Metal pollutants have additive negative effects on honey bee cognition

Environmental pollutants can exert sublethal deleterious effects on animals. These include disruption of cognitive functions underlying crucial behaviours. While agrochemicals have been identified as a major threat to pollinators, metal pollutants, which are often found in complex mixtures, have so far been overlooked. Here we assessed the impact of acute exposure to field-realistic concentrations of three common metal pollutants, lead, copper, arsenic, and their combinations, on honey bee appetitive learning and memory. All treatments involving single metals slowed down learning and disrupted memory retrieval at 24 h. Combinations of these metals had additive negative effects on both processes, suggesting common pathways of toxicity. Our results highlight the need to further assess the risks of metal pollution on invertebrates.

Collector for Copper-Arsenic Ore Flotation

Copper and scheelite concentrates are produced from scheelite-sulfide ores of the Vostok-2 deposit at the Primorsky processing plant. Chalcopyrite, gold, silver, and harmful impurities (arsenopyrite, pyrrhotite) are extracted into the copper concentrate. As a collector, dialkyldithiophosphate-type IMA-I413p reagent is used. Bulk sulfide concentrate is produced using activated carbon and trisodium phosphate; copper cleaner flotation is carried out in the medium of ferrous sulfate. The commercial copper concentrate contains 16 % copper, 33 g/t gold, and 280 g/t silver. The recovery of the metals is 67.6, 44.7, and 50.1 %, respectively. The weight fraction of arsenic in the ore fluctuates in the range of 0.04–0.25%, and that in the concentrate, 0.7–2.3 %. The enterprise looks for ways to increase recovery of the valuable metals and decrease content of arsenic in the copper concentrate to below 1% at the expense of increasing contrast in the separation of chalcopyrite from iron sulfides/arsenopyrite/pyrrhotite. For solving this problem, we performed a study of flotation properties of sulfide collectors based on dialkyldithiophosphates: BTF-15221, BTF -271, non-ionic collector Reaflot-277, and combinations of Reaflot-277 and IMA-I413p. Applying BTF-15221 collector allowed, as compared to the standard IMA-I413p reagent, to increase recovery of copper, gold, and silver and reduce arsenic content in the copper concentrate. The higher selectivity of BTF-15221 as compared to IMA-I413p was confirmed by the fact that the bulk of the increase in copper recovery and decrease in the weight fraction of arsenic in the copper concentrate was achieved in the selective cycle. Besides, during the study, surface activity and hydrophobizing ability of the water-soluble collectors were assessed. Using the example of BTF-15221, it was shown that improvement of the reagent collecting properties can be achieved not only due to increasing the surface activity of the reagent, but also at its decrease – in case of sufficient hydrophobizing ability of the reagent, close to that of the standard reagent. By adjusting these parameters through the use of low-molecular weight homologues of the main components, it is feasible to increase or decrease the selectivity and collecting ability of the reagent. Collector BTF-15221 is of practical interest for further testing in flotation of copper-arsenic and other ore types.

The Copper-Arsenic Eutectic and the Cu3As Phase

In ancient bronze ingots Cu3As was observed beside other impurities like Sb. Moreover, the Cu-As bronzes were studied concerning the decrease in As during melting respectively remelting. To verify the microstructure and hardness of the eutectic and Cu3As phase appropriate mixtures were produced by melting pure Cu and As. The eutectic point in the Cu-As system is at 685 °C and 20.8 wt. % As and the Cu3As phase with 29.56 wt. % As melts at 827 °C. In the sample´s core the microstructure is a homogeneous eutectic, but near the surface it becomes hypoeutectic, i.e. an As loss took place. The lamella thickness of the eutectic was in the range of about 1 µm. The sample with a Cu3As composition showed a proeutectic microstructure with mainly Cu3As and a small amount of eutectic. In the large Cu3As crystals twin lamellae were observed. Additionally, by Vickers indents new twins were introduced. The microhardness of the Cu-As solid solution is 78 HV0.025, of the eutectic 125 HV0.025 and of the Cu3As phase 158 HV0.025. On some surfaces of the Cu3As sample a Cu-rich phase was observed. We are not able to explain this phenomenon, but it is definitively no “inverse segregation”.

