J. C. Joardar

Arsenic mitigation strategy for rice, using water regime management

The response of two varieties of rice plant (BR-28 and BR-29) to arsenic accumulation added from two sources (As III and As V ) under two different water regimes (100 and 75% of field capacity) were examined. Treatments added to soil were 0, 10, 20 and 40 mg As/kg soil. Plant samples were collected after 120 and 140 days from seed sowing, for BR-28 and BR-29 respectively. Delayed seedling emergence; reduced plant growth; yellowing and wilting of leaves; brown necrotic spots on old leaves; and, finally, reduced grain yield of the two varieties, confirmed the symptoms of As toxicity. Arsenic accumulation by plants growing with either As III or As V increased with increasing As treatment, irrespective of water regimes. However, the accumulation was greater in the arsenite-treated soil than that in the arsenate-treated one, indicating the higher phytoavailability of As III . Most of the As taken up by plants was sequestered in the root, followed by straw and grain. In roots of BR-28, the maximum As accumulation from arsenite-treated soil was 17.6 mg/kg dry weight (d.w.) at 100% field capacity (f.c.), whereas at 75% f.c. it was 15.4 mg/kg d.w. and for the roots of BR-29 the values were 31.04 mg/kg d.w and 22.65 mg/kg d.w. at 100 and 75% of f.c. respectively. Arsenic in straw and grain was lower for plants of both varieties at 75% of f.c. However, there have been some varietal differences in the response to As III or As V . The paper discusses the possible management of moisture regimes to reduce the phytoavailability of arsenic, thereby mitigating its toxicity in the rice crop.

Mycorrhizal Colonization Status and Rhizosphere Soil Properties of BCSIR Reserve Forest Rajshahi, Bangladesh

The present investigation has been conducted to assess the AMF (Arbusculr Mycorrhiza Fungi) colonization status along with rhizosphere soil properties of dominant plants and grass species in Rajshahi BCSIR forest of Bangladesh. Roots of six dominant plants (Psidium guajava, Swietenia mahagoni, Artocarpus heterophyllus, Manihot esculenta, Acalypha indica, Fragaria ananassa) and two grass species (Digitaria sanguinalis, Cynodon dactylon) were collected and rhizosphere soil samples were collected from rhizosphere zone. Mycorrhizal colonization percentages and edaphic factors (Soil pH, EC, N, P, Moisture and Soil Temperature) were documented. Highest colonization was obtained in Manihot esculenta (85±5%) followed by Swietenia mahagoni (78±10.36%) and lowest was observed in Acalypha indica (2±1.9%). Mycorrhizal structure as arbuscles, vesicles were present in Psidium guajava, Swietenia mahagoni, Manihot esculenta among the studied species. Research findings indicate that plants species of Rajshahi BCSIR forest is mycorrhizal but not well established as well as mycorrhizal infection is irregularly correlated with edaphic factors.

Potassium, Calcium and Sodium Distribution in Different Part of Common Vegetable Plants Grown under Field Condition

A field experiment was conducted to investigate the distribution of Potassium, Sodium, Calcium in different parts of commonly used vegetables. Complete Randomize Design (CRD) was followed for the experiment. Seeds of nine vegetable plants were collected and cultivated. After 45 days, vegetables were harvested and nutrient concentration in different parts of nine vegetables (leaf, petiole and stem) was measured. The distribution order of potassium, sodium, calcium concentration among leaves, petioles and stems was found as petiole>stem>leaf, petiole>leaf>stem, petiole>leaf>stem, respectively. But individually, high concentration of K, Ca, Na was found in Corchorus capsularis, Amaranthus lividus (Green) and Spinacia oleracia, respectively and low concentration was found in Lagenaria siceraria for all nutrients. The K, Ca, Na concentration among the plants and within different parts of the each vegetable was significant (p<0.05). The present research work revealed that Corchorus capsularis, Amaranthus lividus (Green), Spinacia oleracia was highly nutritious for measured nutrients but Lagenaria siceraria contained low concentration of all measured nutrient. But for all the vegetables, petioles are highly nutritious compared to other parts of vegetables.

