Assessment of the potential bactericide effect of self‐cleaning floors: a proposed protocol

The antibacterial properties of self‐cleaning coatings are based on bactericide nanoparticles (NPs). Ecotoxicity of these NPs have been assessed mostly in suspension, using standard bioassays. Here a protocol is proposed to test actual coating samples, using the Vibrio fischeri bioluminescence inhibition bioassay. The protocol was designed to test bactericide properties of specially coated PVC floors being used in hospital environments under quasinatural conditions, such as prolonged exposure or room temperature. To take into consideration that the light output of the bacteria under prolonged exposure naturally changes, a correction factor is proposed.     

Cu2O纳米颗粒对小麦根系形态及遗传毒性的影响

为了阐明Cu₂O纳米颗粒(NPs)暴露对植物根系的毒性效应,本研究以小麦品种‘周麦18’为材料,采用水培试验方法,研究了10、50、100和200 mg·L^-1浓度的Cu₂O-NPs对小麦幼苗生长、根系活性、形态结构及细胞遗传学毒性的影响。结果表明: 不同浓度的Cu₂O-NPs降低了小麦幼苗的根芽长度、鲜重、根活性和根冠比,增加了初生根的数量;随着Cu₂O-NPs浓度的升高,幼苗根伸长区缩短、根系变硬变脆、根径增加、根冠变大;100 mg·L^-1浓度的Cu₂O-NPs处理下,小麦根尖有丝分裂指数显著降低,根尖细胞形状不规则化、质壁分离、细胞出现空泡化、细胞核核膜模糊、核内染色体异常。在水培条件下,Cu₂O-NPs对小麦幼苗具有一定的遗传学毒性效应,从而影响小麦幼苗的生长发育和根系形态结构。     

氯酸盐生态毒理研究进展

氯酸盐是一类毒性强氧化剂。20世纪,氯酸钠曾被作为非选择性除草剂和脱叶剂在农业生产中大量施用。近年来,氯酸钾作为龙眼产期调控剂也在反季节龙眼生产中应用。然而,氯酸根离子强氧化性对生物体有明显的毒害效应,且其分解产物亚氯酸根和次氯酸根离子对水体和土壤等环境也存在较强的污染效应。本文在介绍氯酸盐理化性质基础上,初步分析了氯酸盐对植物、动物、微生物和人体的毒害效应,探讨了氯酸盐在土壤和水体中的环境行为,提出了如何在生产实践中安全使用氯酸盐,并就氯酸盐在生态环境中的检测方法和生物降解等研究前沿进行了展望。     

Bioluminescence‐based assays for assessing eco‐ and genotoxicity of airborne emissions

Ecotoxicological tests (or bioassays) are controlled, reproducible tests where ecological responses are determined quantitatively. Due to numerous difficulties arising when airborne emissions are sampled, relatively few ecotoxicological assays have been applied. Aerosol particles are generally collected on a filter, which limits the quantity of the sample, thus also limiting the range of available test organisms. Bacterial bioassays require low sample quantity, and make a good choice when eco‐ or genotoxicity of the sample are to be determined. Of bacterial assays, the bioluminescence inhibition test has been proven applicable for assessing toxicity of airborne contaminants. In this paper diverse test protocols and their modifications are reviewed. Copyright © 2016 John Wiley & Sons, Ltd.     

Degradation of aromatic hydrocarbons by white-rot fungi in a historically contaminated soil

Phanerochaete chrysosporium NRRL 6361 and Pleurotus pulmonarius CBS 664.97 were tested for their ability to grow under nonsterile conditions and to degrade various aromatic hydrocarbons in an aged contaminated soil that also contained high concentrations of heavy metals. After 24 days fungal incubation, carbon-CO2 liberated, an indicator of microbial activity, reached a plateau. At the end of the incubation time (30 days), fungal colonization was clearly visible and was confirmed by ergosterol and cell organic carbon determinations. In spite of unfavorable pH (around 7.4) and the presence of heavy metals, both fungi produced Mn-peroxidase activity. In contrast, laccase and aryl-alcohol oxidase were detected only in the soil treated with P. pulmonarius CBS 664.97 and lignin-peroxidase in that with P. chrysosporium NRRL 6361. No lignin-modifying enzyme activities were present in non-inoculated soil incubated for 30 days (control microcosm). Regardless of the fungus employed, a total removal of naphtalene, tetrachlorobenzene, and dichloroaniline isomers, diphenylether and N-phenyl-1-naphtalenamine, was observed. Significant release of chloride ions was also observed in fungal-treated soil, in comparison with that recorded in the control microcosm. Both fungi led to a significant decrease in soil toxicity, as assessed using two different soil contact assays, including the Lepidium sativum L. germination test and the Collembola mortality test.     

