نشریه محیط زیست طبیعی
سال هفتاد و یکم شماره 1 (بهار 1397)

Biochar is a coal produced from plants biomass and agricultural waste in limited Oxygen condition. In the process of producing Biochar no Carbon Dioxide is released into atmosphere, so Biochar is fully carbonated. Many studies have been conducted on the ability of Biochar in improving soil condition and maintaining soil nutrients; however limited studies have been conducted on effect of Biochar on nitrate removal from drainage waters. In this paper, it has been assumed that because of high amount of Carbon in Biochar, using Biochar instead of raw Carbon materials in nitrate removal bioreactors can effectively eliminate the nitrate from subsoil drainage. In order to evaluate the effect of different mixtures of Biochar (0, 10, 15, 20and 30 percent) and effect of different inlet nitrate concentration (40, 160 mg/liter) on bioreactor performance regarding nitrate removal, bioreactors with 125cm poly-ethylene pipes were stimulated. The experiment was performed in factorial method in a random scheme with three repetitions. Results showed that nitrate removal is strongly affected by Biochar percentage used in them. The maximum nitrate removal was reported in pipes with 30% Biochar (96.4%) and the minimum was reported in replication pipes with no Biochar (80.7%). Also, nitrate removal is also affected by concentration of inlet nitrate solution. Nitrate removal percentage in C2 treatment (160 gr/liter) was lower than C1 treatment (40 mg/liter), the results were 89.9% and 91.4% respectively.

Falling dust is containing particles with smaller than 100 microns in size, which is deposited on the surface. Dust has an important role in transforming environmental pollutants. Strontium is one of these pollutants that are released into the atmosphere from natural and human sources and is falling to the ground by dust. Due to strontium has joint transportation routes with calcium can lead to hazards to human health. There are also radioactive isotopes of strontium; including strontium 90 is very harmful due to impaired blood flow. In this study the distribution and abundance of strontium, strontium isotopes found in the mist was falling. After selecting of the sampling stations with appropriate distribution in the city of Yazd is used sediment traps of marbles and dust samples were taken monthly for a year. In order to investigate the changes in the concentration of strontium in samples of dust from the X-ray fluorescence system and for the determination of strontium radioisotopes Geiger Muller instrument was used. Zoning map and local distribution of strontium in the city was prepared in Arc GIS software. The study results showed that the highest concentration of strontium is from the East to the city center and the lowest amount is related to the North West. Zoning results showed that the highest quantity of the strontium in the city center is from Kashani Street to the field Mahdieh. Radioactive isotopes of strontium showed that the samples are lacked radioactive isotopes. So there isn’t any environmental risk from radio isotopes of strontium in falling dust.

A study conducted to determine feeding carrying capacity of Chinkara (Gazella bennettii shikarii Groves, 1993) habitat in one of the driest areas of its distribution range in central Iran. First, we determined the term of critical season in Drarreh-Anjir Wildlife Refuge. Then, considering to species food preferences in critical season, the amount of production was estimated in suitable habitat using double sampling method. Next, we used allowable measure of exploitation or preference values of every species to estimate the amount of accessible forage in the area. Finally, the feeding carrying capacity of chinkara habitat was estimated by subtracting of competitors proportion and determining of daily requirement of chinkara in the area.
The results showed the capacity of the Darreh-Anjir Wildlife Refuge is 626 chinkaras in the study year. In fact, the overall density of chinkara in the study area can be 2.34 heads in a hundred ha. However, the accessible foods in critical season did not limit the species population growth now, because irregular poaching reduced the numbers of chinkara in the study seriously. Considering to the point estimation of chinkara density, Darreh-Anjir area is one of the driest habitats of the species in the world. Based on the results, the Hammada salicornica is the maximum available species in chinkara menu in the study area. So, prevention of Camel grazing for keeping the potential of this species production was suggested in the refuge in all season.

