Table 4.

Incidence of heavy metal tolerance in bacteria from bullfrog farm.

Heavy metal	n	Number of isolates with heavy metal tolerance (µg/ml)															Resistancea
		2.5	5	10	20	40	25	50	100	200	400	150	300	600	1200	2400	n	%
Cadmium	77	-	-	-	-	-	0	5	8	9	30	-	-	-	-	-	69	89.6
Cromium	77	-	-	-	-	-	0	0	0	0	0	-	-	-	-	-	77	100
Copper	77	-	-	-	-	-	-	-	-	-	-	3	7	18	42	77	59	76.6
Mercury	77	0	0	0	0	12	-	-	-	-	-	-	-	-	-	-	77	100

^aResistance Concentration:: Hg²⁺ (10µg/ml); Cd²⁺ and Cr⁶⁺ (100µg/ml); Cu²⁺ (600µg/ml). n : Number of total isolates; - : Not Tested