Seven Powell River sites were studied in July in 1993 and in 2004.
Changes In Powell River Sites Over a Decade
Effluent quality at powell River has improved over the past decade. (See Figure 1.) Species richness at Powell River sites over the same time period have also increased. (See Figure 2.)
Figure 1: Annual average effluent quality for NorskeCanada, Powell River Division (BOD=Biochemical Oxygen Demand, TSS=Total Suspended Solids, AOX = Adsorbable Organic Halides). Data kindly provided by Environment Canada, Pacific and Yukon Region, Environmental Protection Branch and Hatfield Consultants Ltd., 2004.
Figure 2: Powell River intertidal species richness. Mean species richness was significantly greater in 2004 compared to 1993 for Powell River Z(7) = 2.37, p<0.05. (Bard, Shannon, De Raedemaecker, Fien and Willems, Wouter. (2005 Submitted) "A Decade Later: Intertidal diversity is increased as pulp mill pollution is decreased." Water Environmental Research Journal.)