Bacteriological safety assessment,hygienic habits and cross-contamination risks in a Nigerian urban sample of household kitchen environment

Urban household kitchen environment was assessed for safety by determining their levels of indicator bacteria, hygienic habits and risk of cross-contamination. Household kitchens (60) were selected in Warri Town, Nigeria, by the multi-stage sampling technique. Contact surfaces, water and indoor kitchen air were analysed for aerobic plate counts, total and faecal coliforms using Nutrient and McConkey media by swab/rinse method, membrane filtration and sedimentation methods, respectively. Hygienic habits and risk of cross-contamination were assessed with structured questionnaire which included socio-demographic variables. On the basis of median counts, the prevalence of high counts (log cfu/cm²/m³/100 mL) of aerobic plate counts (>3.0), total coliforms (>1.0) and faecal coliforms (>0) on contact surfaces and air was high (58.0–92.0%), but low in water (30.0–40.0%). Pots, plates and cutleries were the contact surfaces with low counts. Prevalence of poor hygienic habits and high risk of cross-contamination was 38.6 and 67.5%, respectively. Education, occupation and kitchen type were associated with cross-contamination risk (P = 0.002–0.022), while only education was associated with hygienic habits (P = 0.03). Cross-contamination risk was related (P = 0.01–0.05) to aerobic plate counts (OR 2.30; CL 1.30–3.17), total coliforms (OR 5.63; CL 2.76–8.25) and faecal coliforms (OR 4.24; CL 2.87–6.24), while hygienic habit was not. It can be concluded that urban household kitchens in the Nigerian setting are vulnerable to pathogens likely to cause food-borne infections.     

对美国格林威治湾底栖动物造成危害的潜在胁迫因子的诊断

格林威治湾是纳拉甘西特湾一处受到多种影响因子作用的城市化形成港湾。本研究鉴定了对于格林威治湾底栖动物的重要影响因素。首先利用现存数据与信息来验证水体受损情况。其次确定了影响来源,影响因素和具体影响的存在。继而探究了来源,影响因素和具体影响之间的关系。这使我们能够鉴定出最可能危害水体的影响因素。本研究评估了化学制品、营养物质和悬浮沉积物3类污染物。这种证据权重的方法表明格林威治湾主要受到富营养化相关的影响因素危害。格林威治湾的沉积物富含碳,低溶解氧浓度的情况十分常见,尤其在格林威治湾西部。底栖生物群落出现发育不良的情况,与在氧气不足情况下的预测结果吻合。尽管我们的分析表明环境中的污染物浓度可能导致有害结果的出现,我们并未在结果中检出毒性。这是由于沉积物中存在大量的有机物,这些有机物限制了污染物的生物可利用性。我们的分析还表明悬浮沉积物的影响对于湾区的大部分区域而言几乎不存在。本分析展示了诊断法步骤可以用于组织和评估影响格林威治湾生态健康的潜在影响因素。诊断法步骤对于管理受到多重因素影响的水体非常有用。
精选自Marguerite Pelletier, Kay Ho, Mark Cantwell, Monique Perron, Kenneth Rocha, Robert M. Burgess, Roxanne Johnson, Kenneth Perez, John Cardin, Michael A. Charpentier. Diagnosis of potential stressors adversely affecting benthic invertebrate communities in Greenwich Bay, Rhode Island, USA. Environmental Toxicology and Chemistry: Volume 36, Issue 2, pages 449–462, July 2017. DOI: 10.1002/etc.3562
详情请见http://onlinelibrary.wiley.com/wol1/doi/10.1002/etc.3562/full
     

Social network characteristics and resource access among formerly displaced households in Lira,Uganda

In rural African communities, the support of extended family, friends, and neighbours is essential in borrowing or leveraging land, labour, food, and money, especially at times of social and financial turmoil. Little is known, though, about the nature of the networks and the conditions under which they may generate greater support in post‐conflict communities. This study, conducted in the Lira district of northern Uganda, examined the composition, proximity, and size of the networks that households utilise to gain access to resources during and after resettlement. Network structures with more kin and co‐resident ties were found to offer greater resource access to households in post‐conflict settings. Furthermore, there was a lack of meaningful linkages outside of a person's own village, especially with regard to households whose head has no or a low level of education. These findings enhance understanding of the specific role of relationships in social support for resource access among households in post‐conflict communities.     

