Aqueous solubility of polychlorinated dibenzo-p-dioxins determined by high pressure liquid chromatography

Water solubilities (S_W) determined by the HPLC generator column method are reported for a series of chlorinated dibenzo-$\text{p}$-dioxins (PCDDs) with S_W ranging from 0.4 ng/L (ppt) for octa-chlorodibenzo-$\text{p}$-dioxin to 430 ng/L for 1,2,3,7-tetrachlorodibenzo-$\text{p}$-dioxin at 20°C. A correlation is demonstrated between S_W and HPLC capacity factors (k′) for these extremely hydrophobic compounds, allowing calculation of S_W of PCDDs from k′ and melting point data.     

Where Did the Agricultural Nonpoint Source Trades Go? Lessons from Virginia Water Quality Trading Programs

Governmental agencies, nongovernmental organizations, and agricultural organizations promote water quality trading programs as an innovative policy to engage agricultural producers in conservation activities. Cost analyses suggest regulated sources can reduce compliance costs by purchasing agricultural nonpoint source credits. Yet, such “point‐nonpoint” trades are rare. This article assesses the demand for agricultural nonpoint sources in well‐developed nutrient trading programs in Virginia for industrial and municipal wastewater treatment plants, municipal stormwater programs, and land developers. Evidence suggests nutrient trading programs in Virginia will not stimulate investments in pollutant reduction practices on working agricultural lands. The lack of demand for agricultural nonpoint source credits can be attributed to a substantial degree to the design features and incentives present in multiple overlapping regulatory programs. The legal setting that dampens regulated source demand for nonpoint source credits in Virginia is broadly representative of conditions found elsewhere in the United States.     

Insights on the solubilization products after combined alkaline and ultrasonic pre-treatment of sewage sludge

This work provides insights on the solubilization products after a simultaneous combination of alkaline and ultrasonic (ALK + ULS) pre-treatment of sewage sludge. Soluble chemical oxygen demand (SCOD) increased from 1200 to 11,000 mg/L after such treatment. Organics with molecular weight around 5.6 kDa were solubilized because of the synergistic effect of ultrasound and alkali. Organics with molecular weight larger than 300 kDa increased from 7.8% to 60%, 16% and 42.3% after ULS, ALK and ALK + ULS treatment, respectively. Excitation emission matrix fluorescence spectroscopy analysis identified soluble microbial product-like and humic acid-like matters as the main solubilization products. Sludge anaerobic biodegradability was significantly enhanced with the simultaneous application of ALK + ULS pre-treatment. ALK + ULS pre-treatment resulted in 37.8% biodegradability increase compared to the untreated sludge. This value was higher compared to the biodegradability increase induced by individual ALK pre-treatment (5.7%) or individual ULS pre-treatment (20.7%) under the same conditions applied.     

Perceptual Indicators of Environmental Health, Future Land Use, and Stewardship

There are important linkages between the health of humans and theenvironment, restoration of degraded lands, and long-term stewardship of public lands, yet most environmental indicators deal only with assessing the physical and biological aspects ofecosystems. In this article, we examine the ratings of perceptionsof several environmental problems for their utility as indicatorsof environmental quality, and examine perceptions of future land use by people interviewed in Santa Fe, New Mexico, near the Department of Energy's (DOE) Los Alamos National Laboratory (LANL). Overall, people with lower incomes rated environmental problems as more severe than others, were more willing to spend federal funds to solve them, and were consistent in their ratingsof severity of environmental problems and their willingness to spend federal funds. Cleaning up LANL and other Department of Energy sites, received the highest rating for expenditure of federal funds. The highest rated future uses for DOE sites were for recreation and for National Environmental Research Parks. People with less education generally gave higher ratings to mostfuture land uses for DOE than did those with more education. However, those with higher education gave higher ratings to nuclear reprocessing, and nuclear material storage. Where there were differences, the people interviewed at Santa Fe rated all environmental problems (except pesticides) as more severe than did those previously interviewed in Albuquerque (located fartherfrom the LANL site), and they were more willing to spend federalfunds on these problems. Ratings for all future land uses did notdiffer between the Santa Fe and Albuquerque respondents. These perception-based indicators show general agreement among peopleliving close and farther away from LANL with respect to cleaningup LANL and the future land uses for the site. These indicators should be considered by regulators, site personnel, and policy makers in future management and land use decisions.     