Heavy Metal Concentration in Some Common Spices Available at Local Market as well as Branded Spicy in Chittagong Metropolitan City, Bangladesh

A study has been conducted to evaluate some heavy metals concentration of spicy from local market of Chittagong metropolitan city, Bangladesh. Total 30 spicy samples of red chili or chili red, coriander, turmeric were collected from five different spots (Khatungonj, Chakbazar, Muradpur, Baluchora, Amanbazar) under Chittagong metropolitan city and metals as Zn, Cu, Cr, Mn, Fe concentration were measured. Metal concentration in red chili, coriander, turmeric were found as increasing order as Cu Khatungonj >Muradpur >Baluchora >Amanbazar, Khatungonj >Chakbazar >Amanbazar >Muradpur >Baluchora, Khatungonj >Chakbazar >Baluchora >Amanbazar >Muradpur, Khatungonj >Chakbazar >Muradpur >Amanbazar >Baluchora, Khatungonj >Chakbazar > Baluchora >Amanbazar >Muradpur respectively. So, spicy of Khatungonj was the highly contaminated with metal followed by chakbazar spicy and least metal concentrated spicy was in Amanbazar at Chittagong city. According to WHO (World Health Organization), Cr and Fe concentrations exceeded the permissible limit of heavy metals in spicy but other metal concentrations was within tolerable limit. The current research’s findings will convey a strong message for the government body, policy maker to establish rules and regulation in order to protect food chain contamination, environment pollution and will be helpful for public awareness. An immediate attention from the concerned authorities is required in order to protect food chain contamination and environment pollution.

Effect of Arsenic Concentration in Irrigation Water and Soil on the Arsenic Content of Vegetables in Bangladesh

Two pot experiments were conducted to examine the effect of arsenic (As) concentration both in irrigation water and in soil on the As content in vegetables grown in a glass greenhouse. In the first experiment, spinach (Spinacia oleracea), green amaranth (Amaranthus viridis) and gima kalmi (Ipomoea aquatica) were grown in soil containing 10 mgAskg, where the irrigation water contained two As levels (0.1 and 0.5 mg L). In the second experiment, gima kalmi (Ipomoea aquatica) was grown in As spiked soil at different levels [10 (control), 15, 20, 30, and 50 mgAskg soil] and with irrigation water without As contamination. The As concentration (mg kg DW) and As accumulation (μg plant) in the edible part of the plants increased significantly with increasing As concentrations in irrigation water and/or soil. When plants were irrigated with As contaminated water, the As concentration of the edible part exceeded its maximum limit Original Research Article Joardar et al.; IJPSS, Article no. IJPSS.2014.007 86 (0.5 mg kg) in spinach and green amaranth at 0.5 mg L of As, but gima kalmi had a smaller amount than the other vegetables. Gima kalmi had the characteristics of a lower As accumulation. Therefore, the risk level of As in irrigation water was suggested to be 0.1 mg L for vegetables. When gima kalmi was grown in elevated levels of As contaminated soil, the As concentration of gima kalmi, even being a low As accumulator, exceeded the maximum limit at the level above 20 mgAskg soil. The risk level of As in soil, therefore, was suggested to be 20 mg kg. The risk value of As concentration in irrigation water and/or in soil needs to be investigated in detail by using many vegetables and/or soils.

Using Asclite to Reduce Arsenic Concentration in Vegetables Grown on Arsenic Contaminated Soil

Three pot experiments were conducted to assess the capacity of asclite in reducing arsenic (As) contents in vegetable plants from arsenic contaminated soil. Asclite is an artificially made granular amorphous iron (Fe)-hydroxide material having high ability in adsorbing As(III) as well as As(V). In the first experiment, Japanese mustard spinach (JMS) (Brassica rapa var. perviridis) was grown in a 242 mg As kg soil with 10 and 20% of asclite application. The second and third experiments were conducted in Japan and Bangladesh, respectively, with JMS and Bangladesh spinach (BS) (Spinacia oleracea) grown in a 50 mg As kg soil where 1 and 2% asclite were applied. Application of asclite to arsenic contaminated soil significantly reduced the arsenic concentration in the edible part of the plants as compared to the control plants. The arsenic concentration in JMS reduced by 43 and 60% at 10 and 20% asclite application when grown in a 242 mg As kg 1 soil. The arsenic concentration was reduced by 29 and 37% in JMS, whereas it was 52 and 74% in BS, at 1 and 2% asclite application, respectively, when grown in a 50 mg As kg soil. There was no significant change in the growth and the nutrient elements concentration in Original Research Article IJPSS, Article no. IJPSS.2014.008 206 the plants. Our findings suggested that asclite could be used to reduce arsenic concentration in vegetables grown on arsenic contaminated soil. Considering the soil type, soil pH, soil arsenic concentration and plant species, further study is required to examine the desirable conditions for reducing the arsenic concentration in vegetable plants with asclite application.