Use of nontarget organism Chironomus sancticaroli to study the toxic effects of nanoatrazine.

Atrazine was banned by the European Union in 2004, but is still used in many countries. Agricultural research employing nanotechnology has been developed in order to reduce the impacts to the environment and nontarget organisms. Nanoatrazine was developed as a carrier system and have been considered efficient in weed control. However, its toxicity must be verified with nontarget organisms. In this context, the aim of the present study was to investigate ecotoxicological effects of solid lipid nanoparticles (empty and loaded with atrazine) and atrazine on Chironomus sancticaroli larvae, evaluating the endpoints: mortality, mentum deformity, development rate and biochemical biomarkers. The contaminant concentrations used were 2, 470, 950, and 1900 µg L-1 in acute (96 h) and 2 µg L-1 in subchronic (10 days) bioassays. An environmentally relevant concentration of atrazine (2 µg L-1) presented toxic and lethal effects towards the larvae. The nanoparticles loaded with atrazine showed toxic effects similar to free atrazine, causing mortality and biochemical alterations on the larvae. The nanoparticle without atrazine caused biochemical alterations and mortality, indicating a possible toxic effect of the formulation on the larvae. In the acute bioassay, most concentrations of nanoparticles loaded with atrazine were not dose dependent for the endpoint mortality. Only the atrazine concentration of 470 µg L-1 was statistically significant to endpoint mentum deformity. The atrazine and nanoparticles (with and without atrazine) did not affect larval development. The results indicate that Chironomus sancticaroli was sensitive to monitor nanoatrazine, presenting potential to be used in studies of toxicity of nanopesticides.

An overview of the potential impacts of atrazine in aquatic environments: Perspectives for tailored solutions based on nanotechnology.

Atrazine is a pre- and post-emergence herbicide used to control weeds in many crops. It was introduced in the late 1950s, but its use has been controversial because of its high potential for environmental contamination. In agriculture, the implementation of sustainable practices can help in reducing the adverse effects atrazine. This review addresses aspects related to the impacts of atrazine in the environment, with focus on its effects on aquatic species, as well as the potential use of nanoencapsulation to decrease the impacts of atrazine. The application of atrazine leads to its dispersal beyond the immediate area, with possible contamination of soils, sediments, plantations, pastures, public supply reservoirs, groundwater, streams, lakes, rivers, seas, and even glaciers. In aquatic ecosystems, atrazine can alter the biota, consequently interfering in the food chains of many species, including benthic organisms. Nanoformulations loaded with atrazine have been developed as a way to reduce the adverse impacts of this herbicide in aquatic and terrestrial ecosystems. Ecotoxicological bioassays have shown that this nanoformulations can improve the targeted delivery of the active ingredient, resulting in decreased dosages to obtain the same effects as conventional formulations. However, more detailed analyses of the ecotoxicological potential of atrazine-based nanoherbicides need to be performed with representative species of different ecosystems.

A contribution to the knowledge of New World Bruchinae (Coleoptera, Chrysomelidae): taxonomic revision of Ctenocolum Kingsolver & Whitehead, with description of five new species.

The aim of this contribution was to review the species of Ctenocolum which are mainly distributed in the Neotropical region. The larvae of this genus have a high degree of specificity with the tribe Millettieae feeding mainly on seeds of Lonchocarpus Kunth (Fabaceae, Papilionoideae) and until now we do not know other bruchine consuming seeds of this genus. Here 13 valid species were studied, five new, divided in two groups, as previosly proposed in literature, group podagricus with Ctenocolum aquilus Albuquerque & Ribeiro-Costa sp. nov., C. biolleyi Kingsolver & Whitehead, C. colburni Kingsolver & Whitehead, C. martiale Kingsolver & Whitehead, C. milelo Albuquerque & Ribeiro-Costa sp. nov., C. podagricus (Fabricius), C. punctinotatus Albuquerque & Ribeiro-Costa sp. nov., C. pygospilotos Albuquerque & Ribeiro-Costa sp. nov. and C. triangulatus Albuquerque & Ribeiro-Costa sp. nov.; group tuberculatum with C. acapulcensis Kingsolver & Whitehead, C. janzeni Kingsolver & Whitehead, C. salvini (Sharp) and C. tuberculatum (Motschulsky). A lectotype is designated for Bruchus salvini and Bruchus pictifemur. Moreover, descriptions, redescriptions, diagnoses, key, geographic distribution and host plant records are also included.