Factors influencing accumulation of Zn, Cu, and Ca in the tissues of spiny-cheek crayfish (Faxonius limosus, Rafinesque, 1817).

Both physicochemical and biological factors affect the degree of metal accumulation in crayfish tissues. The content of metals and correlations between the metal concentrations in different tissues and the total length of crayfish is suitable indicators of contamination of the aquatic environment. The aim of the study was to analyse the effect of age and sex of crayfish on the degree of accumulation of Ca, Cu, and Zn in the muscle and exoskeleton. A total of 100 individuals of the spiny-cheek crayfish (Faxonius limosus, Rafinesque, 1817) were caught from Glowinsk reservoir (Poland) in October 2019 using fyke nets. Metal concentrations were determined in freeze-dried samples of the abdominal muscle, exoskeleton, bottom sediment, and water using atomic absorption spectroscopy (AAS). Here, we show that the highest concentrations of Zn were found in the muscle of 4-year-old females, Cu in 3-year-old males, and Ca in 4-year-old males. Sex was a significant factor affecting the content of Ca in the muscle and Zn in the exoskeleton. Age was a significant factor affecting the content of Zn, Cu, and Ca in the muscle and Zn and Cu in the exoskeleton. The bioconcentration factor (BCF) of Zn and Cu in the muscle and exoskeleton of spiny-cheek crayfish was much higher from water than from sediments, unlike Ca. Furthermore, we found significant correlation for muscle between Zn and total length in 3-year-old females and 4-year-old males and between Cu and TL in 3-year-old males. Analysing the recommended daily intake (RDI) for the investigated minerals confirmed that the consumption of 100 g of spiny-cheek crayfish muscle could meet daily requirement for Zn up to 27.5%, for Ca in 12.4%, and over 100% for Cu. The conducted analyses confirmed that the consumption of crayfish meat was safe for the health of potential consumers in terms of the analysed metal content.

Can acid sulfate soils from the southern Baltic zone be a source of potentially toxic elements (PTEs)?

The mobility of Cr, Cu, Ni, Pb, and Zn in acid sulfate (AS) soils in the reverse delta of the Swina River, NE Poland was studied using extraction of the target metals using the BCR protocol, which targets acid-extractable (F1), reducible (F2), oxidizable (F3) fractions, and aqua regia digestion for residual (F4) fraction. It was assumed that the content of mobile forms determined in air-dried samples during consequent steps of BCR extraction refers to two scenarios of possible release of selected metals from the studied soils: (1) attributed to seasonal soil moisture variation or (2) caused by artificial drainage. The studied AS soils had thin organic layers (muck, peat and mud) overlaying deltaic sands, and contained hypersulfidic material. The field pH was 6.2 ± 0.5 and significantly decreased to 4.3 ± 1.4 after the 8-weeks incubation period. This can be explained by low buffering properties (e.g. lack of carbonates). Total concentrations of metals (Cr 17.9-61.6, Cu 5.7-27.7, Ni 6.2-47.0, Pb 2.2-17.7, and Zn 13.6-130 mg∙kg-1) in the AS soils were diversified but none of the concentrations exceeded the Polish legal limits. Despite the relative low content of analyzed metals, the studied soils can be a potential source of metal contamination affecting the coastal environment in the southern Baltic Sea region that has been overlooked so far. This is confirmed by the high proportion (44-82%) of Cr, Cu, Ni, and Zn in the F1-F3 fractions which can potentially be released as assumed in two scenarios. The BCR protocol seems to be a useful tool for understanding the chemical behavior and fate of metals in AS soils. Challenges in the assessment of metal mobility in the oxidized and unoxidized zones of individual soil profiles occurred due to their complex morphology resulting from the heterogeneous depositional environment under the human impact.

Effects of a Trans-Galactooligosaccharide on Minerals Content of Common Carp (Cyprinus carpio L.) Tissues.

Common carp (Cyprinus carpio L.) is a dominant fish species in aquaculture, and as it is a stomachless species, absorption and digestion of nutrients take place in the intestine. The aim of the study was to evaluate the effects of a prebiotic on the content of selected minerals found in the meat, gills, and skeleton of common carp. The research applied trans-galactooligosaccharide (GOS) prebiotic produced by enzymatic transgalactosylation of milk lactose by whole cells of Bifidobacterium bifidum. The following diets have been applied: control diet without feed additives (C), diet 2 (B1) with 1% of GOS, and diet 3 (B2) with 2% of GOS. In the freeze-dried samples, concentrations of the analyzed metals were determined using atomic absorption spectroscopy (AAS). The content of phosphorus was determined using colorimetric method. The analyses confirmed that the highest level of Mg was detected in the skeleton of fish fed with 1% GOS (2.51 g kg-1) and was significantly higher compared the control treatment (2.11 g kg-1) (P < 0.05). Zn content in fish meat fed with 1% GOS (35.41 mg kg-1) was significantly higher (P < 0.05) than in the control group (24.59 mg kg-1). The tissue that accumulated the greatest amount of Zn was the gills. GOS had a positive effect on Fe accumulation in the meat, gills, and skeleton. It has been concluded that supplementation of feed with 2% GOS significantly influenced the positive correlations between Mg and P in the meat and skeleton, Fe-Ca correlation in gills, and Fe-Zn correlation in the skeleton.

