Role of competition in phytoplankton population for the occurrence and control of plankton bloom in the presence of environmental fluctuations

Termination of harmful algal blooms (HABs) and coexistence of phytoplankton–zooplankton populations are of great importance to human health, ecosystem, environment, tourism and fisheries. In this paper, we propose a three component model consisting of non-toxic phytoplankton (NTP), toxin producing phytoplankton (TPP) and zooplankton (Z). The growth of zooplankton species is assume to reduce due to toxic chemicals released by TPP population. We have extended the model proposed by Chattopadhyay et al. [Chattopadhyay, J., Sarkar, R.R., Pal, S., 2004. Mathematical modelling of harmful algal blooms supported by experimental findings. Ecol. Comp. 1, 225–235] by including competition terms between TPP and NTP. We observe the effect of competition factors both in the presence and absence of the environmental fluctuation. From our field as well as model analysis we observe that competition helps in the coexistence of the species, but if the effect of competition is very high on the TPP population, it results in planktonic bloom. It is shown that the coexistence equilibrium loses its stability when the competition coefficient crosses a critical value and resulting Hopf-bifurcation around the positive equilibrium depicting oscillations phenomena of the populations.     

Low levels of toxic elements in Dead Sea black mud and mud-derived cosmetic products

Natural muds used as or in cosmetics may expose consumers to toxic metals and elements via absorption through the skin, inhalation of the dried product, or ingestion (by children). Despite the extensive therapeutic and cosmetic use of the Dead Sea muds, there apparently has been no assessment of the levels of such toxic elements as Pb, As, or Cd in the mud and mud-based products. Inductively coupled plasma mass spectrometry analysis of eight toxic elements in samples collected from three black mud deposits (Lisan Marl, Pleistocene age) on the eastern shore of the Dead Sea in Jordan revealed no special enrichment of toxic elements in the mud. A similar analysis of 16 different commercial Dead Sea mud cosmetics, including packaged mud, likewise revealed no toxic elements at elevated levels of concern. From a toxic element standpoint, the Dead Sea black muds and derivative products appear to be safe for the consumer. Whatever the therapeutic benefits of the mud, our comparison of the elemental fingerprints of the consumer products with those of the field samples revealed one disturbing aspect: Dead Sea black mud should not be a significant component of such items as hand creams, body lotions, shampoo, and moisturizer.     

基于生物导向的水生态健康监测及评估概述

环境监测是水生态健康监测与评估的重要环节,基于物理、化学监测的传统水质监测通常仅能提供独立的数据信息,不能全面、直观地反映水环境状况。基于生物等生命体导向的水生态监测通过生物对环境的响应,能够直接反应复杂水体状况,在水环境健康监测与评估中占据重要地位。基于病原微生物、指示生物介绍了生物监测中的常规生物指标,总结了包括藻类、无脊椎动物和鱼类在内的常见指示生物在不同类型污染水体中的环境指示作用。从生物毒性效应出发介绍了常用的毒性效应测试方法、分析了污染物在不同生物学水平的响应,从而指明生物毒性效应在水环境健康评估中的发展优势。再从生态完整性角度阐述了生态完整性评价的一般方法和新兴分子生物学技术在水生态健康评估中的应用。重点指出环境毒理学和分子生物学在水环境监测的优势,以期为更加科学精确地进行水生态健康监测预警提供支撑。     

The Spanish toxic oil syndrome: Some explanations for the pathology and an appraisal of the similarities with other episodes of food adulteration

In 1981 in Madrid, a new disease was identified, and attributed to the fraudulent sale of adulterated, industrial-quality oil as olive oil. The competing hypotheses for the clinical symptoms and tissue changes are reviewed but it is also important to note the general similarities between this epidemic and those other incidents where food adulteration has presented an acute hazard.     

镉对鲫鱼过氧化物酶活性的影响

对鲫鱼的内脏组织的过氧化物酶（ＰＯＤ）活性正常值作了测定，结果表明：心脏和肾脏的ＰＯＤ活性较高，鳃和肝胰脏次之，肠和肌肉较低，当水中镉离子浓度为１６ｍｇ／Ｌ、３２ｍｇ／Ｌ时，肾脏、鳃的ＰＯＤ活性显著增强，肝胰脏的ＰＯＤ活性在３２ｍｇ／Ｌ组显著增强，心脏的ＰＯＤ活性在３种能离子浓度下影响均不明显。体外试验表明，镉不能直接影响ＰＯＤ活性。水体中加入ＥＤＴＡ（乙二胺四乙酸）可解除或减轻Ｃｄ＾２＋对鱼的毒     

Gas-phase organics in environmental tobacco smoke: 2. Exposure-relevant emission factors and indirect exposures from habitual smoking

