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Risks Associated with the Use of Chemical Amendments in Aquaculture Pond Management Claude E. Boyd Department of Fisheries and Allied Aquacultures Auburn.

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Presentation on theme: "Risks Associated with the Use of Chemical Amendments in Aquaculture Pond Management Claude E. Boyd Department of Fisheries and Allied Aquacultures Auburn."— Presentation transcript:

1 Risks Associated with the Use of Chemical Amendments in Aquaculture Pond Management Claude E. Boyd Department of Fisheries and Allied Aquacultures Auburn University, Alabama 36849 USA and Laurence Massaut Fundación CENAIM-ESPOL Guayaquil, Ecuador

2 Three types of risks were evaluated: Environmental (ES) Food safety (FS) Handling (HS) Four levels were assigned to each type of risk: No risk = 0Medium risk = 2 Low risk = 1High risk = 3

3 Common nitrogen fertilizer compounds. CompoundApplication rateRisk level and type Urea (H 2 NCONH 2 ) 5-10 kg/ha at 1-4 wk intervals HS = 1; explosive, irritant, possible mutagen. ES = 1; if spilled, eutrophication, ammonia toxicity, acidity. FS = 0; none. Ammonium sulfate ((NH 4 ) 2 SO 4 ) 10-20 kg/ha at 1-4 wk intervals HS = 1; explosive, irritant, avoid inhalation. ES = 1; if spilled, eutrophication, ammonia toxicity, acidity. FS = 0; none. Ammonium nitrate (NH 4 NO 3 ) 5-10 kg/ha at 1-4 wk intervals HS = 1; explosive, irritant, avoid inhalation. ES = 1; if spilled, eutrophication, ammonia toxicity, acidity, FS = 0; none. Sodium nitrate (NaNO 3 ), potassium nitrate (KNO 3 ), and calcium nitrate (Ca(NO 3 ) 2 ) 20-30 kg/ha At 1-4 wk intervals HS = 1; explosive, prolonged KNO 3 exposure may produce anemia, irritant. ES = 1; if spilled, eutrophication, ammonia toxicity. FS = 0; none.

4 Common phosphorus fertilizer compounds. CompoundApplication rateRisk level and type Triple superphospahte (Ca(H 2 PO 4 ) 2 ) 5-10 kg/ha at 1-4 wk intervals HS = 0; none. ES = 1; if spilled, eutrophication. FS = 0; none. Mono- and di- ammonium phosphate (NH 4 H 2 PO 4 and (NH 4 ) 2 HPO 4 ) 5-10 kg/ha at 1-4 wk intervals HS = 1; irritant, monoammonium phosphate is explosive. ES = 1; if spilled, eutrophication FS = 0; none. Phosphoric acid (H 3 PO 4 ) 5-10 kg/ha at 1-4 wk intervals HS = 1; irritant. ES = 1; if spilled, acidity, toxicity, and eutrophication. FS = 0; none.

5 Other fertilizer materials. CompoundApplication rateRisk level and type Potassium chloride or muriate of potash (KCl) 1-2 kg/ha at 1-4 wk intervals 100-500 kg/ha in inland shrimp ponds HS = 1; irritant. ES = 1; if spilled, eutrophication. FS = 0; none. Sodium silicate (Na 2 SiO 3 ) 1-5 kg/ha at 2 wk intervals HS = 0; none. ES = 0; none FS = 0; none. Manure, grass and human wastes 100-500 kg dry wt/ha/wk HS = 0; none. ES = 1; potential oxygen depletion, eutrophication. FS = 1; disease transmission to humans, heavy metal contamination

6 Other fertilizer materials. CompoundApplication rateRisk level and type Trace and secondary element mixes (contains various compounds of Fe, Zn, Cu, B, and Mo) 50-100 g/ha per month HS = 0; none. ES = 1; if spilled, metal toxicity. FS = 0; none. Fertilizer enhancers (e.g., humate) 10-100 kg/ha per month HS = 0; none. ES = 0; none. FS = 0; none. Mixed fertilizers25-100 kg/ha per month HS = 0; none. ES = 1; if spilled, eutrophication. FS = 0; none. Potassium magnesium sulfate 500-1,000 kg/ha in inland shrimp ponds HS = 1; irritant. ES = 1; if spilled, eutrophication. FS = 0; none.

7 Common liming materials. CompoundApplication rateRisk level and type Agricultural limestone (CaCO 3 or CaCO 3  MgCO 3 ) 1-5 tons/ha annually HS = 0; none. ES = 0; none. FS = 0; none. Burnt lime (CaO or CaO  MgO) 0.5-1 tons/ha annually HS = 1; strong caustic, irritant. ES = 1; if spilled, high pH. FS = 0; none. Hydrated lime (Ca(OH) 2 or Ca(OH) 2  Mg(OH) 2 ) 0.5-1 tons/ha annually HS = 1; caustic, irritant. ES = 1; if spilled, high pH. FS = 0; none.

