An Evaluation of Selenium Concentrations in Water, Sediment, Invertebrates, and Fish from the Republican River Basin: 1997–1999

The Republican River Basin of Colorado,Nebraska, and Kansas lies in a valley which contains PierreShale as part of its geological substrata. Selenium is anindigenous constituent in the shale and is readily leached intosurrounding groundwater. The Basin is heavily irrigated throughthe pumping of groundwater, some of which is selenium-contaminated, onto fields in agricultural production. Water,sediment, benthic invertebrates, and/or fish were collected from46 sites in the Basin and were analyzed for selenium to determinethe potential for food-chain bioaccumulation, dietary toxicity,and reproductive effects of selenium in biota. Resultingselenium concentrations were compared to published guidelines orbiological effects thresholds. Water from 38% of the sites (n = 18) contained selenium concentrations exceeding 5 g L^-1, which is reported to be a high hazard for selenium accumulation into the planktonic food chain. An additional 12 sites (26% of the sites) contained selenium in water between 3–5 g L^-1, constituting a moderate hazard. Selenium concentrations in sedimentindicated little to no hazard for selenium accumulation fromsediments into the benthic food chain. Ninety-five percent ofbenthic invertebrates collected exhibited selenium concentrationsexceeding 3 g g^-1, a level reported as potentially lethal to fish and birds that consume them. Seventy-five percent of fish collected in 1997, 90% in 1998, and 64% in 1999 exceeded 4 g g^-1selenium, indicating a high potential for toxicity andreproductive effects. However, examination of weight profilesof various species of collected individual fish suggestedsuccessful recruitment in spite of selenium concentrations thatexceeded published biological effects thresholds for health andreproductive success. This finding suggested that universalapplication of published guidelines for selenium may beinappropriate or at least may need refinement for systems similarto the Republican River Basin. Additional research is needed todetermine the true impact of selenium on fish and wildliferesources in the Basin.     

The extraction of aged polycyclic aromatic hydrocarbon (PAH) residues from a clay soil using sonication and a Soxhlet procedure: a comparative study

A sonication method was compared with Soxhlet extraction for recovering polycyclic aromatic hydrocarbons (PAH) from a clay soil that had been contaminated with tar materials for several decades. Using sonication over an 8 h extraction period, maximum extraction of the 16 US EPA priority PAH was obtained with dichloromethane (DCM)-acetone (1 + 1). The same procedure using hexane-acetone (1 + 1) recovered 86% of that obtained using DCM-acetone (1 + 1). PAH recovery was dependent on time of extraction up to a period of 8 h. The sonication procedure showed that individual PAH are extracted at differing rates depending on the number of fused rings in the molecule. Soxhlet extraction [with DCM-acetone (1 + 1)] over an 8 h period recovered 95% of the PAH removed by the sonication procedure using DCM-acetone (1 + 1), indicating that rigorous sonication can achieve PAH recoveries similar to those obtained by Soxhlet extraction. The lower recovery with the Soxhlet extraction was explained by the observed losses of the volatile PAH components after 1-4 h of extraction. The type of solvent used, the length of time of extraction and extraction method influenced the quantification of PAH in the soil. Therefore, the study has implications for PAH analyses in soils and sediments, and particularly for contaminated site assessments where the data from commercial laboratories are being used. The study emphasizes the importance of establishing (and being consistent in the application of) a vigorous extraction, particularly for commercial laboratories that handle samples of soil in batches (at different times) from a single site investigation or remediation process. The strong binding of PAH to soil, forming aged residues, has significant implications for extraction efficiency. This paper illustrates the problem of the underestimation of PAH using the US EPA method 3550, specifically where a surrogate spike is routinely employed and the efficiency of the extraction procedure for aged residues is unknown. The implications of this study for environmental monitoring, particularly where numerous batches of samples from a single site assessment or remediation program are submitted to commercial laboratories, is that it would be advisable for these laboratories to check their existing method's extraction efficiencies by conducting a time course sonication extraction on their particular soil to determine the optimum extraction time.     

