Search

An anthracene carboxyimide derivative was synthesized as a colorimetric and fluorogenic sensor to determine NO2- with a rapid response (

A paper-based device (PBD) for the detection of chlorpyrifos pesticide at field application was fabricated based on the principles of enzyme inhibition and image processing. Rhizopus niveus lipase, p-nitrophenol palmitate and Whatman No.1 paper were used as an enzyme, substrate and support matrix, respectively. The performance of functionalized PBD was tested for lateral flow assay reaction in pure water (negative control), artificial pesticide water (positive control) and selected fruits and vegetables wash water (test). The digital image of the PBD after the test was captured using an android smartphone and analyzed in MATLAB software. Different colour space models such as, grey, RGB, HSV and YCbCr were studied and the Cb coordinate was chosen for its higher linearity (R2 = 0.988) with pesticide concentration. Experimental variations such as paper length, relative concentration ratio of the substrate and enzyme were investigated to minimize the product cost and analysis time. The developed PBD showed a significant response over wide range of sample solution's pH and operational temperature. Further, a long-term storage stability was measured for developed PBD. The LOD and LOQ were found to be 0.065 mgL−1 and 0.198 mgL−1. The results obtained from newly developed image processing method showed 92.8% accuracy with microtiter plate assay. Higher MRL was determined in the wash water of cauliflower, grapes, coriander leaves, brinjal and bitter guard. Overall, the developed paper biosensor was precise, cost effective and most suitable for field applications.

The potential impact on a variety of bioassay organisms when pulp-mill biosolids from a thermomechanical pulp mill (western Canada) were applied to a reference soil has been investigated in a laboratory setup. The current research assessed acute, chronic, and reproductive impacts using a battery of terrestrial and aquatic organisms. Terrestrial organisms were exposed to soil amended with different concentrations of biosolids, while aquatic organisms were used to assess the impact of biosolids’ runoff into receiving waters. The former bioassays showed that an application rate of 20 tonnes hectare −1 (t ha −1 ) “bone-dry” biosolids applied to reference soil produced no observable adverse impact on the terrestrial organisms. In the latter assays, undiluted (100%) and 50% diluted biosolids’ runoff into receiving water had a detrimental impact on the aquatic organisms. However, concentrations not exceeding 25% (environmentally relevant concentrations) had neither an acute nor chronic impact compared to reference populations. The organisms’ abilities to reproduce were also unaltered. While this study only examined the biosolids from one mill, there is the potential that land-application of characteristically well-defined pulp mill biosolids may constitute an acceptable way of disposing of pulp and paper mill biosolid residues. However, the biosolids coming from different mills, with differing processes, must be dealt with on a case-by-case situation. Each series of biosolids must be rigorously tested for toxicological impact in the laboratory under tightly controlled conditions. Subsequently, field experimentation must be conducted before definitive conclusions can be made.