Romanian National Contract nr 52175 /2009 -PARTENERIATE:
DEVELOPMENT OF HEAVY METALS BALANCE MODELS FOR AGROECOSYSTEMS – METAGRO
USAMVB research activity within the METAGRO project :
(2011) Tudoreanu L., Codreanu M.D., Crivineanu V. and Goran Gh. V. Modeling heavy metals transport and accumulation in plant-animal systems Ed PRINTECH ( published in English)
Introduction
2. CADMIUM AND LEAD UPTAKE AND ACCUMUTATION IN PLANTS (Liliana Tudoreanu)
2.1. Cadmium and Lead in plants, plant populations and communities - cadmium and lead bioavailability and uptake by plants.
2.1.1 Biological systems as hierarchical systems. The soil-plant system ;
2.1.2 Cadmium and lead bioavailability;
2.1.3 Cadmium and lead uptake by plant roots
2.1.4 Pb and Cd accumulation and distribution in plant tissues;
2.1.5 Family dependent Cd and Pb accumulation;
2.1.6 Seasonal variation of Cd and Pb accumulation ;
2.1.7 The effect of fertilisers on the concentrations of CD and PB in pasture plants
2.1.8 Fertilization and sewage sludge application to grasslands and agricultural crops; 2.1.8.1 Cadmium and lead accumulation in plants grown on sewage sludge amended soils; 2.1.8.2 Uptake of cadmium from phosphorus fertilisers ;
2.1.9 The role of root exudates on the mobilisation of cadmium and lead in soils
2.1.10 Mycorrhiza effect on cadmium and lead uptake by plants
2.1.11. Symbiotic nitrogen fixation influenced by cadmium and lead
2.1.12. lon competition
2.1.13 Foliar uptake of cadmium and lead
2.2. Cadmium and lead accumulation and distribution in plant tissues
2.2.1 Cadmium and lead content in grasses and pasture plants
2.2.2 Cadmium and lead accumulation ihigher plants families species and varieties
2.3. Cadmium and lead transport in plants
2.3.1 Cadmium and lead short distance transport in plants
2.3.2 Long distance transport in plants-translocation
2.3.3 Xylem transport
2.4. Plants physiological response to cadmium and lead accumulation
2.4.2 Photosynthesis, respiration and transpiration
2.4.3 Growth affected by cadmium and lead uptake
2.4.4 Protein content of vegetables and grasses in relation to cadmium
2.4.5 Mineral content of cereals, vegetables, legumes and grasses in relation to tissue total concentration for cadmium and lead
2.5. Molecular aspects of plant cell responses to cadmium and lead
2.5.1 Effects on cell membrane and cell biochemical composition;
2.5.2 Molecular aspects of the defence system against metal
2.5.3 Lead and cadmium plant-pathogen interaction
3. MODELS FOR CADMIUM AND LEAD ACCUMULATION IN THE PTANT-ANIMAL SYSTEM (Liliana Tudoreanu)
3.1.1 Empirical, mechanistic and teleonomic models
3.1.1.1 EmPirical models; 3.1.1.2 Teleonomic models; 3.1.1.3 Mechanistic models: (1) Dynamic uptake models - Foliar uptake;(2) Root uptake models; 3.1.1.4 Modelling software and statistical packages
3.1.2 Models for heavy metals uptake and accumulation by plants; 3.1.2.2 Mechanistic models to cadmium and lead accumulation in plants 150