8 Common oxidants. CompoundApplication rateRisk level and type Potassium permanganate (KMnO 4 ) 2-8 mg/LHS = 1; explosive if in contact with organic substances, irritant ES = 1; if spilled, toxicity. FS = 0; none. Hydrogen peroxide (H 2 O 2 ) or calcium peroxide (CaO 2 ) Up to 100 kg/haHS = 1; H 2 O 2 concentrated form is irritant. ES = 1; if spilled, toxicity. FS = 0; none. Calcium hypochlorite (Ca(OCl) 2 ) 30 mg/L before stocking HS = 1; irritant, poisonous. ES = 1; formation of trihalomethanes and chlorinated hydrocarbons that are suspected carcinogens, toxic. FS = 0; none. Sodium, potassium, or calcium nitrate (NaNO 3, KNO 3, or Ca(NO 3 ) 2 ) 1-5 mg/LHS = 1; explosive, prolonged KNO 3 exposure may produce anemia, irritant. ES = 1; if spilled, eutrophication. FS = 0; none.

9 Common coagulants. CompoundApplication rateRisk level and type Aluminum sulfate (Al 2 (SO 4 ) 3  14H 2 O) 15-40 mg/LHS = 1; irritant, acidic. ES = 1; if spilled, acidity and toxicity. FS = 0; none. Ferric chloride (FeCl 3 ) 15-40 mg/LHS = 1; irritant, acidity. ES = 1; if spilled, acidity and toxicity. FS = 0; none. Calcium sulfate (CaSO 4  2H 2 O) 200-500 mg/LHS = 0; none. ES = 0; none. FS = 0; none.

10 Common osmoregulators. CompoundApplication rateRisk level and type Salt (NaCl)100-2,000 mg/LHS = 1; irritant. ES = 1; increase in salinity. FS = 0; none. Calcium sulfate (CaSO 4  2H 2 O) 100-400 mg/LHS = 0; none. ES = 0; none. FS = 0; none.

11 Common algicides. CompoundApplication rateRisk level and type Copper sulfate (CuSO 4  5H 2 O) 0.5-2 mg/LHS = 1; strong irritant. ES = 2; toxicity. FS = 0; none. Chelated copper compounds 0.2-1 mg/LHS = 0; none. ES = 2; toxicity. FS = 0; none. Diuron0.01 mg/L; maximum of nine times/yr HS = 1; irritant. ES = 2; toxicity. FS = 1; possible residues. Dyes (food coloring compounds) 1-5 mg/LHS = 0; none. ES = 0; none. FS = 0; none.

12 Common piscicides. CompoundApplication rateRisk level and type Teaseed cake (active ingredient is sapogenin glycosides) 15 mg/LHS = 0; none. ES = 1; foam strongly, form oil-in-water emulsions and act to protect colloids. FS = 0; none. Rotenone (C 23 H 22 O 6 ) 0.25-2.0 mg/LHS = 1; irritant. ES = 1; toxicity. FS = 0; none. Lime1-2 tons/haHS = 1; caustic, irritant. ES = 1; if spilled, high pH. FS = 0; none.

13 Common probiotics. CompoundApplication rateRisk level and type Live bacterial inocula (non-pathogenic organisms and usually Bacillus species) 1-2 mg/L at 1 or 2 days to 1 week intervals HS = 0; none. ES = 0; none. FS = 0; none. Fermentation products rich in extracellular enzymes 1-2 mg/L at 1 or 2 days to 1 week intervals HS = 0; none. ES = 0; none. FS = 0; none.

14 Miscellaneous compounds. CompoundApplication rateRisk level and type Zeolite (aluminosilicate clay)20-50 kg/ha weeklyHS = 0; none. ES = 0; none. FS = 0; none. Yucca extracts1-2 mg/L monthlyHS = 0; none. ES = 0; none. FS = 0; none. Bactercides: BKC (alkyldimethyl- benzylammonium chloride), providone, iodine (polyvinylpyrrolidone iodine), glutaraldehyde, formalin 1-10 mg/LHS = 0; none. ES = 1; toxicity. FS = 1; possible residues.

15 Miscellaneous compounds. CompoundApplication rateRisk level and type Sodium bicarbonate (NaHCO 3 ) 25 mg/L or higherHS = 0; none. ES = 0; none. FS = 0; none. Iron oxide (FeO)1 kg m 2 HS = 0; none ES = 0; none. FS = 0; none. KILOL (extracts of grapefruit seed) HS = 0; none. ES = 0; none. FS = 0; none. Dipterex (OP insecticide)1-2 mg/LHS = 2; toxicity ES = 2; toxicity FS = 1; possible residue (?)

16 Substances that could enter aquaculture ponds through contamination. CompoundRisk level and type InsecticidesHS = 2; toxic. ES = 3; bioaccumulative. FS = 3; bioaccumulative. PesticidesHS = 2; toxic. ES = 3; bioaccumulative. FS = 3; bioaccumulative. Heavy metals: lead, mercury, arsenic, beryllium, cadmium, chromium, manganese, silver, and zinc HS = 3; most are toxic to humans if absorbed, some carcinogenic. ES = 3; bioaccumulative. FS = 3; bioaccumulative. Aluminum, antimony, barium, copper, cyanide, iron, nickel, and selenium HS = 2; less toxic than above, but high concentrations when absorbed will be toxic. ES = 2; not bioaccumulative. FS = 3; not bioaccumulative.


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