Public perception and health implication of loom-dye effluent irrigation on growth of rice (Oryza sativa L.) and red amaranth (Amaranthus tricolor L.) seedlings.

Loom-dye effluent discharge has constituted a major environmental threat to the people of Belkuchi Upazila of Sirajganj District. The present study was conducted to characterize loom-dye effluents and investigate their health implications by the growth analysis of rice and red amaranth seedlings along with a survey study among the individuals associated with loom-dyeing, weaving, and crop farming activities. A total of twenty-eight loom-dye effluent samples were collected for physicochemical characterization; among them, only three loom-dye effluents, i.e. pink, violet, and black dyes, at concentrations of 0, 10, 25, 50, 75, and 100% were applied as irrigation water to rice and red amaranth. The plant growth experiment was laid out following a completely randomized design with three replicas. Chemical analyses of loom-dye effluents showed the presence of a significant amount of plant nutrients and heavy metals. The mean concentrations of Pb, Cd, Cr, Fe, Mn, Zn, and Cu were 0.938, 0.046, 0.212, 7.109, 0.609, 0.351, and 0.191 mg L-1, respectively. Among the metals, the concentrations of Pb, Cr, Fe, and Mn were above the recommended limit proposed by the irrigation water guideline value. Application of ≤ 25% pink and violet dye effluent and ≤ 10% black dye effluent had significant (p < 0.05) and positive impacts on growth and yield parameters. Heavy metal content in seedlings increased with increasing effluent application rate and crossed the utmost permissible limit at higher concentration. Survey data discovered a moderate knowledge level among the respondents, which might account for the indiscriminate discharge of loom-dye effluent into the surrounding environment. Attitudes, practices, and protective behaviours of the respondents also reflect the caused for long-term pollution through loom-dye effluents. To reduce its negative effects on the health and crop environment, the loom-dye effluents should not be discharged indiscriminately and used for crop irrigation without proper treatment. Furthermore, training programs ought to be introduced to educate the individuals involved in the discharge and subsequent use of loom-dye effluents.

Heavy metals in handloom-dyeing effluents and their biosorption by agricultural byproducts.

The Madhabdi municipality in the Narsingdi district of Bangladesh is a well-known area for textile, handloom weaving, and dyeing industries. These textile industries produce a considerable amount of effluents, sewage sludge, and solid waste materials every day that they directly discharge into surrounding water bodies and agricultural fields. This disposal poses a serious threat to the overall epidemic and socio-economic pattern of the locality. This research entailed the collection of 34 handloom-dyeing effluent samples from different handloom-dyeing industries of Madhabdi, which were then analyzed to determine the contents of the heavy metals iron (Fe), zinc (Zn), copper (Cu), chromium (Cr), manganese (Mn), lead (Pb), and cadmium (Cd). Average concentrations of Fe, Cr, Cu, Pb, Mn, and Zn were 3.81, 1.35, 1.70, 0.17, 0.75, and 0.73 mg L-1, respectively, whereas Cd content was below the detectable limit of the atomic adsorption spectrophotometer. The concentrations of Fe, Cr, Cu, Pb, and Mn exceed the industrial effluent discharge standards (IEDS) for inland surface water and irrigation water guideline values. A biosorption experiment of the heavy metals (Fe, Cr, Cu, Mn, and Zn) was conducted without controlling for any experimental parameters (e.g., pH, temperature, or other compounds present in the effluent samples) by using four agricultural wastes or byproducts, namely rice husk, sawdust, lemon peel, and eggshell. Twenty grams of each biosorbent was added to 1 L of effluent samples and stored for 7 days. The biosorption capacity of each biosorbent is ranked as follows: eggshell, sawdust, rice husk, and lemon peel. Furthermore, the biosorption affinity of each metal ion was found in the following order: Cu and Cr (both had similar biosorption affinity), Zn, Fe, Mn. The effluents should not be discharged before treatment, and efficient treatment of effluents is possible with eggshell powder or sawdust at a rate of 20 g of biosorbent per liter of effluents.