Do salmon farms increase the concentrations of mercury and other elements in wild fish?

Earlier assessments have suggested that salmon farms may act as a source of mercury (Hg) and other elements in local marine environments. In this study, we measured 30 elements in the livers of demersal Atlantic cod (Gadus morhua) and pelagic saithe (Pollachius virens) caught in association with salmon farms (farm associated [FA]; n = 75) or at reference locations (control; n = 80) in three regions throughout the latitudinal extent of Norway (59-70° N). Concentrations of most elements (24 of 30) were higher (20-70%) in cod compared to saithe. In particular, Hg was 6.8 times higher in cod than saithe. Nine elements were significantly different between FA saithe and control saithe, but only four (Hg, U, Cr and Mn) were highest in FA saithe, and this pattern was only detected consistently across all locations for Hg. Thirteen elements differed in concentration between FA cod and control cod, but only three elements (U, Al and Ba) were higher in FA cod than controls, and this pattern was only detected consistently across all locations for Al. After controlling for a set of potentially confounding variables, the estimated concentrations of Hg in saithe livers were ～80% higher in FA fish compared to controls. In contrast, Hg concentrations were ～40% higher in control cod compared to FA cod. Our results do not support the notion that salmon farms in general increase the concentrations of potentially harmful elements in wild fish, and the distribution of Hg and other elements in cod and saithe in Norwegian coastal waters may be more influenced by habitat use, diet, geochemical conditions and water chemistry.     

A COMPARISON OF METHODS FOR CALCULATION OF RADAR-RAINFALL HOURLY ACCUMULATIONS1

ABSTRACT: We compared two interpolation schemes for calculation of hourly accumulation of radar-rainfall. The schemes are: (1) the Advection Method, and (2) the Space-Time Kriging Method. The performance of the methods is investigated using numerical simulation experiments. Space-time evolution of rainfall fields is generated from a stochastic model. The generated fields are sampled following typical radar scanning strategies, and the investigated schemes are applied to obtain accumulated rainfall patterns. The statistical results and a visual analysis of the graphical images suggest that it is advisable to use an interpolation scheme for radar observations even when storm velocity is not high. The Space-Time Kriging Method provides the best results for low wind velocity. The Advection Method has the smallest standard deviation and mean absolute error, and preserves well the true rainfall pattern for high wind velocity.     

A Vibroacoustic Model of Selected Human Larynx Diseases

With the present development of digital registration and methods for processing speech it is possible to make effective objective acoustic diagnostics for medical purposes. These methods are useful as all pathologies and diseases of the human vocal tract influence the quality of a patient’s speech signal. Diagnostics of the voice organ can be defined as an unambiguous recognition of the current condition of a specific voice source. Such recognition is based on an evaluation of essential acoustic parameters of the speech signal. This requires creating a vibroacoustic model of selected deformations of Polish speech in relation to specific human larynx diseases. An analysis of speech and parameter mapping in 29-dimensional space is reviewed in this study. Speech parameters were extracted in time, frequency and cepstral (quefrency) domains resulting in diagrams that qualified symptoms and conditions of selected human larynx diseases. The paper presents graphically selected human larynx diseases.     

REAL-TIME QUALITY CONTROL OF STREAMFLOW DATA—A SIMULATION STUDY1

ABSTRACT: The problem of real-time quality control of streamflow data is addressed. Five methods are investigated via a Monte-Carlo simulation experiment based on streamflow data from Bird Creek basin in Oklahoma. The five methods include three deterministic approaches and two statistical approaches. The relative performance of the investigated methods is evaluated under hypothesized random mechanism generating isolated outliers. The deterministic method based on streamflow gradient analysis and the statistical method based on forecast residual analysis perform best in detecting such outliers.     

