水質與水產生物之關係
謝介士
行政院農委會水產試驗所
東港生技研究中心
The 24 hrs LC50
(ug/l) values and 95% confidence interval of copper for zoea stage
of shrimp
Fish pond
water
Shrimp-1
pond water
Ground sea
water
Shrimp-2
pond water
Hsio-Liu-
Chio area
water
Purified
sea water
42.0 48.2 18.3 55.4 16.5 9.4
(37.3-47.3) (43.7-53.1) (16.4-22.3) (27.5-111.4) (14.5-18.8) (6.2-14.3)
Fig. 1. Relationship between pH and the acute toxicity of
copper to cobia larvae in different kinds of seawater.
LC50 = 21.70 pH - 169.40
(p =0.0034, R2
= 0.84)
0
2
4
6
8
10
12
7.95 8.00 8.05 8.10 8.15 8.20 8.25 8.30
pH
24
-h L
C5
0 (
mg
Cu
/L)
Fig. 2. Relationship between DOC concentration and the
acute toxicity of copper to cobia larvae in different kinds
of seawater.
LC50 = 1.72 DOC + 0.96
(p = 0.017, R2 = 0.71)
0
2
4
6
8
10
12
1.50 2.50 3.50 4.50 5.50
DOC (mg/L)
24-h
LC
50 (
mg
Cu/
L)
水化學
•酸鹼化學(Acid-Base Chemistry)
•錯合化學(Coordination Chemistry)
•沉澱與溶解(Precipitation and Dissolution)
•氧化還原反應(Oxidation-Reduction
Reactions)
錯合化學
• 硫酸銅加入海水,就會產生錯合反應。會產生Cu(OH)+、 Cu(OH)2、 Cu(OH)4
2- 、Cu2(OH)2
4+、 CuCl+ 、CuCl2、 CuCO3、Cu(CO3)2
2+、CuSO4等。
•在海水中加入EDTA,使其與重金屬產生錯合反應,以達到降低重金屬毒性的目的。
依據 Morel (1983) 引用Smith & Martell (1976);Baes & Mesmer (1976); Sunda &
Hanson (1979),所發表的穩定常數值 (Stability constants)(在淡水中,其離子強度(Ionic
strength) I=0),再使用Davies equation,可求得I=0.66時的各種銅錯化合物之穩定常數值(即在鹽度32 psu時)。而I=0.66,是依據Lyman & Fleming (1940) 所發表的
I=0.00147 + 0.03592 Cl + 0.000068 Cl2,Cl是氯度。
[CuT]=[Cu2+]+[CuOH+]+[Cu(OH)20]+[Cu(OH)4
2-]+[Cu2(OH)22+]+[CuCO3
0]+[Cu(CO3)22-]+
[CuSO4]+ [CuCl+]
Cu2+ + OH- =CuOH+ 則K CuOH+ = [CuOH+]/[Cu2+ ][OH-];
K CuOH+查表得5.9,而鹽度32 psu的海水pH 8.1時 paOH-= 14 – paH+ = 5.9
而rOH-依據Debye-Hiickel的方程式求得,故[OH-] = 10 -5.9/ rOH- =10 -5.9 / 0.59 = 10 -5.67 ;
若[Cu 2+ ] = X 則[CuOH+] = 10 5.9* X*10 -5.67 = X*10 0.23
Cu 2+ + 2OH- =Cu(OH)20 則[Cu(OH)2
0] = 10 10.9 *X*(10-5.67)2 = X*10 -0.44
‧‧
[CuT] = (1+10 0.23+10 -0.44+10 -0.68 +10 -1.84X+10 -0.37+ 10 1.75+10 1.5+10 -0.39) X=10-3.80
各種銅錯化合物濃度的計算方法(以銅10mg/l在鹽度32psu為例)
在不同pH值下各種不同的銅錯化合物的百分比
0%
20%
40%
60%
80%
100%
7.0 7.5 8.0 8.5 9.0 9.5
pH value
[CuCl+]
[CuSO4]
[Cu(CO3)22-]
[CuCO30]
[Cu(OH)20]
[CuOH+]
[Cu2+]
沉澱與溶解
•白天光合作用旺盛時,池水中累積高濃度的CO3