Sorption of emitted gas-phase organic compounds onto material surfaces affects environmental tobacco smoke (ETS) composition and exposures indoors. We have introduced a new metric, the exposure relevant emission factor (EREF) that accounts for sorptive uptake and reemission to give the mass of individual ETS constituents available for exposure over a day in which smoking occurs. This paper describes month-long experiments to investigate sorption effects on EREFs and potential ETS exposures under habitual smoking conditions. Cigarettes were smoked in a 50-m³ furnished room over a 3-h period 6–7 days per week, with continuous ventilation at 0.3, 0.6, or 2.1 h⁻¹. Organic gas concentrations were measured every few days over 4-h “smoking”, 10-h “post-smoking” and 10-h “background” periods. Concentration patterns of volatile ETS components including 1,3-butadiene, benzene and acrolein were similar to those calculated for a theoretical non-sorbing tracer, indicating limited sorption. Concentrations of ETS tracers, e.g. 3-ethenylpyridine (3-EP) and nicotine, and lower volatility toxic air contaminants including phenol, cresols, and naphthalene increased as experiments progressed, indicating mass accumulation on surfaces and higher desorption rates. Daily patterns stabilized after week 2, yielding a steady daily cycle of ETS concentrations associated with habitual smoking. EREFs for sorbing compounds were higher under steady cycle versus single-day smoking conditions by 50% for 3-EP, and by 2–3 times for nicotine, phenol, cresols, naphthalene, and methylnaphthalenes. Our results provide relevant information about potential indirect exposures from residual ETS (non-smoker enters room shortly after smoker finishes) and from reemission, and their importance relative to direct exposures (non-smoker present during smoking). Under the conditions examined, indirect exposures accounted for a larger fraction of total potential exposures for sorbing versus non-sorbing compounds, and at lower versus higher ventilation rates. Increasing ventilation can reduce indirect exposures to very low levels for non-sorbing ETS components, but indirect routes accounted for 50% of potential nicotine exposures during non-smoking periods at all ventilation rates.     

Das neue Chemikalienprogramm von UNEP Chemicals

Zusammenfassung  UNEP International Register of Potentially Toxic Chemicals (IRPTC) wurde von der ersten VN-Umweltkonferenz 1972 geschaffen. Sein Einfu? und Zusammenwirken in den 80ziger Jahren mit anderen internationalen Programmen der WHO, FAO, OECD und EG in der Chemikalienkontrolle wird beschrieben. Nach dem Erdgipfel von Rio 1992 werden im VN-Rahmen drei neue Gremien gebildet, die das Fachprogramm des Kapitels 19 der Agenda 21 (umweltfreundliches Chemikalienmanagement) umsetzen sollen: die United nations Commission of Sustainable Development, das Intergovernmental Forum on Chemical Safety und das Interorganization Programme for the Sound Management of Chemicals. Der Erdgipfel brachte auch für IRPTC eine Neuorientierung. Seit 1996 hat UNEP Chemicals, wie sich IRPTC nunmehr nennt, drei Aufgaben in sein Arbeitsprogramm aufgenommen, die beschrieben werden: das internationale übereinkommen zum Prior Informed Consent, das internationale übereinkommen zur Kontrolle der Persistent Organic Pollutants, und schlie?lich sein traditionelles Arbeitsgebiet des Informations-austausches über Stoffe wird weitergeführt.

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Die Aussagen dieses Beitrages sind die Meinung des Autors. Sie müssen nicht mit der Auffassung des Umweitbundesamtes oder von UNEP Chemicals übereinstimmen.     

Zn2+ loading as a critical contributor to the circ_0008553-mediated oxidative stress and inflammation in response to PM2.5 exposures

Inflammation is a major adverse outcome induced by inhaled particulate matter with a diameter of ≤ 2.5 µm (PM_2.5), and a critical trigger of most PM_2.5 exposure-associated diseases. However, the key molecular events regulating the PM_2.5-induced airway inflammation are yet to be elucidated. Considering the critical role of circular RNAs (circRNAs) in regulating inflammation, we predicted 11 circRNAs that may be involved in the PM_2.5-induced airway inflammation using three previously reported miRNAs through the starBase website. A novel circRNA circ_0008553 was identified to be responsible for the PM_2.5-activated inflammatory response in human bronchial epithelial cells (16HBE) via inducing oxidative stress. Using a combinatorial model PM_2.5 library, we found that the synergistic effect of the insoluble core and loaded Zn²⁺ ions at environmentally relevant concentrations was the major contributor to the upregulation of circ_0008553 and subsequent induction of oxidative stress and inflammation in response to PM_2.5 exposures. Our findings provided new insight into the intervention of PM_2.5-induced adverse outcomes.     

Persistent organic pollutants control strategy in China

The development of Persistent Organic Pollutants(POPs) control policy in China in the context of international concerns on POPs was reviewed. The aspects of the Chinese POPs control strategies were analyzed, and compared with those of developed counterparts(e.g. US, EU, Japan). Currently, while the legal framework on POPs management, which complies with intemational guidelines has been established, it should be improved in the areas of special POPs management, risk assessment, the precautionary principle, lifecycle management and technical support capacity. The analysis of Chinese POPs policy and suggestions for strengthening the sciencebased decision making capacity are not only useful for Chinese decision-makers, but also a case study for developing wodd and make a great contribution for the global elimination of POPs to make a toxic-free future.     

Do environmental right-to-know laws affect markets? Capitalization of information in the toxic release inventory

This paper investigates how information contained in the U.S. Environmental Protection Agency's Toxic Release Inventory (TRI) program, one of the largest environmental right-to-know programs, affects prices in the housing market. I use a strengthening of the reporting requirements for the chemical lead in 2001 as exogenous variation to test for housing price changes near existing firms who must now report. Using a difference-in-differences specification, I find that listing an existing firm in the Toxic Release Inventory lowers housing prices up to 11% within approximately 1 mile. The results suggest that housing market participants do capitalize into prices at least some information conveyed by the TRI program.