Ecotoxicity evaluation of PFBSK for the whole environmental compartments and comprehensive comparison of hazard and risk to PFOS

A series of perfluorobutane sulfonate (PFBS)-related substances are produced as the alternatives to corresponding perfluorooctane sulfonate (PFOS). However, there is little reliable information about PFBS available for the whole ecotoxicology compartments. At present, its ecotoxicity of perfluorobutane sulfonate potassium (PFBSK) was selected as a typical PFBS chemical to investigate and evaluate its aquatic, terrestrial, microorganism and sediment toxicity according to the Organization for Economic Cooperation and Development (OECD) guideline under the framework of the REACH regulation. Meanwhile, the ecotoxicology hazard and risk for PFBSK and PFOS were compared comprehensively.

PFBSK did not show acute and chronic aquatic, microorganisms and terrestrial animal toxicity, while exhibited some terrestrial plants toxicity. The ecotoxicology of PFBSK decreased sharply except for terrestrial plants compared with PFOS. Especially, for acute and chronic aquatic ecotoxicity, PFBSK is lower than 100 times those of PFOS.

Although the similar terrestrial plants toxicity level was observed for PFBSK and PFOS, the lower risk of PFBSK was deduced for the reason that there was far less chances to be exposed and retained in the soil and sediment for its high water solubility and low adsorption.

In conclusion, PFBSK showed lower ecotoxicity hazard and risk than those of PFOS. PFBSK could be an environmental friendly alternative to PFOS.     

Bioassays with freshwater snails Biomphalaria sp.: from control of hosts in public health to alternative tools in ecotoxicology

Ecotoxicology is the science responsible for the study of the adverse effects of chemicals on ecosystems considering biotic and abiotic components. Several invertebrate groups have long been used to evaluate the aquatic toxicity of chemical compounds. Among these organisms, the microcrustaceans are the most recommended in Brazilian and international protocols (e.g. Daphnia sp. and Ceriodaphnia sp.). Until the beginning of the 1990s, the use of mollusks with ecotoxicological purposes was non-existent, except for the species tested as target of molluscicides in public health studies. Since the second half of this same decade the tests with mollusks have begun to be disseminated in several countries, valuing endemic species and especially the scarcity of test species in benthic habitats. In the early 2000s, with the disclosure of the harmful effects of pollutants with endocrine disrupting properties, gastropods have begun to be used not to evaluate lethal effects, but rather to observe physiological effects such as reproduction and embryonic development. Since then, assays with these approaches, especially with freshwater snails Lymnaea stagnalis and Biomphalaria sp., have been considered to be innovative and highly sensitive, often more than those achieved with traditional groups of test organisms in ecotoxicology (such as microcrustaceans and fishes).     

Bioremediation of Diesel-contaminated Soil by Composting with Locally Generated Bulking Agents