Exploring Persistence in Streamflow Forecasting

In this study, the authors explore three persistence approaches in streamflow forecasting motivated by the need for forecasting model skill evaluation. The authors use streamflow observations with 15 min resolution from the year 2008 to 2017 at 140 United States Geological Survey streamflow gauges monitoring the streams and rivers over the State of Iowa. The spatial scale of the basins ranges from about 7 to 37,000 km². The study explores three approaches: simple persistence, gradient persistence, and anomaly persistence. The study shows that persistence forecasts skill has strong dependence on basin scales and weaker but non‐negligible dependence on geometric properties of the river network for a given basin. Among the three approaches explored, anomaly persistence shows highest skill especially for small basins, under about 500 km². The anomaly persistence can serve as a benchmark for model evaluations considering the effect of basin scales and geometric properties of river network of the basin. This study further reiterates that persistence forecasts are hard‐to‐beat methods for larger basin scales at short to medium forecast range.     

Near-road multipollutant profiles: associations between volatile organic compounds and a tracer gas surrogate near a busy highway

This research characterizes associations between multiple pollutants in the near-road environment attributed to a roadway line source. It also examines the use of a tracer gas as a surrogate of mobile source pollutants. Air samples were collected in summa canisters along a 300 m transect normal to a highway in Raleigh, North Carolina for five sampling periods spanning four days. Samples were subsequently measured for volatile organic compounds (VOCs) using an electron capture gas chromatograph. Sulfur hexafluoride (SF6) was released from a finite line source adjacent to the roadway for two of the sampling periods, collected in the canisters and measured with the VOCs. Associations between each VOC, and between VOCs and the tracer, were quantified with Pearson correlation coefficients to assess the consistency of the multi-pollutant dispersion profiles, and assess the tracer as a potential surrogate for mobile source pollutants. As expected, benzene, toluene, ethylbenzene, and m,p- and o-xylenes (collectively, BTEX) show strong correlations between each other; further BTEX shows a strong correlation to SF6. Between 26 VOCs, correlation coefficients were greater than 0.8, and 14 VOCs had coefficients greater than 0.6 with the tracer gas. Even under non-downwind conditions, chemical concentrations had significant correlations with distance. Results indicate that certain VOCs are representative of a larger multi-pollutant mixture, and many VOCs are well-correlated with the tracer gas.     

Possibilistic regression analysis of influential factors for occupational health and safety management systems

The code of occupational health and safety (OHS) is an influential regulation to improve the on-the-job safety of employees. A number of factors influence the planning and implementation of OHS management systems (OHSMS). The evaluation of OHSMS practice is the most important component when forming a health and safety environmental policy for employees. The objective of this research is to develop an intelligent data analysis (IDA) in which possibilistic regression being endowed with a convex hull approach is used to support the analysis of essential factors that influence OHSMS. Given such subjective terms, the obtained samples can be conveniently regarded as fuzzy input/output data represented by membership functions. The study offers this vehicle of intelligent data analysis as an alternative to evaluate the influential factors in a successful implementation of OHS policies and in this way decrease an overall computational effort. The obtained results show that several related OHSMS influential factors need to be carefully considered to facilitate a successful implementation of the OHSMS procedure.     

Comparative toxicity assessment of in situ burn residues to initial and dispersed heavy fuel oil using zebrafish embryos as test organisms

Environmental Science and Pollution Research - In situ burning (ISB) is discussed to be one of the most suitable response strategies to combat oil spills in extreme conditions. After burning, a...     

Filtration Properties of Nonwovens

Abstract

This paper presents the results and conclusions from experimental investigations concerning filtration properties of nonwovens. The needled nonwovens were made from polyester fibres (PTE) with average fibre diameter 12 µm and polypropylene fibres (PP) with average fibre diameter 32 μm. Nonwovens were produced out of each of those fibres or out of a mixture of polyester and polypropylene fibres. This paper also presents investigations of nonwoven fabric made of polypropylene fibres (PP) with average fibre diameter 2.6 μm, which was formed according to melt-blown technology. Oil mist, as challenge aerosol, was used to evaluate the performance of filter media at various aerosol velocities. The average oil mist test aerosol particle diameter was 0.3 μm. Filter penetration was measured at oil mist concentration 0.24 g/m³.     

Analysis and DNA interaction of the profluralin herbicide

Environmental Chemistry Letters - The increasing use of pesticides is a major health issue. There is therefore a need for improved analytical methods and more knowledge on the interaction of...