Particulate matter (PM) can strongly affect redox biochemistry and therefore induce the response of the immune system and aggravate the course of autoimmune diseases. Nanoparticles containing transition metal compounds possessing semiconductor properties (TiO2, ZnO) may act as photocatalysts and accelerate the generation of reactive oxygen species (ROS) and reactive nitrogen species (RNS). In this study, the NIST standard reference material, SRM 1648a, has been analyzed in terms of this consideration. Organic compounds present in SRM 1648a were removed by cold oxygen plasma treatment. Samples of SRM 1648a with removed organic content (<2% of organic carbon, <1% of nitrogen) were obtained within 2 h of this treatment. The treatment did not affect the morphology of the powder. The reference material and PM2.5 collected in Kraków are composed of smaller particles and nanoparticles forming aggregates. The efficiency of (photo)generation of hydroxyl radicals and singlet oxygen was compared for original and organics-free samples. The analyzed samples showed the highest activity towards ROS generation when exposed to UV-vis-NIR light, moderate under UV irradiation, and the lowest in dark. Data collected in the present study suggest that the organic fraction is mostly responsible for singlet oxygen generation, as almost twice higher efficiency of 1O2 generation was observed for the original NIST sample compared to the material without the organic fraction. However, particulate matter collected in Kraków was found to have a five times higher activity in singlet oxygen generation (compared for original NIST and Kraków dust samples).

The level of production of nanoparticles will inevitably lead to their appearance in air, water, soils, and organisms. A theoretical framework that relates properties of nanoparticles to their biological effects is needed to identify possible risks to human health and the environment. This paper considers the properties of dispersed metallic nanoparticles and highlights the relationship between the chemical stability of these nanoparticles and their in vitro toxicity. Analysis of published data suggests that chemically stable metallic nanoparticles have no significant cellular toxicity, whereas nanoparticles able to be oxidized, reduced or dissolved are cytotoxic and even genotoxic for cellular organisms. The ability of metallic nanoparticles to be oxidized, reduced or dissolved in biological media can be used to predict their toxicity in vitro.

Arsenic (As) is a ubiquitous metalloid classified as one of the most hazardous substances, but information about its exposure and effects in free-living passerines is lacking. The aim of this study is to elucidate the effect of an As manipulation experiment on survival, growth and physiology of great tits (Parus major). Wild P. major nestlings inhabiting an unpolluted area were dosed with water, 0.2 or 1 μg g⁻¹ d⁻¹ of sodium arsenite (Control, Low and High As groups), whereas those living in a metal-polluted area were dosed with water (Smelter group). Birds accumulated As in tissues (liver, bone and feathers) in a dose-dependent way. Nestlings exposed to 1 μg g⁻¹ d⁻¹ of sodium arsenite showed reduced number of fledglings per successful nest, and those exposed to 0.2 μg g⁻¹ d⁻¹ had reduced wing growth, which could have post-fledging consequences such as increased predation risk. These results suggest that the LOAEL for effects on nestling survival and development in great tits is likely equal to or below 1 μg g⁻¹ d⁻¹. However, limited effects on the biochemical parameters evaluated were found. It has been shown that As may produce oxidative stress and tissue damage, so further research exploring this issue will be carried out in a future study.

Fitness, (biometric measurements, reproduction) and behaviour that are ecologically relevant biomarkers in assessing the quality of estuarine sediments were studied by comparing the responses of the polychaete worm Nereis diversicolor – a key species in estuaries – along a pollution gradient. Intersite differences were shown for all the measured parameters: size–weight relationships, energy reserves as glycogen and lipids, sexual maturation patterns, total number of oocytes per female, total and relative fecundity, burrowing behaviour. The physiological and behavioural status of N. diversicolor was consistently disturbed in the larger, most contaminated estuaries (Loire and Seine, Fr.) compared to reference sites (Bay of Bourgneuf, Goyen estuary, Fr.). Many classes of potentially toxic chemicals present in these estuaries most likely contribute to these impairments but food availability may act as a confounding factor, interfering with the potential impact of contaminants. Fitness, and behaviour in Nereis diversicolor are affected by anthropogenic pressure.