Municipal Compost Public Health, Waste Management, and Urban Agriculture: A Decadal Study of Fugitive Pb in City of Boston, Massachusetts, USA.

Compostable materials constitute roughly half of waste generated globally, but only 5% of waste is actually processed through composting, suggesting that expanding compost programs may be an effective way to process waste. Compostable waste, if properly collected and processed, has value-added end use options including: residential and park landscaping, remediation of brownfield sites, and as growing media in urban agriculture (UA). Since 2001, our lab has partnered with The Food Project, a non-profit focused on youth leadership development through urban farming. From 2006 to 2022 we collected compost materials that were delivered to the farm from a variety of local sources and analyzed a suite of biogeochemical properties including lead (Pb) concentrations, organic carbon, and grain size distribution. Pb concentrations of Boston's municipal compost always exceeded the current City of San Francisco soil and compost purchase standard (80 µg/g). In 2012 Boston's composting program was halted when it exceeded the 400 µg/g Environmental Protection Agency's Pb in soil benchmark. Urban Pb is geomobile and must be managed to minimize resuspension and transport of fines whose Pb concentration is often elevated compared to bulk compost. Consequently, urban farmers have to source lower Pb compost from suburban suppliers at significantly greater cost. Over a 15 year period and through several city vendor contracts, Pb concentrations in municipal compost remain at levels that warrant continued surveillance and risk assessment.

Sorption and desorption behavior of four antibiotics at concentrations simulating wastewater reuse in agricultural and forested soils.

Due to rises in antibiotic resistance, fate and transport of antibiotics in soil systems requires greater understanding to determine potential risks to human and animal health. Adsorption coefficients (Kd and Kf) are standard measures for determining sorption capacity and partitioning behavior of organic contaminants in solid matrices. Frequently, sorption studies use higher antibiotic concentrations (mg L-1) and larger spiked water volume to mass of soil (>5:1), which may not reflect sorption behaviors of antibiotics at low concentrations (ng L-1 - µg L-1) in natural soils. The aim of this study was to determine sorption and desorption behaviors of four antibiotics commonly found in soils due to wastewater reuse using parameters replicating typical soil conditions. Concentrations (µg L-1) of sulfamethoxazole (SMX), trimethoprim (TMP), lincomycin (LIN) and ofloxacin (OFL) were equilibrated with four soil types at a 2:1 ratio of spiked water volume to mass of soil, which better represents field conditions. Log Kf and log Kfoc value ranges in this study were 1.88-1.95 and 3.2-4.7 for TMP, 0.43-1.4 and 2.7-3.2 for SMX, and 0.65-1.4 and 2.0-4.1 for LIN, respectively. Ofloxacin adsorbed tightly to soil particles, and adsorption coefficients could not be calculated. Sorption values were higher than previous studies that used similar soil types but had higher ratios of spiking solution to mass of soil (>5:1). Overall, OFL and TMP are expected to strongly interact with soil particles and be less mobile, while SMX and LIN are expected to be more mobile due to weaker sorption interactions.

Bitter-blockers as a taste masking strategy: A systematic review towards their utility in pharmaceuticals.

Acceptable palatability of an oral dosage form is crucial to patient compliance. Excipients can be utilised within a formulation to mask the bitterness of a drug. One such category is the bitter-blockers. This term is used inconsistently within the literature and has historically been used to describe any additive which alters the taste of an unpleasant compound. This review defines a bitter-blocker as a compound which interacts with the molecular pathway of bitterness at a taste-cell level and compiles data obtained from publication screening of such compounds. Here, a novel scoring system is created to assess their potential utility in a medicinal product using factors such as usability, safety, efficacy and quality of evidence to understand their taste-masking ability. Sodium acetate, sodium gluconate and adenosine 5'monophophate each have a good usability and safety profile and are generally regarded as safe and have shown evidence of bitter-blocking in human sensory panels. These compounds could offer a much needed option to taste-mask particularly aversive medicines where traditional methods alone are insufficient.

Less information results in better midsession reversal accuracy by pigeons.

