HCHs and DDTs in Soils around Guanting Reservoir in Beijing, China: Spatial-Temporal Variation and Countermeasures

Table 2

Composition of HCH and DDT in soil samples in 2003, 2007, and 2009.

Ratio	Year	Average	Minimum	Maximum	Percentage of sites with a ratio less than 1
𝛼-HCH/γ-HCH	2003	1.35	0.25	3.35	8.9%
	2007	0.42	0.12	0.73	15.0%
	2009	2.76	2.25	3.26	0
(DDE + DDD)/p,p^′-DDT	2003	2.52	0.24	25.2	23.2%
	2007	1.25	0.09	4.22	41.7%
	2009	7.07	0.24	40.1	8.2%