Multivariate tools to investigate the spatial contaminant distribution in a highly anthropized area (Gulf of Naples,Italy)

Environmental Science and Pollution Research - The Gulf of Naples located in a high anthropized coastal area is subjected to an infrastructural intervention for the installation of a submarine...     

Stream water chemistry in the arsenic-contaminated Baccu Locci mine watershed (Sardinia, Italy) after remediation

The abandoned Pb–As Baccu Locci mine represents the first and only case of mine site remediation in Sardinia, Italy. Arsenic is the most relevant environmental concern in the Baccu Locci stream watershed, with concentrations in surface waters up to and sometimes over 1 mg/L. The main remediation action consisted in creation of a “storage site”, for the collection of contaminated materials from different waste-rock dumps and most of tailings piles occurring along the Baccu Locci stream. This paper reports preliminary results on the level of contamination in the Baccu Locci stream after the completion of remediation measures. Post-remediation stream water chemistry has not substantially changed compared to the pre-remediation situation. In particular, dissolved As maintains an increasing trend along the Baccu Locci stream, with a concentration of about 400 μg/L measured at a distance of 7 km from the storage site. Future monitoring will provide fundamental information on the effectiveness of remediation actions conducted and their applicability to other mine sites in Sardinia. At the stage of mine site characterisation of future remediation plans, it is recommended to pay more attention to the understanding of mineralogical and geochemical processes responsible for pollution. Moreover, mixing of materials with different composition and reactivity in a storage site should require careful consideration and long-term leaching tests.     

Accumulation of organochlorine contaminants in loggerhead sea turtles, Caretta caretta, from the eastern Adriatic Sea

We analyzed 15 polychlorinated biphenyls (PCBs) and five organochlorine pesticides (OCPs) in fat tissue of 27 loggerhead sea turtles (Caretta caretta) from eastern Adriatic Sea with the curved carapace length ranging from 25.0 to 84.5 cm. The PCB profile was dominated by hexa- and hepta-chlorinated congeners, with PCB-153 (median: 114.9 ng g⁻¹ wet mass), PCB-138 (80.0 ng g⁻¹ w.m.), and PCB-180 (26.7 ng g⁻¹ w.m.) detected with the highest levels. Toxic mono-ortho congeners PCB-118, PCB-105 and PCB-180 with dioxin-like toxicity were found in >70% samples. 4,4′-DDE (81.0 ng g⁻¹ w.m.) prevailed the OCP signature, accounting for 80% of the total DDTs. A significant increasing trend in accumulation with size was found for PCB-52 (r_s = 0.512, p < 0.01) and PCB-114 (r_s = 0.421, p < 0.05). Comparison of our results with organochlorine contaminant (OC) pattern in some prey taxa suggest that contamination occurs primarily through the food web, with biomagnification factors of 0.14-6.99 which were positively correlated with the octanol-water partition coefficient (log K_ow; p < 0.05). This study, based upon a fairly large sample size collected mostly from incidentally captured animals over a short time period (June 2001-November 2002), present a temporal snapshot of OC contamination in wild, free-ranging loggerheads from Adriatic feeding grounds and provide a baseline for monitoring the regional OC trends in this endangered species.     

Effects assessment: boron compounds in the aquatic environment

In previous studies, boron compounds were considered to be of comparatively low toxicity in the aquatic environment, with predicted no effect concentration (PNEC) values ranging around 1 mg B/L (expressed as boron equivalent). In the present study, we describe an evaluation of toxicity data for boron available for the aquatic environment by different methods.For substances with rich datasets, it is often possible to perform a species sensitivity distribution (SSD). The typical outcome of an SSD is the Hazardous Concentration 5% (HC₅), the concentration at which 95% of all species are protected with a probability of 95%. The data set currently available on the toxic effects of boron compounds to aquatic organisms is comprehensive, but a careful evaluation of these data revealed that chronic data for aquatic insects and plants are missing. In the present study both the standard assessment factor approach as well as the SSD approach were applied. The standard approach led to a PNEC of 0.18 mg B/L (equivalent to 1.03 mg boric acid/L), while the SSD approach resulted in a PNEC of 0.34 mg B/L (equivalent to 1.94 mg boric acid/L). These evaluations indicate that boron compounds could be hazardous to aquatic organisms at concentrations close to the natural environmental background in some European regions. This suggests a possible high sensitivity of some ecosystems for anthropogenic input of boron compounds. Another concern is that the anthropogenic input of boron could lead to toxic effects in organisms adapted to low boron concentration.     