The midsession reversal task involves a simultaneous discrimination between Stimulus 1 (S1) and Stimulus 2 (S2) in which, for the first half of each session, choice of S1 is reinforced and S2 is not, and for the last half of each session, choice of S2 is reinforced and S1 is not. With this task, even after considerable training, pigeons tend to make anticipatory errors as they approach the reversal and they continue to make perseverative errors following the reversal. In the present research, we tested the hypothesis that reversal accuracy would improve by devaluing choice of S2 relative to S1. In Experiment 1, correct choice of S1 was reinforced 100% of the time, whereas correct choice of S2 was reinforced only 20% of the time. This manipulation reduced anticipatory errors but did not increase perseverative errors. In Experiment 2, choice of S1 required a single peck, whereas choice of S2 was devalued by requiring 10 pecks. A similar result was found. In Experiment 3 we devalued S1 by requiring 10 pecks and found decreased accuracy in the form of increased anticipatory errors. Paradoxically, in Experiments 1 and 2, by encouraging the pigeons to avoid using the feedback from choice of S2, and rely solely on feedback from choice of S1, discrimination reversal errors were reduced. The results have implications for attentional theories of learning and theories of behavior change. They also have implications for the conditions responsible for pigeons' tendency to time the occurrence of the change in reinforcement contingencies. (PsycINFO Database Record (c) 2019 APA, all rights reserved).

Contrast between what is expected and what occurs increases pigeon's suboptimal choice.

When pigeons are given a choice between 50% signaled reinforcement and 100% reinforcement they typically do not choose optimally, sometimes even preferring 50% reinforcement. Smith and Zentall (J Exp Psychol Anim Behav Process 42:212-220, 2016) proposed that choice depends primarily on the predictive value of the signal for reinforcement associated with each alternative (both 100% reinforcement) and not the frequency of the signal for reinforcement (50% vs. 100%). With extended training, however, Case and Zentall (Behav Process, 2018) found that pigeons actually show a reliable preference for the 50% reinforcement alternative. They suggested that contrast between the expected outcome at the time of choice (50% reinforcement) and the value of the signal for reinforcement (100% reinforcement) is the mechanism responsible for the preference for the suboptimal alternative (for the optimal alternative there should be no contrast). In the present research, we tested the contrast hypothesis by increasing the probability of reinforcement for choice of the suboptimal alternative to 75%, thereby reducing the contrast between expected and obtained reinforcement and found a reduced preference for the suboptimal alternative. That is, increasing the probability of reinforcement for choice of the suboptimal alternative decreased suboptimal choice. Thus, preference for the suboptimal alternative appears to result from two mechanisms: (1) the value of the signal for reinforcement that follows choice of the alternative and (2) positive contrast between the expected and obtained probability of reinforcement. We compared this interpretation with other hypotheses.

To peck or not peck: Which do pigeons prefer?

Animals are expected to minimize time and effort to reinforcement. Thus, not pecking should be preferred over pecking. However, even if time is held constant, pigeons often peck when it is allowed but not required (e.g., fixed time schedules), but with such schedules pecking may be adventitiously reinforced. In the present experiment, to better compare a schedule of reinforcement that requires pecking with one that requires the absence of pecking, we compared a modified fixed-interval (FI) schedule in which reinforcement follows the first peck after the interval has elapsed and a differential-reinforcement-of-other behavior (DRO) schedule, which requires pigeons to abstain from pecking for a similar interval. The delay to reinforcement was matched on a trial-by-trial basis by yoking the duration of the FI to match the DRO schedule that preceded it. Of 12 pigeons, six preferred the DRO schedule over the FI schedule and six did not show a schedule preference. Those that were indifferent between the schedules apparently had a stronger spatial preference than their schedule preference. Individual differences in the preference of the pigeons may have been related to their behavior during the DRO schedule.

Sameness May Be a Natural Concept That Does Not Require Learning.

It has been assumed that when pigeons learn how to match to sample, they learn simple stimulus-response chains but not the concept of sameness. However, transfer to novel stimuli has been influenced by pigeons' tendency to be neophobic. We trained pigeons on matching ( n = 7) and mismatching ( n = 8) with colors as samples and, with each sample, one color as the nonmatching comparison. We then replaced either the matching or the nonmatching stimulus with a familiar stimulus never presented with that sample. Results suggest that for both matching and mismatching, pigeons locate the stimulus that matches the sample: If the task involves matching, they chose it; if it involves mismatching, they avoid it. Thus, the concept of sameness is the basis for correct choice with both tasks. This finding suggests that sameness is a basic concept that does not have to be learned and may have evolved in many species, including humans.