Study of the relationships between bone lead levels and its variation with time and the cumulative blood lead index, in a repeated bone lead survey

The study aims were to: (i) investigate long term human lead metabolism by measuring the change of lead concentration in the tibia and calcaneus; and (ii) assess whether improved industrial hygiene was resulting in a slow accumulation of lead in an exposed workforce. 109Cd excited K X-ray fluorescence was used to measure tibia lead and calcaneus lead concentrations in 101 workers in a secondary lead smelter. 51 subjects had had similar bone lead measurements 5 years previously. Most of the other subjects had been hired since the first survey. Measurements of whole blood lead were available for the large majority of subjects. Tibia lead concentrations fell significantly (p<0.001) in the 51 subjects with repeated bone lead measurements, from a mean of 39 microg Pb (g bone mineral)(-1) to 33 microg Pb (g bone mineral)(-1). The change correlated negatively with the initial tibia lead concentration, producing an estimate for an overall half-life of 15 years, with a 95% confidence interval of 9 to 55 years. Adding continuing lead exposure and recirculation of bone lead stores to the regression models produced half-life estimates of 12 and 9 years, respectively, for release of lead from the tibia. The repeat subjects showed no net change in calcaneus lead (64 microg Pb (g bone mineral)(-1) initially, 65 microg Pb (g bone mineral)(-1) 5 years later). Subjects not measured previously had average lead concentrations of 15 microg Pb (g bone mincral)(-1) in the tibia and 13 microg Pb (g bone mineral)(-1) in the calcaneus. The rate of clearance of lead from the tibia (9 to 15 years) is towards the more rapid end of previous estimates. The lack of a significant fall in the calcaneus lead was surprising. Attempts should be made to repeat this observation. If confirmed, it would have implications for models of lead metabolism. The relatively low lead concentrations in the non-repeat subjects are reassuring. However, observation after a longer period of employment would be desirable.     

Determination of n-alkanes and polycyclic aromatic hydrocarbons in atmospheric particulate and vapour phases in Oviedo, Spain, by GC-MS

A GC-MS procedure for the determination of hydrocarbons in air samples from Oviedo, Spain, was developed. Air hydrocarbons were sampled with a high volume sampler equipped with a holder containing a glass fiber filter, to trap the particulate phase, and two polyurethane foams to capture hydrocarbons of the vapour phase. Compounds were extracted with CH2Cl2 by Soxhlet extraction and then fractionated using column chromatography with alumina silica. Analyses of the fractions were performed by GC-MS in the electron ionization mode. PAHs and n-alkanes were the compounds examined in this work. Samples collected in the vicinity of the Faculty of Chemistry (a semi-urban area) were analysed. The total concentration of PAHs in the air samples analysed ranged from 28 to 76 ng m(-3). The total concentration of n-alkanes and PAHs in the vapour phase exceeded the concentration in the particulate phase in the samples analysed.     

Indoor and outdoor formaldehyde concentrations in homes in residential areas in Greater Cairo

Indoor and outdoor measurements of formaldehyde were conducted at seven flats located in residential areas in Greater Cairo, during spring and summer seasons 1999. The mean daytime formaldehyde concentrations in kitchens, bedrooms and living rooms were 89, 100 and 100 ppb, respectively, in the seven flats. Significant positive correlations were found between the concentrations of formaldehyde found in these three rooms. On the other hand, no significant differences were found between the mean formaldehyde concentrations in these three rooms. The maximum mean concentration of formaldehyde (147 ppb) was recorded in a new flat, while the minimum concentration (43 ppb) was observed in an old flat. The maximum hourly and daytime concentrations were 350 and 225 ppb, respectively. Air temperature, relative humidity and the age of the flat are factors affecting the emission and concentration of formaldehyde. The maximum indoor and outdoor formaldehyde concentrations were recorded during the summer season. During the spring, 38% of the samples indicated that the concentration of formaldehyde in the seven flats exceeded 0.1 ppm, the American Society of Heating, Refrigerating, and Air Conditioning Engineers' (ASHRAE) standard; in the summer, this figure increased to 53%.     

Evaluation of airborne lead in the welding working environment

Manual and automatic welding machines (which use leaded alloys) are considered to be important sources of the emission of lead fumes into the general air of the working environment. Three workplaces at a television factory were selected for the present study, to determine the control class of the working unit. The concentrations of conventional measurements ("A" sampling points) were lower than the administrative control level (statutory standard of lead, 150 microg m(-3)), whereas the maximum concentration of 264.1 microg m(-3) ("B" sampling point) was higher at one working unit than the administrative control level. However, the control classes varied between class III (bad) and class I (good).     

