The main objective of this work was to develop and validate an analytical method using solid-liquid extraction and liquid chromatography coupled with mass spectrometry in tandem (LC-MS/MS) for the simultaneous determination of the herbicide 2-(2,4-dichlorophenoxy)acetic acid (2,4-D) and the insecticide fipronil and its degradation products, fipronil sulfone and fipronil sulfide in different types of soil from Brazil (Oxisol and Entisol). Solid-liquid extraction was performed in two cycles using 20 mL of dichloromethane per cycle and sonication. The extraction efficiency of 2,4-D was more influenced by soil composition than the other compounds. The limits of quantification of the method were between 0.015 and 0.75 mg kg-1 and recovery values from 61 to 118%, with a maximum relative standard deviation (RSD) value of 4%. The method was further applied to over 500 real soil and sediment samples. 2,4-D and fipronil concentrations varied from 0.03 to 1145 µg kg-1 and 1.1 to 282 µg kg-1, respectively.

Sugarcane is considered one of the greatest alternatives for the biofuels sector due to the high potential in the production of ethanol and its respective by-products. Processes of converting degraded pastures into sugarcane crops have been increasingly common in Brazil, as well as the use of pesticides to control plant diseases and pests in several crops. The objective of this work was to evaluate the occurrence of 2,4-D, ametryn, tebuthiuron, fipronil and its degradation products (fipronil sulfide and fipronil sulfone) in clay and sandy soils when applied to pasture and sugarcane management. Solid-liquid extraction and liquid chromatography coupled to mass spectrometry were used to quantify the compounds. The optimized method was validated with the following parameters: linear range from 0.5 to 300 µg L-1; linearity (r) > 0.99; precision with CV from 1.0 to 15.0%; accuracy of 60 to 117%, instrumental limit of detection (LOD) from 0.1 to 1.0 µg L-1 and instrumental limit of quantification (LOQ) of 0.5 µg L-1 for all pesticides, except 2,4-D (5.0 µg L-1). Pesticides concentrations of the experimental farms ranged from 0.1 to 266 µg kg-1, with the highest concentrations found in the months of pesticide’s application. The results showed the persistence of some pesticides in the soils even after months of use.

Drinking water disinfection has been viewed as one of the major advances in public health protection in history. However, while it has been very successful in assuring microbiological safety, disinfection also brought relevant concerns about chemical safety and the potential unintended health hazards associated with disinfection byproduct (DBP) exposure. DBPs represent one of the most important groups of chemical compounds to which humans are exposed through drinking water, as epidemiological studies have consistently associated long-term exposure with multiple adverse health effects. It is established that disinfection is an essential component of providing microbiologically safe drinking water and shall never be compromised. Yet, chemical safety regarding DBP exposure remains a largely uncovered and highly discussed topic. Several DBPs have been reported in the past few decades, yet research on formation, toxicity and occurrence remains scarce for most compounds. Also, for each identified DBP, many remain undiscovered. In view of an ever-growing list of DBPs and the existing gaps in available research, identifying overall driving agents of toxicity is still a major challenge for public health protection. This review attempts to provide an insight on contemporary issues regarding the overall safety of drinking water and the trade-off between microbiological and chemical risks, considering current challenges in water and sanitation access and existing regulations. history However (DBP longterm long term effects compromised Yet topic decades formation Also undiscovered evergrowing ever growing tradeoff trade off risks regulations

Pesticides are widely used worldwide in urban and rural environments. Since most pesticides are not selective for target species the concern about possible impacts on human health has increased for the workers exposed to these substances (occupational exposure) and for the general population (environmental exposure). Epidemiological studies, in vivo and in vitro have associated several diseases with pesticide exposure, such as cancer, diabetes, Parkinson’s, and others. Therefore, chemistry plays an important role in evaluation of external (food and drinking water) and internal (human biomonitoring) exposure to pesticides through of analytical methodologies, for instance, chromatography coupled with mass spectrometry, proving to be an important complement in the evaluation of risks of pesticides in human health.