Non-electrostatic surface complexation models for protons and lead(II) sorption onto single minerals and their mixture

Potentiometric titrations and lead sorption tests were conducted using muscovite, clinochlore, hematite, goethite, quartz, and a mixture of these same minerals. Mechanistic models were developed to represent and interpret these data. The aim was isolating the specific contribution of each mineral in proton and lead binding. Acid-base properties of each single mineral as well as their mixture were represented by discrete models, which consider the dissociation of n monoprotic sites (n-site/n-K(H) models). A one-site/one-K(H) model (logK(H1) = 10.69) was chosen for quartz (dissociation of SiOH edge hydroxyl groups). Goethite and hematite (FeOH groups) were represented by the same one-site/one-K(H) model (logK(H1) = 10.35). Three-site/three-K(H) models were used for muscovite (logK(H1) = 4.18; logK(H2) = 6.65; logK(H3) = 9.67) and clinochlore (logK(H1) = 3.84; logK(H2) = 6.57; logK(H3) = 9.71) assuming that SiOH and AlOH of the aluminosilicate matrix dissociate in the acid-neutral pH range while SiOH groups of quartz inclusions dissociate in the basic range. Similarly, the mixture of these minerals was represented by a three-site/three-K(H) model (logK(H1) = 3.39; logK(H2) = 6.72; logK(H3) = 10.82). According to crossed comparisons with single minerals, the first two sites of the mixture were associated with the aluminosilicate matrix (SiOH and AlOH respectively) and the third site with iron oxides (FeOH) and quartz groups. Additivity of proton binding in the mixture was demonstrated by simulating the mixture's titration curve. A unified model for the entire set of titration curves (single minerals and mixture) was also developed introducing a three-peak distribution function for proton affinity constants. Experimental data for lead sorption onto the mixture and individual minerals in 3-5 pH range denoted the competition between protons and metallic ions. The entire set of lead isotherms (individual mineral and mixture data) was represented adequately by a unified model taking into account both monodentate and bidentate complexes with the three active sites (additivity of lead binding). Experimental data of metal distribution in solid and liquid phases were successfully simulated by implementing the protonation and the surface complexation constants into the database of a dedicated software for chemical equilibria.     

Germination,root elongation,and photosynthetic performance of plants exposed to sodium lauryl ether sulfate (SLES): an emerging contaminant

Environmental Science and Pollution Research - The anionic surfactant SLES (sodium lauryl ether sulfate) is an emerging contaminant, being the main component of foaming agents that are increasingly...     

大气超细颗粒物观测和扩散模拟研究进展

总结了近年来不同地区对不同环境下大气超细颗粒物的观测和扩散模拟研究进展。大量的观测研究结果表明,大气超细颗粒物的时空分布、组成特征、形成和成长的特性因观测地区的不同而存在很大差异,受气象因素和局部污染源的影响很大;其来源主要包括固定、移动燃烧源的直接排放和大气中颗粒成核现象,前一种来源一般是局部的,而后一种来源则是区域性的。目前,大多数关于大气超细颗粒物扩散的模拟研究都是针对其质量浓度的,对其数浓度扩散的模拟研究主要集中在小范围(机动车排放烟云的研究方面),在城市区域范围上的研究和应用还很少。最后,探讨和展望了大气超细颗粒物今后的主要研究方向和研究中面临的挑战。     

Genotoxicity evaluation of water soil leachates by Ames test, comet assay, and preliminary Tradescantia micronucleus assay

Combining genotoxicity/mutagenicity tests and physico-chemical methodologies can be useful for determining the potential genotoxic contaminants in soil samples. The aim of our study was to evaluate the genotoxicity of soil by applying an integrated physico-chemical-biological approach. Soil samples were collected at six sampling points in a Slovenian industrial and agricultural region where contamination by heavy metals and sulphur dioxide (SO₂) are primarily caused by a nearby power plant. The in vitro alkaline version of the comet assay on water soil leachates was performed with Caco-2 and HepG2 cells. A parallel genotoxicity evaluation of the samples was performed by Ames test using Salmonella typhimurium and the Tradescantia micronucleus test. Pedological analyses, heavy metal content determination, and different physico-chemical analyses, were also performed utilizing standard methodology. Water leachates of soil samples were prepared according to standard methods. Since only a battery of biotests with prokaryotic and eukaryotic organisms or cells can accurately estimate the effects of (geno)toxicants in soil samples and water soil leachates, a combination of three bioassays, with cells or organisms belonging to different trophic levels, was used. Genotoxicity of all six water soil leachates was proven by the comet assay on both human cell lines, however no positive results were detected by bacterial assay, Ames test. The Tradescantia micronucleus assay showed increase in micronuclei formation for three samples. According to these results we can assume that the comet assay was the most sensitive assay, followed by the micronucleus test. The Ames test does not appear to be sensitive enough for water soil leachates genotoxicity evaluations where heavy metal contamination is anticipated.     

Analysis of short-chain chlorinated paraffins: a discussion paper

Short-chain chlorinated paraffins are a class of organic compounds widely used in many industrial applications, extensively diffused into the environment, persistent, bioaccumulative, and toxic towards aquatic organisms. However, their study and monitoring in the environment are still limited. Because of the enormous number of positional isomers that characterise their mixtures, the analysis of this class of pollutants is very difficult to perform. Beside this, the lack of certified reference materials poses a problem for the assessment of the quality assurance/quality control of any analytical procedure. At present, the scientific community does not agree on any analytical reference method, although the monitoring of short-chain chlorinated paraffins has already started in order to comply with the Water Framework Directive of the European Union on water quality. In this paper the regulatory framework, in which chlorinated paraffins are included, and the status concerning their determination are summarized. The main analytical difficulties still existing are discussed, and the definition of a method-defined parameter as well as the development of a standardised method are suggested as a way to obtain comparable monitoring data.