Chemical Exports Research Articles

INDUCTION OF THE MULTIDRUG RESISTANCE-ASSOCIATED PROTEIN FAMILY OF TRANSPORTERS BY CHEMICAL ACTIVATORS OF RECEPTOR-MEDIATED PATHWAYS IN MOUSE LIVER

The multidrug resistance-associated proteins (Mrp) are ATP-dependent transporters that export a variety of conjugated and unconjugated compounds out of cells. There are nine identified Mrp transporters in humans, with murine orthologs for all except Mrp8. Because nuclear receptors mediate induction of phase I enzymes, Mrp transporter expression might be similarly regulated by these receptors to coordinate metabolism and export of chemicals from liver. To test the hypothesis that Mrp expression may be coordinately regulated with phase I enzyme expression in liver, 15 different compounds were given representing known transcriptionally mediated pathways: aryl hydrocarbon receptor (AhR), pregnane X receptor (PXR), constitutive androstane receptor (CAR), peroxisome proliferator-activated receptor alpha (PPARalpha), and nuclear factor-E2-related factor 2 (Nrf2). Each of these compounds induced expression of their respective target enzyme in liver, demonstrating that the chemical regimens were effective. The AhR ligands [2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD), polychlorinated biphenyl 126 (PCB126), and beta-naphthoflavone] induced Mrp2, -3, -5, and -6 mRNA expression. The CAR activator 1,4-bis[2-(3,5-dichloropyridyloxy)]benzene (TCPOBOP) induced Mrp2, -3, -4, -6, and -7 mRNA expression. Mrp3 was also induced by two other CAR activators phenobarbital and diallyl sulfide, two PXR ligands, pregnenalone-16alpha-carbonitrile and spironolactone, and the PPARalpha ligands clofibrate, ciprofibrate, and diethylhexylphthalate. The Nrf2 activators (butylated hydroxyanisole, oltipraz, and ethoxyquin) induced Mrp2-6. In conclusion, a variety of mechanisms are suggested for Mrp3 induction, including AhR, CAR, PXR, PPARalpha, and Nrf2, whereas on a whole, a predominant role for AhR and Nrf2 in hepatic induction of the Mrp family was observed. Thus, these specific transcription factors are implicated in regulation of both drug metabolism and efflux transport.

La réglementation américaine en matière de contrôle des armes chimiques et biologiques

After identifying the role of the Australia Group which is a multilateral body designed to control export of sensitive chemicals, as well as « equipment » and « technical data » designed to fabricate chemical or bacteriological weapons, this study briefly overviews U.S. policy in terms of export controls, and then attempts to review the current U.S. regulations on chemical and bacteriological weapons. With regard to chemical weapons, the analysis goes back to the Iran-Irak war and traces the evolution of the various controls imposed on chemicals. With the March 13, 1991 decision, export controls exist on 50 chemicals and the warning list has now been reduced to zero. With regards to biological weapons, a whole new list of controls is now being discussed within the Australia Group. A list of 29 countries has been drawn up and the U.S. hope that the Australia Group will adopt similar controls when it meets in December 1991. The article also contains five annexes : the classification of groups countries for export control reasons ; a list of countries under foreign policy controls ; the classification of microorganisms according to their class and degree of pathogenicity; a list of the fifty precursors under control; and the chronological evolution of the U.S. controls imposed on chemicals.

Temporal and spatial variability of cation and silica export in an alpine watershed, Emerald Lake, California

