Combined Effects of Pesticides and Electromagnetic-Fields on Honeybees: Multi-Stress Exposure.

Honeybee and general pollinator decline is extensively reported in many countries, adding new concern to the general biodiversity loss. Many studies were addressed to assess the causes of pollinator decline, concluding that in most cases multi-stress effects were the most probable ones. In this research, the combined effects of two possible stress sources for bees, pesticides and electromagnetic fields (multi-stress conditions), were analyzed in the field. Three experimental sites were chosen: a control one far from direct anthropogenic stress sources, a pesticide-stress site and multi-stress one, adding to the same exposure to pesticides the presence of an electromagnetic field, coming from a high-voltage electric line. Experimental apiaries were monitored weekly for one year (from April 2017 to April 2018) by means of colony survival, queen activity, storage and brood amount, parasites and pathogens, and several biomarkers in young workers and pupae. Both exposure and effect biomarkers were analysed: among the first, acetylcholinesterase (AChE), catalase (CAT), glutathione S-transferase (GST) and alkaline phosphatase (ALP) and Reactive Oxygen Species (ROS); and among the last, DNA fragmentation (DNAFRAGM) and lipid peroxidation (LPO). Results showed that bee health conditions were the worst in the multi-stress site with only one colony alive out of the four ones present at the beginning. In this site, a complex picture of adverse effects was observed, such as disease appearance (American foulbrood), higher mortality in the underbaskets (common to pesticide-stress site), behavioral alterations (queen changes, excess of honey storage) and biochemical anomalies (higher ALP activity at the end of the season). The overall results clearly indicate that the multi-stress conditions were able to induce biochemical, physiological and behavioral alterations which severely threatened bee colony survival.

Polybrominated diphenyl ether contamination in soil, vegetation, and cow milk from a high-mountain pasture in the Italian Alps.

This study investigates contamination by 13 polybrominated diphenyl ether (PBDE) congeners in a high-mountain pasture located in the Italian Alps. The trend of PBDE contamination in three soil layers was investigated by a spring-summer sampling period to understand the importance of different environmental variables, such as seasonality, topographical aspect, and soil features. We also evaluated PBDE accumulation in grasses covering the plateau, and because the study area has been used for a pasture for a long time, we measured PBDE levels in milk from grazing cows. Overall, we found moderate PBDE contamination in Andossi soils, with differences depending on the layer, mountain side, and organic matter content. The vegetation of the plateau had greater PBDE concentrations than the soils and showed a grass/soil accumulation ratio between 2 and 12, indicating that deposition from the atmosphere is actually the dominant process in this area. Last, PBDE concentrations in milk followed similar seasonal trends as the vegetation but showed variations in congener abundance in agreement with the biotransformation susceptibility, absorption efficiency, and residence time of different BDEs in dairy cattle.

Quantitative inter-specific chemical activity relationships of pesticides in the aquatic environment.

Inter-species correlations could be a useful tool for predicting toxicity and for establishing sensitivity ratios among species. In this paper, quantitative inter-specific chemical activity relationships (QICAR) for aquatic organisms were developed to verify if such an approach could be utilised for estimating toxicological data when no other information is available. Inter-specific toxicity relationships on fish, Daphnia and algae were performed for pesticides considering a large data set (more than 600 compounds) and grouping the data either on a functional (herbicides, fungicides and insecticides) or chemical class base. Good correlations were found between several fish species and they were improved by excluding, from the data set, highly specific compounds such as organophosphorus insecticides. Relationship between fish (rainbow trout) and Daphnia was significant for the whole data set, but clearly improves if congeneric classes of pesticides are considered. The most significant results were found for azoles (fungicides) and for all data set of pesticides with the exclusion of organophosphorus and carbamate insecticides. As expected, toxicity on algae does not correlate either with fish or with Daphnia on the whole data set, but excluding the classes acting specifically toward one organism (insecticides and several classes of herbicides), good relationships were found. The analysis of the data permits the conclusion that the specificity in the mode action of pesticides is the key parameter for expecting or not inter-specific relationships. By the relative specificity of action of a group of compounds towards two species, the probability of obtaining a QICAR for this group can be derived. In general, compounds acting with the same level of specificity towards two different species, have a higher probability of showing inter-specific relationships and the lower the specificity of the mode of action of the compounds (e.g. narcotics or less inert chemicals), then the stronger are the relationships.