INTERPRETING RESULTS FROM ADDITIONAL WATER TESTS

We have been asked for addition toxicity information on other compounds and have given them below. If some industry is suspected to be dumping contaminated effluent, we may ask for these elements to be tested, but this is rare.

These include:

1. Selenium: No specific toxicity data is available, but the USEPA 1986 has set 54 - 410 ppb (parts per billion) as an action level for this compound in marine environments. This element is necessary in small amounts in feeds.

If you suspect a large contamination, have an independent laboratory test this parameter for you.

2. Chromium: Chromium is toxic to marine organisms at 2000 to 105,000 ppm. The most toxic form, hexavalent chromate, is produced in pickling and plating operations, anodizing aluminum, leather tanning, manufacturing of paints, dyes and explosives. Also used to inhibit corrosion in open and closed system cooling towers. After PG&E lost a lawsuit over hexavalent chromium discharged to drinking water of the plant's neighbors, causing major health problems and a movie, named Erin Brockovich became a huge hit, most manufacturers of chemical water treatment for cooling towers can easily convince their clients to use other corrosion inhibitors with less hazardous environmental consequences attendant to accidental release from holding lagoons, so hopefully we will see less hexavalent chromium in ground water, reservoirs and recreational ponds and lakes.

I recommend CHEMetrics kits K2810B (measures 0 to 120 mg/L and 120 to 1200 mg/L) and K2810C (measures 0 to 1200 mg/L and 1200 to 12, 000 mg/L), but you can also purchase K2810D to measure 0 to 30 mg/L and 30 to 300 mg/L and K2810A to measure 0 to 60 mg/L and 60 to 600 mg/L, if you want to test the entire range possible with visual test kits, using the Diphenyl Carbazine method, APHA Standard Methods for Analysis of Water and Wastewater, method 3500-Cr-D (approved in 1995) Alternatively, you can ask an accredited USEPA laboratory to perform this test for you, especially valuable if you intend to sue the company discharging hexavalent chromium to a source that could end up in your lake, pond or reservoir.

4. Zinc: Zinc causes acute marine toxicity at 192 to 320,000 ppm, depending on the species and is chronically toxic at levels of 120 ppm. The average acceptable level of zinc in potable water is 1 mg/L.

Although CHEMetrics offers test kits that measure up to 6 mg/L, to test for serious contamination, send sample to an accredited USEPA laboratory that tests water and wastewater.

8. Hydrogen Sulfide: Hydrogen sulfide inhibits aerobic respiration, inhibits muscle contractions, including breathing, and promotes excess breakdown of glucose. Hydrogen sulfide develops when sulfate-reducing bacteria grow up in the anaerobic sludge of a pond, and no harm is noticed shrimp, prawns, catfish and other bottom-feeders disturb the sludge layer, releasing hydrogen sulfide into the water, where it is first noticed when dead shrimp, prawns or fish float to the surface and a rotten egg odor, is observed. The rotten egg odor will be noticed when as little as 0.25 micrograms of unionized hydrogen sulfide is present in each 1 Liter of pond water. Levels of unionized H2S in ponds is toxic above 0.033 mg/L are toxic to shrimp and many fish. Some researchers suggest that H2S above 0.005 mg/L should be considered toxic and treated with ALKEN CLEAR-FLO 1005

If a pond owner attempts mechanical dredging to recover pond depth taken up by organic sludge, this process can accidentally release sufficient hydrogen sulfide gas to cause human deaths, unless workers wear NIOSH approved SCBA (self-contained breathing apparatus). See Biodredging to learn about biological dredging of ORGANIC sludge, another option for recovering pond depth lost to an accumulation of organic sludge. If sufficient percentages of inorganic sludge are present (sand, rocks, dirt, etc.) washed down due to soil erosion, mechanical dredging may be the only option to recover pond depth, but to avoid issues with hydrogen sulfide, sludge should be pre-treated with ALKEN ENZ-ODOR 6 to avoid the risk of releasing dangerous levels of hydrogen sulfide when the mechanical dredging begins. This pre-treatment is especially important if the pond is located close to the owner's home. Alkalinity and nitrate levels should be tested to determine if addition of sodium nitrate or ALKEN ENZ-ODOR 9 are also needed or if pond pollution levels are sufficient to prevent formation of acid during oxidation of unionized hydrogen sulfide in the sludge layer of the pond.

CHEMetrics test kit recommended by Alken-Murray for pond testing is: K-9510: 0 - 1 ppm & 1 - 10 ppm., since any level above 10 ppm will have killed everything in the pond and be obvious due to severe rotten egg odor coming frrom the pond. For wastewater testing, Alken-Murray recommends CHEMetrics kits K-9510D for 0 - 30 and 30 - 300 ppm, K9510A for 0 - 60 ppm and 6 0 - 600 ppm, K9510B for 0 to 120 and 120 to 1200 ppm, and 9510C for 0 - 1200 and 1200 to 12,000 ppm, providing you the entire possible range of sulfide in water. The protocol for all of these kits is the APHA Standard Methods method 4500-S-2D, which uses methylene blue methodology to detect sulfides in solution in water.

 9. Sulfate: I have not found any aquatic limits for sulfate, but the US Public Health has set 250 mg/L as the limit allowed in drinking water.

This test requires an independent laboratory to test. . We usually do not test for this parameter in natural waterbodies, but it is of interest in wastwater treatment.