Development of a soil exposure assessment for plant protection products in Brazil: Requirements, options, and recommendations.

The Brazilian Environmental Authority (IBAMA) has recently identified soil organisms as a priority area for risk assessment development for plant protection products. This includes consideration of which species in soil fauna are important to be tested for risk assessment purposes, which ecotoxicological tests should be used, and which exposure models would be suitable, considering Brazilian soils, local agricultural practices, and local biodiversity. In this brief communication, we present proposals and recommendations for the selection of appropriate regulatory exposure assessment techniques to support initial or foundation tier assessment. Integr Environ Assess Manag 2023;19:862-869. © 2022 FMC Corporation, Syngenta, Adama, Bayer AG, BASF SE. Integrated Environmental Assessment and Management published by Wiley Periodicals LLC on behalf of Society of Environmental Toxicology & Chemistry (SETAC).

Three-dimensional printing in orthopaedic surgery: review of current and future applications.

Three-dimensional (3D) printing is a rapidly evolving technology with the potential for significant contributions to surgical practice. There are many current applications for 3D printing technology with future applications being explored. This technology has applications in preoperative planning, education, custom manufacturing (implants, prosthetics and surgical guides) and exciting potential for biological applications. This article reviews the current and future applications of 3D technology in orthopaedic surgery.

Endosulfan and gamma-HCH in the arctic: an assessment of surface seawater concentrations and air-sea exchange.

Arctic seawater concentrations of two currently used pesticides, endosulfan and gama-HCH, were collated from a variety of cruises undertaken throughout the 1990s up to 2000 for different regions of the Arctic Ocean. Surface seawater concentrations for alpha- and beta-endosulfan ranged from <0.1-8.8 (mean 2.3) pg/L and 0.1-7.8 (mean 1.5) pg/L, while gamma-HCH concentrations were approximately 100 fold higher than alpha-endosulfan, ranging between <0.70 and 894 (mean 250) pg/L. Geographical distributions for alpha-endosulfan revealed the highest concentrations in the western Arctic, specifically in the Bering and Chukchi Seas with lowest levels toward the central Arctic Ocean. In contrast, gamma-HCH revealed higher concentrations toward the central Arctic Ocean, with additional high concentrations in the coastal regions near Barrow, Alaska and the White Sea in northwest Russia, respectively. A fugacity approach was employed to assess the net direction of air-water transfer of these two pesticides, using coupled seawater and air concentrations. For alpha-endosulfan, water-air fugacity ratios (FR) were all <1 indicating net deposition to all regions of the Arctic Ocean, with the lowest values (0.1-0.2) evident in the Canadian Archipelago. Given the uncertainty in the temperature-adjusted Henry's Law constant (factor approximately10), it is plausible that equilibrium may have been reached for this compound in the western fringes of the Arctic Ocean where the highest water concentrations were observed. Similarly, FR values for gamma-HCH were generally <1 and in agreement

An ecological risk assessment for triclosan in lotic systems following discharge from wastewater treatment plants in the United States.

A modeling study was conducted to examine the distribution of concentrations of the antimicrobial triclosan (2,4,4'-trichloro-2'-hydroxydiphenyl ether) in rivers following discharge from wastewater treatment plants (WWTPs). Most uses of triclosan are disposed of down residential drains and ultimately reach WWTPs. A modeling analysis was conducted to simulate the discharge of triclosan in WWTP effluents to rivers and calculate the expected concentrations based on characteristics of the reach where the discharge occurred, the estimated concentration of triclosan in the WWTP effluent, and the physicochemical properties of triclosan. A probabilistic exposure assessment was conducted based on data on the characteristics of U.S. reaches receiving wastewater discharges and the physicochemical characteristics of triclosan. A risk assessment was conducted by comparing the estimated concentrations with toxicity endpoint concentrations for species representative of key ecological groups. For fish and invertebrates, neither acute nor chronic risks are of concern, and no concerns exist for vascular aquatic plants. However, certain types of algae are the most sensitive species to triclosan by more than an order of magnitude than other algal or aquatic plant species. For these algae, the potential exists for some risk from triclosan exposure near the WWTP discharge location during low-flow-rate periods for some WWTPs with small dilutions. The risks downstream are lower because of dissipation of triclosan.

Crab: snail size-structured interactions and salt marsh predation gradients.

We studied size-structured predator-prey interactions between blue crabs (Callinectes sapidus) and marsh periwinkles (Littoraria irrorata) with a combination of field studies, laboratory experiments and individual-based modeling. Size distributions of Littoraria differed among years at the same sites in a salt marsh and could largely be explained by dominance of strong cohorts in the population. At a given site, abundance increased with elevation above tidal datum. Size-selective predation by blue crabs does not appear to be an important regulator of snail size distributions but may have a major effect on local abundance. Laboratory studies indicated that predator-prey interactions between Callinectes and Littoraria are strongly size-dependent. Crabs were generally effective at feeding on periwinkles at size ratios greater than approximately 6 (crab width: snail length). At lower size ratios crabs were far less effective at manipulating the snails, which often survived but with damaged shells. An individual-based model which incorporated information about incidence of snail shell scarring (resulting from non-lethal interactions) and snail density, predicted reduced predation rates and smaller average crab size with distance from the low tide refugium for crabs.