DBNPA (2,2-dibromo-3-nitrilopropionamide)

Manufacturer Name: Dow Time-Release Antimicrobial CT Tablets

Manufacturer: Dow Chemical

DBNPA AGENDA

• Features
• Product Forms
• Chemistry / Degradation
• Mode of Action
• Microbiology
• Analysis
• Product Stewardship

DBNPA Features

• Quick Kill
• Rapid Degradation
• Low Use Concentrations

Time-Release Antimicrobial CT

• Cost-effectiveness
• Efficacy to alkaline pH
• No added toxicity to effluent
• Reduced manpower requirements
• Can be used with existing feeders
• no odors from use
• Easy to handle
• Convenient

Product Forms

DBNPA = (2,2-dibromo-3-nitrilopropionamide)

• DBNPA 100 PTECH = Solid DBNPA (white crystalline solid)
• Antimicrobial 7287 = 20% DBNPA in PEG/Water
• Antimicrobial 8536 = 5% DBNPA in PEG/water
• Dow Time-Release Antimicrobial CT = 40% DBNPA in a tablet

DBNPA Tablets

• 2.75" Diameter x 1.75" Height
• 200 gram tablet
• Time-Release Antimicrobial CT
  • 40% DBNPA
  • 60% Inerts
    • Hydroxypropyl methylcellulose
    • Lactose
    • Stearic Acid
• 25 Tablets per Pail
• Wrapped in Water-Soluble Film

DBPNA Degradation

• Complete degradation to naturally-occurring products (carbon dioxide, ammonia, and bromide ion)
• Does NOT release bromine (not an oxidizer)
• Degraded by reactions with water, nucleophiles, and ultraviolet light; rate is dependent on pH and temperature
• Approximate half-life of 24 hr @ pH 7, 2 hr @ pH 8, 15 min @ pH 9

Degradation Route

• Hydrolysis
  • attack at carbonyl carbon<>
  • Major route in pure water
  • pH / temperature dependent
    
• Nucleophilic Reaction
  • Major route in natural waters
  • debromination
    
• Same Products from Both Routes
  • CO₂ + NH₃ + Br ^-

Decomposition Pathways of DBNPA

Half-life (log scale) vs. pH for Hydrolysis of DBNPA

DBNPA Compatibility

• Primary incompatibility is strong nucleophiles / reducing agents

DBNPA Mode of Action

• Not an Oxidizing Biocide
• Inhibits Enzymes
• Reacts with Cellular Membranes

DBNPA Microbiology

Bacterial and Fungal Minimum Inhibitory Concentrations

Organism		Concentration (PPM)
Bacteria
Escherichia coli		10
Legionella pneumophila		20
Pseudomonas aeruginosa		10
Fungi
Aspergillus niger		100
Candida albicans		50
Penicillium chrysogenum		100
Saccharomyces cervisiae		50
Trichoderma		100

Rate of Kill for DBNPA

DBNPA Analysis

• Iodometric Titration
  • Moderate sensitivity
  • Poor selectivity
  • Fast, easy
  • Minimal instrumentation
• HPLC
  • Sensitive to 0.1 ppm
  • Selective

HPLC of DBNPA

• Column ZORBAX ODS, 4.6mm x 15cm
• Eluent 4g NaOH
  • 14g 85% H₃PO₄
  • 140ml Acetonitrile
  • q.s. to 1 L with water
• Flow 2.5 mL/min
• Detection UV @ 214 nm

Product Stewardship

DBNPA (A.I) Toxicology Data

Acute Oral		LD50 160 mg/kg (rat)
Acute Eye		Permanent injury (rabbit)
Skin Irritation		Moderate (rate)
Skin Absorption		LD50 2000 mg/kg (rat)
Skin Sensitization		Non-sensitizing (man)
Inhalation		No effect (rat)
Mutagenicity		Negative

Sub-Chronic Studies

• 13 week dermal - no observed effect level = 1031 mg/kg/day
• teratology - fetal no adverse effect level = 10mg/kg/day
• 2-generation reproduction study - no effect level for reproductive parameters > 10-17 mg/kg/day

DBNPA Environmental Data

Wildlife LC₅₀/LD₅₀

Species		Range
Freshwater Fish		1.0 - 1.6 mg/L
Marine Organisms		0.6 - 80 mg/L
Birds		150 - 216 mg/kg

• Octanol/Water Partition Coefficient = 6.1
• Bioconcentration Factor (fish flesh) = 20
• COD - 0.91 p/p (Dichromate); 0.50 p/p (Permanganate)
• Biodegradation Studies (OECD 301 & 306) in progress
• No detrimental effects to wastewater treatment operations