Heavy metal content and mobility in urban soils of public playgrounds and sport facility areas, Poland.

Among the threats to air, soil, and water posed by urbanization, heavy metals appear particularly hazardous. Playgrounds and sport facilities are unique urban places, widely used by children and youth. The aim of this research was to evaluate heavy metal pollution in urban soils, identify relationships among topsoil metal distributions, and assess related health risks in two Polish cities - Warsaw and Bydgoszcz. According to the Regulation of the Polish Minister of the Environment guidelines for total content of Pb, Cu, Zn, Ni, Cd and Co our study sites were classified as uncontaminated. Applied Geoaccumulation Index (Igeo; Müller, 1969) largely confirmed this classification, with only two of the investigated Warsaw areas "moderately polluted" with Pb. Generally, only Pb and Zn concentrations exceeded reference background levels for Polish soils. The highest concentrations of Pb and Zn were found in the city centers, the oldest areas where pollution risk is potentially the highest. Metal mobility and solubility were mainly correlated with total content, indicating potential risk from lead and zinc. At some sites in Warsaw, where mean Pb concentration was 87.25 mg kg-1 and Zn 207.25 mg kg-1, health risks from ingestion and inhalation seemed significant, particularly for children. In Bydgoszcz use of the studied playgrounds and sport facility areas did not pose a risk to human health. Finally, the study (especially in Warsaw) indicates the need for continued monitoring and suggests lowering permissible limits of these metals in soils, especially in recreational areas, may decrease childrens' exposure risk to these pollutants.

Heavy Metals Bioaccumulation in Tissues of Spiny-Cheek Crayfish (Orconectes limosus) from Lake Goplo: Effect of Age and Sex.

The aim of the present work was to assess the concentrations of metals in the abdominal muscle and exoskeleton of 3-year-old males and 4-year-old females and males of spiny-cheek crayfish (Orconectes limosus) collected from Lake Goplo. A total of 93 males and 35 females were collected in autumn (October 2014). The analyzes of heavy metals were conducted by means of atomic absorption spectroscopy with a PU9100X spectrometer. The content of mercury was determined using AMA 254 mercury analyser. As analyses indicated heavy metals accumulated in the muscle and exoskeleton in the following sequence: Zn > Cu > Pb > Mn > Ni > Hg and Mn > Pb > Zn > Ni > Cu > Hg, respectively. Statistically significant differences between 3- and 4-year-old males were found for all analyzed metals. Gender dependent differences were calculated only for Ni in the muscle tissue and for Mn and Hg in the exoskeleton. In comparison with the study carried out 2 years ago notably higher concentrations of Pb were found in the muscle and a higher content of Zn, Pb, Mn and Ni was determined in the exoskeleton.

Impact of highway traffic and the acoustic screen on the content and spatial distribution of heavy metals in soils.

Recent years have witnessed intensification of road traffic and, with it, the amount of substances emitted by vehicles. Such emissions need to be monitored for public health purposes. The aim of this study was to evaluate the impact of the highway traffic on the total content and bioavailability of Zn, Cu, Ni, Cd, Cr and Pb in nearby soils as well as influence of an acoustic screen on spatial distribution of the metals. The material included 40 soil samples collected from 15 research points located 5, 10, 25 and 50 m away from the road acoustic screen and from 4 points between the screen and the highway. Additionally, 5 research points were located next to the metal barrier. Selected physicochemical properties of soils were determined: soil texture, soil pH, TOC and CaCO3 content. The total content of heavy metals in the soils was determined by AAS after digestion in aqua regia and bioavailable forms in 1 M diethylenetriaminepentaacetic acid. The research found low impact of the highway traffic on the content of heavy metals in soils; however, due to a very short period of this potential impact (5 years), the moderately polluted category of geo-accumulation index of cadmium and high bioavailability of lead indicate the need of repeating the research within the next several years. Furthermore, the road acoustic screen significantly influenced spatial distribution of the metals in soils.