Characterization of the pro-inflammatory potencies of purified Jatropha phorbol esters by a gene expression-based in vitro bioassay

The oil extracted from Jatropha seeds is an emerging biodiesel feedstock that also contains several pro-inflammatory phorbol esters. These phorbol esters can elicit adverse inflammatory responses through activation of the protein kinase C, as previously described for the prototypical phorbol ester 12-O-tetradecanoylphorbol-13-acetate. We extracted and purified the six phorbol esters identified in Jatropha oil and assessed their pro-inflammatory activities using a recently developed gene expression-based bioassay. Borrowing from an approach used for the assessment of dioxin toxicity, we expressed their pro-inflammatory potencies in relation to the potency of 12-O-tetradecanoylphorbol-13-acetate (in terms of 12-O-tetradecanoylphorbol-13-acetate toxic equivalency factors). The pro-inflammatory potencies of Jatropha phorbol esters were orders of magnitudes below the potency of 12-O-tetradecanoylphorbol-13-acetate. Interestingly, the cytotoxicity of phorbol esters did not appear to be directly related to their pro-inflammatory potencies. Calculations based on phorbol ester potencies and concentrations led to overestimation of the pro-inflammatory activity of Jatropha oil, as measured by the same gene expression-based bioassay. The preliminary results presented here suggest that further work on the described approach may lead to the development of valuable tools and metrics to quantify and predict the pro-inflammatory activities of complex phorbol ester mixtures.     

Modeling Past and Future Acidification of Swedish Lakes

Decades of acid deposition have caused acidification of lakes in Sweden. Here we use data for 3000 lakes to run the acidification model MAGIC and estimate historical and future acidification. The results indicate that beginning in about 1920 a progressively larger number of lakes in Sweden fell into the category of “not naturally acidified” (∆pH > 0.4). The peak in acidification was reached about 1985; since then many lakes have recovered in response to lower levels of acid deposition. Further recovery from acidification will occur by the year 2030 given implementation of agreed legislation for emissions of sulphur (S) and nitrogen (N) in Europe. But the number of catchments with soils being depleted in base cations will increase slightly. MAGIC-reconstructed history of acidification of lakes in Sweden agrees well with information on fish populations. Future acidification of Swedish lakes can be influenced by climate change as well as changes in forest harvest practices.     

Quantification of bisphenol A, 353-nonylphenol and their chlorinated derivatives in drinking water treatment plants

Bisphenol A (BPA) and nonylphenols (NP) are of major concern to public health due to their high potential for human exposure and to their demonstrated toxicity (endocrine disruptor effect). A limited number of studies have shown that BPA and NP are present in drinking water. The chlorinated derivatives that may be formed during the chlorination step in drinking water treatment plants (DWTP) exhibit a higher level of estrogenic activity than their parent compounds. The aim of this study was to investigate BPA, 353NP, and their chlorinated derivative concentrations using an accurate and reproducible method of quantification. This method was applied to both surface and treated water samples from eight French DWTPs producing from surface water. Solid-phase extraction followed by liquid chromatography?Ctandem mass spectrometry was developed in order to quantify target compounds from water samples. The limits of detection ranged from 0.3 to 2.3?ng/L for BPA and chlorinated BPA and from 1.4 to 63.0?ng/L for 353NP and chlorinated 353NP. BPA and 353NP were found in most analyzed water samples, at a level ranging from 2.0 to 29.7?ng/L and from 0 to 124.9?ng/L, respectively. In most of DWTPs a decrease of BPA and 353NP was observed between surface water and treated water (36.6 to 78.9?% and 2.2 to 100.0?% for BPA and 353NP, respectively). Neither chlorinated BPA nor chlorinated 353NP was detected. Even though BPA and 353NP have been largely removed in the DWTPs studied, they have not been completely eliminated, and drinking water may consequently remain a source of human exposure.     