AbstractA reaction set of possible mineral weathering reactions is proposed to explain observed cation and silica export for the Emerald Lake watershed, a small Sierra Nevada, California catchment. The reaction set was calculated through a stoichiometric mole‐balance method, using a multiyear record of stream flow and snowpack chemical analyses and site‐specific mineral compositions. Reaction‐set calculations were intended to explore how the processes controlling stream cation and silica export depend on differing bedrock mineralogy across the catchment as snowmelt and runoff patterns change over the year. Different regions within the watershed can be differentiated by lake inflow subdrainages, each exhibiting different stream‐flow chemistry and calculated weathering stoichiometry, indicating that different silica and cation generation processes are dominant in wet steep portions of the catchment. Short‐term differences in stream concentrations were assumed to reflect ion exchange equilibria and rapid biological processes, whereas long‐term persistent stream concentration differences in different areas of the catchment were assumed to reflect spatial variability in mineral weathering stoichiometry. Mineralogical analyses of rock samples from the watershed provided site‐specific chemical compositions of major mineral species for reaction calculations. Reaction sets were evaluated by linear regression of calculated versus observed differences between snowmelt and stream‐flow chemistry and by a combined measure. Initially, single weathering reactions were balanced and evaluated to determine the reactions that best explained observed stream chemical export. Next, reactions were combined, using mineral compositions from different rock types to estimate the dependence of ion fluxes on lithology. The seasonal variability of major solute calculated fluxes is low, approximately one order of magnitude, relative to the observed three orders of magnitude variability in basin discharge. Reaction sets using basin‐averaged lithology and Aplite lithologies gave superior explanations of stream chemical composition. Copyright © 2004 John Wiley & Sons, Ltd.

Prior Informed Consent for Hazardous Chemicals Trade – Implementation in EC Law

Summary: The issue of trade in hazardous chemicals has long been contentious on the international agenda. Gradually the notion of prior informed consent has developed as a means to strengthen the regulatory abilities of importing countries, taking its legally binding form in the 1998 Rotterdam Convention. It is now being implemented by the EC, itself a Party to the Convention, through Regulation (EC) No 304/2003 concerning the export and import of dangerous chemicals. Compared to the Convention, the Regulation is progressive, particularly by increasing the number of chemicals subject to prior informed consent procedure and applying it also in relation to non-party countries. It even imposes an absolute export ban on certain substances. On some points the Regulation falls short of formally fulfilling the Community's obligations but this may not entail negative repercussions if handled in a constructive and prudent manner. In the end however, the attainment of beneficial effects for human health and the environment is contingent upon the ability of importing developing countries to create regulatory systems and authorities able to utilize the provided system in an efficient manner and effectively execute informed decisions on chemicals import. How the Regulation's commitments regarding technical assistance will be implemented remains to be seen.

Protective Role of Hydroxysteroid Sulfotransferase in Lithocholic Acid-induced Liver Toxicity

Supplement of 1% lithocholic acid (LCA) in the diet for 5-9 days resulted in elevated levels of the marker for liver damage aspartate aminotransferase and alkaline phosphatase activities in both farnesoid X receptor (FXR)-null and wild-type female mice. The levels were clearly higher in wild-type mice than in FXR-null mice, despite the diminished expression of a bile salt export pump in the latter. Consistent with liver toxicity marker activities, serum and liver levels of bile acids, particularly LCA and taurolithocholic acid, were clearly higher in wild-type mice than in FXR-null mice after 1% LCA supplement. Marked increases in hepatic sulfating activity for LCA (5.5-fold) and hydroxysteroid sulfotransferase (St) 2a (5.8-fold) were detected in liver of FXR-null mice. A 7.4-fold higher 3alpha-sulfated bile acid concentration was observed in bile of FXR-null mice fed an LCA diet compared with that of wild-type mice. Liver St2a content was inversely correlated with levels of alkaline phosphatase. In contrast, microsomal LCA 6beta-hydroxylation was not increased and was in fact lower in FXR-null mice compared in wild-type mice. Clear decreases in mRNA encoding sodium taurocholate cotransporting polypeptide, organic anion transporting polypeptide 1, and liver-specific organic anion transporter-1 function in bile acid import were detected in LCA-fed mice. These transporter levels are higher in FXR-null mice than wild-type mice after 1% LCA supplement. No obvious changes were detected in the Mrp2, Mrp3, and Mrp4 mRNAs. These results indicate hydroxysteroid sulfotransferase-mediated LCA sulfation as a major pathway for protection against LCA-induced liver damage. Furthermore, Northern blot analysis using FXR-null, pregnane X receptor-null, and FXR-pregnane X receptor double-null mice suggests a repressive role of these nuclear receptors on basal St2a expression.