Today, due to drought and shortage of water, using of unconventional water in agriculture, particularly effluent from municipal wastewater treatment has particular significance. The limiting factors using of wastewaters is heavy metals. The aim of this study was to compare the concentrations of heavy metals Cr, Cu and Ni in the organs of alfalfa under two models of irrigation. Examples of roots, stems and leaves of alfalfa was collected from two regions: 1- irrigated with treated wastewater, and 2- irrigated with well water, to the heavy metal concentrations measured.Dry and ashed samples of alfalfa were digested using concentratednitric acid. Heavy metals (Cr, Cu and Ni) concentration measured using an ICP-OES instrument(PerkinElmer, USA). The highest concentration of heavy metals, were found in roots of alfalfa. Compare this concentrations with critical concentration show that the metals concentration range is not critical, with that exception of the roots of alfalfa irrigated with water that of metal Cr, potential exposure limits have been critical. The t-test results, only for the metal Cr, showed a statistically significant difference between the two types of irrigation. The one-way ANOVA and Tukeys comparison results also indicates that there was a significant difference between the root, stem and leaf of alfalfa in terms of Cr and Ni concentrations, but in terms of the Cu is not the case. Based on these results, irrigation with treated wastewater Birjand in terms of the accumulation of the heavy metal Cr, Cu and Ni, has no adverseeffects on alfalfa.

Increasing agricultural waste especially pesticides in runoff, water surface and subsurface as well as environmental risks posed by these contaminants has led to its removal from industrial effluents, urban and rural waste water are particular importance. Occurrence of pesticides in wastewater and environmental hazards resulting from its, has created deep concerns about the public health. Paraquat is the most widely used herbicides in Iran and the world. Due to human activities, constant amount of this herbicide is being increasing in the water. Parkinson's disease is the major effect of this pollutant. In recent years, the use of advanced oxidation processes on the basis of strong oxidizing species has received much attention In order to completely remove the dangerous and complex compounds. Among the advanced oxidation methods, Photocatalytic processes have high efficiency in the degradation of various organic materials to biodegradable matter, carbon dioxide and water. In this study, first, the process of photocatalytic has been reviewed. Then, the degradation of paraquat under the visible light in the presence of La,S-TiO2 synthesized Nanophotocatalyst were done. Moreover, for the first time, the effect of operating parameters, including the catalyst dose, H2O2 amount and volume of contamination on the photocatalytic removal efficiency were investigated and evaluated. The results show that the use of H2O2 of 2mL, catalytic dose of 100 mg and volume of contamination of 50 mL, 71.8 % of the Paraquat “Gramoxone” was removed over four hours under visible light irradiation. Furthermore, the results show that the modified synthesized photocatalysis (La,S-TiO2) has much higher photocatalytic activity than undoped TiO2 for the degradation of paraquat at the optimum point.

Understanding where threatened species prefer to live and distinguishing their basic habitat requirements are the first priority for any decision making and action plans. Habitat suitability models is one of the available tools for improving this knowledge. Wild goat (Capra aegagrus) is a vulnerable species which is widely distributed in Iran, but the ecology of this species is not sufficiently studied. The purpose of this study was modelling seasonal habitat suitability and habitat associations of wild goat in Kolah-Qazi National Park, one of its typic habitats in cental Asia .Logistic Regression approach was used to model wild goat habitat suitability using both the presence and absence points. Elevation, distance to water trough, distance to settlement, distance to public road, and distance to guard patrol road were recognised as the most important variables determining habitat suitability of wild goat. According to the produced habitat suitability maps, in winter wild goat herds aggregated in mountain borders but in autumn their distribution is more evenness and the extent of suitable habitats in winter was more than the summer. The accuracy of both winter and revealed good efficiency The obtained results have implications for conservation of wild goat across its distribution range.

Understanding phylogeography and genetic variation is a crucial to enhance conservation planning of species. Due to high level of fragmentation affecting many endangered species, unveiling their genetic status is prioritized to promote long-term persistence. Accordingly, the current investigation was carried out on a wide-ranging predator, the Persian leopard. We examined sequence variation in the mitochondrial NADH-5 gene with 550 base pairs for 38 leopards from different parts of Iran. Three closely related haplotypes were identified for the entire country. Apart from one commonly found haplotype throughout Iran, south Caucasus and Turkmenistan, two localized haplotypes were sequenced from southern Zagros and eastern Alborz. Our data supported that leopards do now show spatially differentiated genetic variation based on investigated gene in Iran as well as neighboring countries and possess lower genetic diversity comparing to other leopard subspecies or larger carnivores. It is essential to enhance conservation of the Persian leopard within southern Zagros where a specific haplotype occurs.