Impact on blood Pb levels of maternal and early infant feeding practices of First Nation Cree in the Mushkegowuk Territory of northern Ontario,Canada

Exposure to Pb in-utero and in infancy has been associated with cognitive risk, even at low blood Pb levels of 0.48-0.96 micromol L(-1). Based on the hypothesis that wild game consumed by First Nation women of Mushkegowuk Territory contains Pb that might be transferred through blood or breast-milk to the fetus or infant, the study's objectives were to describe: (1) Pb in maternal and cord blood at birth and infant blood at 4 months, and (2) dietary influence on Pb status. Cord and maternal Pb were 0.10 +/- 0.08 and 0.11 +/- 0.06 micromol L(-1) (x +/- SD), respectively, and were significantly correlated (r = 0.77, p < 0.0001, n = 70), as was infant blood Pb (0.08 +/- 0.05 micromol L(-1)) with matched cord blood (r = 0.65, p < 0.0001, n = 30). Two cord blood samples (3%) were above 0.48 micromol L(-1). Pb in breast-milk at 0.010 +/- 0.008 micromol L(-1) (n = 25), was significantly lower than Pb in commercial formula or evaporated milk-based feedings (range 0.02-0.05 micromol L(-1), p < 0.05), and correlated with matched maternal blood Pb (r = 0.55, p < 0.005). However, in a sub-sample of infants (n = 31), blood Pb was similar for breastfed and formula-fed groups, though above the evaporated milk-fed group (p < 0.05). Maternal consumption of wild fowl, mammals and fish, estimated from the previous year, provided, respectively, 128 +/- 124, 46 +/- 68 and 8 +/- 13 MJ annum(-1). Traditional animal food intake, especially wild fowl, correlated significantly with cord blood Pb (Spearman rank correlation, p = 0.017). Although blood and milk Pb levels were largely within acceptable ranges, the presence of some elevated levels and association between blood Pb and traditional game consumption may reflect the legacy of using lead-containing ammunition.     

The effects of subsampling and sampling frequency on the use of surface-floating pupal exuviae to measure Chironomidae (Diptera) communities in wadeable temperate streams

Community, diversity, and biological index metrics for chironomid surface-floating pupal exuviae (SFPE) were assessed at different subsample sizes and sampling frequencies from wadeable streams in Minnesota (USA). Timed collections of SFPE were made using a biweekly sampling interval in groundwater-dominated (GWD) and surface-water-dominated (SWD) streams. These two types of stream were sampled because they support different Chironomidae communities with different phenologies which could necessitate sampling methodologies specific to each stream type. A subsample size of 300 individuals was sufficient to collect on average 85% of total taxa richness and to estimate most metrics with an error of about 1% relative to 1,000 count samples. SWD streams required larger subsample sizes to achieve similar estimates of taxa richness and metric error compared to GWD streams, but these differences were not large enough to recommend different subsampling methods for these stream types. Analysis of sample timing determined that 97% of emergence occurred from April through September. We recommend in studies where estimation of winter emergence is not important that sampling be limited to this period. Sampling frequency also affected the proportion of the community collected. To maximize the portion of the community, collected samples should be taken across seasons although no specific sampling interval is recommended. Subsampling and sampling frequency was also assessed simultaneously. When using a 300-count subsample, a 4-week sampling interval from April through September was required to collect on average 71% of the community. Due to differences in elements of the chironomid community evaluated by different studies (e.g., biological condition, phenology, and taxonomic composition), richness estimates are documented for five sampling intervals (2, 4, 6, 8, 10, and 12 weeks) and five subsample sizes (100, 200, 300, 500, and 1,000 counts). This research will enhance future studies by providing guidelines for tailoring SFPE methods to study specific goals and resources.     

