Pauline Lindstedt - IT - Lunds universitet

Effekter av utsläpp från ett pappers- och massabruk på bottenfaunan i en å– en fallstudie i LesseboånPauline LindstedtExamensarbete i vattenvård, 20 pEkologiska institutionen, Limnologiska avdelningen,Lunds universitet, 2006Handledare:Per Nyström, Ekologiska institutionen, Lunds universitet.AbstractThe effects of effluent from a pulp and paper mill on the invertebrate fauna of a stream were examined.Modified Hester-Dendy multiple-plate artificial substrate samplers were used to sample the fauna bothupstream and downstream the effluent of Lessebo pulp and paper mill for 38 days in the fall of 2005.More than 42 000 individuals were indentified to 16 species and 24 families. The most conspiciouschange in fauna composition was the loss of pollution intolerant species, mainly in the ordersEphemeroptera, Plecoptera and Trichoptera. Moreover Oligochaeta and Chironomidae, organismsthat are tolerant to both low oxygen levels and pollution, dominated downstream the effluent. A shift inthe functional feeding groups was also detected with all five groups represented upstream and no groupconstituting more than 35 %. Downstream shredders were absent and gathering collectors constituted92 %. Water samples were taken on eight fauna sample locations on three occations during the faunasampling period. The water chemistry upstream showed levels indicating no, or mild, organic pollutionor oxygen depletion. Generally BOD, COD, temperature and conductivity increased the furtherdownstream the effluent the sample was taken while oxygen and pH decreased. No evident trend wasseen for the levels of suspended solids. The most probable cause of the observed changes in fauna isthe substantial amount of suspended matter that is released with the effluents and the decrease indissolved oxygen due to it.