For old wood, the new polish slightly reduces the emission factor while for new wood the polish increases the emission factor slightly but the difference is likely more a function of the age of the wood than the polish. For example, given the old wood where the emissions are already low, adding the new polish may provide an apparent sink for the formaldehyde as it accumulates in the coating. In contrast, for the new wood, the initial emission rate is high and the coating may simply add a diffusion layer that increases the time that the emission from the wood paneling takes to drop to a constant level. With or without the coating, the new wood is clearly the major source of formaldehyde emissions among the materials tested. The aging of the formaldehyde emissions and the affect of the polish coating were tested further by removing the backing plate from the new wood with new polish after the initial conditioning and testing period was complete and reversing the material to expose the unfinished face. Our premise was that the formaldehyde diffuses to and accumulates at the surface of the material when the surface is covered so the initial emissions after uncovering the surface are expected to be high then drop with time towards an constant value. The results are illustrated in Figure 5. The initial test of the polished side was repeated 4 times over 15 days.
To test the emissions of aldehydes from the unfinished side of the same new wood material,pots with drainage holes the sample was flipped to expose the unfinished side and the polished side was sealed and the sample was returned to the test chamber to test the unfinished face. The first measurement found formaldehyde emissions from the unfinished face significantly in excess of the polished side but the emissions decreased rapidily over the next week. The material was flipped again exposing the poished side again that had been sealed for a week and the emission factor doubled but resumed dropping over the next day. Overall, the results indicate that the emission factor of formaldehyde from the new wood with new polish is approaching that of the new wood with no applied polish over time. The standard emission factors for formaldehyde from each of the main wall surface materials listed in Table 3 are compared to field measured values for the PBC building that were collected previously using Equation 3 along with the building parameters listed in Table 4. The results are listed in Table 5 for each material and each floor as a range of concentrations estimated with ACH values representing the maximum and 50% of the maximum accounting for the fact that the demand response system will likely run the ventilation at less than the maximum value. These ranges are summed for the total wall area based on loading factors for each material and the range of total concentraions are compared to the measurements in the last row of the table. Assuming no other significant loss pathways for formaldehyde, the three primary wall materials can easily account for the measured concentrations.
According to the National Center for Health Statistics , there have been increasing pharmaceutical prescriptions for the past 30 years, and they have almost tripled in the past 14 years alone . For agriculture, in 2013 over 6.6 million kg of the 9.1 million kg of antibiotics used were to increase production . Common Bcontaminants of emerging concern^ can be excreted by both humans and animals with little or no change in the chemical structures and, not surprisingly, they have been appearing in wastewater, and in some cases tap water, over the past few years .Most wastewater treatment facilities are not capable of removing all pharmaceuticals , resulting in these compounds being found in effluent. In addition, during heavy storms, untreated wastewater overflow can release even higher concentrations of some pharmaceuticals, which then directly contaminate the environment . Many of these compounds can be found at biologically active concentrations in surface waters around the world . In addition, there is also an increased effort to use reclaimed wastewater in drought-affected areas , resulting in increased exposure. In agriculture/livestock operations, pharmaceuticals are found in manure that is used as fertilizer for feed and crops, effectively compounding the pharmaceutical concentrations . Current research shows that these chemicals tend to be both pseudopersistant in soil and detrimental to soil microbes . Our recent studies of the effects of pharmaceuticals on aquatic insects show that at concentrations found in reclaimed water, CECs can alter development of the medically important mosquito Culex quinquefasciatus, its susceptibility to a common larvicide, and its larval microbial communities .
Female Megaselia scalaris, which are ecologically important detritivores, also displayed an increased developmental period, which could jeopardize the population’s survival when exposed to CECs . Also, the common agricultural pest Trichoplusia ni was negatively affected by antibiotics through a plant matrix . A common birth control agent, 17α-ethinylestradiol, and Bisphenol-A, a common plasticizer, have been shown to cause deformities in the midge Chironomus riparius . However, aquatic insects’ constant exposure to these CECs is likely greater than most terrestrial insects. Interestingly, many CECs were not designed to specifically to impact microbes but have been shown to affect microbial communities. For example, the mental stimulant caffeine can alter biofilm respiration, and diphenhydramine, an antihistamine, has been shown to modify the microbial community of lake biofilms . Therefore, accurately predicting the consequences of specific CECs, even in model insects, currently is difficult if not impossible. This problem is exacerbated by a general lack of information regarding effects of pharmaceuticals and other CECs on the microbial communities of terrestrial insects. Arthropods, such as insects and crustaceans, rely on hormones to grow, develop, mate, and produce pigmentation . However, many pharmaceuticals, especially mammalian sex hormones, are structurally similar to chemicals that these organisms rely on for development. These pharmaceuticals bind to receptors and either increase or disable their counterparts’ natural function. Endocrine disruption has been noted in birds, reptiles, and arthropods, primarily in the modification of primary and secondary sexual characteristics, and changes in courtship behaviors . While most arthropod hormones do not closely match those of mammals, their molting hormone is very similar in structure to the mammalian female sex hormone 17β-estradiol. Increased molting events and inhibition of chitobiase, the enzyme responsible for digestion of the cuticle during insect molting, have been noted in crustaceans exposed to mammalian hormones . In addition to these effects, pharmaceuticals have been shown to have delayed cross-generational effects . Aphids are phloem-limited hemimetabolous insects . Myzus persicae is polyphagous, highly cosmopolitan, and an efficient vector of plant viruses . This insect overwinters in the egg stage on Prunus species, and when their host plants are over-populated and/or stressed, they begin producing alates to disperse and colonize new plants . The sexual forms are also alates and are formed in autumn temperatures wherever peaches or suitable host plants are available . Economically, M. persicae is most damaging in the spring, when the insects hatch and feed on new peach leaves, and serve as vectors of over 100 different plant viruses . The aphid microbiome has been extensively studied and is well understood, making aphids excellent models for microbial community and biological research . Previous research has determined that antibiotics can reduce fecundity, reduce population growth, and increase mortality of aphids . Previous findings were usually due to the reduction of Buchnera, a key symbiont that provides required nutrients the aphids cannot make themselves or acquire from their diet . Currently,drainage pot there is no information regarding pharmaceutical effects at the concentrations found in reclaimed water on the growth and development of phloem-limited insects or their microbial community composition. Many herbivores can be exposed to these contaminants after the CECs enter surface waters, soil, and plants from wastewater reuse and unintended discharge.
