Iodine is an essential trace element for both humans and animals. It is essential to produce important hormones by the thyroid gland. In most inland areas, the soils are iodine deficient and its amount is insufficient to produce agricultural crops with adequate iodine content to cover the recommended daily intake. In connection with the occurrence of iodine deficiency disorders (IDDs), it has been the subject of intensive research in the past. However, following the introduction of iodized table salt in the food industry, problems related to IDD were not solved and studies on iodine mobility and bioavailability from soils are rare even today and have remained insufficiently investigated. In many countries, mainly in Europe, the prescription rate of medicaments used to treat goiter is still high. Thus, there are a considerable amount of studies looking for alternative methods for iodine supplementation in foodstuffs among the use of iodized table salt. In most cases, the subject of these studies are agricultural crops. This mini review presents the consequences of inadequate and excess iodine intake, the current status of iodine supplementation and the most recent alternative methods of the application of iodine in agriculture and its effect on the quality of used plant species.

Contamination of soils with three metals due to the highway and railway transport was studied. Copper was selected as a suitable indicator for both kinds of transportation. Sodium served to assess the level of contamination resulting from the road salting in winter. Mercury was determined in samples taken close to the railway in order to test its release from impregnated wooden ties. All analyses were determined using the methods of the trace element analysis; values are expressed as dry matter. The highest concentrations of copper, sodium and total mercury in soil samples were 52.7 mg/kg, 770 mg/kg and 0.181 mg/kg respectively. The highest copper content was observed in soils taken close to the railroad and the highway. Elevated sodium levels originated from winter road salting – the highest winter value was 770 mg/kg as compared with maximal summer value of 416 mg/kg. The concentration of total mercury in soils depended on the type of railway ties used – the highest values for location with wooden and concrete ties were 0.181 mg/kg and 0.145 mg/kg, respectively. Wooden railroad ties are considered as a potential source of mercury because of impregnation with antifungal mercury compounds.