Water run-off

Tannin-containing woods can also suffer from dark-brown stains produced by alkali, usually from a concrete or a detergent source. Conversely, fair-faced concrete can be similarly stained by the run-off water from unprotected hardwood surfaces. Some woods, e.g. afzelia, ayan and idigbo, give yellow contaminating dyes with alkaline detergents and should not be used in washrooms and kitchens. 

Munthe J, Hultberg H, Lee Y-H, Parkman H, I verfeldt A, Renberg I. 1995a. Trends of mercury and methylmercury in deposition, run-off water and sediments in relation to experimental manipulations and acidification. Water Air Soil PoUut 85(2) 743-748. 

For solids run-off it is assumed that this run-off water contains 200 parts per million by volume of solids thus the corresponding velocity term U12 is 200 x 10 6t Jn, i.e., 10 s m/h. This corresponds to the loss of soil at a rate of about 0.1 mm per year. If these solids were completely deposited in the aquatic environment (which is about l/10th the soil area), they would accumulate at about 0.1 cm per year, which is about a factor of four less than the deposition rate to sediments. The implication is that most of this deposition is of naturally generated organic carbon and from sources such as bank erosion. 

Fam et al. [11] determined hydrocarbons in run-off water from catchments in San Francisco Bay using liquid chromatography and high-resolution gas chromatography. 

The engine timing has to be retarded for the car to run off water. This adjustment should be made to the point where the engine mns the best and this is likely to be different for each make of engine. The Chevy Camaro ... 

The pesticides methyl and ethyl parathion were determined in run-off water er preconcentration on XAD-2. This allowed analyses of these compounds at the parts per billion level (497). Parathion and paraoxon obtained from leaf extracts and orchard soil have also been determined (492). The separation of 30 carbamate pesticides by RPC has been described (493). Various modes of postcolumn fluorometric detection of carbamate insecticides have been reported including post-colun)n reaction between o-phthalaldehyde and methylamine, a carbamate hydrolysis... 

In examining environmental run-off water he ran into a problem. His samples were very dilute, so the first step would be some form of concentration. Studies with pure material show that it is sufficiently nonpolar to stick easily to a Ci8 SFE cartridge from an aqueous solution. 

Briefly recalled, the WASTOXHAS approach consists in characterizing the ecotoxicological hazard potential of contaminant fluxes from waste leachate obtained under defined conditions with two different dynamic leaching procedures laboratory simulated leaching tests and field leaching tests. The approach developed below considered a specific scenario that simulates a waste deposit receiving rain or run-off water (Perrodin et al., 2002). 

These waste simulation trials based on laboratory column experiments still needed to be validated using a field approach. Two field leaching tests were thus built on an experimental site (CERED, Vernon, France) to simulate real conditions of a waste deposit site receiving rain or run-off water (Perrodin et al., 2002). The first... 

Run-off waters from fields (containing pesticides and loaded with nutrients as a result of the application of fertilizers)... 

Arsenical herbicides (methane arsonate, dimethyl arsenite) and inorganic arsenic at the pg L 1 level have been determined in run-off water [266],... 

To determine Paraquat in agricultural run-off water Payne [194] separated the sediment from the sample (2L) by adding calcium chloride to aid flocculation, leaving the mixture overnight in a refrigerator for the sediment to settle. A 1L aliquot of the filtrate is extracted with dichloromethane. The dichloromethane extracts are concentrated by evaporation and the Trifluralin and Diphenamid are determined by direct injection, without further purification on to a glass column 1,8x6mm od packed with 10% DC 200 on Gas-Chrom Q and operated at 220°C with helium as carrier gas (lOOmL min-1) and a Coulson electrolytic-conductivity detector (N mode). Paraquat is determined in the filtrate by a modification of a conventional colorimetric method. Recoveries of the three substances were between 82 and 95% from water. 

Cytrolane and cyolane were determined in spiked run-off water to demonstrate the applicability of the thin-layer mercury amalgamated gold detector for the determination of insecticide residue. A chromatogram of a sample spiked with 0.94 pg/ml and... 

Figure 13. Chromatogram of run-off water spiked with 0.94 pg/mL of cytrolane (Cyt) and 0.84 fig of cyolane (Cyo) (mobile phase 0.02M acetate buffer, pH 4.15 containing 30% methanol (v/v) at a flow rate of 0.5 mL/min TL-9A electrochemical transducer was set at —1.25 V vs. Ag/AgCl reference electrode)...