2-,若池中含有適量的Ca2+,就會進行沉澱反應,產生CaCO3,使CO3
2-濃度降低而抑制池水pH值之上升。
•農業用石灰(碳酸鈣)CaCO3在池水中,會因解離而溶解,而其溶解度受水溫、鹽度及CO2的影響。
氧化還原反應
• Chlorination
Cl2 + H2O ↔ HOCl + H+ + Cl-
HOCl + NH3 → NH2Cl + H2O
NH2Cl + HOCl → NHCl2 + H2O
NHCl2 + HOCl → NCl3 + H2O
NHCl2 + NCl3 → N2 +2 HOCl + 3Cl- +H+
酸鹼化學
Weak Acids and Bases in Natural Waters
Freshwater Seawater
Mean
Warm
Surface
Deep
Atlantic
Deep
Pacific
Carbonate 0.97 mM 2.1 mM 2.3 mM 2.5 mM
Silicate 220 µM < 3 µM 30 µM 150 µM
Ammonia 0-10 µM < 0.5 µM < 0.5 µM < 0.5 µM
Phosphate 0.7 µM < 0.2 µM 1.7 µM 2.5 µM
Borate 1 µM 0.4 mM 0.4 mM 0.4 mM
Reactions- log K
I = 0 I = 0.5 M
H2O ↔ H+ + OH- 14.00 13.89
CO2(g) + H2O ↔ H2CO3* 1.46 1.51
H2CO3* ↔ HCO3
- + H+ 6.35 6.30
HCO3- ↔ CO3
2- + H+ 10.33 10.15
H2SiO3 ↔ HSiO3- + H+ 9.86 9.61
HSiO3- ↔ SiO3
2- + H+ 13.10 12.71
H3PO4 ↔ H2PO4- + H+ 2.15 1.87
H2PO4- ↔ HPO4
2- + H+ 7.20 6.72
HPO42- ↔ PO4
3- + H+ 12.35 11.89
NH3(g) ↔ NH3(aq) -1.87 -1.64
NH4+ ↔ NH3(aq) + H+ 9.24 9.47
H2S(g) ↔ H2S (aq) 0.99 0.99
H2S(aq) ↔ HS- + H+ 7.02 6.98
HS- ↔ S2- + H+ 13.9 13.45
B(OH)3 + H2O ↔ B(OH)4- + H+ 9.24 8.97
酸鹼化學(如何調整溶液之pH值)
• H2PO4- ↔ H+ + HPO4
2-; pKa,2= 7.2
Ka,2= [H+][HPO42-]/[H2PO4
-]
logKa,2 = log [H+] + log [HPO42-]/[H2PO4
-]
-log [H+] = -logKa,2 + log [HPO42-]/[H2PO4
-]
pH = 7.2 + log {[HPO42-]/[H2PO4
-]}
故可用Na2HPO4與NaH2PO4來調pH值。
酸鹼化學(如何調整溶液之pH值)
•以142公克Na2HPO4與120公克NaH2PO4分別配製1公升的1 M 的Na2HPO4與NaH2PO4 。
• 若全部加入1公噸水中, 則pH值是7.2。
• 若同樣是1公噸水, 而Na2HPO4加1公升但NaH2PO4加0.1公升,則pH值是8.2。
• 若同樣是1公噸水, 而Na2HPO4加0.1公升但NaH2PO4加1公升,則pH值是6.2。
酸鹼化學
• 水中pH值表示水的酸鹼值,即水中氫離子活性的負對數值,以pH=-log{H+} 來表示。
• 水中鹼度是指水中和酸之能力,即酸滴定到一定pH值,所消耗之當量數,常用每公升多少毫當量(meq/L) 或以等量的碳酸鈣每公升含量 (mg/L) 來表示。水中鹼度的主要來源是氫氧化物、碳酸氫鹽類及碳酸鹽類等三類物質,其他尚有硼酸、矽酸及磷酸等。
酸鹼化學(光合作用和呼吸作用)
• CO2 + H2O ↔ ”CH2O” + O2
• CO2 + H2O ↔ H2CO3* ↔ HCO3
- + H+
• HCO3- ↔ CO3
2- + H+
• pH < 6.3 CO2 + H2O ↔ ”CH2O” + O2
• 6.3< pH < 10.3 HCO3- + H+ ↔ ”CH2O” + O2
• pH >10.3 CO32- + 2H+ ↔ ”CH2O” + O2
酸鹼化學
• 決定淡水養殖池水pH值的因子,是二氧化碳濃度與碳酸氫鹽濃度或碳酸氫鹽濃度與碳酸鹽濃度的比值。
• 決定海水養殖池水pH值的主要因子,則是碳酸氫鹽濃度與碳酸鹽濃度的比值。
植物性浮游生物對池水pH值及鹼度之影響
• CO2 + H2O → (CH2O) + O2
• HCO3- + H+ → (CH2O) + O2
• 106 CO2 + 16 NO3- + H2PO4
- + 122 H2O + 17 H+ → C106H263 O110N16P1 + 138 O2
