Identities, concentrations, and sources of pesticide exposure in pollen collected by managed bees during blueberry pollination

Bees are critical for crop pollination, but there is limited information on levels and sources of pesticide exposure in commercial agriculture. We collected pollen from foraging honey bees and bumble bees returning to colonies placed in blooming blueberry fields with different management approaches (conventional, organic, unmanaged) and located across different landscape settings to determine how these factors affect pesticide exposure. We also identified the pollen and analyzed whether pesticide exposure was correlated with corbicular load composition. Across 188 samples collected in 2 years, we detected 80 of the 259 pesticide active ingredients (AIs) screened for using a modified QuEChERS method. Detections included 28 fungicides, 26 insecticides, and 21 herbicides. All samples contained pesticides (mean = 22 AIs per pollen sample), with pollen collected from bees on conventional fields having significantly higher average concentrations (2019 mean = 882.0 ppb) than those on unmanaged fields (2019 mean = 279.6 ppb). Pollen collected by honey bees had more AIs than pollen collected by bumble bees (mean = 35 vs. 19 AIs detected at each farm, respectively), whereas samples from bumble bees had higher average concentrations, likely reflecting differences in foraging behavior. Blueberry pollen was more common in pollen samples collected by bumble bees (25.9% per sample) than honey bees (1.8%), though pesticide concentrations were only correlated with blueberry pollen for honey bees. Pollen collected at farms with more blueberry in the surrounding landscape had higher pesticide concentrations, mostly AIs applied for control of blueberry pathogens and pests during bloom. However, for honey bees, the majority of AIs detected at each farm are not registered for use on blueberry at any time (55.2% of AIs detected), including several highly toxic insecticides. These AIs therefore came from outside the fields and farms they are expected to pollinate. For bumble bees, the majority of AIs detected in their pollen are registered for use on blueberry during bloom (56.9% of AIs detected), though far fewer AIs were sprayed at the focal farm (16.7%). Our results highlight the need for integrated farm and landscape-scale stewardship of pesticides to reduce exposure to pollinators during crop pollination.

Influence of Anti-Caking Agents on the Highly Effective Organic Coatings for Preventing the Caking of Ammonium Nitrate Fertilizers

Ammonium nitrate fertilizers have a tendency to cake during storage. The aim of this study was to examine the effectiveness of organic coatings for preventing the caking of ammonium nitrate fertilizers and to assess the influence of the composition and physicochemical properties of the anti-caking agents used as coatings for fertilizers on their effectiveness. CAN (calcium ammonium nitrate) and AN (ammonium nitrate) fertilizers were coated with three anti-caking agents. A GC–MS technique was used for the identification and quantitative determination of the composition of the organic coatings. The influence of the following physicochemical parameters of the preparations was assessed: density, viscosity, melting point, water content, and base number. The effectiveness of anti-caking agents was determined by measuring the force needed to crush the clumped uncoated and coated fertilizers, which were previously subjected to thermal cycles under load. Composition studies showed that all the tested preparations contained hexadecylamine and octadecylamine in comparable amounts and a slack wax. The results demonstrate that the key parameters of an effective anti-caking agent are low water content, appropriate viscosity, and appropriate content of fatty amines. This study can facilitate the development of innovative coatings with similar or higher efficiency, yet with a reduced negative impact on the environment.

Composition of cooling load formed by non-transparent envelopes of a common office building under air-conditioning intermittent operation

Under air-conditioning intermittent operation, interior envelopes become the quasi-exterior ones of a partial room and thereby may cause the specified heat loss. However, it is unknown for the heat transfer capacity rate of interior envelopes in the room heat loss, which is of vital significance on the optimization direction of envelopes. To analyze the cooling load composition formed by non-transparent envelopes, an office building was chosen and inner surface heat flows in the studied room were measured under the different intermittent groups of air-conditioning in the adjacent rooms, and combined with the envelop area and heat flow values, the heat transfer capacity through the different envelops could be gained. The results showed that the air-conditioning operation in the adjacent rooms had a large effect on the heat transfer capacities, and the higher the room area, the more remarkable the air-conditioning operation in the adjacent rooms. The average heat transfer capacity rate of the exterior envelope was 21%–35% for room with two exterior walls and only 7%–10% for room with one exterior wall, which were much lower than those of the interior envelopes. It showed that thermal performance of the interior envelopes should be paid more attention to under air-conditioning intermittent operation.