Comparison of specific versus literature species sensitivity distributions for herbicides risk assessment

Species sensitivity distributions (SSDs) are an important predictive tool in risk assessment. Usually, literature data are used to build SSDs that are mostly based on planktonic species. But, to get adequate protective thresholds for environmental communities, one could argue that SSD should be built on ecotoxicological data obtained from species found in the ecosystem that should be protected. This is particularly true when benthic algae are of concern. Due to the lack of literature data, building SSD on benthic microalgae is difficult. This paper aims in comparing SSDs, and thus protective thresholds (hazardous concentration that affects 5 % of the species of a community, HC₅), built on ecotoxicological data obtained (1) from literature and (2) with specific bioassays on benthic diatoms from a lake. Thresholds were derived for protection against four herbicides separately and for a mixture of them. Sensitivity data obtained from literature were statistically lower than the specific data for all herbicides: Species tested in the literature were usually more sensitive (mainly chlorophytes), leading to more protective lower HC₅. The HC₅ thresholds (literature or specific) derived for protection against the mixture were also compared to the observed sensitivity of an assemblage of benthic diatom species exposed to an increasing range of herbicide mixture concentrations. We observed that one species within the assemblage (Fragilaria rumpens) was affected at a concentration below both the literature and the specific HC₅ thresholds.     

Control of Claus Plant Sulfur Compound Emissions

The body of information of this paper is directed to those individuals charged with selecting a process to control atmospheric sulfur emissions from Claus plants serving refineries, gas processing installations, and chemical plants. The TGT process developed by the French Petroleum Institute (IFP) is an extension of the Claus reaction itself in the liquid phase. Mixed H₂S and SO₂ in tail gas from Claus units is fed to a packed tower in which a solution of proprietary catalyst in a high BP polyglycol circulates countercurrent to the gas flow. The mixed gases react with the catalyst to form a complex, which in turn reacts with more gases to produce elemental sulfur. Reaction temperature keeps the sulfur above its melting point. Product accumulates in the boot of the tower and is drawn off continuously through a seal leg.

The IFP TGT process is simple in design and units have simple construction, characterized by use of low carbon steel and the use of very few pieces of equipment. Of all processes used today to take effluent sulfur values down to 1000 ppm SO₂ after incineration, the IFP TGT process requires the least capital investment and the lowest operating costs. Twenty-six full scale plants are operating or under design or construction: nine each in the U.S. and Japan, five in the U.S.S.R. and Poland, two in western Europe and one in Canada. Capacities of the Claus plants served range from 45 to 800 Lt/d sulfur.     

Assessment of Health Effects of Fluctuating Concentrations Using Simplified Pharmacokinetic Algorithms

Abstract

The purpose of this study was to develop a simple, practical method to improve the accuracy of assessing health effects by determining the concentration patterns inside the body resulting from fluctuating external pollutant concentrations. Linear pharmacokinetic processes were assumed, and the attenuations of the high- and low-frequency components of the external pattern when entering through the "biological window" were determined. Similar attenuations also were determined for the "time-averaged sampling window." It was shown that when the averaging time was less than 1/4 of the biological half-life, no information of biological significance was lost. Thus, a simple arithmetic step equation was proposed to convert external time-averaged concentrations to "biologically effective concentrations" proportional to internal concentrations. Calculations could readily be made in real time by a monitoring instrument, or even with a pocket calculator. Another simple algorithm was proposed for determining a "biological damage parameter" representative of cumulative damage if the body repair process is slow. Finally, simple algorithms were proposed for calculating body burdens from total absorbed mass rates, a procedure that should be useful for pollutants such as lead that may enter the body through multiple pathways. Results were compared with experimental and hypothetical data to show their utility.