• 106 CO2 + 16 NH4+ + H2PO4
- + 106 H2O → C106H263
O110N16P1 + 106 O2 + 15H+
• 106 HCO3- + 16 NO3
- + HPO42- + 16 H2O + 124 H+
→ C106H263 O110N16P1 + 138 O2
• 106 HCO3- + 16 NH4
+ + HPO42- + 92 H+ →
C106H263O110N16P1 + 106 O2
酸鹼化學(在密閉系統中,水中微生物對pH值及鹼度之影響)
• Sulfate reduction
SO42- + 2”CH2O”+ 2H+ →
H2S +2H2O +2CO2
• Alkalinity increases by 2 eq
per mole sulfate reduced;
pH <6.3 → pH increases;
7.0 > pH > 6.3 → pH ≒constant
pH >7.0 → pH decreases
酸鹼化學(在密閉系統中,水中微生物對pH值及鹼度之影響)
• Methane fermentation
”CH2O” + 2”CH2O” →
CH4 (g) + CO2
• Alkalinity remains constant
pH < 6.3 → pH ≒ constant
pH > 6.3 → pH decreases
酸鹼化學(在密閉系統中,水中微生物對pH值及鹼度之影響)
• Nitrification
2NH4+ + 3O2 → 2NO2
- + 4H+ + 2H2O
2NO2- + O2 → 2NO3
-
• Denitrification
4NO3- + 5”CH2O” + 4H+
→ 2N2 + 5CO2 + 7H2O
• Alkalinity decreases by 2 eq per mole of ammonium oxidized
pH decreases throughout pH range
no effect on alkalinity
• Alkalinity increases by 1 eq per mole of nitrate reduced
pH < 6.3 → pH increases
pH > 6.3 → pH decreases slightly
兩種水混合後之pH值?(River A pH=8.2 Alk=10-3 eq/l; River B pH=5.7 Alk=10-5 eq/l)
• River A
At a pH of 8.2, HCO3- is roughly 100 times larger than the
other carbonate species:
AlkA = -[H+] + [OH-] + [HCO3-] + 2[CO3
2-] = 10-3
therefore [HCO3-] + 2 * 10 -10.3 * 10 8.2 [HCO3
-] = 10-3
[HCO3-] = 10-3.01 K= [H+] [HCO3
-] / [H2CO3*]
[H2CO3*] = 10 6.3 * 10-8.2 * 10-3.01 = 10 -4.91
[CO32-] = 10 -10.3 * 10 8.2 * 10-3.01 = 10 -5.11
CTA = [HCO3
-] + [H2CO3*] + [CO3
2-] = 10 -3.00
兩種水混合後之pH值?(River A pH=8.2 Alk=10-3 eq/l; River B pH=5.7 Alk=10-5 eq/l)
• River B
At a pH of 5.7, H2CO3* is the principal carbonate
component:
AlkB = -[H+] + [OH-] + [HCO3-] + 2[CO3
2-] = 10-5
therefore [HCO3-] = 10-5 + 10-5.7 = 10-4.92
[H2CO3*] = 10 6.3 * 10-5.7 * 10-4.92 = 10 -4.32
CTB = [HCO3
-] + [H2CO3*] = 10 -4.22
兩種水混合後之pH值?(River A pH=8.2 Alk=10-3 eq/l; River B pH=5.7 Alk=10-5 eq/l)
• Initial Mix. Before CO2 exchange
Alkmix = 2/5 Alk A + 3/5 Alk B = 10 -3.39 eq/l
CTmix = 2/5 CT
A + 3/5 CTB = 10-3.36 M
The pH of the mixture is expected to be approximately neurtral, and HCO3
- is thus expected to be the principal component for the carbonate system.
