Influence of pesticides on Chlorella, Chlorococcum, Stigeoclonium (Chlorophyceae), Tribonema, Vaucheria (Xanthophyceae) and Oscillatoria (Cyanophyceae)

Abstract

An examination was made of the influence of atrazine, simazine, malathion and 2,4-D on total chlorophyll produc tion by Chlorella vulgaris, Ch/orococcum hypnosporum, Sfigeoc/onium fenl/e, Tribonema sp. , Val/cheria geminata and Oscil/aforia lulea.The herbicide 2,4-D in concentrations up to 100 mg/I did not alter chlorophyll production by the algae. Ch/O/·o coccum was not influenced by the pesticides . When added individually, atrazine, simazine and malathion inhibited chlorophyll production at a concentration of I mg/I or greater except for Sligeoc/onium, in which production was not influenced by I mg/I simazine . Results were variable when the pesticides were present individually at a con centration of I fig/I. The three pesticides stimulated chlorophyll production by Chlorella when present individually at 0· 1 and 0·5 fig/I. The same was true for simazine and malathion on Tr ibonema and Oscillaloria. A complete examination was not made for all the algae in these lower concentrations of pesticides. A significant interaction was present among atrazine, simazine and malathion. Combinations of two pesticides resulted in more inhibition, less inhibition or stimulation of chlorophyll production depending upon the con centrations used.Treatment of Va ucheria with 1 fig/I malathion caused a production of brown crystals inside the cytoplasm, a formation of a second cell wall inside the first and distortion of gametangia developing at the time of initial treatment.

A synthesis of the effects of pesticides on microbial persistence in aquatic ecosystems

“…Similarly, in a study of nine algal species, while a majority of herbicides examined did have adverse direct effects (as stated above), no inhibition of algal growth was observed with exposure to 2,4-D at a lower concentration of 2917 µg L −1 (Peterson et al, 1994). Additionally, no inhibition of chlorophyll production was noted with 2,4-D at concentrations ranging from 1–100 000 µg L −1 (Torres and O'Flaherty, 1976), although it should be noted that the measurement of chlorophyll production measured in this study differed from measurements of growth in the previous two studies. Lastly, picloram (1760 µg L −1 ), while found to inhibit growth of most cyanobacterial species, actually promoted growth of four algal species tested (Peterson et al, 1994); while this supports the idea of species-specific differences regarding herbicide effects, it should also be noted that this is the only study reviewed here to test this chemical.…”

“…Malathion inhibited chlorophyll production and resulted in death of cyanobacteria at concentrations between 1 – 1000 µg L −1 , overlapping with ecologically relevant concentrations of malathion (DeLorenzo, Scott, and Ross, 2001; Torres and O'Flaherty, 1976). The organophosphate diazinon inhibited growth of cyanobacteria at concentrations of 400 000 and 500 000 µg L −1 (Singh, 1973).…”

Herbicide effects on planktonic systems of different complexity

“…Direct effects on target organisms in single species tests (Chlorella) have been reported occasionally at concentrations as low as 1 #g atrazine/L (e.g. Torres & O'Flaherty, 1976), but the effective concentration is often much higher (Butler, 1977). This suggests that direct effects on algae are dependent on algal species and culture conditions.…”

Growth, photosynthesis, active oxygen species and antioxidants responses of paddy field cyanobacterium Plectonema boryanum to endosulfan stress

“…Similar inhibitory effect on growth of cyanobacteria with other insecticides-BHC, carbofuran, phorate and malathion-was correlated with the inhibition in chlorophyll a synthesis, photosynthetic activity and nitrogen fixation in Oscillatoria, Haplosiphon sp. and Calothrix braunii ARM 367 (Kaushik and Venkataraman, 1983;Torres and O'Flaeerty, 1976). An isolate of paddy field cyanobacterium Nostoc linkia exhibited 6-75% reduction in growth when exposed to 1 mg/ml to 25 mg/ml of endosulfan (Satish and Tiwari, 2000).…”