(b)

Measured Pb concentration (μg/L)	LT50 (h)	95% Confidence limits	Measured Ni concentration (μg/L)	LT50 (h)	95% Confidence limits	Measured Fe concentration (μg/L)	LT50 (h)	95% Confidence limits
475	110.26	79.32–153.28	19045	105.13	71.40–154.79	548.93	41.36	18.84–90.81
1160	72.39	53.61–97.76	29115	80.76	58.88–110.77	771.18	22.66	11.64–44.10
3410	55.66	42.32–73.21	52045	48.61	32.46–72.78	1084.0	10.13	5.53–18.57
4829	43.55	29.86–63.51	66665	17.59	11.88–26.05	3370.02	6.93	4.02–11.93
8973	9.15	5.90–14.17	90290	13.17	10.31–16.82	5836.64	4.20	2.82–6.25