There is minimal information available regarding effects of CECs when translocated through plants to terrestrial insects, especially those with specialized feeding techniques. Depending on the acquisition and sequestration by their host-plant species, insects with phloem-limited feeding methods, such as aphids, could have either reduced or increased exposure to CECs. Because previous research demonstrated a substantial change in both the biology and microbial communities of other insects when treated with ecologically relevant levels of CECs , and since aphid growth and development rely on symbionts, we hypothesized that aphids could be affected in similar ways. To test this hypothesis, we conducted bio-assays of aphids reared on a key host plant, Capsicum annuum, exposed to CECs at concentrations found in reclaimed water. Any effects would have potentially important implications from agricultural perspectives. Also, as there is currently little information on effects of CECs on terrestrial insects acquired through a plant matrix, our findings would have possible interest for integrated pest management research.Bell peppers were grown from seeds in 10.16-cm2 pots in UC soil mix no. 3 and fertilized with Miracle Gro nutrient solution at labeled rate and watered as needed in the UCR greenhouse. When plants were approximately 10 cm tall, their roots were washed with D.I. water and they were transplanted to 475-mL Mason jars . Mason jars were coated with FolkArt Multi-Surface acrylic paint on the outside to prevent root exposure to light. Jars were filled with hydroponic growth media containing CEC concentrations described in Table 5.1 with average pH of 7.0 ± 0.5 as in Pennington, Rothman, Dudley, et al. . Treatment media were prepared utilizing stock solutions of treatment compounds dissolved in 5:45 methanol:D.I. water with aliquots of < 500 μL being dissolved in 18 L. Growth media were stored at room temperature in blackened 19-L tanks to protect the CECs from photo degradation and to prevent algal growth. Hydroponic growth media were drained, by Erlenmeyer filter flask and vacuum, and replaced every 3 days to hinder bacterial and fungal growth and maintain CEC concentrations. After filtering through a HEPA-CAP air filter, house air was bubbled into jars through black irrigation tubing to aerate the hydroponic growth media. Each container included one of five CEC treatments or an untreated control hydroponic solution, and was used to water four plants. Plants grew 3 weeks before 10 M. persicae were placed evenly on two fully expanded leaves per plant.Data regarding population growth were collected daily and the experiment was ended after 2 weeks. Three life-stage groupings were collected from each plant, with a minimum sample size of 20 individuals per life stage , and stored in 200 proof ethanol at 62 ± 2 °C until DNA extractions were performed. Plants were separated into parts , weighed, and immediately frozen at − 62 ± 2 °C.Our work demonstrates that the selected CECs did not affect population dynamics or microbial communities of M. persicae reared on bell peppers. Many plants will translocate CECS . However, some plants can metabolize and/or sequester xenobiotics in tissues other than phloem, thereby removing the CEC exposure to aphids . As aphid species rely heavily on the endosymbiont Buchnera species to grow and develop, many aphid populations treated with high concentrations of antibiotics will not survive . However, aphid microbial communities were not affected when treated with antibiotics and other CECs at the low concentrations found in reclaimed water, which is possibly why there were no discernable effects on the aphid population as a whole. While treatments used in our study have previously been demonstrated to have negative effects for at least two other species of insects , this work suggests that aphids are either not exposed to CECs through their host plant, or their bacterial symbionts are not sensitive to them, or depleted enough, to alter their basic biology. Plants treated with antibiotics typically have lower levels of intracellular calcium due to chelation . However, in our study, we did not notice any obvious signs of calcium stress , possibly due to the use of a hydroponic solution which contains more than enough metal ions to provide adequate nutrients to the plants, even with some chelating. We did notice an overall decrease in mass for plants treated with antibiotics likely due to a slowed growth rate from direct action of the antibiotics on plant growth .