggs of the lake salmon (Salmo salar m. sebago). In bioaccumulation studies, the eggs were exposed to low concentrations (0.051-0.056 micromol/l, 13.583-14.915) of waterborne [14C]-labeled PCP at two developmental stages: (1) 3 weeks after ferti...

The benthic macroinvertebrates Lumbriculus variegatus and Chironomus riparius were used in toxicity and bioaccumulation tests to determine the toxic concentrations and accumulation potential of sediment associated herbicides. The tested chemicals were ioxynil, bentazone, and pendimethalin. The bioaccumulation tests with L. variegatus were performed...

This study investigated the effectiveness of phosphorus (P) as an in situ remediation technique in site soils collected from the Tri-State mining area. The site soils were treated with two different types (KH(2)PO(4) and Super Triple Phosphate fertilizer) and levels (600 and 5,000 mg/kg) of phosphorus. A toxicokinetic approach was used to determine...

Abstract: This research investigated the effectiveness of phosphorus (P) and organic matter (OM) as possible in situ remediation techniques for metal contaminated soils. The study was designed to determine the bioavailability of ph, Zn, and Cd individually and in combination to the earthworm Eisenia fetida in an artificial soil amended with varying...