Raw feedstock vs. biochar from olive stone: Impact on the sorption-desorption of diclosulam and tropical soil improvement.

The addition of carbon-rich materials, such as raw feedstocks (RAW) and biochars, to agricultural soils is on the rise. This activity has many advantages, such as improving fertility, increasing water retention, and sequestering carbon. However, they can also increase the sorption of residual herbicides in the soil, reducing the effectiveness of weed control. Thus, the objective of this study was to evaluate soil improvement and the sorption-desorption process of diclosulam in soil unamended and amended with RAW from olive stone and their biochars produced in two pyrolysis temperatures (300 and 500 °C). Oxisol was used in this study, unamended and amended with RAW and biochars (BC300 and BC500) in a rate of 10% (w w-1). The sorption-desorption process was assessed by batch-equilibrium experiments and the analysis was performed using high-performance liquid chromatography (HPLC). The addition of the three materials to the soil increased the contents of pH, organic carbon, P, K, Ca, Mg, Zn, Fe, Mn, Cu, B, cation exchange capacity, base saturation and decreased H + Al. The unamended soil had Kf (Freundlich sorption coefficient) values of diclosulam sorption and desorption of 1.56 and 12.93 mg(1 - 1/n) L1/n Kg-1, respectively. Unamended soil sorbed 30.60% and desorbed 13.40% of herbicide. Soil amended with RAW, BC300, and BC500 sorbed 31.92, 49.88, and 30.93% of diclosulam and desorbed 13.33, 11.67, and 11.16%, respectively. The addition of RAW and biochars from olive stone has the potential to change the soil fertility, but does not interfere with the bioavailability of diclosulam in weed control under field conditions, since the materials slightly influenced or did not alter the sorption-desorption of diclosulam.

Concentrations of polycyclic aromatic hydrocarbons in liver samples of juvenile green sea turtles from Brazil: Can these compounds play a role in the development of fibropapillomatosis?

Fibropapillomatosis (FP) poses a significant threat to the conservation of green sea turtles (Chelonia mydas). Polycyclic aromatic hydrocarbons-PAHs are considered mutagenic, carcinogenic and toxic, and can act as cofactor of this disease. In order to evaluate possible differences between green sea turtles with and without FP, we monitored 15 PAHs in liver samples of 44 specimens (24 with FP) captured in Brazil. We detected eight PAHs and quantified phenanthrene in all green sea turtles with FP. Specimens without FP presented lower values than the tumored ones (1.48 ng g-1 and 17.35 ng g-1, respectively; p < 0.0001). There were no significant differences between tumored and non-tumored specimens, among studied areas, or Southwest Atlantic Fibropapillomatosis Score. Even though we found higher concentrations in the liver samples of green sea turtles with FP, further studies are necessary to confirm if these pollutants are involved in the pathogenesis of the disease.

Effects of the exposure to atrazine on bone development of Podocnemis expansa (Testudines, Podocnemididae).

The use of pesticides is a widely spread practice in Brazilian agriculture, and dispersion of these substances is an important factor for the fauna and flora. Atrazine is an endocrine disruptor in the xenoestrogen class that is used worldwide in agricultural practices. In Brazil, its use is permitted in several crops. Podocnemis expansa is a representative of the Testudines order that is the largest freshwater reptile of South America. Its distribution enables it to get in contact with molecules that are commonly used as pesticides, which may cause deleterious effects in target populations. In order to evaluate the possible effects of the exposure to atrazine on bone ontogeny of this species, eggs were artificially incubated in sand moistened with water contaminated with atrazine at concentrations equal to 0, 2, 20 or 200 µg/L. Embryos were collected throughout incubation and submitted to diaphanization of soft tissues with potassium hydroxide (KOH); bones were stained with Alizarin red S and cartilages by Alcian blue. Embryos were evaluated for the presence of abnormalities during the different stages of pre-natal development of skeletal elements. No effect of atrazine was observed on bone development during the embryonic phase in P. expansa individuals, in the conditions of this study.

