Bio-accessibility and health risk assessment of some selected heavy metals in indoor dust from higher institutions in Ondo State,Nigeria

Environmental Science and Pollution Research - Risks of heavy metal exposure from contaminated indoor dust constitute a major threat to human health. In this paper, heavy metals in deposited indoor...     

Rapid adaptation to crisis events: Insights from the bait crisis in the Maine lobster fishery

Climate change, overfishing, and other anthropogenic drivers are forcing marine resource users and decision makers to adapt—often rapidly. In this article we introduce the concept of pathways to rapid adaptation to crisis events to bring attention to the double-edged role that institutions play in simultaneously enabling and constraining swift responses to emerging crises. To develop this concept, we draw on empirical evidence from a case study of the iconic Maine lobster (Homarus americanus) industry. In the Gulf of Maine, the availability of Atlantic herring (Clupea harengus) stock, a key source of bait in the Maine lobster industry, declined sharply. We investigate the patterns of bait use in the fishery over an 18-year period (2002–2019) and how the lobster industry was able to abruptly adapt to the decline of locally-sourced herring in 2019 that came to be called the bait crisis. We found that adaptation strategies to the crisis were diverse, largely uncoordinated, and imperfectly aligned, but ultimately led to a system-level shift towards a more diverse and globalized bait supply. This shift was enabled by existing institutions and hastened an evolution in the bait system that was already underway, as opposed to leading to system transformation. We suggest that further attention to raceways may be useful in understanding how and, in particular, why marine resource users and coastal communities adapt in particular ways in the face of shocks and crises.Supplementary InformationThe online version contains supplementary material available at 10.1007/s13280-021-01617-8.     

Remediation of a chlorinated aromatic hydrocarbon in water by photoelectrocatalysis

Photoelectrocatalysis driven by visible light offers a new and potentially powerful technology for the remediation of water contaminated by organo-xenobiotics. In this study, the performance of a visible light-driven photoelectrocatalytic (PEC) batch reactor, applying a tungsten trioxide (WO₃) photoelectrode, to degrade the model pollutant 2,4-dichlorophenol (2,4-DCP) was monitored both by toxicological assessment (biosensing) and chemical analysis. The bacterial biosensor used to assess the presence of toxicity of the parent molecule and its breakdown products was a multicopy plasmid lux-marked E. coli HB101 pUCD607. The bacterial biosensor traced the removal of 2,4-DCP, and in some case, its toxicity response suggests the identification of transient toxic intermediates. The loss of the parent molecule, 2,4-DCP determined by HPLC, corresponded to the recorded photocurrents. Photoelectrocatalysis offers considerable potential for the remediation of chlorinated hydrocarbons, and that the biosensor based toxicity results identified likely compatibility of this technology with conventional, biological wastewater treatment.     

Estimating the Economic Value of National Parks with Count Data Models Using On-Site,Secondary Data: The Case of the Great Sand Dunes National Park and Preserve

We estimate an individual travel cost model for Great Sand Dunes National Park and Preserve (GSD) in Colorado using on-site, secondary data. The purpose of the on-site survey was to help the National Park Service better understand the visitors of GSD; it was not intended for a travel cost model. Variables such as travel cost and income were estimated based on respondents’ Zip Codes. Following approaches found in the literature, a negative binomial model corrected for truncation and endogenous stratification fit the data the best. We estimate a recreational benefit of U.S. $89/visitor/year or U.S. $54/visitor/24-h recreational day (in 2002 U.S. $). Based on the approach presented here, there are other data sets for national parks, preserves, and battlefields where travel cost models could be estimated and used to support National Park Service management decisions.     

The impact of alum addition on organic P transformations in poultry litter and litter-amended soil

Poultry litter treatment with alum (Al(2)(SO(4))(3) . 18H(2)O) lowers litter phosphorus (P) solubility and therefore can lower litter P release to runoff after land application. Lower P solubility in litter is generally attributed to aluminum-phosphate complex formation. However, recent studies suggest that alum additions to poultry litter may influence organic P mineralization. Therefore, alum-treated and untreated litters were incubated for 93 d to assess organic P transformations during simulated storage. A 62-d soil incubation was also conducted to determine the fate of incorporated litter organic P, which included alum-treated litter, untreated litter, KH(2)PO(4) applied at 60 mg P kg(-1) of soil, and an unamended control. Liquid-state (31)P nuclear magnetic resonance indicated that phytic acid was the only organic P compound present, accounting for 50 and 45% of the total P in untreated and alum-treated litters, respectively, before incubation and declined to 9 and 37% after 93 d of storage-simulating incubation. Sequential fractionation of litters showed that alum addition to litter transformed 30% of the organic P from the 1.0 mol L(-1) HCl to the 0.1 mol L(-1) NaOH extractable fraction and that both organic P fractions were more persistent in alum-treated litter compared with untreated litter. The soil incubation revealed that 0.1 mol L(-1) NaOH-extractable organic P was more recalcitrant after mixing than was the 1.0 mol L(-1) HCl-extractable organic P. Thus, adding alum to litter inhibits organic P mineralization during storage and promotes the formation of alkaline extractable organic P that sustains lower P solubility in the soil environment.     

