## 1 Introduction  
The threats resulting from environmental pollution make it necessary to regularly monitor the content of heavy metals and toxic substances in plants, soil, water, and air [1, 2]. Due to rapidly developing civilization and thus chemicalization, the ecological balance in nature and the economy has been disturbed. The dynamic development of industry and irrational use of fertilising waste in agriculture, e.g., industrial and municipal sewage sediment and coal combustion ashes, contribute to the excessive accumulation of heavy metals in plants and soils, threatening humans and animals [2, 3, 4, 5, 6, 7]. Plants intended for consumption are a include natural source of heavy metals. Therefore, they are a threat to the health quality of agricultural produce [8, 9]. The source of contamination with heavy metals in cultivated plants is the soil, and their concentration depends on the content of these elements in the parent rock and the course of soil-forming processes. Most heavy metal compounds are readily soluble in the soil solution and therefore are easily absorbed by plants [10]. Agricultural soils may become contaminated with heavy metals through excessive and inappropriate use of mineral and organic fertilizers, limiting, composts made from waste or fertilizers obtained, for example, from industrial sludge leachate, which, apart from nutrients and organic matter, also contains metals that quickly accumulate in the soil [6]. Increasing the amount of organic matter in mineral soils limits crop plant uptake of heavy metals. Therefore, it is advisable to successfully supplement soils with organic matter from, for example, waste, organic-mineral or organic fertilizers produced with their participation. Applying phosphorus to the soil reduces the uptake of heavy metals by plants because, with a higher content of its easily soluble forms, sparingly soluble zinc, cadmium, lead, and copper phosphates may precipitate. However, using potassium fertilisation can increase the availability of heavy metals for plants [11; 12]. Among crops, rape seed is currently the second most frequently produced oilseed. The main producers are China, India, Canada and the European Union. The increase in rape seed cultivation area results from the increase in the consumption of vegetable oils by people and the demand for feed protein. In addition, the attractiveness of rape seed cultivation is influenced by its high profitability [13; 14]. Cereal cultivation also increases. The coronavirus pandemic affected the economy, as a greater demand for cereal products was shown [15; 16]. Currently cereal cultivation is carried out in the world on 728 million ha including triticale on 3,809,192 ha [17]. Fertilizers are critical to agricultural production, according to the IMF, and global demand for them increased by 6.3% in 2021, which, combined with supply disruptions, pushed prices up by 78.6% [18; 19], that's why it began acquisition of new sources of organic matter and nutrients for plants. On the other hand, the intensive development of technological processes to produce innovative human goods generates much waste. This waste should be reused or disposed of following legal provisions. Thermal utilisation is expensive, so attempts are made to manage or process raw waste. Many wastes are characterised by a reasonably high content of organic matter and essential nutrients for plants. They may also contain excessive amounts of heavy metals and other chemical compounds that may harm the environment. Therefore, various wastes, preparations, or substances of fertilising importance are tested to determine their impact on soil fertility indices, the size and quality of plant yields and their impact on the environment [20; 21; 22; 23; 24; 25; 26; 27]. The research was carried out to verify the hypothesis that the accumulation of heavy metals by the two tested crops is related to the presence of industrial sewage sludge.