4. HEAVY METALS ACCUMULATION IN ANIMALS
4.1. Heavy metals accumutation in farm animals
4.1.1 Copper accumulation in sheep (G.V. Goran)
4.1.2. Cadmiumandleadaccumu|ationindairycows (M.D.Codreanu,G.V. Goran)
4.1.3 Cadmium, lead and zinc accumulation in hoeses from the Copsa Mica area (V. Crivineanu, G.V. Goran)
4.1.4 Effect of lead accumulation on nutrients (G.V. Goran)
4.2. Heavy metals accumutation in honey and wax (M.D. Codreanu)
4.3. Models for heavy metals accumulation in animals
4.3.1 Conceptual models of cadmium and lead kinetics in animals (G.V.Goran)
4.3.2 Transforming urinary cadmium concentrations into dietary intake values for humans (an EFSA approach).
4.4. Models for heavy metals accumulation in animals
4.4.1 Models for heavy metals accumulation in sheep (Liliana Tudoreanu, C.J,C. Phillips)
4.4.2 Models for heavy metals accumulation in dairy cows (Liliana Tudoreanu,M.D. Codreanu, G.V. Goran, V. Crivineanu)
4.4.3 Models for heavy metals accumulation in farm horses (Liliana Tudoreanu, V. Crivineanu, G.V. Goran)
4.4.4 Models for heavy metals accumulation in honey (M.D. Codreanu, Liliana Tudoreanu)
4.4.5 Food chain risk assessment models (Liliana Tudoreanu)
5. MODELLING HEAVY METALS BALANCE OF REGIONAL AGROECOSYSTEMS (Liliana Tudoreanu)
5.1. Models for mass flux balance for heavy-metal accumulation in agricultural systems
5.2. An endogenious plant - animal submodel for heavy metals balance in agro-systems
6. APENDIX. ENVIRONMENTAL DATA ON HEAVY METALS CONCENTRATTON IN THE COPSA MICA (ROMANTA) AREA
6.1. Characterization of the investigated area
6.2. Toxicological characterization of the investigated area
7. REFERENCES
As a result of atmospheric deposition, irrigation, fertilization and addition to soil of sewage sludge, increasing amounts of cadmium and lead are entering the food chain mediated by plant uptake. The soil-plant system plays a crucial role in the food chain and it represents the first ring to be monitored and set under control in order to minimize the heavy metals entrance in the food chain.
Since 1976 Nriagu reported that the total annual natural emission for cadmium is about 0.83x106kg/ year and 7.3x106 kg/year for anthropogenic emissions. He also estimated lead natural emissions to be 24.5x106kg/year and the anthropogenic emissions to be about 449x106 kg/year. These data become impressive when compared to the net annual cadmium and lead removal (Smilde, 1989) by agronomic crops on arable land estimated to be about 1.4g/ha for cadmium and about 1.5g/ha for lead. Appreciation of the source, speciation and fate of toxic metals in biological systems becomes fundamental for understanding the short and long term consequences of their presence in the environment as well as for setting of any toxicity thresholds of these metals in biological systems. It is largely known that maximum tolerable levels of metals in animal feed are mainly based on human food residue consideration thus the effects of the metal on the animal welfare are indirectly considered.
For the domesticated ruminants edible plants are virtually all herbage, fodder, grain and pulse crops hence animal diets might show geographical patterns with sometimes large differences in cadmium and lead ingestion levels. Considering this facts we defined the following goal, output and objectives for our work:
The analyses of the crops and topsoil (0-15 cm) from 29 Australian farms and background topsoil revealed that cadmium in cropped soils was 0.11 to 6.37 mg /kg with a mean of 1.33-mg /kg and the background soils had an average concentration of 0.36-mg/ kg. Soils derived from shale had the highest background cadmium levels. As we can see the likelihood of feedlot animals experiencing high heavy metals intake will depend on the feeding system. In a review published in 1992 Kabata-Pendias and Pendias showed that the ranges of the normal and potentially toxic concentrations of cadmium and lead in mature leaf tissue for various plant species are:
Cadmium:
- Normal concentrations 0.05-0.2 mg/kg dry matter;
- Excessive or toxic( for plant) 5-30 mg/kg dry matter
- Tolerable in agricultural crops about 3 mg/kg dry matter
Lead:
- Normal concentration: 5-10 mg/kg dry matter in mature plant leaves
- Toxic( for plants) : 30-300mg/kg dry matter
- Tolerable in agricultural crops: 10mg/kg dry matter
The most valuable animal foods are characterised by a high nutritional value combined with high intake. Voluntary intake shows big differences between materials of similar digestibility. Forage legumes such as lucerne (alfalfa) and red clover show greater intake of materials of similar digestibility. Another important factor influencing ruminants' intake is the grazing behaviour, which can varies with time; a particular plant specie can be selected at a one time of the year and rejected at another, reflecting changes in both animal and plants. The grazing behavior will also affect the pasture dominant plant species over years as well as the total cadmium and lead ingested by animals. Soil ingestion during grazing is another factor contributing to heavy metals intake by ruminants.
Some recent (1998) researches targeting area like China revealed that Pb content was low in maize (35.4 ng Pb/g; grain and flour in combination), wheat flour (28.8 ng Pb/g) and rice flour (22.7 ng Pb/g). In soybean lead levels was 30.8 ng Pb/g dry weight and Cd level was 55.7 ng Cd/g dry weight.
An attempt to assess the published literature since 1972 (UTAB computer database-Nelleseen, 1992) showed that copper, zinc, cadmium, lead and nickel were the most heavily studied metals. The data analysis revealed that a broad spectrum of plants (1400 species) have been studied with 54% of all data on wild plant species. The most frequently studied plant species were Zea mays (corn), Phaseolus vulgaris (bean) and Triticum aestivum (wheat).
The major ways of heavy metals contamination are the fertilisation practice of agricultural soils and the industrial emissions.
Agricultural soils are constantly fertilised and a general overview of heavy metals concentrations in some fertilizers is described in table1 (Alloway, 1995):
During the last thirty years mathematical models were constantly developed for the use of agronomic systems management, playing and important role in crop production and grassland management as well as in grazing systems management or animal husbandry. The mathematical modelling is the main technique used for prediction or as a decision tool for agronomic systems. The computer simulation has become important in biological sciences as mathematical models have the ability to make quantitative prediction about the future behavior of the biological system under study.