CT - Alk =[H+] – [OH-] + [H2CO3*]-[CO3
2-] = 10-4.54
TOTHCO3 = [H2CO3*] + [HCO3
-] + [CO32-] = CT = 10-3.36
In the neutral pH range, [H2CO3*] is the major positive term in the
CT - Alk equation. [H2CO3*] = 10-4.54
[HCO3-] = CT – [H2CO3
*] = 10-3.39
Therefore [H+] = ([H2CO3*]/[HCO3
-])*10-6.3 = 10-7.45
pH mix = 7.45, initially.
兩種水混合後之pH值?(River A pH=8.2 Alk=10-3 eq/l; River B pH=5.7 Alk=10-5 eq/l)
• Mix Equilibrate with Atmosphere. After CO2 equilibration
Alk mix = 10 -3.39 eq/l
Pco2 = 10-3.5 atm
With the components H+ and CO2, the TOTH equation is
TOTH = [H+] - [OH-] - [HCO3-] - 2[CO3
2-] = -Alk = -10-3.39
Graphical examination shows that [HCO3-] is the major term
of the TOTH equation:
H2CO3* ↔ HCO3
- + H+
[HCO3-] = 10-3.39 = (10-1.5*10-6.3* Pco2)/[H+]
therefore [H+] = (10-1.5*10-6.3*10-3.5)/10-3.39 = 10-7.91
pH mix = 7.91, eventually.
The method of computing the concentration of
carbonate and bicarbonate in waterThe 1st and 2nd apparent dissociation constant will be calculated by the equation of Edmond and Gieshes (1970).
PK’1 = 3404.71/T + 0.032786T – 14.7122 – 0.19178 Cl1/3
PK’2 = 2902.39/T + 0.02379T – 6.4710 – 0.4693 Cl1/3
T is temperature (oK). Cl is chlorinity (O/oo).
Carbonate alkalinity = A = MΣHCO3- + 2MΣCO32-
ΣCO2 = C = MΣH2CO3 + MΣHCO3- + MΣCO32- = A * FT
The FT value was presented by Parson et al. (1992).
If h = aH+ = 10-pH, x = MΣH2CO3 , y = MΣHCO3- , z = MΣCO32-.
Therefore, A = y + 2z
C = x + y + z
K’1 = hy/x = (aH+ + * MΣHCO3-)/ MΣH2CO3
K’2 = hz/y = (aH+ * MΣCO32-)/ MΣHCO3-
Therefore, x = MΣH2CO3 = h2C / (h2 + h K’1 + K’1 K’2)
And y = MΣHCO3- = h K’1 C / (h2 + h K’1 + K’1 K’2)
And z = MΣCO32- = K’1 K’2 C / (h2 + h K’1 + K’1 K’2)
池塘魚類死亡之原因探討
缺 氧藻類毒害 農 藥
魚的行動
受害魚種
魚的大小
發生或死亡時間
池中浮游生物
水中溶氧量
水中pH值
水色及氣味
浮頭或聚於注水口
鯉魚抵抗力最強
大魚先死
夜間及清晨
藻類死亡或頻死,僅存少量動物性浮游生物
< 1 – 2 ppm
6.0 – 7.5
棕色或灰色或黑色
浮游、乏力、嚴重時痙攣
所有魚種
小魚先死
日間(太陽越大越嚴重)
藻類繁盛,但均屬同一種,動物性浮游生物極少
過飽和
9.5以上
深綠色、棕色或黃色,有時有腐臭味
類似藻毒
如果濃度不太高則受害魚一種一種死亡
小魚先死
不分晝夜
如為殺蟲劑則藻類正常,動物性者死亡,如為除草劑則反之
正常
7.5 – 9.0
水色正常
Thanks
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