Search

The correct detection and quantification of pollutants in water is key to regulating their presence in the environment. Biosensors offer several advantages, such as minimal sample preparation, short measurement times, high specificity and sensibility and low detection limits. The purpose of this review is to explore the different types of optical biosensors, focusing on their biological elements and their principle of operation, as well as recent applications in the detection of pollutants in water. According to our literature review, 33% of the publications used fluorescence-based biosensors, followed by surface plasmon resonance (SPR) with 28%. So far, SPR biosensors have achieved the best results in terms of detection limits. Although less common (22%), interferometers and resonators (4%) are also highly promising due to the low detection limits that can be reached using these techniques. In terms of biological recognition elements, 43% of the published works focused on antibodies due to their high affinity and stability, although they could be replaced with molecularly imprinted polymers. This review offers a unique compilation of the most recent work in the specific area of optical biosensing for water monitoring, focusing on both the biological element and the transducer used, as well as the type of target contaminant. Recent technological advances are discussed.

In many countries, soil contamination and lead exposure is a persistent human and environmental health issue, while in others, it is an emerging concern. Defining the extent of lead contamination and assessing human health risk allow for efficient prevention agendas. The different types of land uses delimit the exposure frequency and hence can influence the evaluation of possible threats. In this study, human health risk assessment is performed under different land use scenarios, after determining the concentration of lead in topsoil of a rehabilitated space. An analytical hybrid method was used to determine the concentrations of the heavy metal. Human health risk indicators, hazard quotient and cancer risk, were subsequently calculated and compared under such scenarios of varying population exposure by land use. Results indicate that an increasing exposure can set health risk indicators above the tolerable levels. Correctly defining the exposure frequency by land use is very important to determine the actual risk levels of a site. Local regulators should take this information into account before designing prevention plans, especially in localities where migration and urbanization are major development factors and since the land use of a public place could change over time and alter the exposure frequency to soil. [ABSTRACT FROM AUTHOR]

A multisyringe flow injection system with spectrophotometric detection is presented as a fast, robust and low-reagent consumption system for the determination of azinphos methyl (AzMe) in water samples. Determination is based on the Griess reaction. The analyte is hydrolyzed and the reaction product reacts with nitrite in acid medium to form the diazonium salt that reacts further with 1-naphtol reagent to produce an azo compound. The azo derivative is spectrophotometrically monitored at 485 nm. The influence of several chemical and flow variables has been investigated. Under the optimum analytical conditions, the linearity of the calibration curve for AzMe ranges from 1 to 32 μg mL−1. The detection limit is 0.17 µg mL−1, and recoveries between 95 to 109% have been obtained. The repeatability (RSD) is 0.8% for a 10 μg mL−1 solution, and the injection throughput is seven samples h−1. The system has been satisfactorily applied to the determination of AzMe in spiked river and dam water samples. The results were in agreement at the 95% confidence level with those obtained by HPLC. [ABSTRACT FROM AUTHOR]