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This work presents a new optical microfluidic paper biosensor for the detection of organophosphate pesticides and carbamate pesticides. The assay strip is composed of a paper support (1×17.6 mm) onto which acetylcholine esterase (AChE) and acetylcholine chloride (AChCl) are deposited, in such a way that there is a small hole between them that ensures that they only come into contact in the reaction zone when they are carried by a solution of the sample by lateral flow to the reaction zone containing bromocresol purple (BCP) as the pH indicator, immobilized by sol-gel. The sensor operates at room temperature and the rate of the inhibited reaction serves as an analytical signal, which is measured using a camera by quantifying the appropriate colour coordinate. Calibration curves were obtained for chlorpyrifos and carbaryl, with a useful concentration range from 0.24 to 20 µg•L -1 for carbaryl and from 2.00 to 45 µg•L -1 for chlorpyrifos. The detection limits were 0.24 and 2.00 µg•L -1 , respectively, and with reproducibility around 4.2-5.5%. The method was applied to the determination of pesticides in different water samples, with no sample preparation.

α-cellulose isolated from African star apple seed shell (ASASS) was used as the raw material for the production of food-grade carboxymethyl cellulose (CMC). Preparation of CMC from ASASS cellulose was carried out by an etherification process, using sodium hydroxide and monochloroacetic acid (MCA) at various temperature. The cellulose and CMC were characterized by FTIR, XRD and SEM techniques. Degree of substitution (DS) was determined using potentiometric titration. Solubility increased with DS of CMC increased together with varied conditions but decreased at a certain level. The optimum results of varied conditions were 0.8015 DS for 30% NaOH concentrations; 0.6259 DS for 50℃ temperature and 0.9254 DS for the amount of MCA. The FTIR spectra revealed the functional group modification of native cellulose to CMC, with absorptions at-1-1 1409.49 cm and 1640.05 cm indicating ether and carboxyl functional group respectively. The results of XRD analysis showed that crystallinity of isolated cellulose decreased in the CMC and SEM showed the elongated long fibres in cellulose while the fibrils in CMC are short and rough. The obtained product is well suited for pharmaceutical and food additives.

The concentration and spatial distribution of the gamma ray emitting 238 U, 232 Th, 40 K and 137 Cs radionuclides in dumpsite soils in Agbara were analyzed with the aim of evaluating the radiation hazards and excessive lifetime cancer risk using well calibrated HPGe c-ray spectrometry technique. The ranges of activity concentrations of 238 U, 232 Th, 40 K and 137 Cs are 11.5 ± 1.0 M 166 ± 40 Bq kg À1 , 15.6 ± 1.8 M 31.4 ± 2.3 Bq kg À1 , 20.4 ± 1.3 M 366 ± 30 Bq kg À1 and 0.52 ± 0.1 M 8.44 ± 0.2 Bq kg À1 respectively. Radiological parameters such as absorbed dose rate, radium equivalent, annual effective dose equivalent, internal and external hazard indices, gamma level index, activity utilization index, annual genetic significant dose equivalent, exposure rate and excessive lifetime cancer risk were calculated to know the complete radiological hazardous nature of the dumpsite soils to the inhabitants of the sites. The calculated radiological parameters were higher than the world average value in two of the sampling points. The ratio of the detected radioisotopes was calculated for spatial distribution of natural radionuclides in the study area. RESRAD computer code was applied to calculate the total effective dose equivalent (TEDE). The code was also used to calculate the probability of excess lifetime cancer incurred by dwellers/inhabitants of the dumpsites, the level of which was determined to be 0.5 Â 10 À4 and 2.5 Â 10 À5 for Idowale and Ibijola dumpsite soils over a period of 30 years respectively. Therefore, the radiological risks to the general populations from waste enhanced naturally occurring radioactive materials (WENORM) from the Idowale dumpsite top soils are considered to be significant.