Avoidance of low doses of naphthalene by Collembola

The introduction of behavioural aspects of soil animals in ecological risk assessment would allow us to better assess soil quality, all the more if a range of animal populations are considered. We compared the avoidance behaviour of several strains of springtails (Arthropoda: Collembola) obtained from different soils. Naphthalene, a polycyclic aromatic hydrocarbon (PAH), widely represented in soils polluted with hydrocarbons, was tested in aqueous solutions on nine springtail species issuing from four sites. Fine quartz sand saturated with an aqueous solution of naphthalene was avoided by most of the tested species, avoidance being, however, detected down to a concentration of 0.030 mg L(-1). Folsomia candida (Isotomidae) was shown to be relatively tolerant to pollutants compared to other Collembola such as Mesaphorura macrochaeta, Mesaphorura yosii (Onychiuridae), Parisotoma notabilis (Isotomidae) and Arrhopalites caecus (Arrhopalitidae). Differences between strains could not be explained by properties of the original soils.     

Rates and processes affecting As speciation and mobility in lake sediments during aging

Sediments from an arsenic(As) contaminated groundwater vent site were used to investigate As( Ⅲ) binding, transformation and redistribution in native and iron oxide amended lake sediments using aging spiked batch reactions and a sequential extraction procedure that maintains As(V) and As( Ⅲ) speciation. In the native sediments, fractionation analysis revealed that 10% of the spiked As( Ⅲ) remained intact after a 32-day aging experiment and was predominantly adsorbed to the strongly sorbed(NH_4H_2PO_4 extractable) and amorphous Fe oxide bound(H_3PO_4 extractable) fractions. Kinetic modelling of the experimental results allowed identifying the dominant reaction path for depletion of dissolved As( Ⅲ) to As( Ⅲ)absorbed on to the solid phase, followed by oxidation in the solid phase. Arsenite was initially adsorbed primarily to the easily exchangeable fraction((NH_4)_2SO_4 extractable), then rapidly transformed into As(V) and redistributed to the strongly sorbed and amorphous Fe oxide bound fractions. Oxidation of As( Ⅲ) in recalcitrant fractions was less efficient. The iron oxide amendments illustrated the controls that iron oxides can have on As( Ⅲ) binding and transformation rates. In goethite amended samples As( Ⅲ) oxidation was faster and primarily occurred in the strongly sorbed and amorphous Fe oxide bound fractions. In these samples,19.3 μg Mn was redistributed(compared to the native sediment) from the easily exchangeable and crystalline Fe oxide bound fractions to the strongly sorbed and amorphous Fe oxide bound fractions, indicating that goethite may act as a catalyst for Mn(Ⅱ) oxidation, thereby producing sorbed Mn( Ⅲ/Ⅳ ), which then appears to be involved in rapidly oxidizing As( Ⅲ).     

Passive air sampling of DDT, chlordane and HCB in the Pearl River Delta, South China: implications to regional sources

The Pearl River Delta (PRD) is one of the largest fast-developing economic zones in China. Hong Kong and the mainland part of the PRD differed in socio-economic development history and chemical management policies. Polyurethane foam (PUF)-passive air sampling (PAS) was deployed at 21 regional air quality monitoring stations across the PRD in summer and winter, respectively. Dichloro-diphenyl-trichloroethane (DDT), chlordane and hexachlorobenzene (HCB) were analyzed with GC-MS. High total DDT (240-3700 pg m(-3)) and chlordane (100-2600 pg m(-3)) concentrations were observed. Concentrations of DDTs and chlordane were higher in summer than winter; HCB vice versa. Spatially, the mainland part of the PRD generally displayed higher DDT concentrations than Hong Kong. Antifouling paint for fishing ships in coastal China was suggested to be an important current DDT source in the coast. The reason is unknown for the very low trans-/cis-chlordane (TC/CC) ratios (0.27) found in the mainland in winter. HCB concentrations were relatively uniform across the PRD, and long range transport of HCB from inland/North China to the PRD in winter was suggested.     

Effects of ultraviolet light (315 nm), temperature and relative humidity on the degradation of polylactic acid plastic films

The influence of temperature (30, 45 and 60 degrees C) and relative humidity (RH) (30%, 50% and 100%) on the degradation of poly(l-lactic acid) (PLA) films were studied. In addition, the effects of ultraviolet (UV) light (315 nm) on the degradation of PLA films were also analyzed. Various analytical techniques were applied to observe changes in the properties of PLA polymer films. FTIR spectroscopy was used as semi-quantitative method to get information about the chemistry of the degradative process. The degradation rate of PLA was enhanced by increasing temperature and RH, factors responsible for a faster reduction of the weight-average molecular weight (M(W)), of the glass transition temperature (Tg) and of the percentage of elongation at break. Moreover, UV treatment accelerated these phenomena.     

Degradation of phenols in olive oil mill wastewater by biological,enzymatic, and photo-Fenton oxidation

Background, aim, and scope  

Olive oil mill wastewater (OOMW) environmental impacts minimization have been attempted by developing more effective processes, but no chemical or biological treatments were found to be totally effective to mitigate their impact on receiving systems. This work is the first that reports simultaneously the efficiency of three different approaches: biological treatment by two fungal species (Trametes versicolor or Pleurotus sajor caju), enzymatic treatment by laccase, and chemical treatment by photo-Fenton oxidation on phenols removal.     

Delivering an accredited non-invasive prenatal diagnosis service for monogenic disorders and recommendations for best practice

The identification of cell-free fetal DNA circulating in maternal blood combined with technological developments, in particular next-generation sequencing, is enabling the development of safer prenatal diagnosis. While this technology has been widely applied as a highly sensitive screening test for aneuploidy, there has been relatively little clinical application for the diagnosis of monogenic disorders. In the UK, we have established non-invasive prenatal diagnosis (NIPD) as a clinical service for a range of inherited disorders. The results from NIPD do not require confirmation by invasive testing and are welcomed by patients and health professionals alike. Here, we describe the technical approaches used, current practice and outline recommendations for best practice when delivering an NIPD service from an accredited laboratory. © 2017 John Wiley & Sons, Ltd.