Chemical transport from paired agricultural and restored prairie watersheds.

A five-year record of streamflow and chemical sampling data was evaluated to assess the effects of large-scale prairie restoration on transport of NO3-N, Cl, and SO4 loads from paired 5,000-ha watersheds located in Jasper County, Iowa. Water quality conditions monitored during land use conversion from row crop agriculture to native prairie in the Walnut Creek watershed were compared with a highly agricultural control watershed (Squaw Creek). Combining hydrograph separation with a load estimation program, baseflow and stormflow loads of NO3-N, Cl, and SO4 were estimated at upstream and downstream sites on Walnut Creek and a downstream site on Squaw Creek. Chemical export in both watersheds was found to occur primarily with baseflow, with baseflow transport greatest during the late summer and fall. Lower Walnut Creek watershed, which contained the restored prairie areas, exported less NO3-N and Cl compared with upper Walnut Creek and Squaw Creek watersheds. Average flow-weighted concentrations of NO3-N exceeded 10 mg/L in upper Walnut Creek and Squaw Creek, but were estimated to be 6.6 mg/L in lower Walnut Creek. Study results demonstrate the utility of partitioning loads into baseflow and stormflow components to identify sources of pollutant loading to streams.

Man-made chemicals found in remote areas of the world: the experimental definition for POPs.

Members of the United Nations Economic Commission for Europe (UN-ECE) signed a legally binding protocol on persistent organic pollutants (POPs) in February 1998 under the Convention on Long-Range Transboundary Air Pollution. A treaty that intends to control the production, import, export, disposal and use of toxic chemicals that persist for decades in the environment has been formally signed at a conference in May 2001 in Stockholm. The 2001 POP treaty, like the 1998 LRTAP POP protocol, contains a provision on adding further chemicals to the initial group of twelve or fifteen. The occurrence of a compound or a group of compounds in so called remote and pristine areas, e.g. in the Artic or in the Southern Hemisphere, proves its stability under the chemical and biological conditions of the environment. Compounds identified in this way, in samples taken primarily in very remote regions of the planet, are classified by their environmental fate and global distribution as persistent organic pollutants (POPs), regardless of any political assessments.

China's Accession to the World Trade Organization: Implications for the Korean Economy

This paper is exploring the impact on the two proximate economies, Korea and China, of China’s accession to the World Trade Organization. We try to figure out how the aggregate effects, export performance, domestic production, and flows of foreign direct investments can be affected by this exciting event, using computable general equilibrium approach. Compared to great beneficial effects on China, the impact on the Korean economy would be marginal. In textiles, wearing apparels, and automobiles, Korea’s export to China is likely to increase while there may be small effect on the exports of electronics, chemicals, and machinery. Both China and Korea would benefit from the inflows of international direct investments on the global scale, but they can be fiercer competitors in attracting foreign investors with China’s membership in the World Trade Organization as a turning point.

U.S. Chemical Surplus Dropped Sharply In 2001

The U.S. chemical Industry, already suffering from depressed demand in 2001, got no help from foreign trade last year. Exports rose minimally, and that growth was vastly outpaced fay the rise in imports from foreign producers, sending the chemical trade balance to its lowest level in decade. According to data from the Commerce Department, in 2001 the value of exports of chemicals and allied products rose just 0.6% to $80.2 billion. Meanwhile, imports rose 7.1% to $78.9 billion. The result was a 78.7%, or $4.70 billion, slide in the chemical trade surplus, to $1.29 billion. Two factors contributed to the decline: the strength of the dollar against foreign currencies, which shows no sign of abating, making U.S. products more expensive overseas and overseas products cheaper and more competitive in the US.*, and slowing overseas economies, which cut demand for U.S. exports. A third factor also affected two chemical sectors: inorganic ...

Xenobiotic transporters: another protective mechanism for chemicals.

