Heavy metals as well as other pollutants are widespread and create deleterious impact to the environment and human health. There are different in situ and ex situ technologies of immobilization and removal of contaminants; electrokinetic remediation is one of such technologies. It can be applied for treatment of wide areas, e.g., former industrial and military firing-grounds. Technology is applicable to water soluble contaminants at sites with homogeneous soils that are fine-grained and exhibit both, high permeability and high moisture contents. The aim of the study was to test the efficiency of electrokinetic remediation for copper contaminated clayey soil in laboratory conditions. Pilot scale experiments were applied to test the efficiency of electrokinetic removal of contaminants from soil by application of low voltage direct current (DC). Experimental results show that the use of DC power can be selected for treatment of heavy metal contaminated soils. Batch scale experiments were done by using clayey soil with known physico-mechanical properties, spiked with copper solution of known concentrations. Electric force was changed by varying its parameters. The article gives batch experimental results for diffusion of copper ions in soil under the influence of the external electric field.

Malt is a natural food product produced by germinating cereal grains. Safety of cereal grains and cereal products is a very important area. Experiments were carried out at the Faculty of Food Technology of the Latvia University of Agriculture. The research object was rye malt. The purpose of the research was to investigate and compare the influence of copper and selenium on microbiological indicators of rye malt. Rye grains of 96% viability were soaked and germinated at temperature +6 ± 2 °C for 4 days, using copper(II) sulphate pentahydrate CuS04*5H2 O solutions (Cu concentration 10 mg LE-1, 50 mg LE-1, 100 mg LE-1) and for 3 days using sodium selenate Na2 SeO4 solutions (Se concentration 3 mg LE-1, 5 mg LE-1, 10 mg LE-1) then the soaked grains dried in the oven for 24 hours. The total plate count and yeast colony forming units were determined in rye malt samples. The obtained results showed that the increasing of copper and selenium concentration in solution significantly changes microflora of rye malt comparing with the control sample.

Human milk provides infant with the required nutrients for growth and development. The aim of preliminary study was to determine macro- and micronutrients content in mature human milk among lactating women residing in Latvia and dietary habits affecting it. The study was carried out from November 2016 to February 2017. In total, 24 pooled diurnal milk samples were collected from mothers whose infants had reached the age of at least two months. Personal information of each participant was recorded, including mother’s age, weight and height parameters, sex and age of an infant, parity, breastfeeding pattern, milk expression method used for sampling. Eating habits were obtained using Monthly Food Frequency Questionnaire. Analysed elements were determined using inductively coupled plasma mass spectrometry (ICP‑MS Agilent 7700x, Japan). Concentrations ranged from 227.52 to 398.34 mg LE-1 for calcium, 58.56 – 256.38 mg LE-1 for sodium, 445.33 – 736.71 mg LE-1 for potassium, 25.73 – 49.52 mg LE-1 for magnesium, till 3.17 mg LE-1 for iron, 0.28 – 2.77 mg LE-1 for zinc, 0.06 – 0.43 mg LE-1 for copper, 2.00 – 44.00 µg LE-1 for manganese, 1.00 –10.00 µg LE-1 for chrome which is comparable to data obtained from other studies although chrome and manganese concentration was even higher than observed in literature. Cobalt and selenium content was below detection limit. Zinc content in human milk negatively correlated with baby’s age (p is less than 0.05). The content of majority of essential minerals in human milk was affected by mother’s dietary habits; however, more samples need to be analysed for representative conclusions.

The mean content of minerals in grains varies significantly among different parts of the world as it depends on the type of grain growing conditions and fertilizer application. In this study, the content of minerals in the wheat, oat and barley grains of the crop of the year 2006 from different regions of Latvia were investigated. The grain samples were analysed for K, Mg, Ca, Na, Cu, Mn, Fe, and Zn using Atomic Absorbtion Spectrometer, and for P using spectrophotometer. Phosphorus content in different types of grains varied from 3.10 to 5.65 g kgE-1, potassium - from 4.37 to 6.10 g kgE-1, calcium - from 0.40 to 1.40 g kgE-1, magnesium - from 1.20 to 1.68 g kgE-1, manganese – from 14.50 to 55.54 g kgE-1, copper - from 3.35 to 6.01 g kgE-1, zinc - from 18.72 to 31.84 g kgE-1, iron - from 42.39 to 120.40 g kgE-1, and sodium - from 32.34 to 55.52 g kgE-1. The greatest difference was found between the content of manganese and iron in barley, wheat and oat grains, but small difference was between the mean content of P, K, Zn, Cu, Mg, and Na.

In Latvia have not been carried out comparable studies regarding chemical pollution in organic and conventional milk, therefore the aim of the present study was to investigate the level of contamination in organic and conventional milk samples by heavy metals and aflatoxin M1. A total of 9 organic bulk milk and 9 conventional bulk milk samples were collected from different regions of Latvia. The content of lead, cadmium, copper, iron, and zinc were detected by flame technique, using atomic absorption spectrophotometer (AAS). The level of aflatoxin M, in organic and conventional milk samples was determined by high-performance liquid chromatography. The means of lead concentration in organic and conventional samples were 0.024 and 0.31 mg kgE-1 wet weight that exceed the permissible level for such a product. The cadmium content in organic and conventional milk samples is very low and fairly constant in all types of milk. The legally accepted upper limits of iron, copper and zinc are not exceeded by any analyzed milk sample, not even from conventional bulk milk. The study including heavy metals and aflatoxin M1 in a range of organic and conventional milk samples found no significant differences between organic and conventional milk (p=0.05) in the level of aflatoxin M1 and the heavy metals.

Scots pine (Pinus sylvestris L.) is the most common wood species in Latvia. It is classified as not durable, therefore additional protection against microorganisms is needed prior its use outdoors. Presently Cu-containing wood preservatives are commonly used, but the biggest drawback is the poor Cu fixation, therefore raising concerns about the impact on the environment. Three types of specimens were used to carry out the experiments – untreated, Latvian originated Scots pine; Scots pine commercially treated with preservatives that belong to a group of Cu-boron-triazole (CBA) products; and Scots pine, impregnated with micronized-Cu solution using a standard full cell process. In order to make sure that all of the specimens are equal in their components, elemental analysis was performed and content of nitrogen (1.2 – 2.5 g kgE-1), carbon (485.5 g kgE-1), oxygen (456.0 g kgE-1) and hydrogen (55.6 g kgE-1) was determined. The treated specimens were leached according to the European standard EN 84. For micronized-Cu impregnated Scots pine the total Cu content in leachates obtained by atomic absorption spectroscopy was 0.15 mg gE-1 of wood, and 0.06 mg gE-1 of absolute dry matter with CBA preservative impregnated Scots pine wood. Subsequently, according to the European standard EN 113, treated Scots pine blocks were exposed to brown-rot fungus Coniophora puteana and to white-rot fungus Trametes versicolor for 16 weeks. Mass loss for wood treated with micro-Cu was 48.4% (484 g kgE-1) and 1.5% (15 g kgE-1) respectively, but for CBA – 49.5 % (495 g kgE-1) and 1.2% (12 g kgE-1). Both samples proved to be inappropriate for outdoor use (use class 3).