Long term investigation of 137Cs in chicken meat and eggs from northwest Croatia

Abstract

This paper presents the results of long-term investigations of ¹³⁷Cs activity concentrations in chicken meat and eggs from northwest Croatia for the period 1987–2018. The research has been done as a part of monitoring program of radioactive contamination in Croatia. The highest activity concentrations in both of these foodstuffs were measured in 1987 and have been decreasing exponentially ever since. The Fukushima-Daiichi accident in 2011 did not cause any increase of ¹³⁷Cs activity concentrations. The ecological half-life for ¹³⁷Cs was estimated to be 8.0 and 8.4?years for chicken meat and eggs respectively. The correlation between ¹³⁷Cs in fallout and chicken meat as well as between ¹³⁷Cs in fallout and eggs is very good, the respective correlation coefficients being 0.79 and 0.72, indicating that fallout was the main source of ¹³⁷Cs contamination in both foodstuffs. The estimated effective doses received by adult members of the Croatian population due to the intake of radiocaesium by chicken meat and egg consumption for the overall observed period are very small, 2.0 and 0.6 µSv respectively. Therefore, chicken meat and chicken egg consumption was not a critical pathway for the transfer of radiocaesium to humans.     

Study of MCPA and MCPP herbicides mobility in soils from North-West Croatia as affected by presence of fertilizers

The mobility of acid herbicide (4-chloro-2-methylphenoxy)acetic acid [MCPA] and 2-(4-chloro-2-methylphenoxy)propionic acid [MCPA] in soils of North-West Croatia has been studied by soil thin-layer chromatography (STLC). Mobility of MPCA and MCPP was influenced by the change in concentration of soluble salts and the effect of mineral composition of the system studied, i.e. content of kaolin and sand in soil thin layer. The objective of this work was also to investigate how the mobility of phenoxy herbicides MCPA and MCPP is altered by the presence of fertilizers when both coexist in soil as a result of human activity. It has been found that mobility of acidic herbicides increases with application of fertilizers especially on soil with low clay and low organic matter content.     

Quantifying the efficiency of soil sampling designs: A multivariate approach

The objective of this paper is to quantify and compare the loss functions of the standard two-stage design and its composite sample alternative in the context of multivariate soil sampling. The loss function is defined (conceptually) as the ratio of cost over information and measures design inefficiency. The efficiency of the design is the reciprocal of the loss function. The focus of this paper is twofold: (a) we define a measure of multivariate information using the Kullback–Leibler distance, and (b) we derive the variance-covariance structure for two soil sampling designs: a standard two-stage design and its composite sample counterpart. Randomness in the mass of soil samples is taken into account in both designs. A pilot study in Slovenia is used to demonstrate the calculations of the loss function and to compare the efficiency of the two designs. The results show that the composite sample design is more efficient than the two-stage design. The efficiency ratio is 1.3 for pH, 2.0 for C, 2.1 for N, and 2.5 for CEC. The multivariate efficiency ratio is 2.3. These ratios primarily reflect cost ratios; influence of the information is small.     

Determination of selected neonicotinoid insecticides by liquid chromatography with thermal lens spectrometric detection

We studied the analysis of trace amounts of neonicotinoid insecticides by liquid chromatography coupled with a thermal lens spectrometric detector (TLS). This multi-residue analysis method is based on the reversed phase separation on C₁₈ column, isocratic elution and collinear dual beam TLS detection. The insecticides thiamethoxam, imidacloprid, acetamiprid and thiacloprid were detected with retention times of 4.4, 5.7, 6.5 and 8.5 min and limits of quantifications of 50, 89, 10, and 25 μg/L, respectively. The retention times agreed well with those obtained by the same chromatographic method but using a diode-array detector (DAD). The limits of quantifications for imidacloprid were identical in both techniques. However, the limits of quantifications for thiamethoxam, acetamiprid and thiacloprid were up to 8.5 times lower using the TLS detector compared to the diode-array detector. The applicability of the developed procedure was tested on spiked river water and potato samples.     

Post-war levels of persistent organic pollutants (POPs) in air from Serbia determined by active and passive sampling methods

For the duration of the war accident in former Yugoslavia, several industrial and military targets were burnt and damaged, resulting in a significant release of persistent organic pollutants. Locations heavily targeted in the attacks were later defined by UNEP as four “hot spots”: Kragujevac, Novi Sad, Pancevo and Bor. We analyzed concentration levels of pollutants collected in 2004 and 2005 in air samples from the city of Kragujevac, Serbia, following the war accident of 1999. Pollutants included polycyclic aromatic hydrocarbons (PAHs), hexachlorocyclohexane (HCH), dichloro-diphenyl-trichloroethane (DDT), dichloro-diphenyl-dichloroethylene (DDE), dichloro-diphenyl-dichloroethane (DDD) and polychlorinated biphenyls (PCBs). We present results obtained during air sampling campaign conducted in July 2004 by the active sampling method; and during September 2004–June 2005 by the passive sampling method. Our findings show the occurrence of residual quantities of DDT, HCH, PCBs and PAHs in air samples. High levels of PCBs are probably due to the destruction of transformers during the war accident.     

Automatic construction of concept hierarchies: The case of foliage-dwelling spiders

In this paper, we present the hierarchical variable dependencies that were obtained from raw data with the use of two machine learning techniques on an ecological data set. The data set contains features of field margins and the corresponding number of spider species inhabiting them. This data set was used before by domain experts to construct a fuzzy qualitative model with hierarchical variable dependencies, which we use for comparison with our results. One of the machine learning methods constructs a hierarchical structure similar to the one in the experts’ model, while revealing some additional interesting relations of environmental features with respect to the number of spider species. The other method constructs a different hierarchy from the one proposed by the experts, which, according to our classification performance experiments, might be even more appropriate.     

中国－喜马拉雅柴胡属的花粉形态及其系统学意义

本文报道了中国－喜马拉雅柴胡属（ＢｕｐｌｅｕｒｕｍＬ．）２４种，７变种，２变型的花粉形态研究结果，全部在光学显微镜和扫描电镜下作了比较观察。有关柴胡属花粉形态的研究，除大苞柴胡（Ｂ．ｅｕｐｈｏｒｂｉｏｉｄｅｓＮａｋａｉ）和红柴胡（Ｂ，ｓｃｏｒｚｏｎｅｒｉｆｏｌｉｕｍＷｉｌｌｄ．）外．其余均为首次报道，根据该属花粉粒的形态和萌发孔特征，其花粉形态可分为三个类型，即：近菱形角孔类型、矩形边孔类型及其二者之间的过渡类型。花粉形态资料支持德国植物系统学家德鲁特（Ｏ，Ｄｒｕｄｅ，１８９８）关于柴胡属的系统位置，将其隶于芹亚科（Ａｐｉｏｉｄｅａｅ），芹族（Ａｐｉｅａｅ），葛缕子亚族（Ｃａｒｉｎａｅ）。     

华阳发电公司综合污水的治理

介绍了华阳发电有限责任公司综合污水治理工艺，并对其处理效果和经济效益进行分析，为同类污水的处理提供了工程实例。