PM10 and PM2.5 source apportionment in the Barcelona Metropolitan area, Catalonia, Spain

Levels of total suspended particles, PM10, PM2.5 and PM1 were continuously monitored at an urban kerbside in the Metropolitan area of Barcelona from June 1999 to June 2000. The results show that hourly levels of PM2.5 and PM1 are consistent with the daily cycle of gaseous pollutants emitted by traffic, whereas TSP and PM10 do not follow the same trend, at least in the diurnal period. The PM2.5/PM10 ratio is dependent on the traffic emissions, whereas additional contribution sources for the >10 μm fraction must be taken into account in the diurnal period. Different PM10 and PM2.5 source apportionment techniques were compared. A methodology based on the chemical determination of 83% of both PM10 and PM2.5 masses allowed us to quantify the marine (4% in PM10 and <1% in PM2.5), crustal (26% in PM10 and 8% in PM2.5) and anthropogenic (54% in PM10 and 73% in PM2.5) loads. Peaks of crustal contribution to PM10 (up to 44% of the PM10 mass) were recorded under Saharan air mass intrusions. A different seasonal trend was observed for levels of sulphate and nitrate, probably as a consequence of the different thermodynamic behaviour of these PM species and the higher summer oxidation rate of SO₂.     

Behavioral changes in fish exposed to phytoestrogens

We investigated the behavioral effects of exposure to waterborne phytoestrogens in male fighting fish, Betta splendens. Adult fish were exposed to a range of concentrations of genistein, equol, beta-sitosterol, and the positive control 17beta-estradiol. The following behaviors were measured: spontaneous swimming activity, latency to respond to a perceived intruder (mirror reflection), intensity of aggressive response toward a perceived intruder, probability of constructing a nest in the presence of a female, and the size of the nest constructed. We found few changes in spontaneous swimming activity, the latency to respond to the mirror, and nest size, and modest changes in the probability of constructing a nest. There were significant decreases, however, in the intensity of aggressive behavior toward the mirror following exposure to several concentrations, including environmentally relevant ones, of 17beta-estradiol, genistein, and equol. This suggests that phytoestrogen contamination has the potential to significantly affect the behavior of free-living fishes.     

Planktonic ciliates in a hypertrophic pond: functional role and importance

Taxonomical composition and abundance of the planktonic ciliate assemblage in a Lake Tezozomoc, a hypertrophic pond located into an urban park in Mexico City, was investigated along the rainy season (May to October). The aims of the study were to know the main trophic roles and ecological significance of ciliates in a highly productive environment. A low number of taxa (27) and a wide abundance fluctuation (104-387 cil ml(-1)) were found. The most abundant species (up to 162 cil ml(-1)) was Halteria grandinella, an oligotrich ciliate that graze on bacteria and picoplankton, but also several big body sized species that feed on pico and nanoplankton were abundant. Sudden temporal changes in species dominance occurred. Ciliate biomass was very high and fluctuated widely (1.6-88 10(6) microm(3) ml(-1)) being dominated by the >50 microm size fraction that mainly included the pico and nanoplankton feeders. Ciliates are a very important component in the plankton of hypertrophic lakes and their main control factor seems to be the grazing by big-body size Daphnia species.     

Spatial variations of human health risk associated with exposure to chlorination by-products occurring in drinking water

During disinfection, chlorine reacts with organic matter present in drinking water and forms various undesirable chlorinated by-products (CBPs). This paper describes a study of the spatial variability of human health risk (i.e., cancer effects) from CBP exposure through drinking water in a specific region. The region under study involves nine drinking water distribution systems divided into several zones based on their characteristics. The spatial distribution of cancer risk (CR) was estimated using two years of data (2006-2008) on various CBP species. In this analysis, trihalomethanes (THMs) and haloacetic acids (HAAs) served as surrogates for CBPs. Three possible routes of exposure (i.e., via ingestion, inhalation and dermal contact) were considered for each selected compound. The cancer risk assessment involved estimating a unit risk (R(T)) in each zone of the selected distribution systems. A probabilistic analysis based on Monte Carlo simulations was employed. Risk assessment results showed that cancer risk varied between systems, but also within individual systems. As a result, the population of the same region was not exposed to the same risk associated with CBPs in drinking water. Unacceptable levels (i.e., R(T) > 10(-4)) for the estimated CR were determined for several zones in the studied region. This study demonstrates that a spatial-based analysis performed to represent the spatial distribution of risk estimates can be helpful in identifying suitable risk management strategies. Suggestions for improving the risk analysis procedure are also presented.     

A targeting approach for ecosystem protection

The Critical Ecosystems Team of the US Environmental Protection Agency (EPA), Region 5, has developed an approach to prioritize and target ecologically high-quality areas for enhanced environmental protection in the Midwestern states of Illinois, Indiana, Ohio, Michigan, Minnesota and Wisconsin. Using this approach, we intend to employ a pro-active strategy to protect the environment by protecting and restoring natural ecosystems rather than the traditional EPA approach of remediating and attempting to restore already degraded habitats. The approach consists of two components: (1) partnership and (2) criteria. For the partnership component, we collected, mapped, and summarized information on ecosystems considered critical to federal and state agencies, tribes and non-profit organizations. Multi-county areas with high numbers of ecosystems identified by a variety of partners were designated as ‘Ecologically Rich Regions’. These Ecologically Rich Regions highlight broad geographic areas where there are high levels of partner interest and, correspondingly, areas with high potential for forming collaborative partnerships for enhanced environmental protection. The second component, which relies on criteria, is still under development and defines critical ecosystems as having three important properties: (1) high ecological diversity, (2) potential for long-term sustainability and (3) presence of relict native ecosystems or communities. The information compiled under both components of this ecosystem targeting approach will inform ecological risk managers and assessors about important ecosystems that should be considered in risk management and assessment processes.     

三唑酮在设施栽培土壤及大白菜中的消解动态及残留

为评价三唑酮在大白菜施用后的环境安全性,建立了GC测定蔬菜及土壤中三唑酮残留的方法,进行露地与设施栽培条件三唑酮在大白莱和土壤中的消解动态和最终残留研究.在大白菜和土壤中的最低检测质量分数均为0.001 mg/kg,三唑酮的平均加标回收率为81.5％～110.6％,变异系数为1.32％～6.04％.消解动态试验为2倍推荐使用剂量施药1次,三唑酮在设施栽培大白菜的半衰期分别为2.72～3.30 d和3.21～3.35 d;露地栽培为2.35～2.87 d和2.30～3.12 d.设施栽培大白菜中三唑酮残留量与用药量正相关,随着施药量的增加,消解速度减慢,残留量相应增大.研究可为制定三唑酮设施栽培大白菜上最大残留限量和合理使用准则以及风险评估提供科学依据.     

Understanding the RCRA corrective action process

The Resource Conservation and Recovery Act (RCRA) was enacted in 1976. The Hazardous and Solid Waste Amendments (HSWA) of 1984 specify “corrective action” requirements for protecting human health and the environment from environmental contamination at active hazardous waste treatment, storage, and disposal facilities. RCRA and its corrective action requirements are designed to prevent the creation of new Superfund sites by regulating and remediating active facilities. The RCRA corrective action process has four basic components: the facility assessment, facility investigation, corrective measures study, and corrective measures implementation. This article presents an overview of the RCRA corrective action process and presents four case studies from three U.S. EPA regions.