The use of wheeled skidders is well accepted practice for the extraction of timber from the forest, but this has tended to cause the greatest environmental problems. The aim of this study was survey wood extraction effects on tree regeneration and herbaceous cover biodiversity. The research location was Gardeshy district of Wood and Paper Co. in Mazandaran Province. Two plots with 400 m2 area considered at regular intervals on each side of the skid trail from skid trail. In this plots nine 2*2 meter microplot were used for counting of tree regeneration and percentage of herbaceous cover. Biodiversity indices (Shanon, Simpson), richness indices (Menhinick, Margalef) and uniformity indices (Equitability or Evenness) were estimated with PAST software, then analyzed data with SPSS software. The results of this study showed that the pH, electrical conductivity, nitrogen, potassium, calcium and carbon of soil were not statistically different at different distances from the skid trail and also biodiversity, richness and uniformity indices for herbaceous species and woody species regeneration don’t have significantly difference in different distance from skid trail.

This research was done to compare Pb accumulation in Myrtus communis and Pinus brutia in different concentration (0, 200, 500 and 1000). Results showed Pb accumulation in root and leave of Olea europaea increased with increasing Pb concentration. The highest Pb accumulation in root of Olea europaea in concentration of 1000 was equal to 101 mg/kg, that of this only 38 mg/kg (37.6 percent) transferd to leaves. The highest Pb accumulation in root of Thuja orientalis in concentration of 500 mg/kg was equal to 235 mg/kg, that of this only 30 mg/kg (12.5 percent) transferd to leaves.. proline significantly increased in Thuja orientalis in Pb concentration of 500 and 1000 mg/kg. Proline and soluble sugar increased in Olea europaea only in Pb concentration of 200 mg/kg. Sugar soluble increased in Thuja orientalis only in Pb concentration of 500 mg/kg. The solouble sugar increased with increasing Pb concentration in Thuja orientalis and the highest sugar was measured in 500 mg/l. For determining the maximum Pb adsorbed with soil, Langmuier isothermal adsorption equation constants were calculated. The result detects, Maximum Pb adsorbed by soil is at about 1000 mg/kg. It is concluded that under condition of this experiment both plants are able to grow in Pb-contaminated soil and Thuja orientalis did better work.

This study was conducted to measure the concentration of five heavy metals, including lead, cadmium, mercury, arsenic, and chrome in muscle liver, and gill of the gray mullet, Liza aurata in southern part of the Caspian Sea. The samples were collected from 100 adult gray mullet in 10 stations during the sexual maturity (in the fall) and sexual rest (in the spring). The muscle, liver, and gill tissues of each fish were separated in order to measure the concentration of the heavy metals. The acid digestion method was used to extract the metals from the tissues. The concentration was determined using a graphite furnace atomic absorption spectrometer. The mean concentration of lead, cadmium, mercury, arsenic, and chrome in the muscle tissue respectively was 1.40, 0.43, 0.16, 0.07 and 0.54 µg/g during the sexual maturity and 1.90, 0.93, 0.24, 0.12 and 0.61 µg/g during the sexual rest. Generally, the uptake of heavy metals during the sexual rest (Pb>Cd>Cr>Hg>As) was higher than that during the sexual maturity (Pb>Cr>Cd>Hg>As). The concentration of the metals in the three tissues was as follows: liver > gill > muscle. The difference between tissues in terms of the concentration of the metals was significant. The comparison of the data obtained for the muscle tissue with the standards of the World Health Organization and Australian National Health and Medical Research Council showed that the concentration of all the five heavy metals (Pb, Cr, Cd, Hg, As) was higher than the global standard level, and thus, the consumption of this fish can harm people.