Xenobiotic transporters are responsible for the uptake of some chemicals into cells, and extremely important for the export of chemicals out of cells. A number of families of xenobiotic transporters have been cloned the last few years. Some microsomal enzyme inducers will enhance the plasma disappearance and biliary excretion of some xenobiotics that are not biotransformed in the intact animal, as well as in isolated hepatocytes. This is due to an up-regulation of xenobiotic transporters. As a result, some microsomal enzyme inducers will enhance the elimination and decrease the toxicity of some chemicals by enhanced transport.

SEEPAGE LOSSES FROM ANIMAL WASTE LAGOONS: A SUMMARY OF A FOUR–YEAR INVESTIGATION IN KANSAS

Seepage losses from animal waste lagoons can affect groundwater quality if liquid effluent is not properly contained within the basin. Seepage rates from 20 anaerobic lagoons were measured using water balance methods. Study locations included 14 swine sites, 5 cattle feedlots, and a single dairy. Seepage results and basin geometry were used to estimate the hydraulic conductivity (Ks) of the compacted soil liner at each site. Seepage data and waste chemistry were used to calculate rates of chemical export into the vadose zone. Profiles of ammonium–nitrogen (N) and other chemicals were determined by sampling soils beneath old lagoons. Seepage rates from 20 lagoons averaged 1.1 mm/d and ranged from 0.2 to 2.4 mm/d. Fifteen of the 20 lagoons had seepage rates between 0.5 and 1.5 mm/d. The variation among locations was small despite large differences in soil types and depths to groundwater. On average, the Ks of lagoon liners was 1.8 U 10–7 cm/s. Variation in seepage rates and Ks among sites was lognormally distributed. There was evidence that seepage was moderated by the organic sludge that blankets the bottom of lagoons. Concentrations of nitrogen, phosphorus, and other waste constituents were, on average, 3 to 5 times higher in swine waste lagoons compared to cattle feedlot lagoons. Ammonium–N seepage into the subsoil ranged from 2000 to 5000 kg ha–1 yr–1 at the larger swine sites but averaged 385 kg ha–1 yr–1 at cattle feedlots. Soil cores showed that concentrations of ammonium–N, organic–N, phosphorus, and other cations were highest near the original floor of the lagoon but decreased markedly with depth. In most cases, concentrations of nutrients in the soil returned to background levels about 3 m under the lagoons. Additional research is needed on fate and transport of contaminants that accumulate beneath lagoons and best management practices for lagoon closure.

Hydrological controls on chemical export from an undisturbed old-growth Chilean forest

Stream water chemical concentrations from an undisturbed, temperate, old-growth Chilean forest were analyzed to gain insights into hydrological controls on watershed-scale losses of different nutrients and chemical elements. Our goal was to understand how hydrological and biogeochemical processes interact to control patterns of export of dissolved chemicals from these types of forested watersheds. The study is unique in that the monitored watershed lies in a part of the world that receives very little anthropogenic influence and this is the first study of its type in this part of the world. A small, densely forested, montane watershed was continuously monitored for stream discharge and precipitation and was sampled biweekly for stream-, precipitation-, and soil-water chemistry. Three different forms of hydrological controls were used to describe how concentrations of different elements changed as a function of increased stream water discharge: dilution of elements due to decreased relative contributions by baseflow sources, increased concentration due to enhanced hydrological access to elements in to shallow soil horizons, and no net effect, i.e. hydrologically constant. A hyperbolic relationship was used to describe element concentration as a function of stream discharge to quantify the variations for major ions, cations, and organic forms of nutrients. In general, this hydro-biogeochemical system showed the most distinct dilution and enhanced hydrological access for chemicals with large concentration differences between deep and shallow soil water. Deep soil water sources were most distinct for Ca2+ and Si, both of which demonstrated dilution. In contrast, variations in H+ concentrations resembled enhanced hydrological access indicating shallow soil sources, coupled with the consumption of acidity by weathering or cation exchange in deeper soil layers. Rainwater sometimes enhanced and sometimes tempered the observed trends. Potassium was the least hydrologically variable element (hydrologically constant) in this study, possibly due to strong biological mechanisms internal to the watershed. The approach used here is a simple method to identify the importance of hydrologic variations in controlling streamwater chemistry relative to internal biogeochemical sources and processes.

