Anthropogenic activities increase the amount of potentially toxic elements (PTEs) in the environment and consequently affect the quality of soils and water resources. This study aimed to investigate the concentrations, spatial distribution, and sources of soil and sediment pollution at the watershed scale for the following PTEs: aluminum (Al), barium (Ba), cerium (Ce), cobalt (Co), chromium (Cr), copper (Cu), iron (Fe), lanthanum (La), manganese (Mn), neodymium (Nd), nickel (Ni), lead (Pb), praseodymium (Pr), scandium (Sc), samarium (Sm), thorium (Th), titanium (Ti), vanadium (V), yttrium (Y) and zinc (Zn). One hundred and eighty-eight composite samples collected from preserved Cerrado areas, channel banks, agricultural areas, pastures, and riverbed sediments were used. Environmental contamination was assessed using geochemical indices and ecological risk assessment. The concentration of these elements often followed the order of riverbed sediment > channel bank > pasture > agricultural areas. Based on the pollutant load index, riverbed sediments and channel banks were classified as polluted, acting as a source of PTEs. The Gurgueia watershed, Brazil, was classified as unpolluted to moderately polluted, with low to no enrichment by PTEs. These values serve as a basis for future monitoring of the impacts resulting from the advance of agricultural and industrial activities in the region.

The Gilbués desertification perimeter encompasses approximately 6,200 km2 in northeastern Brazil. It is widely recognized for its advanced stage of soil degradation. Its landscape is characterized ...

The black aphid Aphis craccivora Koch (Hemiptera: Aphididae) is pointed out as one of the main pests of cowpea, causing injuries through the suction of sap on the plants. Conventional control involves the use of systemic chemical pesticides, which, from indiscriminate use, can cause contamination of the environment, applicators and other people, causing the selection of resistant insect populations. In view of this scenario, this study proposes to evaluate the toxicity, repellency and impact on population growth of A. craccivora when exposed to neem and manipueira extract. Leaf discs of cowpea plants were made, which were immersed in the concentrations of extract and volume of cassava, using the residual effect methodology for these experiments. Toxicity tests were performed to determine the sublethal concentrations LC20 and LC30 of neem extract and manipueira volume. In addition, tests were conducted to evaluate the repellency of the treatments, observing the behavior of the insects in relation to the previously determined concentrations. The study also analyzed the impact of the lethal concentration (CL) of neem extract and cassava extract on the population growth of A. craccivora, calculating the growth rate of the insect. The results showed that neem has a higher lethal concentration, both in LC50 and LC90, showing to be more toxic, with 0.99 times and 1.69 times, compared to cassava, in relation to the repellent effect, only neem in CL30 was repellent, while in the other concentrations, LC20 of neem itself and CL20 and LC30 of manipueira, had a neutral classification. In the population growth the CL20 concentrations of neem and manipueira extracts there was no difference, however, it was evident that manipueira has a higher population growth rate in relation to neem.

O ácaro rajado Tetranychus urticae (Acari: Tetranychidae) é uma praga polífaga atacando diversas culturas, dentre estas são exemplos o feijão, algodão, soja, milho, tomate e entre outras. Seu controle