Plant protein production under the effect of wastewaters and heavy - PowerPoint PPT Presentation

Plant protein production under the effect of wastewaters and heavy metal pollution D. Papaioannou, I. K. Kalavrouziotis, P. H. Koukoulakis, F. Papadopoulos, P. Psoma, A. Mehra Prof. Dr. Ioannis K. Kalavrouziotis Hellenic Open University School of Science and Technology

The application of treated wastewater for irrigation of vegetables has been shown to be a very appropriate recycling option for environmental and economic purposes. The treated wastewater contains plant nutrients and organic matter, but also contains variable levels of heavy metals. The food quality and crop growth are affected by heavy metal accumulation in soils.

The aim … of the present work is to study the effect of wastewater reuse and of heavy metal mixtures added to the soil for its artificial enrichment of soil on the quality and quantity characteristics of Beta vulgaris L. proteins studied in relation to beet yield, edible root dry matter heavy metal content, nitrogen concentration, and crude protein yield.

Experimental Soil The experimental soil was collected from the top layer (0- 30cm depth) from a non cultivated agricultural area. Physicochemical characteristics of the experimental soil. Sand 56 OM % 2.11 Clay % 12 EC mS cm -1 0.21 Silt 32 pH 6.2 Cd Co Cr Ni Pb N-NO 3 P mg kg -1 0.04 0.42 0.03 2.8 0.9 25 6 K Mg Ca Fe Zn Mn Cu mg kg -1 75 260 >2000 20.09 2.3 33.6 88.6 The soil was a light textured sandy loam (SL) It was slightly acid, with low electrical conductivity Medium content in organic matter The heavy metal composition was very low

Preparation … The experiment was consisted of 48 pots. 10 kg of dry experimental soil transferred in each plastic pot (10.5 kg of soil with a moisture content 5%). Twelve treatment ( T 1 , T 2 , … .T 12 ) were composed of a mixture of heavy metals (Zn, Mn, Cd, Cu, Co, Cr, Ni and Pb) and the concentration of each metal being 0, 2, 4, 6, 8, … , 22 mg per kg soil for the 12 treatments, respectively. The 12 treatments were replicated 4 times. The bottom of the pots was closed, so that there was no loss of metals due to leaching. After the preparation of 48 pots was sown with six seeds of the test plant beet ( Beta vulgaris L.) The plants were irrigated with treated municipal wastewater (TMWW).

When the cultivation was completed, after 4 months… Chemical Analyses Soil analysis included: mechanical analysis, organic matter, pH, available soil P, K, and Na, micronutrients Zn, Mn, and Cu and heavy metals Cd, Co, Cr, Ni, and Pb. Plant tissue analysis The micronutrients Zn, Mn, Cu, heavy metals Cd, Co, Cr, Ni, and Pb were measured by ICP Total Nitrogen was determined by the Kjeldahl method. Nitrogen Protein was estimated by multiplying the total Nitrogen by 6.25 TMWW analysis The TMWW was processed and the microelements and heavy metals were determined by ICP

Table . Mean concentration of soil heavy metals determined at the period of the beet harvesting Heavy metals in soil (mg kg -1 ) Treatments Zn Mn Cu Cd Co Cr Ni Pb mean SD mean SD mean SD mean SD mean SD mean SD mean SD mean SD T1 1.28 0.10 32.35 2.50 85.51 5.83 0.09 0.03 0.13 0.00 0.02 0.02 1.65 0.15 1.16 0.3 T2 2.05 0.08 31.78 1.96 92.01 4.29 1.15 0.09 0.19 0.01 0.03 0.02 2.36 0.18 1.67 0.17 T3 2.49 0.28 29.08 2.88 89.03 5.24 2.23 0.15 0.23 0.01 0.02 0.01 2.75 0.18 2.45 0.25 T4 3.01 0.20 30.97 2.77 92.51 7.73 3.23 0.39 0.32 0.03 0.04 0.02 3.53 0.37 3.15 0.08 T5 3.72 0.11 36.57 2.24 90.17 4.67 4.16 0.55 0.46 0.05 0.05 0.03 4.86 0.43 3.94 0.19 T6 4.44 0.40 26.34 3.23 91.68 6.73 5.56 0.64 0.44 0.03 0.04 0.02 5.42 0.56 5.39 0.66 T7 4.83 0.91 28.16 2.36 89.83 7.99 6.18 1.06 0.46 0.06 0.07 0.04 5.86 0.81 5.99 0.72 T8 5.95 0.22 26.88 2.82 101.46 4.48 8.19 0.41 0.52 0.05 0.10 0.01 6.82 0.17 6.88 0.37 T9 6.60 0.50 26.56 2.39 100.34 4.47 9.81 0.39 0.65 0.07 0.09 0.01 8.09 0.49 8.18 0.39 T10 7.88 0.79 25.44 3.25 102.57 7.60 10.76 0.84 0.62 0.10 0.10 0.04 8.62 0.86 8.85 0.93 T11 9.85 0.69 25.38 2.68 103.39 5.54 11.82 0.79 0.73 0.04 0.18 0.05 9.28 0.46 9.97 0.81 T12 10.18 0.88 23.72 3.93 102.25 11.57 14.07 1.97 0.80 0.16 0.22 0.06 11.15 0.46 11.38 1.36 SD = standard deviation

Effect of soil heavy metal levels to plant beet yield The increased levels of applied metals decreased significantly and linearly the dry matter yield of beets, of roots, above ground parts, and whole plant. This negative relation could be explained as result of the toxic effect of the increasing heavy metals concentration in soil, consequence of the applied metal mixtures treatments. Examples of Zn and Cd and beet dry matter yield

Effect of soil heavy metal composition on beets The soil’s heavy metals are transferred from soil to Beta vulgaris L. in variable quantities. The relation of the heavy metal concentration in soil with that in beet tissue was found positive for the metals Zn, Mn, Cd, Co, and Ni where concentrations in the plant increased with the corresponding increasing soil concentrations, reflecting elevated soil pollution and unfavorable effect of the beet quality.

Effect of soil heavy metal composition on beets Relation between soil Zn, Cd, Co and Ni to their concentration in beet dry matter

Effect of metals on beet N concentration and crude protein yield The mean beet dry matter nitrogen concentration was positively affected by metal concentrations in the soil, for example Zn, Cd and Ni, Co.

Effect of metals on beet N concentration and crude protein yield Consequently, the beet percent crude protein also increased with increasing heavy metal concentrations calculated by multiplying total N by the factor 6.25 (AOAC, 1990). Table . Nitrogen contents of the plant beet samples and calculated nitrogen protein expressed as percentages (%) of the dry matter

Effect of extractable soil metals on percent crude protein The effect of DTPA extractable soil Zn, Cd and Ni, Co (mg kg -1 ), on beet percent crude protein under the effect of heavy metal mixture treatments and wastewater reuse.

Conclusions  Τ he applied soil heavy metals treatments under the effect of the wastewater decreased the beet dry matter yield, due to the metal toxic effect.  Α ffected positively and statistically significantly the beet quality parameters, such as the total N concentration, the heavy metal content, and beet crude protein yield.  Τ he increasing heavy metal soil pollution level, increased significantly the total beet N concentration and consequently the percent crude protein concentration of beets.

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