Procrastination in the pigeon: Can conditioned reinforcement increase the likelihood of human procrastination?

Procrastination is the tendency to put off initiation or completion of a task. Although people are typically known to procrastinate, recent research suggests that they sometimes "pre-crastinate" by initiating a task sooner than they need to (Rosenbaum et al. in Psychological Science, 25(7), 1487-1496, 2014). A similar finding of precrastination was reported by Wasserman and Brzykcy (Psychonomic Bulletin & Review, 22, 1130-1134, 2015) with pigeons using a somewhat different procedure. In the present experiment, we used a procedure with pigeons that was more similar to the procedure used by Rosenbaum et al. Pigeons were given a choice between two sequences of events (concurrent chains). Choice of the procrastination chain resulted in color A, which 15-s later would change to color B and 5-s later resulted in reinforcement. Choice of the precrastination chain resulted in color C, which 5-s later would change to color D and 15-s later resulted in reinforcement. Thus, both chains led to reinforcement after 20 s. Results indicated that the pigeons procrastinated. That is, they preferred the 15-5 chain over the 5-15 chain. The results are consistent with Fantino's (Journal of the Experimental Analysis of Behavior, 12, 723-730, 1969) delay reduction theory, which posits that stimuli that signal a reduction in the delay to reinforcement, such as the 5-s stimulus that occurred immediately prior to reinforcement, serve as strong conditioned reinforcers and should be preferred. In support of this theory, the pigeons pecked most at the 5-s stimulus that led immediately to reinforcement, indicating that it had become a strong conditioned reinforcer. The results suggest that delay reduction theory, a theory that emphasizes the attraction to stimuli that predict reinforcement with a short delay, also may contribute to human procrastination behavior because when task completion comes just before the deadline, it may become a stronger conditioned reinforcer than if task completion comes earlier.

Prior commitment: Its effect on suboptimal choice in a gambling-like task.

Animals choose suboptimally when provided with cues that signal whether reinforcement is coming or not. For example, pigeons do not prefer an alternative that always provides them with a signal for reinforcement over an alternative that provides them with a signal for reinforcement only half of the time and a signal for the absence of reinforcement the rest of the time. In the present research, we tested the hypothesis that if the results of the choice are delayed, pigeons will choose less suboptimally. We tested this hypothesis by forcing pigeons to wait following their choice, requiring them to complete a fixed-interval 20-s schedule prior to receiving the signals for reinforcement. In Experiment 1, we gave the pigeons a choice between (a) a 50% chance of receiving a signal for reinforcement or a 50% chance of receiving a signal for the absence of reinforcement and (b) a 100% chance of receiving a signal for reinforcement. When the signal for reinforcement was delayed, most of the pigeons chose optimally. When it was not delayed, most of the pigeons chose suboptimally. In Experiment 2, we gave the pigeons a choice between (a) a 25% chance of receiving a signal for reinforcement or a 75% chance of receiving a signal for nonreinforcement and (b) a 100% chance of receiving an unreliable signal for reinforcement (predicting reinforcement 75% of the time). When the signal was not delayed, the pigeons showed a strong tendency to choose suboptimally but they chose suboptimally much less when the signal was delayed.

Uptake of Three Antibiotics and an Antiepileptic Drug by Wheat Crops Spray Irrigated with Wastewater Treatment Plant Effluent.

