Organochlorine pesticides (OCPs) are widely used around the world as insecticides, herbicides, fungicides, nematicides, and rodenticides. Despite banned in Brazil, the usage remains occurring in many countries. The persistence and extreme mobility of OCPs contribute to the contamination of the environment and the human body. The OCPs bioaccumulation in adipose tissue triggers the excretion into human milk during breastfeeding. Hence, the present study determined eighteen OCPs residues in the breast milk of mothers from the Western Region of Bahia State, Brazil. Nine different residue species were found, including beta-Hexachlorocyclohexane (9.24 ± 0.00 ng g⁻¹ fat), delta- Hexachlorocyclohexane (22.15 ± 10.48 ng g⁻¹ fat), Heptachlor (58.08 ± 74.13 ng g⁻¹ fat), Aldrin (142.65 ± 50.65 ng g⁻¹ fat), Dieldrin (774.62 ± 472.68 ng g⁻¹ fat), Endosulfan I (408.44 ± 245.51 ng g⁻¹ fat), Dichloro-diphenyl-dichloro-ethylene (29.17 ± 22.42 ng g⁻¹ fat), Dichloro-diphenyl-trichloro-ethane (28.87 ± 0.00 ng g⁻¹ fat) and Methoxychlor (1699.67 ± 797.43 ng g⁻¹ fat). The Methoxychlor presence in all samples may reveal a recent exposure, while Dieldrin and Endosulfan I analyses can point to distant past exposure.

The determination of some pesticides in surface sediments can provide important information about their distribution in the water column. This work aimed to determine the distribution of the classes of pesticides along the Ondas River’s hydrographic basin (ORHB), in eighteen different points, during the dry and rainy periods. The pesticides were extracted from the sediment samples by solid-liquid extraction and then analyzed using a gas chromatograph coupled to mass spectrometry. After the development and validation of the method, nineteen pesticides from the group of organochlorine, organophosphates, carbamate and thiocarbamate, pyrethroids, and strobilurins were quantified in at least one point in the two collection periods, with accuracy varying between 86 and 126%. The average concentrations were 0.020 ng g⁻¹ (carbofuran) to 249.123 ng g⁻¹ (dimethoate) and 0.029 ng g⁻¹ (carbofuran and sulfotep) to 533.522 ng g⁻¹ in the dry and rainy periods, respectively. The results showed a wide distribution of pesticide residues in the ORHB, with higher levels for dimethoate, phenitrothion, and malathion, which may be related to their agricultural use in the region. In Brazil, it does not have specific legislation for maximum permitted values of pesticides in sediment, allowing for inappropriate or prohibited use and, consequently, affecting water quality.

Ion chromatography (IC) is one of the most used analytical methods for the determination of inorganic cations and anions, as well as organic ions. It is considered a method of separation with simple steps, low cost and with good efficiency in chromatographic separation. In addition, it has good validation metrics such as sensitivity, selectivity, precision, robustness, low detection limit and quantification. IC easily replaces conventional wet chemistry methods, which tend to have more analysis steps. The easy extraction of samples, in most cases, does not require organic solvents, facilitating the disposal of waste. Since its creation, IC has accumulated advantages and good acceptance in the food, pharmaceutical, environmental monitoring industries, in addition to increasing implementation in academic research laboratories.