Trade Surplus Still Falling

On the heels of the latest foreign trade data from the government, the American Chemistry Council (ACC) released a forecast that shows slowing growth in foreign trade for the U.S. chemical industry for the remainder of this year and little improvement in the chemical trade surplus next year. In the first six months of the year, Commerce Department data show chemical exports increased 7.0% from the same period in 2000 to $41.6 billion, but imports rose a much faster U% to $40.3 billion, drivingthe surplus down 63% to $1.3 billion. Accentuating this depressing news, ACC doesn't see much improvement anytime soon. In fact, says Martha G. Moore, ACC's senior economist, growth for exports and imports will slow in the second half of this year from what it was in the first six months. Thus, for the full year, according to the forecast, exports will rise about 6% while imports will grow some 13%. However, the ...

Processes regulating watershed chemical export during snowmelt, Fraser Experimental Forest, Colorado

In the Central Rocky Mountains, snowfall dominates precipitation. Airborne contaminants retained in the snowpack can affect high elevation surface water chemistry during snowmelt. At the Fraser Experimental Forest (FEF), located west of the Continental Divide in Central Colorado, snowmelt dominates the annual hydrograph, and accounts for >95% of annual stream water discharge. During the winters of 1989–1993, we measured precipitation inputs, snowpack water equivalent (SWE) and ion content, and stream water chemistry every 7–10days along a 3150–3500m elevation gradient in the subalpine and alpine Lexen Creek watershed. The study objectives were to (1) quantify the distribution of SWE and snowpack chemical content with elevation and aspect, (2) quantify snowmelt rates, temperature of soil, snowpack, and air with elevation and aspect, and (3) use change in upstream–downstream water chemistry during snowmelt to better define alpine and subalpine flowpaths. The SWE increased with elevation (P<0.001) and was greater on NE aspects (P<0.05). Subalpine soils were unfrozen. Snowmelt occurred throughout winter at low elevation (3150m), SE aspect stations. By snowpack peak water equivalent (PWE), the snowpack lost about a third (0.24m) of its moisture. The subalpine snowpack had warm (>− 3°C) temperatures throughout winter which resulted in significant snowpack ion loss. By snowpack PWE in mid May, the snowpack had lost almost half the cumulative precipitation H+, NH4+, and SO42− inputs and a third of the NO3− input. Windborne soil particulate inputs late in winter increased snowpack base cation content. Variation in subalpine SWE and snowpack ion content with elevation and aspect, and wind redistribution of snowfall in the alpine resulted in large year-to-year differences in the timing and magnitude of SWE, PWE, and snowpack ion content. The alpine stream water ion concentrations changed little during snowmelt indicating meltwater passed quickly through surface porous soils and was well mixed before entering the stream. Conversely, subalpine stream water chemistry was diluted during snowmelt suggesting much melt water moved to the stream as shallow subsurface lateral flow.

INDIA'S FINE CHEMICALS

FOR YEARS, MANUFACTURERS OF generic drugs and pharmaceutical ingredients have complained about losing out to low-cost competition from India. Indeed, India's exports of fine chemicals have grown rapidly over the past decade. Yet despite its growing international profile, India's fine chemicals industry is far from healthy A handful of firms face bright prospects while the future is bleak for most others. As India becomes a full-fledged member of the World Trade Organization (WTO), its fine chemicals industry is at a crossroad. The mood was somber in mid-January at an industry conference in Mumbai held by the Indian magazine Chemical Weekly . Participants groaned about unfavorable government policies and increasing competition from China. But Indian companies face their most serious challenge in preparing to abide by the international regime protecting intellectual property rights that will take effect in 2005. Few companies have sufficient capabilities to develop differentiated products or to establish th...