The Mid-Canada Radar Line and First Nations' people of the James Bay region, Canada: an evaluation using log-linear contingency modelling to analyze organochlorine frequency data

Abandoned radar line stations in the North American arctic and sub-arctic regions are point sources of contamination, especially for PCBs. Few data exist with respect to human body burden of organochlorines (OCs) in residents of communities located in close proximity to these radar line sites. We compared plasma OC concentration (unadjusted for total lipids) frequency distribution data using log-linear contingency modelling for Fort Albany First Nation, the site of an abandoned Mid-Canada Radar Line station, and two comparison populations (the neighbouring community of Kashechewan First Nation without such a radar installation, and Hamilton, a city in southern Ontario, Canada). This type of analysis is important as it allows for an initial investigation of contaminant data without imputing any values. The two-state log-linear model (employing both non-detectable and detectable concentration frequencies and applicable to PCB congeners 28 and 105 and cis-nonachlor) and the four-state log-linear model (using quartile concentration frequencies for Aroclor 1260, PCB congeners [99,118,138,153,156,170,180,183,187], beta-HCH, p,p'-DDT +p,p'-DDE, HCB, mirex, oxychlordane, and trans-nonachlor) revealed that the effects of subject gender were inconsequential. Significant differences (p < 0.05) between the groups examined were attributable to the effect of location on the frequency of detection of OCs or on their differential distribution among the concentration quartiles. In general, people from Hamilton had higher frequencies of non-detections and of concentrations in the first quartile (p < 0.05) for most OCs compared to people from Fort Albany and Kashechewan (who consume a traditional diet of wild meats that does not include marine mammals). An unexpected finding was that, for Kashechewan males, the frequency of many OCs was significantly higher (p < 0.05) in the 4th concentration quartile than that predicted by the four-state log-linear model, but significantly lower than expected in the 1st quartile for beta-HCH. The levels of PCBs found for women in Fort Albany and Kashechewan were greater than those reported for Dene (First Nation people) and Métis (mixed heritage) of the western Northwest Territories (NWT) who did not consume marine mammals, and for Inuit living in the central NWT (occasional consumers of marine mammals). Moreover, the levels of total p,p'-DDT were greater for Fort Albany and Kashechewan women compared to these same aboriginal groups.     

Algae: the world��s most important ��plants����an introduction

Early in the history of life, algae changed the planet??s atmosphere by producing oxygen, thus paving the way for the evolution of eukaryotic organisms. In an era in which the consumption of fossil fuels is a prime topic of concern, few people realize that the oil we currently exploit comes mostly from Cretaceous deposits of marine algae. Moving from ancient times to the present, the algae remain more important than most people realize. Today, the production of oxygen by algae (ca. 50% of all oxygen production) is another reason for saying ??our lives depend on algae.?? Those who love seafood should thank the algae because algae are the primary producers upon which aquatic ecosystems depend. Thanks should come from all who are vegetarians or omnivores, because all land plants derive from a freshwater class of green algae and all land-animals??including the cows that provide the steaks for meat-lovers??depend directly or indirectly on land plants for food and often for shelter as well. As we use up the oil deposits provided by the ancient algae, we are turning to the modern algae for help. Given the photosynthetic abilities of the algae, they are one of the major focuses for sustainable biofuel production and CO₂ consumption. Finally, the algae that give us the air we breathe, the food we eat, and the fuel for our cars (past and, perhaps, future), are also a source of active pharmaceutical compounds that can be used against drug-resistant bacterial strains, viruses (including Herpes Simplex and AIDS), and cancers. Roses are pretty and oak trees are impressive, but no other groups of ??plants?? have done so much, for so long, and, for so many as have the algae!