Hexachlorobenzene (HCB), listed on the Stockholm Convention on persistent organic pollutants and regulated as a hazardous priority pollutant by the Water Framework Directive (WFD), is ubiquitously distributed in the environment and assumed to mildly biomagnify in aquatic foodwebs. The proposal to include trophic magnification factors (TMFs) in the procedure for comparing contaminant levels in biota at different trophic levels (TLs) with WFD environmental quality standards requires adequate selection of TMFs. In the first step of our study, we compared two independently obtained datasets of pentachlorobenzene (PeCB) and HCB concentration ratios from passive sampling (PS) in water and in fish through routine monitoring programs in Norway to evaluate possible biomagnification. In this procedure, PeCB is used for benchmarking the bioconcentration in fish, and the observed HCB/PeCB ratios in fish are compared with ratios expected in the case of (i) HCB bioconcentration or (ii) biomagnification using published TMF values. Results demonstrate that it is not possible to confirm that HCB biomagnifies in fish species that would be used for WFD monitoring in Norway and challenges the proposed monitoring procedures for such compounds in Norwegian or European waters. In the second step, fish-water chemical activity ratios for HCB and PeCB as well as for polychlorinated biphenyls where biota and PS were conducted alongside were calculated and found to rarely exceed unity for cod (Gadus morhua), a fish species with a TL of approximately 4.

• Klíčová slova
• biota, fish, hexachlorobenzene, passive sampling, polychlorinated biphenyls, water framework directive,
• MeSH
• bioakumulace MeSH
• chemické látky znečišťující vodu * analýza   MeSH
• hexachlorbenzen analýza   MeSH
• monitorování životního prostředí metody   MeSH
• polychlorované bifenyly * analýza   MeSH
• potravní řetězec MeSH
• ryby MeSH
• voda MeSH
• zvířata MeSH
• Check Tag
• zvířata MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH
• Názvy látek
• chemické látky znečišťující vodu * MeSH
• hexachlorbenzen MeSH
• polychlorované bifenyly * MeSH
• voda MeSH

The freely dissolved concentration of persistent organic pollutants (POPs) is one of the most important parameters for risk assessment in aquatic environments, due to its proportionality to the chemical activity. Chemical activity difference represents the driving force for a spontaneous contaminant transport, such as water-aquatic biota or water-sediment. Freely dissolved concentrations in sediment pore water can be estimated from the concentrations in a partition-based passive sampler equilibrated in suspensions of contaminated sediment. Equilibration in the sediment/passive sampler system is slow, since concentrations of most POPs in the water phase, which is the main route for mass transfer, are very low. Adding methanol to sediment in suspension increases the POPs' solubility and, consequently, the permeability in the water phase. The resulting higher aqueous concentrations enhance POPs mass transfer up to three times for investigated POPs (polycyclic aromatic hydrocarbons, polychlorinated biphenyls, organochlorine pesticides) and shorten equilibrium attainment to less than 6 weeks. The addition of methanol to the aqueous phase up to a molar fraction of 0.2 changed the POPs equilibrium distribution ratio between sediment and passive sampler by less than a factor of two. As a result, the pore water concentrations of POPs, calculated from their amounts accumulated in a passive sampler, are affected by methanol addition not more than by the same factor.

• Klíčová slova
• Mass transfer, Partitioning, Passive sampling, Persistent organic pollutants, Sediment,
• MeSH
• chemické látky znečišťující vodu analýza   MeSH
• chlorované uhlovodíky analýza   MeSH
• geologické sedimenty analýza   MeSH
• methanol chemie   MeSH
• monitorování životního prostředí metody   MeSH
• pesticidy analýza   MeSH
• polychlorované bifenyly analýza   MeSH
• polycyklické aromatické uhlovodíky analýza   MeSH
• rozpustnost MeSH
• Publikační typ
• časopisecké články MeSH
• Názvy látek
• chemické látky znečišťující vodu MeSH
• chlorované uhlovodíky MeSH
• methanol MeSH
• pesticidy MeSH
• polychlorované bifenyly MeSH
• polycyklické aromatické uhlovodíky MeSH

Bioaccumulation, the accumulation of a chemical in an organism relative to its level in the ambient medium, is of major environmental concern. Thus, monitoring chemical concentrations in biota are widely and increasingly used for assessing the chemical status of aquatic ecosystems. In this paper, various scientific and regulatory aspects of bioaccumulation in aquatic systems and the relevant critical issues are discussed. Monitoring chemical concentrations in biota can be used for compliance checking with regulatory directives, for identification of chemical sources or event-related environmental risk assessment. Assessing bioaccumulation in the field is challenging since many factors have to be considered that can affect the accumulation of a chemical in an organism. Passive sampling can complement biota monitoring since samplers with standardised partition properties can be used over a wide temporal and geographical range. Bioaccumulation is also assessed for regulation of chemicals of environmental concern whereby mainly data from laboratory studies on fish bioaccumulation are used. Field data can, however, provide additional important information for regulators. Strategies for bioaccumulation assessment still need to be harmonised for different regulations and groups of chemicals. To create awareness for critical issues and to mutually benefit from technical expertise and scientific findings, communication between risk assessment and monitoring communities needs to be improved. Scientists can support the establishment of new monitoring programs for bioaccumulation, e.g. in the frame of the amended European Environmental Quality Standard Directive.

• Klíčová slova
• Chemical assessment, Ecotoxicology, Environmental quality, Environmental quality standards, Monitoring, Passive sampling, Water framework directive,
• Publikační typ
• časopisecké články MeSH