aerzzn PRECISION

Air Quality Instruments

F s SCIENTIFIC

Determine air quality with speed and accuracy

Aeron Contlnuous No, Monltor- Correlates with ASTM D 2012. Gives continuous measure of NO, (or NO) in the atmosphere. Sen- sitivity is 0.02 ppm or better.

Aeron Automatic Tape Sampler/ Recorder-Complies with ASTM D 1704. Sample spots are 1 in. dia. on 2 in. centers. Automati- cally records O-1OO0/o l ight trans- mission.

Aeron Tape Spot Evaluator-Com- panion unit for the Automatic Tape Sampler. Evaluates spots at a rate of 720 spots per hqur. In- dicates percent of l ight transmit- tance directly.

Aeron Sequentlal Sarnpler-Com- plies with ASTM D 1605, D 1607, D 1609. Has 12 stations, each ac- commodating 3 tubes. Operates unattended-for up to 4 days.

Aeron Hlgh Volume Air Sampler -Complies with ASTM D 2009 and with USPHS Specifications. High capacity blower-up to 80 c.f.m. free air.

Aeron Sulphur Dloxlde and Dust- Fa l l Mon l to r lng Statlon-Corn- plies with ASTM D 2010 (for SO,) and ASTM D 1739 (for dust-fall). Compact, stable stand assembles wi thout tools. Also sulphat ion plate holders.

Ask your Precis ion Sc ien t i f i c Dealer for a no-obligation dem- onstration, complete performance data on Aeron Air Quality Instru- ments, or wr i te us. Precis ion Scientific Company, 3737 W. Cort- land St., Chibago, 1 1 1 . 60647.

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their effluents. ORSANCO standards do not include many of the toxic wastes from heavy industry. The Ohio River basin leads all others in the number of violations of water quality criteria for public water supplies. During the late summer and fall, effluents from heavy industry such as steel kill off beneficial communities of fish-food plankton which produce oxygen, and give rise to unwanted, but toxic-tol- erant blue-green algae, similar to those in Lake Erie. These organisms have not read ORSANCO’S reports, but dur- ing the 16-week steel strike in the sum- mer of 1959, the real water quality greatly improved because steel mill contamination ceased.

ORSANCO’S predictions that the high navigation dams would result in a bet- ter control of stream flow to regulate waste assimilation did not turn out that way. Instead, toxic wastes accumulate in huge deposits in the newly formed deep pools and destroy many of the beneficial uses of the river. These ooze deposits use oxygen, produce unwanted treatment expense for water treatment plants, impart taste and odor, and im- pair recreational use of the river.

Louis G. Williams University of Alabama University, Ala. 35486

Don’t stop flushing yet!

DEAR SIR: Since writing the Viewpoint col-

umn on the deficiencies of the flush toilet for the January issue of ES&T

(page l l ) , I have noted some reac- tion to the effect that it will no longer be necessary to spend large sums of money to build sewage treatment plants.

If the “dry method” or some better way of keeping human wastes out of flowing water is proved successful by research, it will take many years or even decades to adopt it widely. Therefore, present efforts to con- struct treatment plants should con- tinue apace. Even if such wastes are not handled by treatment plants in the future, our expanding population will generate other wastes (wash water, industrial, off-street, etc.) that will need the facilities now being con- structed and planned.

Harold H. Leich 5606 Vernon P1. Bethesda, Md. 20034

Circle NO. 13 on Readers’ Service Card

188 Enj i ronmental Science & techno log^