Determining organochlorine pesticides in samples of green sea turtles by QuEChERS approach / Determinação de pesticidas organoclorados em amostras de tartarugas verdes pelo método QuEChERS

Some Organochlorine Pesticides (OCPs) can pose numerous adverse effects on biota. Marine turtles face numerous threats, in particular those related to anthropogenic activities. Therefore, development and improvement methodologies for monitoring chemical compounds are a relevant task. In this work, we developed a methodology based on the QuEChERS (Quick, Easy, Cheap, Effective, Rugged and Safe) extraction for detection of twelve OCPs, by gas chromatography with electron capture detector, in fat and liver samples of green sea turtles. Quantification limits were lower than 5.3 ng g-1; acceptable recovery rates for most compounds; medium matrix effect; matrix-calibration with linearity at the range from 1.0 to 200 ng g-1. This methodology provides contributions for the study of pesticide residues with adverse effects on sea turtle health, important skills for new directions in conservation issues(AU)

Alguns Pesticidas organoclorados (OCPs) podem causar numerosos efeitos adversos na biota. As tartarugas marinhas enfrentam diversas ameaças, em especial aquelas relacionadas às atividades antropogênicas, por isso o desenvolvimento de melhorias nos métodos para monitorar compostos químicos são tarefas importantes. Neste trabalho foi desenvolvida uma metodologia baseada na extração QuEChERS (Quick, Easy, Cheap, Effective, Rugged and Safe) para a detecção de doze OCPs, por cromatografia gasosa com captura de elétrons, em amostras de gordura e fígado de tartarugas verdes. Os limites de quantificação ficaram abaixo de 5.3 ng g-1; com taxas de recuperação aceitáveis para a maioria de compostos; efeito matriz médio; calibração da matriz com linearidade variando de 1.0 a 200 ng g-1. Esta metodologia traz contribuições ao estudo de resíduos com efeito adverso na saúde das tartarugas marinhas, sendo importante instrumento para novas direções em temas de conservação(AU)

Determining organochlorine pesticides in samples of green sea turtles by QuEChERS approach / Determinação de pesticidas organoclorados em amostras de tartarugas verdes pelo método QuEChERS

Some Organochlorine Pesticides (OCPs) can pose numerous adverse effects on biota. Marine turtles face numerous threats, in particular those related to anthropogenic activities. Therefore, development and improvement methodologies for monitoring chemical compounds are a relevant task. In this work, we developed a methodology based on the QuEChERS (Quick, Easy, Cheap, Effective, Rugged and Safe) extraction for detection of twelve OCPs, by gas chromatography with electron capture detector, in fat and liver samples of green sea turtles. Quantification limits were lower than 5.3 ng g-1; acceptable recovery rates for most compounds; medium matrix effect; matrix-calibration with linearity at the range from 1.0 to 200 ng g-1. This methodology provides contributions for the study of pesticide residues with adverse effects on sea turtle health, important skills for new directions in conservation issues...

Alguns Pesticidas organoclorados (OCPs) podem causar numerosos efeitos adversos na biota. As tartarugas marinhas enfrentam diversas ameaças, em especial aquelas relacionadas às atividades antropogênicas, por isso o desenvolvimento de melhorias nos métodos para monitorar compostos químicos são tarefas importantes. Neste trabalho foi desenvolvida uma metodologia baseada na extração QuEChERS (Quick, Easy, Cheap, Effective, Rugged and Safe) para a detecção de doze OCPs, por cromatografia gasosa com captura de elétrons, em amostras de gordura e fígado de tartarugas verdes. Os limites de quantificação ficaram abaixo de 5.3 ng g-1; com taxas de recuperação aceitáveis para a maioria de compostos; efeito matriz médio; calibração da matriz com linearidade variando de 1.0 a 200 ng g-1. Esta metodologia traz contribuições ao estudo de resíduos com efeito adverso na saúde das tartarugas marinhas, sendo importante instrumento para novas direções em temas de conservação...