Water harvesting and collection To avoid water losses after strong rains, surface run-off is collected using bunds and ideally brought into the proximity of the plants. To avoid run-off from the field, the water is retained with micro-catchments and by field contour cultivation. Run-off water that has left the fields is slowed down by terraces, bunds on contour lines, dams and hedges and, if possible, collected. 

Once a pesticide does its job, the toxicant doesn t immediately disappear but becomes a factor in the environment. Hence, the chemist must be concerned with the ultimate fate of this material in relation to drift, residual nature in soil, residue in run-off water, and effect on food chain. 

To prevent accumulation of ash and slag in the water circuit, some water is discharged continuously. In a combined chemical and physical treatment sulfides, cyanides and suspended solids (ash) are removed. A concentrated sludge has to be filtered off and disposed of. The run-off water from the filters is stripped of ammonia and after pH-adjustment sent to a biological treatment unit. Uhde [532] has developed an alternative route for soot treatment in which the soot is filtered off and subjected to combustion, and the filtered water is recycled to the quench and scrubbing circuits. Let down water is treated as described above. This soot treatment technique avoids not... 

A major source of water for leaching is the normally acidic run-off water from the mining operation itself. O Leary (02) describes a technique of cleaning up to 900 gal/min of mine and tailings water at the Butte operation of the Anaconda Company. The suspended solids, which at times are in excess of 2% by weight, are equivalent to about 50 tons of mud per day. Since copper is recovered from this stream by precipitation and the barren liquor is used to leach the mine w aste dumps, solids, and colloidal materials have to be removed. With a flocculant, a 98% reduction in solid content is attained with a feed stream containing 0.22% solid. 

Benzothiazoles from vulcanization of rubber tires are found so enriched in some situations that they are used as a marker for street run-off water. Thiocya-natomethylthiobenzothiazole used as a fungicide in wood protection and antifouling paints may degrade into benzothiazoles and methylthiobenzothiazole is used in vulcanization processes, so these materials find their way into rivers and ultimately estuaries. Bester et al. (1997) determined the presence of benzothiazole and methylthiobenzothiazole in estuarine and marine waters. Their concentrations range from 0.04 ngL to 1.37 ngL . Methylthiobenzothiazole and benzothiazole vary from 0.25 ng L to 2.7 ngL in the North Sea, while 55 ngL methylthiobenzothiazole was found in the Elbe River. 

Aqueous waste streams include process water, utility waste water, and site run-off. Water that is used or formed in the process must be sent to effluent treatment. Common process water effluents include... 

It is also a best practice to collect run-off water from the plant area and treat it in the site waste water plant before discharging it to the environment. Run-off water can come from rain, fire hydrant flushing, and equipment washing. As the water flows over the ground around the plant, it can become contaminated with organic chemicals that have leaked from the plant. Most plants are designed so that all the run-off is collected into local sewers or ditches that are routed to the site waste water treatment plant. 

The industrialized countries also oversee emissions and effluents that issue from manufacturing sites and research buildings. Pharmaceutical companies control effluent content to eliminate or minimize the release of harmful or potentially harmful chemicals. Regulations prohibit the discharge of, for example, heavy metals into sewage or storm run-off waters, fipcos therefore monitor their aqueous effluents, sometimes continuously. 

Monitoring of phosphates also takes place within industry as part of environmental management and within processes that employ phosphate containing chemicals. Self-monitoring of nutrients in soils and run-off waters is also increasing within the agricultural sector. 

Garcia-Falc6n, M. S., Perez-Lamela, C., and Simal-Gandara, J., Strategies for the extraction of free and bound polycyclic aromatic hydrocarbons in run-off waters rich in organic matter, Anal. Chim. Acta, 508, 177-183, 2004. 

The long-term control of these tailings must include the prevention of their use in construction materials for dwellings and a ban on using run-off water for irrigation. 

Nicosia, S., Carr, N., and Gonzales, D. A. 1990). Run off field movement and dissipation of. soil incoiporated carbofuran from three commercial rice fields The potential discharge in agricultural run off water Gov. Rep. Announce. 22, 90. 

The use of a roof and a reinforced yard allows the collection of run-off water and therefore prevents uncontrolled emissions to water and soil. Direct emissions to soil are also minimised since mixing of the material with soil is prevented. 

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