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Water testing laboratories can help protect staff from harmful chemical fumes with the durable acid-resistant Acid Gas Fume Hood from Sentry Air
Water testing laboratories use corrosive acids to preserve drinking water samples. These chemicals produce fumes that can cause health hazards to the operator and nearby employees if inhaled. Water testing facilities, such as municipal drinking water or wastewater laboratories, should use proper engineering controls, including ductless or ducted fume hoods, to minimize exposure to harmful chemical fumes.
What is water testing?
Water testing is a procedure specified by the EPA for collecting and preserving water samples to test for trace and total elemental composition. Water testing mainly measures the concentration of harmful metals in a sample to help protect the general population from drinking unsafe water. However, water testing can also test the alkalinity of water. If water is too acidic, it can easily corrode pipes and release additional harmful metals into the water supply.
What metals does water testing test for?
The main contaminants tested for in trace metals water analysis include lead, copper, arsenic, chromium, cadmium, nickel, antimony, and barium. The chart below summarizes the metal type and the importance of testing in water sources.
| Metal | Why it’s Tested |
| Lead | Toxic at low levels and can come from the plumbing |
| Copper | Comes from the plumbing and pipes |
| Arsenic | Naturally occurs and is highly toxic |
| Chromium, Cadmium, Nickel, and Antimony | Comes from industrial sources |
| Barium | Naturally occurring and highly regulated |
Water Testing Procedure
The water testing procedure for trace metals water analysis is detailed in the U.S. EPA’s Method 200.8 (U.S. EPA 1994). This process starts with collecting samples in an approved container. Then, concentrated nitric acid is added to the sample to bring the pH below 2. This important step helps preserve the sample by preventing dissolved metals from separating from the water, preventing the container from absorbing the metals, and reducing the effects of biologics on the sample results. After preserving the sample, it is held for 16 hours, and the pH is verified. If the pH is not low enough, more nitric acid is added. Next, the sample is analyzed using Inductively Coupled Plasma – Mass Spectrometry (ICP-MS). This process heats the sample to separate the metal ions, which are then analyzed by a mass spectrometer.
To test water samples for total metals, facilities perform a similar procedure following the U.S. EPA’s Method 3005A called acid digestion (U.S. EPA 1992). Acid digestion entails adding the nitric acid to the water sample and then heating it under controlled conditions. The acid dissolves the suspended particles and converts metals into dissolved forms. Then the sample is cooled, diluted, filtered, and analyzed for its composition.
For water alkalinity testing, water testing laboratories use hydrochloric acid instead of nitric acid, following ASTM D1067-16 for proper testing procedures.
Water Testing Health Hazards
Water testing procedures utilize corrosive acids that produce harmful fumes. Nitric acid and hydrochloric acid pose similar health hazards, including skin irritation or burns from skin contact. If inhaled, these acid gas fumes can irritate the nose, throat, or lungs, leading to coughing, shortness of breath, or wheezing. Exposure to high concentrations can cause chemical pneumonitis, fluid buildup in the lungs, or severe trouble breathing. Chronic long-term exposure can lead to bronchitis, reduced lung function, and increased susceptibility to respiratory infections (NJ Department of Health 2016). OSHA regulates workplace exposure to both nitric acid and hydrochloric acid. Please see the chart below for exposure limits, both mandatory and recommended.
| Chemical | OSHA PEL (legal standard) |
NIOSH REL (recommended) |
ACGIH (recommended) |
| Nitric Acid | 2 ppm (avg over 8 hrs.) | 2 ppm (avg over 10 hrs.) 4 ppm (15 min short-term) |
2 ppm (avg over 8 hrs.) 4 ppm (15 min short-term) |
| Hydrochloric Acid | 5 ppm | 5 ppm | 2 ppm |
Water Testing Engineering Control Solutions
The U.S. EPA recommends using fume hoods when working with nitric or hydrochloric acid for water testing. These chemicals should be regarded as potential health hazards and used with caution (US. EPA 1994, p. 8).
Low Concentrations – Stainless Steel Ductless Fume Hoods with Acid Gas Filter
For water testing facilities that use low concentrations of nitric acid and/or hydrochloric acid, Stainless Steel Ductless Fume Hoods provide vital operator protection by containing and capturing most of the harmful acid fumes. These systems use a powerful fan to draw chemical fumes from under the hood into the filtration system. The specialty-treated Acid Gas Activated Carbon filter adsorbs most of the chemical fumes and removes them from the airflow. Then the filtered air is released back into the surrounding room, creating a recirculating airflow pattern.
Benefits of Stainless-Steel Ductless Fume Hoods
• Durable stainless-steel construction designed to hold up against corrosive chemicals.
• Reliable and low maintenance – the only maintenance is filter changes.
• Specialty-treated activated carbon filter designed to improve adsorption of acid gas fumes.
• Quiet operation
• Available in a variety of sizes: 30”, 40”, and 50” wide (custom sizes available)
• Made in the USA
• Quick lead time – 5 business days on standard-size hoods
Low Concentrations – Stainless Steel Ductless Fume Hoods with Acid Gas Filter
The Acid Gas Fume Hood is a specially designed ducted or exhaust hood for use with corrosive acids such as nitric acid and hydrochloric acid. Facilities that use higher concentrations should consider implementing this durable, long-lasting fume hood. The Acid Gas Fume Hood is constructed of all acid-resistant components, including the sides, base, hinges, and exhaust collar. This lightweight hood features a one-piece, seam-welded design made of acid-resistant polypropylene. The polycarbonate sash has been upgraded with an abrasion-resistant coating (AR2), providing added scratch resistance, durability, and chemical resistance. The Acid Gas Fume Hood connects to an external exhaust system (not included) that releases chemical fumes outside of the building, away from the operator.*
Benefits of the Acid Gas Fume Hood:
• Durable and reliable external venting solution
• One-piece seam-welded design
• Constructed of acid-resistant polypropylene
• Acid-resistant hinges and exhaust collar
• Polycarbonate sash with AR2 coating
• Available in 40” width – great for a variety of workplaces
• Fewer leak points and no mechanical joints to fail or corrode
• 6” exhaust collar – compatible with standard duct systems (not included)
• Made in the USA
*Please note: The end user is ultimately responsible for conforming to all applicable exhaust ventilation regulations. Consult local, state, and federal agencies regarding the suitability of your application prior to venting fumes to the environment. It is your ultimate responsibility to ensure the safety and suitability of your application. For more information, contact a local safety professional (certified industrial hygienist) for conformance and suitability.
Help protect water testing laboratory employees from inhaling harmful acid gas fumes with reliable and durable fume hoods from Sentry Air.
Contact us today to get started!
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References
NJ Department of Health (2016). Hazardous Substance Fact Sheet: Hydrogen Chloride. Retrieved from: https://nj.gov/health/eoh/rtkweb/documents/fs/1012.pdf
NJ Department of Health (2016). Hazardous Substance Fact Sheet: Nitric Acid. Retrieved from: https://nj.gov/health/eoh/rtkweb/documents/fs/1356.pdf
U.S. EPA. (1992). Method 3005A: Acid Digestion of Waters for Total Recoverable or Dissolved Metals for Analysis by FLAA or ICP Spectroscopy. Retrieved from: https://www.epa.gov/sites/default/files/2015-12/documents/3005a.pdf
U.S. EPA. (1994). Method 200.8: Determination of Trace Elements in Waters and Wastes by Inductively Coupled Plasma-Mass Spectrometry. Revision 5.4. Cincinnati, OH. Retrieved from: https://www.epa.gov/sites/default/files/2015-06/documents/epa-200.8.pdf