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Salinity intrusion is a global concern in relation to sustainable agricultural practices. About three-fourths of the coastal area in Bangladesh is affected by different levels of salinity. This study was conducted to observe the effects of NaCl-salinity on tomato (Lycopersicon esculentum Mill.) plants in a pot experiment. Morphological properties and yield of five varieties of Bangladesh Agricultural Research Institute tomato (BARI-T 1, BARI-T 2, BARI-T 3, BARI-T 4, and BARI-T 5) plants were exposed to NaCl-salinity (2, 4, 6 and 8 dS/m) through irrigation. Morphological properties such as number of leaves, leaf length, leaf width, number of days of flowering, number of flowers and number of branches were observed. Results showed that morphological properties of all studied tomato plants were affected by increasing NaCl-salinity, except number of days of flowering, and yield was reduced compared to the control group (tap water; 0.043 dS/m). The post-harvest pot soil was also affected by NaCl-salinity irrigation. This study can be useful in selecting salt-tolerant varieties in saline-affected areas.

Solid waste production is rapidly increasing in Bangladesh and landfill leachate is the consequence of the decomposition of this waste. These leachates contain heavy metals and significant amount of dissolved organic matter (DOM). DOM is known to have considerable role in heavy metals speciation. Hence, it is important to characterize DOM/leachate and evaluate toxic metals binding affinity of DOM. The objectives of this study were to characterize the DOM in landfill leachate through physico-chemical and optical analyses and to investigate the toxic metals (Ni2+, Pb2+ and Hg2+) binding affinity of three different ages (fresh sample L-1, young sample L-2 and mature sample L-3) DOM samples. Results suggested that leachate is a potential pollutant which contained very high organic pollutant load. Conditional stability constant (LogK) and percentages of fluorophores that correspond to metal binding (%f) values indicated that young DOM sample (L-2) had the highest binding affinity to all the three metals ions. In general, DOM samples showed the following order affinity to the metal ions; Ni2+ binding affinity: L-2 > L-3 > L-1, Pb2+ binding affinity: L-2 > L-3 > L-1 and Hg2+ binding affinity: L-2 > L-1 > L-3.

A total of 21 water samples were collected from surface water (ponds and river) and groundwater samples from shallow tube well (STW) and deep tube well (DTW) from Gopalganj Sadar Upazila to evaluate the salinity hazard and suitability for irrigation purposes. Both surface and groundwater of the study area maintained the trend of Cl− > SO4 2− > PO4 3−. The cation trend in both surface and groundwater of the study area was Na+ > K+ > Ca2+ > Mg2+ > Fe. Correlation matrices and principal component analysis (PCA) confirmed the stress of salinity from elevated electrical conductivity and total dissolved solids (TDS) with Na+, K+, Cl− and total hardness (TH) in relation to Ca2+, Mg2+, PO4 3− and SO4 2−. Salinity hazard classification and Wilcox diagram for irrigation water classification demonstrate that shallow tube wells containing low alkali and low sodium hazard are an excellent source of irrigation waters and fall under good to fair class of water (55 % samples). Higher TH, sodium adsorption ratio (SAR), soluble sodium percentage (SSP) and other important analysis indicated that most of the surface water and DTW were not suitable for irrigation. Therefore, the best irrigation water quality was from STW. Nevertheless, to sustainably and efficiently utilize the existing water resources, cyclic conjunctive uses of river water, STW and DTW as well as excavation of pond to store rainwater were suggested.

Comparative study was conducted to correlate arsenic (As), iron (Fe), copper (Cu), manganese (Mn), calcium (Ca2+), magnesium (Mg2+), potassium (K+), nitrate (NO3 −), phosphate (PO4 3−), and ammonia (NH3) by determining their concentration at different depths of the tube-wells in the selected study area at Singair, Manikganj Bangladesh. Total 99 tube-well water samples were collected from the study area. In most of the sampling points, the present concentrations of As were less than the previous concentrations. The correlation between As and Fe was positively significant. It can be suggested possible adsorption/co-precipitation of As with Fe in shallow aquifer. However, the relationship between As and Mn was not significantly observed. On the other hand, relationship between Cu and As showed a positive significant correlation. The correlation between As and PO4 3− was also significant, although the correlation between As and NO3 − was not significant. PO4 3− may come from phosphate fertilizers application and can be a contributor of As in the shallow aquifer. The PCA biplot also indicated the significant relationship between As, Cu, Fe and PO4 3−. Excessive withdrawal of tube-well water along with aquifer dynamics and ionic interference might be responsible for the mobilization of As in the study area.

Background: Cow milk is considered as one of the responsible food sources contaminated with heavy metals. The objectives of the study were to assess the content of selected metals in cow milk and its associated human health risks in the food chain of Bangladesh. A total of 90 cow milk samples of Branded, Dairy and Domestically produced milk were collected randomly from different sources of Savar Upazila in Dhaka area. Cadmium (Cd), chromium (Cr), lead (Pb), manganese (Mn), copper (Cu) and iron (Fe) contents in collected milk samples were determined using Flame Atomic Absorption Spectrometry (FAAS). To ensure quality control, one of the best quality control parameters i.e. recovery test; from eight various sample digestion methods were used. The Hazard Quotient (HQ) and Carcinogenic Risk (CR) values were also calculated. Results: From the results, it was found that, the orders of heavy metal content in brand, dairy and domestic cow milk were Cr > Fe > Cu>Mn > Cd > Pb, Cr > Fe > Mn > Cu > Cd > Pb and Fe > Cr > Mn > Cu > Cd > Pb, respectively. Among the six metals, only Cr showed to exceed the highest Estimated Daily Intake (EDI) rate (for brand cow milk: 0.413 mg/day, dairy farm cow milk: 0.243 mg/day, domestic cow milk: 0. 352 mg/day),and the comparison percentages of calculated values per permeable values were as follows; 206.5 % for brand cow milk,121.5 % for dairy farm cow milk and 176.0 % for domestic cow milk. Hazard Quotients (HQ) values and Carcinogenic Risk (CR) values were found within the acceptable level. Conclusion: Although, the metal content in sampled cow milks were within the safe limit, the potential human health risks cannot be neglected for the regular/long time consumption of heavy metal contained cow milk.