Exploring data quality for some inorganic and organic constituents of inhalable particulate matter (PM10)

Quality assurance (QA) assessments of air pollution data sets provide a basis for evaluating the significance of various substances in the atmosphere. For non-criteria pollutants, QA results are seldom reported in the technical literature and are often difficult to estimate. The present report provides a summary of QA results such as recovery, precision and accuracy data. Of the six trace elements and nine organic constituents compared in detail, recoveries, laboratory precision and laboratory accuracy values were 100%, ±3% to ±19% and-2 to-13% for the former group and 69% to 98%, ±7% to 23% and-15 to-34% for the later group. System precision varied from ±22% to ±47% for the trace elements and ±42% to ±83% for the organic constituents. Limitations in the interpretation of non-criteria particulate-phase pollutant data bases are discussed with some emphasis placed on receptor-modelling and risk assessment applications. Finally, the relevance of NBS certified materials for QA estimates in non-criteria air pollutant studies is also reviewed.     

Environmental audits: Proposed terminology

This paper presents a review of the fast developing subject of environmental auditing with the authors proposing a series of definitions. Of particular concern is a move towards the development of an accepted vocabulary for environmental impact assessment, even though the international dimension of the subject makes this a difficult task. Use of the word audit has become an accepted part of EIA vocabulary, however there are several types of audits being undertaken today. Presently, there are no commonly accepted definitions, consequently this paper will attempts to address this issue. Definitions for seven types of environmental audits are suggested, derived from the experience of the authors and from a review of the current literature. It is hoped that by the presentation of these definitions that such terms will be advocated for future EIA work, and thereby reducing confusion that otherwise may occur. The paper concludes with a brief review of the status of auditing.     

Problems of correlation of global and local monitoring of air pollution

1. The Air Polluttion Monitoring System has got a significant development of late, which is in direct relation with a considerable extention and improvement of the observation network in cities and industrial areas, with creation of a new network for assessing regional and global background of the atmosphere pollution, as well as with the wide involvement of meteorologists to monitoring organization.
2. While developing a new global monitoring system, it is necessary to take into account its relationship with the local monitoring within the region of air pollution sources, i.e. at the \lsimpact\rs level. The need in such an account is dictated first of all by the physics of pollutant spreading that states: changes in air pollution over large territories must be in a certain agreement with greater changes in the vicinity of emission sources. Methods applied in the global and local monitoring have also a number of common peculiarities. White organizing regional network for observations of the background pollution of the atmosphere twin stations (one of the pair of stations located outside the city boundaries in a small community, and the other, in the nearest city with the population of 200–400 thousand inhabitants) were established in the U.S.S.R. and in a number of socialist countries in Europe.
3. Implementation of the twin-station principles in the U.S.S.R. has contributed to data interpretation and representativity assessment as well as to correction of the station location. Observation results from the Soviet background stations and those abroad have been compared by now according to a number of indices.
4. The correlation of monitoring systems of various scales tells positively both on mutual improvement and completion of observational methods. The methods of obtaining integral characteristics of air pollution were used for the global monitoring, in particular spectral actinometric observations and chemical analysis of the precipitation composition. Now they find still wider employment. Thus methods of spectral actinometric measurements and data processing were used to estimate the degree of aerosol pollution of a number of industrial centres. The theory of solar radiation spreading and aerosol contents determination in urban atmosphere has also been developed. It is a generalization of an earlier developed theory, used to estimate global atmosphere pollution basing on actinometric data. The organization of precipitation collection and analysis on a network of stations around Leningrad and in Donbass area enables us to compare the admixture content in precipitations falling in industrial and agricultural areas.
5. A considerable increase of possibilities to measure microconcentrations of sulphur dioxide, nitrogen oxides and of a number of other pollutants is connected with the use of solid solvents for sampling. Their use will allow to avoid establishment of special laboratories at background stations and only send samples by post for their analysis in centralized laboratories.

They will also allow to considerably increase precision and accuracy of measurements. The international comparisons of methods of air pollution measurements on the background level allow to judge about the effiency of these methods.