**3. Admissible heavy metal contents in soil binding in Poland**

In Poland respective boundary heavy metal contents are specified in the Ordinance of the Minister of the Environment of 9 September 2002 on soil quality standards and land quality standards. These standards were established taking into consideration the current and forecasted functions for the following categories of land types (Table 1):

**1.** Category A:

years an increasing body of research has focused on engineering bioremediation, such as e.g. an *in situ* technology of phytoremediation, utilizing the capacity of plants to accumulate high amounts of pollutants from the environment. Research conducted for many years now has identified a relatively numerous group of plants potentially applicable in this new environ‐

At present a major ecological problem is connected with the penetration to the environment of heavy metals, which at higher concentrations are strongly toxic to humans and animals (resulting in e.g. increased disease incidence), and have a negative effect on soil properties as

Literature sources present various definitions of an element to be considered a heavy metal. One of these hypotheses says that they are elements with specific gravity greater than 4.5, 5, 6 and 7 g cm-3. It is a physical term, which is understood and used differently in various contexts. There are also many definitions based on atomic number. Some of them are considered to be nutrients for living organisms (essential nutrients e.g. Fe, Cu, Zn, Mn, Ni) and others are redundant or toxic (e.g. Cd, Pb, Hg, Al, As). Their common characteristic is connected with the fact that at excessive concentrations in the environment they have an adverse effect on plant growth and development, and when incorporated in the food chain may also pose a

**2. Soil factors influencing availability of heavy metals to plants**

Physico-chemical properties of soil influencing contents of phytotoxic forms of heavy metals include the type of soil, its grain size distribution, reaction, organic matter content, sorption

Mother rock is a natural source of heavy metals in soils. The amounts of elements coming from mother rock constitute the geochemical background posing no threat to soil fertility [67]. Other sources of heavy metals include geochemical processes and anthropogenic factors. In soil heavy metals are subjected to processes affecting their concentrations and chemical forms [4]. In individual soil horizons their content depends on anthropogenic and

Soil reaction is a major factor influencing the form and availability of heavy metals to plants [67]. Soil acidity may lead to their increased concentrations in soil [3, 13, 30, 48, 93, 112] and their excessive uptake by plants [42, 93]. According to Tyler and Olsson [118], concentrations of Cu and Pb increase also at pH 7.5 – 7.8 as a result of formation of stable complexes with ligands, which solubility is connected with solubility of organic substance. Liming results in a reduced content of available forms of heavy metals in soil [39]. Soil reaction is a factor determining the force with which heavy metals are bound by organic substance and mineral

Organic substance found in soil contributes to the limitation of the amounts of heavy metals available to plants [38, 47], since it binds very strongly Cr3+, Fe3+, Pb2+, Ni2+ and Co2+ ions and

ment decontamination technology.

576 Environmental Risk Assessment of Soil Contamination

hazard for animals and humans.

climatic factors [67, 114].

compounds [2, 60].

properties and redox potential [43, 67, 68, 73].

well as quality and physiological activity of plants.


land, as well as developed and urbanized areas except for industrial areas, surface mining land in use and municipal areas;

**3.** Category C – industrial areas, surface mining land in use, transportation areas.

Attachment to the Ordinance of the Minister of the Environment of 9 September 2002 (item 1359)


**Table 1.** Admissible concentrations in soil (mg kg-1 dry matter)

Based on the multiannual analyses the Institute of Soil Science and Plant Cultivation in Puławy, Poland (IUNG) specified boundary heavy metal contents in soils to be utilized agriculturally (Table 2). As it was reported by Ociepa et al. [94], the mean content of heavy metals in agriculturally utilized soils in Poland is lower than in countries of Western Europe or the USA, which results mainly from a lesser share of farms with intensive agricultural production systems and a lesser intensity of industrial processes. The same authors reported that approx. 90% agriculturally utilized area have natural levels of toxic metals. Several percent of this area have elevated contents (I0 ) of mainly cadmium and zinc, while approx. 3% are polluted (II-V0 ) with metals. The greatest percentages of polluted soils are found in the Śląskie, MałoPolande and Wrocławskie provinces of Poland.


Pollution rate: 0 – natural content, I – elevated content, II – weak pollution, III – medium pollution, IV – strong pollution, V – very strong pollution

\*soil classes:

land, as well as developed and urbanized areas except for industrial areas, surface mining

Attachment to the Ordinance of the Minister of the Environment of 9 September 2002 (item

Arsenic 20 20 20 25 25 55 60 25 100 Barium 200 200 250 320 300 650 1000 300 3000 Chromium 50 150 150 190 150 380 500 150 800 Tin 20 20 30 50 40 300 350 40 300 Zinc 100 300 350 300 300 720 1000 300 3000 Cadmium 1 4 5 6 4 10 15 6 20 Cobalt 20 20 30 60 50 120 200 50 300 Copper 30 150 100 100 100 200 600 200 1000 Molibdenum 10 10 10 40 30 210 250 30 200 Nickel 35 100 50 100 70 210 300 70 500 Lead 50 100 100 200 100 200 600 200 1000 Mercury 0,5 2 3 5 4 10 30 4 50

Based on the multiannual analyses the Institute of Soil Science and Plant Cultivation in Puławy, Poland (IUNG) specified boundary heavy metal contents in soils to be utilized agriculturally (Table 2). As it was reported by Ociepa et al. [94], the mean content of heavy metals in agriculturally utilized soils in Poland is lower than in countries of Western Europe or the USA, which results mainly from a lesser share of farms with intensive agricultural production systems and a lesser intensity of industrial processes. The same authors reported that approx. 90% agriculturally utilized area have natural levels of toxic metals. Several percent of this area

with metals. The greatest percentages of polluted soils are found in the Śląskie, MałoPolande

) of mainly cadmium and zinc, while approx. 3% are polluted (II-V0

)

**Category B Category C**

**Depth [m below ground level]**

**Water permeability of soil [m/s] Up to below Up to below Up to below** 1∙10-7 1∙10-7 1∙10-7

0-0.3 0.3-15.0 >15 0-2 2-15

**3.** Category C – industrial areas, surface mining land in use, transportation areas.

land in use and municipal areas;

578 Environmental Risk Assessment of Soil Contamination

**Table 1.** Admissible concentrations in soil (mg kg-1 dry matter)

have elevated contents (I0

and Wrocławskie provinces of Poland.

1359)

**Pollutant Category A**

a. Very light soils with low silt and clay contents ( < 10%), irrespective of pH (in KCl)


b. Light soils (10 - 20% silt and clay), neutral reaction (pH > 6.5)


c. heavy soils (>35% silt and clay), highly acid (pH < 4.5)


d. Medium heavy soils (20-30% silt and clay) and heavy soils (> 35%).

**Table 2.** Boundary values in mg kg-1 heavy metals in the surface layer (0 – 20 cm) of soils with different degrees of contamination (IUNG 1992)