The Role of Salmonella Genomic Island 4 in Metal Tolerance of Salmonella enterica Serovar I 4,[5],12:i:- Pork Outbreak Isolate USDA15WA-1

Multidrug-resistant (MDR; resistance to >3 antimicrobial classes) Salmonella enterica serovar I 4,[5],12:i:- strains were linked to a 2015 foodborne outbreak from pork. Strain USDA15WA-1, associated with the outbreak, harbors an MDR module and the metal tolerance element Salmonella Genomic Island 4 (SGI-4). Characterization of SGI-4 revealed that conjugational transfer of SGI-4 resulted in the mobile genetic element (MGE) replicating as a plasmid or integrating into the chromosome. Tolerance to copper, arsenic, and antimony compounds was increased in Salmonella strains containing SGI-4 compared to strains lacking the MGE. Following Salmonella exposure to copper, RNA-seq transcriptional analysis demonstrated significant differential expression of diverse genes and pathways, including induction of at least 38 metal tolerance genes (copper, arsenic, silver, and mercury). Evaluation of swine administered elevated concentrations of zinc oxide (2000 mg/kg) and copper sulfate (200 mg/kg) as an antimicrobial feed additive (Zn+Cu) in their diet for four weeks prior to and three weeks post-inoculation with serovar I 4,[5],12:i:- indicated that Salmonella shedding levels declined at a slower rate in pigs receiving in-feed Zn+Cu compared to control pigs (no Zn+Cu). The presence of metal tolerance genes in MDR Salmonella serovar I 4,[5],12:i:- may provide benefits for environmental survival or swine colonization in metal-containing settings.

Impact of Textile Dyes on Human Health and Environment

The textile industry is one of the important industries that generates a large amount of industrial effluents. Color is the main attraction of any fabric. Manufacture and use of synthetic dyes for fabric dyeing has therefore become a massive industry. Synthetic dyes have provided a wide range of colorfast, bright hues. However, their toxic nature has become a cause of grave concern to environmentalists. Use of synthetic dyes has an adverse effect on all forms of life. Presence of sulphur, naphthol, vat dyes, nitrates, acetic acid, soaps, enzymes chromium compounds, and heavy metals like copper, arsenic, lead, cadmium, mercury, nickel, and cobalt and certain auxiliary chemicals all collectively make the textile effluent highly toxic. These organic materials react with many disinfectants, especially chlorine, and form byproducts (DBPs) that are often carcinogenic and therefore undesirable. This effluent, if allowed to flow in the fields, clogs the pores of the soil resulting in loss of soil productivity. This chapter gives an overview on the health and environmental impact of dyes.

Breast Cancer With Relevance for Heavy Metals, Mycotoxines, and Pesticides

Certain environmental contaminants such as heavy metals, pesticides, and mycotoxins are presumed to play a crucial role in the etiology of breast cancer, which is the most common tumor in women worldwide. In fact, the exposure to heavy metals poses risk in causing human cancers. Several investigations indicated strong contribution of heavy metals especially copper, arsenic, zinc, cadmium, lead, and aluminum in breast cancer. Furthermore, it has been reported that the excessive use of pesticides in agriculture in order to improve the productivity contaminates food materials and can be responsible to induce breast cancer in women. It is also noted that some fungi produce several type of mycotoxins such us zearalenone, aflatoxin, and ochratoxin that are dangerous for human health and can especially cause breast cancer. Thus, the objective of this chapter is to discuss the experimental data regarding the involvement of heavy metals, pesticides, and mycotoxins as well as the recent insights on the molecular mechanisms involved in the progress of breast cancer.