Herein, we conducted a study toward understanding the impact of composting of the diesel-contaminated soil with some locally available bulking agents (rice husks (RHs), sawdust (SD), and wood chips (WCs)). In order to ascertain the effectiveness of petroleum degradation by the process assayed, we compared the protocols with monitored natural attenuation (MNA). The overall degradation pattern was modeled with non-linear regression by comparing the experimental data with first and second-order kinetic equations. At the end of the six-week study, the amount of total petroleum hydrocarbon removed from contaminated soil was 98.26 ± 1.33% (amendment with SD + RHs + WCs), 96.89 ± 1.20 (RHs amendment), 96.55 ± 1.29% (amendment with SD), 90.01 ± 0.22% (WCs amendment), and 85.02 ± 0.21% (MNA). The degradation of TPH trends followed a second-order kinetic model for all the four compost treatments while the MNA was found to follow a first-order (slower) degradation pattern. In general, the results of the parameter estimate showed that amendment with mixture of the three bulking agents was 1.08 (8%) slower (k₂ = (1.289 ± 0.16) × 10^?5 (g mg^?1 d^?1), r² = 0.991) than SD amendment alone (k₂ = (1.392 ± 0.14) × 10^?5 (g mg^?1 d^?1), r² = 0.995). However, the mixture of the bulking agents was found to be 1.67, 1.41, and 2.4 times faster than amendments with WCs, rice, and MNA, respectively. The phytotoxicity test revealed that all the compost treatments except WCs resulted in germination index of ≥80% after six weeks of bioremediation tests. The outcome of the current investigation confirms the effectiveness of bulking agents (especially when combined) in the supply of nutrients for the bioremediation of diesel-impacted soil.     

湘西河流表层沉积物重金属污染特征及其潜在生态毒性风险

花垣河和峒河是湘西地区受到锰矿和铅锌矿生产影响严重的两条河流。通过表层沉积物采样分析了Cd、Pb、Cu、Ni、Cr、Zn和Mn的总量,根据BCR连续提取程序分析沉积物样品中重金属的地球化学赋存形态,采用内梅罗指数法和地积累指数法评价了沉积物重金属污染特征,根据重金属的富集程度探讨了重金属污染来源,采用淡水生态系统沉积物质量基准(SQGs,TEL/PEL)和毒性单位评价了花垣河和峒河沉积物中重金属元素的生态毒性风险。结果表明,花垣河和峒河绝大多数位点的表层沉积物中Cd、Pb、Cu、Ni、Cr、Zn和Mn的总量高于参照点,形成严重的复合污染,花垣河沉积物中重金属的污染水平明显高于峒河,但沿程变化规律不明显,而峒河沉积物中重金属的沿程变化较有规律,即上游含量低,中下游含量较高。两条河流表层沉积物中富集程度居前列的均为Cd、Pb、Zn和Mn。花垣河和峒河沉积物重金属污染主要来源于矿业生产所产生废渣和废水的点排放。在花垣河和峒河的大多数位点,Cd、Pb和Mn的形态具有共同特征,其生物可利用态均较大程度地超过生物不可利用态,而且Mn和Cd的生物可直接利用态所占比例远高于其它重金属,而Cu和Cr的生物可直接利用态所占比例很低。花垣河沉积物中Cd、Pb和Zn在所有位点极大地超过PEL,在峒河中下游,Cd、Pb、Ni和Zn超过PEL,具有较大的潜在生物毒性。除上游S1位点外,花垣河的其余各位点都具有明显的急性毒性,峒河中下游各位点具有明显的急性毒性,这些河段需要重点治理。     

A Theoretical Model for Utilizing Mammalian Pharmacology and Safety Data to Prioritize Potential Impacts of Human Pharmaceuticals to Fish

Due to the potential for long-term, low-level exposure of environmental species to pharmaceuticals in the environment, concerns over chronic ecotoxicity have been raised. Pharmaceuticals typically have specific enzyme and receptor-based modes of action, which are extensively studied in mammals during drug development. A survey of the literature demonstrated that there is conservation of many enzyme/receptor systems between mammalian and teleost systems. Based on this conservation of enzyme/receptor systems across teleost species, a model has been developed to utilize the information from mammalian pharmacology and toxicology studies to evaluate the potential for chronic receptor mediated responses in fish. In this model, a measured human therapeutic plasma concentration (H_TPC) is compared to a predicted steady state plasma concentration (F_SSPC) in fish, and an effect ratio (ER = H_TPC/F_SSPC) is computed. The lower the ER, the greater the potential for a pharmacological response in fish. Data collection and model validation will strengthen the applicability of this approach as a viable tool for prioritizing research initiatives that examine the potential impact of pharmaceuticals on fish.