From Toxic Dust And Algae To Ill Winds From Africa

Main Category: Water - Air Quality / Agriculture
Also Included In: Conferences;  Public Health;  Biology / Biochemistry
Article Date: 23 Nov 2009 - 1:00 PST

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Toxic dust: Toxins in coal-tar-based sealcoats in parking lots may be the culprit in contaminated house dust, according to a USGS study. PAHs - or polycyclic aromatic hydrocarbons - are large molecules found in oil, coal and tar deposits, and can have toxic effects. It's long been known that PAHs are often found in house dust; however, the specific sources of these PAHs are largely undetermined. Researchers found that dust from indoor areas near parking lots with coal-tar-based sealcoat had substantially elevated concentrations of PAHs. The study: PAHs in house dust and relation to coal-tar-based pavement sealcoat.

Eensy-weensy spiders play large role as sentinels of contaminants: Spiders that live near water may be an effective warning system for contaminants in aquatic ecosystems, according to a new USGS and U.S. Environmental Protection Agency study. Scientists examined PCB (polychlorinated biphenyls) levels in shoreline-living spiders at Lake Hartwell, a Superfund site in South Carolina, and used this information to map contaminant concentrations in lake sediment. Future monitoring studies will use the spiders as indicators of ecosystem recovery from PCB contamination. Researchers also made risk maps for a spider-eating bird, the Carolina wren, which could be exposed to PCBs through eating spiders. These spiders rely heavily on adult aquatic insects for food and play a key ecological role in the transfer of contaminants between water and land ecosystems. In spite of this, they are underused as a sentinel species at contaminated sediment sites. The study: using riparian spiders as sentinels of PCB export and risk.

It's an ill wind that blows: African dust making it across the ocean: Increasing quantities of African dust have blown across the Atlantic Ocean to the Caribbean and Americas over the past few decades. During that time, the dust's composition has changed. In this study, African dust air masses in Africa and the Caribbean were analyzed for persistent organic contaminants and metals. These potentially toxic contaminants can originate from the burning of plastics, biomass and waste; widespread use of pesticides, plastics, and pharmaceuticals; and increased industrialization. Multiple pesticides and other contaminants, including carcinogens, suppressors of immune systems, disruptors of endocrine systems, and nervous system or liver toxins were identified from all sample sites. All are known to persist in the environment, accumulate in organisms, and are toxic at very low concentrations. The study: Chasing clouds of dust: transoceanic transport of synthetic organic pollutants and trace metals with African dust.

Invasive carp and the secret language of scent: The chemical language of invasive Asian carp may eventually be turned against them in the fight to help eradicate these harmful invaders from the Mississippi River. Asian carp, introduced into the Mississippi River in the 1970s and 80s, are now abundant throughout the lower Missouri, the Mississippi and Ohio rivers, posing a threat to native species. Carp seem to have a chemical language effective for predator defense and reproduction in murky environments, so researchers put this language to the test by subjecting young carp to extracts prepared from the skins of other carp. The result: the young carp, upon detecting the extracts, significantly avoided them by moving from the area, becoming immobile, and schooling. This "alarm substance" may be effective in repelling carp from habitat critical to native species. Young carp were also attracted to the chemical stimuli of schooling carp, which can assist in conventional eradication methods. The study: Use of pheromones to control invasive Asian carp.

Toxic algae may be harming endangered suckers in Klamath Lake: Preliminary data suggest that algal toxins may be hindering the population growth of endangered Lost River suckers and shortnose suckers in Upper Klamath Lake in southern Oregon. This lake is characterized by high levels of nitrogen and phosphorus, nutrients that promote large, frequent cycles of cyanobacterial or algal blooms from spring through fall. Researchers evaluated the presence and effects of these toxins, specifically microcystins, which are harmful to other aquatic life, in the lake's water and in fish from the lake. Examination of liver tissues from juvenile suckers revealed adverse physiological effects consistent with tissue damage associated with microcystin exposure. Significant concentrations of the toxins were reported form all field sampling stations in the lake. The study: Cyanobacterial toxins found in Upper Klamath Lake, Oregon: implications for endangered fish.

Wading through the sources of lake contamination: Contamination of urban lakes and streams by polycyclic aromatic hydrocarbons (PAHs) is widespread and has been increasing over the last 40 years in the United States. These PAHs can be toxic to bottom-dwelling organisms, can cause tumors in fish, and several are believed to cause cancer in humans. In this study, researchers examined five sources of PAHs in 40 urban lakes from across the United States, including coal-tar-based pavement sealcoat, coal combustion, oil combustion, vehicle emissions and wood combustion. Of the five sources studied, sealcoat was the strongest contributor to PAH contamination in lake sediment. This research can help those trying to reduce pollution levels in the urban environment by providing them with a better understanding of PAH sources. This study, Sources of PAHs to urban lakes in the United States, will be presented on Nov. 23 at 11:20 a.m. in the Jefferson Room.

Tiny particles with big effects: Industrially produced nanoparticles are being dispersed into the environment from a range of everyday human activities. Use of consumer nanoproducts, such as sunscreen with zinc oxide or bed sheets and socks containing silver nanoparticles, all have the potential to release metals into the environment. Some of these particles can be toxic, but little is known about how nanoparticles will accumulate in the environment. Interactions between nanoparticles and living organisms are influenced by the unique physico-chemical properties of each kind of nanoparticle. This study introduces a new approach to evaluate the toxicity of nanoparticles with metal as an ingredient, and offers a way to begin to understand potential beneficial uses and potential environmental risks. The study: Characterizing the bioavailability and toxicity of engineered nanoparticles using enriched isotope tracers and biodynamic modeling.

Cause of feminized male sturgeon remains elusive: The number of male shovelnose sturgeon with female characteristics in the Missouri River has increased from about 3 percent in 1968 to 15 percent in 2001. USGS researchers examined the levels of PCBs (polychlorinated biphenyls) and organochlorine pesticides in normal and intersex fish to see whether these hormone-mimicking compounds were associated with the condition. Although the compounds were all present in sturgeon at levels of concern, no differences in levels between intersex male fish and normal male fish were detected. Still, reproductive development is complex and can depend on many factors, including a fish's age at its first exposure. These fish are also exposed to many other compounds that have not yet been tested. Recent findings of intersex in endangered pallid sturgeon underscore the need to find the cause of this condition. The study: Intersex gonads in Missouri River shovelnose sturgeon: occurrence, severity, and association with contaminants.

The SETAC conference is being held in New Orleans from Nov. 19-23. For more info on the conference, visit their Web site.

Source: Jennifer Donovan
Michigan Technological University