Variations in pesticide leaching related to land use, pesticide properties, and unsaturated zone thickness

Pesticide leaching through variably thick soils beneath agricultural fields in Morgan Creek, Maryland was simulated for water years 1995 to 2004 using LEACHM (Leaching Estimation and Chemistry Model). Fifteen individual models were constructed to simulate five depths and three crop rotations with associated pesticide applications. Unsaturated zone thickness averaged 4.7 m but reached a maximum of 18.7 m. Average annual recharge to ground water decreased from 15.9 to 11.1 cm as the unsaturated zone increased in thickness from 1 to 10 m. These point estimates of recharge are at the lower end of previously published values, which used methods that integrate over larger areas capturing focused recharge in the numerous detention ponds in the watershed. The total amount of applied and leached masses for five parent pesticide compounds and seven metabolites were estimated for the 32-km2 Morgan Creek watershed by associating each hectare to the closest one-dimensional model analog of model depth and crop rotation scenario as determined from land-use surveys. LEACHM parameters were set such that branched, serial, first-order decay of pesticides and metabolites was realistically simulated. Leaching is predicted to be greatest for shallow soils and for persistent compounds with low sorptivity. Based on simulation results, percent parent compounds leached within the watershed can be described by a regression model of the form e(-depth) (a ln t1/2-b ln K OC) where t1/2 is the degradation half-life in aerobic soils, K OC is the organic carbon normalized sorption coefficient, and a and b are fitted coefficients (R2 = 0.86, p value = 7 x 10(-9)).     

Measuring the Impact of Urbanization on Channel Widths Using Historic Aerial Photographs and Modern Surveys1

Abstract: Land use in a watershed is commonly held to exert a strong influence on trunk channel form and process. Land use changes act over human time‐scales, which are short enough to measure effects on channels directly using historic aerial photographs. We show that high‐resolution topographic surveys for the channels of paired watersheds in the Lehigh Valley, Pennsylvania, are comparable, but have channel widths that have changed dramatically in the past five decades. The two watersheds, Little Lehigh Creek and Sacony Creek, are similar in most aspects except in their respective amount of urban land use. Aerial photographs of the urbanized Little Lehigh Creek show that a majority of the measured widths (67 of 85) were statistically wider in 1999 than in 1947. In contrast, the measured widths from the agricultural Sacony Creek are more evenly distributed among those that widened (18), narrowed (28), and those that were statistically unchanged (6) from 1946 to 1999. From 1946 to 1999 the only section of Sacony Creek that widened was that reach downstream of the only sizable urban area in the watershed. The current land use in Sacony Creek watershed resembles that of 1946, while the Little Lehigh Creek watershed has more than tripled its urban area. These data, in concert with other recent hydrologic data from the watersheds suggest that the increase in urban area‐generated peak discharges is the mechanism behind the widening that occurred in the Little Lehigh Creek. These wider channels can affect water quality, aquatic habitat, suspended sediment loads, and river esthetics.     

Kinetics of particulate organic matter removal as a response to bioflocculation in aerobic biofilm reactors.

Recent research has identified that the major fraction of chemical oxygen demand in domestic wastewaters is in particulate form. The research presented herein develops the kinetics of particle removal as a response to bioflocculation at the surface of aerobic biofilms. This study focuses on the removal of particles that are maintained in aqueous suspension after 30 minutes of gravity settling. It is helpful to consider the particulate organics removal process in biofilms as the sum of four steps, namely (1) external transport of the particles to the biofilm surface, (2) bioflocculation, (3) organic particulate hydrolysis, and (4) diffusion and reaction of the solubilized organics by the bacterial cells comprising the biofilm. Organic (native corn starch) and inorganic particle (Min-U-Sil 10 [U.S. Silica Company, Berkeley Springs, West Virginia]) suspensions, with micronutrients, were continuously fed to a rotating disc biofilm reactor to verify a first-order kinetic expression that has been used to describe bioflocculation and to demonstrate that bioflocculation is the primary particle removal mechanism. Extracellular polymeric substances were extracted and quantified to describe the role they play in the bioflocculation process.