Pricing to Market of German Exporters: Evidence from Panel Data

This paper investigates pricediscrimination of German exporters across differentforeign markets. We examine the degree of pass-throughof exchange rate fluctuations in the pricing of 70export items. The model is estimated using panel dataon export unit values. Parameter estimation relies onGMM first difference, fixed effects, LAD, OLS firstdifference, and the random coefficients model. Themain results for 70 manufactured goods and 15destination countries between 1990–1994 are: Thedegree of pricing to market differs among destinationsand products. Highest pricing to market is observedfor U.S., Japan, Italy and Spain. Pricing to market ismore prevalent in exports of chemicals and fertilisersthan in machinery products.

China trade deal should boost U.S. chemical exports

U.S. chemical exports to China are expected to expand and diversify as the result of the breakthrough trade agreement reached between the two nations last week. The deal struck by Washington and Be...

Abnormally high fluoride levels in commercial preparations of 40 per cent silver fluoride solution: contraindications for use in children.

Although a 40 per cent solution of silver fluoride would be expected to contain 6 per cent fluoride (60,000 ppm), F-levels of 100,000 ppm and 120,000 ppm were found in 14 commercial samples analysed at The University of Western Australia in 1993 and 1994. To determine whether F-levels in 40 per cent AgF preparations have remained high, the present investigation was aimed at analysing different batches of commercial preparations obtained more recently. Fluoride ion analysis was carried out on 24 AgF samples using the Ion-Selective Electrode technique. Independent analyses of the same samples were carried out by a private chemical testing laboratory (Genalysis). Ten samples supplied by Agson Chemical Export were found to contain between 75,000 and 100,000 ppm F-: Genalysis reported 80,000 to 120,000 ppm. Fourteen samples supplied by Southern Dental Industries were found to contain between 70,000 and 120,000 ppm F-; Genalysis reported 88,000 to 108,000 ppm F-. These results confirm significantly higher than expected F-levels (ANOVA p < 0.05) in commercial preparations of 40 per cent AgF. The solutions tested were found to contain a mixture of ammonium fluoride, sodium or potassium fluoride, and silver fluoride. The additional presence of silver difluoride and hydrofluoric acid resulting from the manufacturing process has been suggested as an explanation for the much higher than expected levels of fluoride ion. In view of possible toxicity of 40 per cent AgF in young children, it is concluded that such a highly concentrated solution should not be used clinically; instead, lower strength AgF solutions should be investigated for their efficacy in caries treatment.

Trade surplus plummets as chemical imports soar

The U.S. chemical trade surplus was almost halved in March on a year-to-year basis as imports hit their highest level ever on a less than 1% rise in exports. According to the latest data from the Department of Commerce, the value of U.S. chemical exports totaled $6.00 billion in March, up just 0.3% from March 1997, whereas imports soared 20% to $5.01 billion. Thus, the chemical trade surplus, long a boasting point for the industry, dropped 46% to $990 million. On a month-to-month basis, the chemical trade surplus was off about 20% from February, continuing a downward trend. Exports were up 10%; imports increased 19%. The huge March decline pushed the surplus for the first quarter of the year down to about $3.48 billion, a 25% drop from the same three months of 1997. Exports for the quarter totaled $17.1 billion, up 3%, and imports rose 13% to $13.7 billion. Observers blamed much of the ...

Chemical trade surplus increases 14% in 1997 to $20.5 billion

It's an old, but largely happy, story for the U.S. chemical industry—another good year in foreign trade in 1997. The industry sent more chemicals overseas than ever before. And although imports of chemicals increased, they were not enough to put a damper on the chemical trade surplus, which also showed a healthy rise. Data from the Department of Commerce put the total value of chemical exports for last year at about $70.8 billion, a 13% rise from 1996. Imports of chemicals increased 12% to $50.3 billion. This produced an excess of exports over imports, or trade surplus, of $20.5 billion, 14% above the 1996 surplus. Last year's surplus, in fact, was the second highest on record: The largest chemical trade surplus was in 1995 at $21.3 billion. There might have been a record if it had not been for the fourth quarter. Through the first three quarters of the year, exports were up 13% to ...