Fate, behavior, and aquatic toxicity of the fungicide DDAC in the Canadian environment

Abstract

National water quality guidelines for protection of aquatic life were developed to address concerns regarding toxicity of antisapstains entering surface waters. A review of environmental chem-( ) istry, fate, and toxicology of didecyl dimethyl ammonium chloride DDAC was conducted. DDAC is used in Canada in antisapstain formulations for treatment of freshly sawn lumber, in disinfectant formulations, and as a molluscicide. DDAC is an active ingredient in the most widely used antisapstain formulation ( ) Kop-Coat NP-1 , and one of the most widely used pesticides in British Columbia; 454,400 kg of DDAC were used by lumber mills for antisapstain purposes in 1996. DDAC, a cationic surfactant, is highly water soluble, and binds rapidly to suspended solids and sediments. It is not persistent in the water column; movement to solid phase and microbial degradation are expected to be main routes of dissipation.( ) y1DDAC was reported to affect rainbow trout Oncorhynchus mykiss at levels as low as 0.1 mg L , and Daphnia magna at levels as low as 0.03 mg L y1 . It is not expected to bioaccumulate. An interim water quality guideline of 1.5 g L y1 derived according to the Canadian Council of Ministers of the ( ) Environment's CCME protocol for the derivation of water quality guidelines for protection of aquatic life is recommended. ᮊ

Swimming speed alteration of Artemia sp. and Brachionus plicatilis as a sub-lethal behavioural end-point for ecotoxicological surveys

“…The absence of a sub-lethal response in Artemia sp. exposed to this compound can be explained by a report by Juergensen et al (2000). They report that DDAC acts, in aquatic organisms, primarily via the gill epithelia, by hindering gas transfer until suffocation, thus suggesting that the toxicity curve of DDAC is comparable to an ''all-or-none'' response.…”

Antimicrobial activity of polysiloxane coatings containing quaternary ammonium-functionalized polyhedral oligomeric silsesquioxane

“…Complete functionalization was confirmed by 1 H NMR. 29 Si NMR was used to ensure that the cubic structure of POSS remained intact after the reaction. The tertiaryamino-functionalized POSS was then used as a precursor to generate Q-POSSs.…”

“…A sweep width of 7503 Hz was used with 16,000 data points, resulting in an acquisition time of 2.184 s. Sixteen scans were obtained with a relaxation delay of 4 s. 29 Si NMR spectra were collected using a JEOL 400 MHz spectrometer operating at 79.43 MHz. Acquisition parameters included a 62.5 kHz sweep width, 16,000 data points, and an acquisition time of 0.21 s. A total of 14,000 scans were collected.…”

“…Several factors such as aggregation of QAC molecules in solution, steric interactions, affinity of the QAC for the microorganism surface, and diffusivity through the cell wall affect the QAC chemical structure-antimicrobial activity relationships. 28,29 Q-POSS with C12 alkyl chain length and chlorine as a counter ion provided the highest, broadest-spectrum antimicrobial activity. Thus, the alkyl chain lengthcounter ion combination for dodecyldimethylammoniumchloride-POSS (Q-12-Cl) provided the best balance of lipophilicity and diffusivity to enable both effective binding to the outer surface of the bacterium cell structure and diffusivity through the cell wall to the cell interior.…”

Biodegradation of an aldehyde biocide in rotating biological contactors

“…The widespread application of biocides in many industries to overcome the growth of planktonic cells and/or sessile cells in a biofilm can cause environmental and ecological problems because sooner or later the biocides have to be discharged into the environment either natural water or municipal effluent treatment plants (Johnston et al 1998;Reuter 1998;Bailey et al 1999;Sarlin et al 1999;Juergensen et al 2000;Nishihara et al 2000).…”