Macronutrients, trace metals and health risk assessment in agricultural soil and edible plants of Mahshahr City, Iran.

In this study, we evaluate the geochemistry of macro- (Fe, P, Ca, S, K, Na, Mg) and micronutrients (Mo, Cu, Pb, Zn, Co, Mn, Cd, Sr, Cr, Hg, Se), along with possible health risks of heavy metals contamination in agricultural soils and vegetables of the Mahshahr industrial port in Iran. Calculation of geochemical coefficients revealed the low pollution load of Mahshahr agricultural soils. Most of the investigated elements exhibited lower concentrations in soil than international standards. Element concentrations in plant samples were far below the permissible values set by environmental agencies. Based on permissible values, there was deficiency of several soil elements, including Cu, in vegetables because they are mostly present in the soil residual phase. An exception was Mn, which is the most mobile element in soil. The transfer factor (TF) of elements showed the following trend: K > Na > P > S > Mo > Hg > Se > Zn > Cd > Cu > Mg > Mn > Ca > Cr > Co ≈ Fe = Pb. There was high transfer of major elements from soil to plants, and lower values for micronutrients and heavy metals. The calculated daily intake (DIM) and health risk index (HRI) for ten plant species for adults were < 1, while the HRI was larger than 1 for Mn via radish consumption. According to geochemical investigations and statistical tests such as principal component analysis, Kruskal-Wallis, and correlation coefficient calculations, plant species play the most important role in elemental uptake by plants.

Simultaneous optimization of parameters influencing organic mulch test using response surface methodology.

Wind erosion could be regarded as one of the most important phenomena especially in arid lands in the globe, which destroys vast areas with its rapid growth. Due to global droughts and climate change, vegetation is weakened and soil particles are more easily exposed to wind erosion. Today, various methods have been developed to control wind erosion. One of the most commonly used methods is the use of mulch. Mulch has several types (physical-chemical). The purpose of this research is to make organic mulch with inexpensive and available compounds to prevent environmental pollution as well as preventing wind erosion. For this purpose, Chaff, Manure, Biosolids and Black Strap mixture were used. The surface response method (RSM) was utilized to perform the relevant tests and create optimal situation. In this study, the central composite design (CCD) in RSM modeling was applied to make the optimal experimental conditions of erosion and penetration resistance. The effect of concentration of Chaff, Manure, Biosolids and Black Strap, was evaluated in erosion and penetration resistance and each variable was coded at five levels. The optimum values for penetration resistance of 1.8 (kg/cm2) for Chaff, Manure, Biosolids, and Black Strap, were 11.32, 15.72, 19.23 and 4.37 g, respectively. Also, the optimum values of mulch combination for wind erosion of 1.8 kg/cm2 for Chaff, Manure, Biosolids, and Black Strap, were 12.49, 19.95, 16.71 and 7.15 g, respectively. By increasing the use of these compounds, adhesion and erosion resistance increased and more consumption of Black Strap had a reverse effect. This was due to the loosing of soil particles and creating exponential mode in graphs. According to the results, no particular distinction was found between predicted data by Design-Expert software and experimental data and simulation results can be expressed reliably.

Optimization of parameters affecting organic mulch test to control erosion.

Wind erosion is considered as one of the most influential factors in the destruction of land in arid and deserted areas. There is a weak ecosystem in arid lands which wind erosion can move soil particles. Mulch is a compound that is used nowadays to control wind erosion. This study aims to create organic mulch in order to prevent wind erosion and environmental pollution. In order to create this type of mulch, different available materials such as blackstrap, manure, biosolids, and straw have been used. Response Surface Methodology (RSM) was applied to create this kind of mulch as well. Also, Central Compound Design (CCD) in RSM modeling was applied to optimize the mulch compound so as to decrease erosion and increase the thickness of crust and its penetration. In addition, each variable was coded and the concentration of straw effect (2-10 g m-2), biosolids (8-24 g m-2), manure (8-24 g m-2) and blackstrap (5-15 g m-2) on wind erosion and penetration were studied. The optimum values of crust thickness (1.5 mm) for straw, manure, blackstrap, and biosolids were 12.48, 19.94, 7.16, and 16.70 g respectively. The optimum values for penetration resistance for straw, manure, blackstrap, and biosolids were 11.31, 15.71, 4.36, 19.24 g as well. As these materials were used more and more in the compound, penetration resistance soared due to adhesion and crust in the compound. However, more use of blackstrap brought about a reverse result. The results indicated that there was not a considerable difference between predicted data and experimental data, and the model was acceptable in simulation.