With rising demands on water supplies necessitating water reuse, wastewater treatment plant (WWTP) effluent is often used to irrigate agricultural lands. Emerging contaminants, like pharmaceuticals and personal care products (PPCPs), are frequently found in effluent due to limited removal during WWTP processes. Concern has arisen about the environmental fate of PPCPs, especially regarding plant uptake. The aim of this study was to analyze uptake of sulfamethoxazole, trimethoprim, ofloxacin, and carbamazepine in wheat ( L.) plants that were spray-irrigated with WWTP effluent. Wheat was collected before and during harvest, and plants were divided into grain and straw. Subsamples were rinsed with methanol to remove compounds adhering to surfaces. All plant tissues underwent liquid-solid extraction, solid-phase extraction cleanup, and liquid chromatography-tandem mass spectrometry analysis. Residues of each compound were present on most plant surfaces. Ofloxacin was found throughout the plant, with higher concentrations in the straw (10.2 ± 7.05 ng g) and lower concentrations in the grain (2.28 ± 0.89 ng g). Trimethoprim was found only on grain or straw surfaces, whereas carbamazepine and sulfamethoxazole were concentrated within the grain (1.88 ± 2.11 and 0.64 ± 0.37 ng g, respectively). These findings demonstrate that PPCPs can be taken up into wheat plants and adhere to plant surfaces when WWTP effluent is spray-irrigated. The presence of PPCPs within and on the surfaces of plants used as food sources raises the question of potential health risks for humans and animals.

Vadose Zone Transport of Natural and Synthetic Estrogen Hormones at Penn State's "Living Filter" Wastewater Irrigation Site.

The increase in endocrine-disrupting compounds in the environment has generated research focused on the behavior of these compounds in natural soil and water ecosystems. To understand how estrogens behave in the soil environment as a result of 25+ yr of wastewater irrigation, soils from Penn State's "Living Filter" wastewater irrigation site were extracted and analyzed for two natural estrogens (17ß-estradiol and estrone) and one synthetic estrogen (17α-ethynylestradiol). Soil estrogen concentrations were compared for two independent variables: type of land cover and sampling time. Soils were sampled from cropped and forested land areas, and soils were sampled 2 d and 3 wk after a single 12-h effluent irrigation event. A nonirrigated control site was sampled to provide natural background data. For 17ß-estradiol, the nonirrigated mean concentration was 0.68 ± 0.11 ng cm, and the irrigated values, including samples from both land areas and time frames, ranged from 0.99 ± 0.11 to 1.82 ± 0.69 ng cm. For estrone, the nonirrigated mean concentration was 2.36 ± 0.22 ng cm, and the irrigated values, including samples from both land areas collected and time frames, ranged from 2.18 ± 0.20 to 6.24 ± 3.14 ng cm. The 17α-ethynylestradiol nonirrigated mean concentration was 0.47 ± 0.40 ng cm. The irrigated values, including samples from both land areas and time frames, ranged from 0.25 ± 0.06 to 1.37 ± 0.39 ng cm. This study found that time of sampling, land cover, and irrigation can affect estrogen concentrations in soils, resulting in levels that exceed natural background and require improvements in management practices.

An MVA-based vaccine targeting the oncofetal antigen 5T4 in patients undergoing surgical resection of colorectal cancer liver metastases.

We investigated the use of a therapeutic vaccine, TroVax in patients undergoing surgical resection of colorectal cancer liver metastases. Systemic immunity generated by vaccination before and after resection of metastases was measured in addition to assessing safety and analyzing the function and phenotype of tumor-associated lymphocytes. Twenty patients were scheduled to receive 2 TroVax vaccinations at 2-week intervals preoperatively and 2 postoperatively; if immune responses were detected, 2 further vaccinations were offered. Blood was taken at trial entry and 2 weeks after each vaccination; tumor biopsies were collected at surgery. 5T4-specific cellular responses were assessed by lymphocyte proliferation and enzyme-linked immunosorbent spot, with antibody responses by enzyme-linked immunosorbent assay. Immunohistochemistry characterized the phenotype of tumor-infiltrating lymphocytes. Seventeen of 19 colorectal cancer patients showed 5T4 expression in the liver metastases or surrounding stroma and 18 mounted a 5T4-specific cellular and/or humoral response. In patients who received at least 4 vaccinations and potentially curative surgery (n=15), those with above median 5T4-specific proliferative responses or T-cell infiltration into the resected tumor showed significantly longer survival compared with those with below median responses. Seven of 8 patients who had preexisting proliferative responses to 5T4 were longer-term survivors; these patients showed significantly higher proliferative responses after vaccination than those who subsequently died. These data suggest that the magnitude of 5T4 proliferative responses and the density of CD3 cells in colorectal cancer liver metastases are associated with longer survival. These observations warrant more studies to identify the precise underlying mechanisms.