An integrative water quality evaluation in two surface water bodies from a tropical agricultural region in Cartago, Costa Rica.

A monitoring study was carried out in two micro-catchments in the Reventazón basin, in Northern Cartago, Costa Rica; pesticide occurrence and water quality were analyzed. Twelve pesticides were detected, five insecticides (chlorpyrifos, carbofuran, cypermethrin, imidacloprid, and oxamyl), four fungicides (carbendazim, imazalil, metalaxyl, and thiabendazole), and three herbicides (diuron, linuron, and terbutryn); eight of them presented risk quotients RQ >1, which implies a high risk for the environment. The water quality evaluation included fourteen physicochemical and microbiological parameters, out of which thermotolerant coliforms, nitrate, and total phosphorus exceeded a selected threshold value in every sample. Five metals were also included in the evaluation, Pb was the most frequent, followed by few detections of Cd, Cu, and Cr. Four water quality indexes (WQIs) were applied, two of them, the CCME WQI, based on physicochemical parameters, and the BMWP-CR WQI, based on benthic macroinvertebrate recount adapted to Costa Rican species, categorized all the sampling points as "bad" and "very bad" quality. This work of monitoring is important in the Latin American region, where there is a lack of information for regulation improvement and management decisions. These results showed poor management of the micro-catchments in this agricultural rural area.

Pharmaceuticals in farms and surrounding surface water bodies: Hazard and ecotoxicity in a swine production area in Costa Rica.

The presence of pharmaceuticals in the environment is known to have multiple origins; livestock activities comprise one scarcely studied source, both globally and specially in Latin-America. This work aims to study the occurrence of pharmaceuticals in wastewater from swine farms and their surrounding surface waters, in a highland livestock production area of Costa Rica. The monitoring of 70 pharmaceutical active compounds resulted in the detection of 10 molecules in farm wastewater (influents and effluents of the on-farm treatment system), including compounds of animal and human use. A 57% of effluents showed high hazard (ΣHQ > 1), mainly due to the compounds risperidone, ketoprofen, ibuprofen and naproxen. Additionally, ecotoxicological tests with Daphnia magna and Microtox classified at least 21% of the effluents as very toxic (10 < TU ≤ 100); likewise, 86% of effluents exhibited germination index (GI) inhibition values over 90% for Lactuca sativa. Seven molecules were detected in surface water, six of them of human use (1,7-dimethylxanthine, caffeine, cephalexin, carbamazepine, gemfibrozil, ibuprofen) and one (acetaminophen) of dual (human and veterinary) use; nonetheless, most of the detections were found in sampling points closer to human settlements than animal farms. Considering the set of molecules and their distribution, the livestock influence on surface water seems minimal in comparison with the urban influence. Only 16% of surface water samples showed high risk, mainly due to ibuprofen, gemfibrozil and caffeine; similarly, 45% samples presented GI inhibition >20% (no toxicity was determined towards Daphnia magna or Microtox). These findings in surface water suggest an incipient environmental risk in the area.

Pesticide occurrence and water quality assessment from an agriculturally influenced Latin-American tropical region.

A monitoring study was carried out in three agriculturally influenced microcatchments in Costa Rica during 2012-2014, for pesticides and water quality parameters. A total of 42 pesticides were analyzed, detecting the following in water samples: two herbicides (oxyfluorfen, diuron), four insecticides (carbofuran, chlorpyrifos, oxamyl, ethion), and two fungicides (thiabendazole, carbendazim); while in sediment samples only the insecticides, chlorpyrifos and cypermethrin were found. Water quality was also assessed by the Canadian Council of Ministers of the Environment Water Quality Index and the National Sanitation Water Quality Index, the first one classified most of the sampling point as marginal and poor quality while the second one classified most of them as good quality, the most affected parameters were nitrate, phosphorous, suspended solids and organic matter content. The results suggest that the water quality in the microcatchments seems to be affected by the nearby agricultural and urban activities in the region.

Occurrence of pharmaceuticals, hazard assessment and ecotoxicological evaluation of wastewater treatment plants in Costa Rica.

The continuous release of pharmaceuticals from WWTP effluents to freshwater is a matter of concern, due to their potential effects on non-target organisms. The occurrence of pharmaceuticals in WWTPs and their associated hazard have been scarcely studied in Latin American countries. This study aimed at monitoring for the first time the occurrence of 70 pharmaceutical active compounds (PhACs) in WWTPs across Costa Rica; the application of the hazard quotient (HQ) approach coupled to ecotoxicological determinations permitted to identify the hazard posed by specific pharmaceuticals and toxicity of the effluents, respectively. Thirty-three PhACs were found, with 1,7-dimethylxanthine, caffeine, acetaminophen, ibuprofen, naproxen, ketoprofen and gemfibrozil being the most frequently detected (influents/effluents). HQ for specific pharmaceuticals revealed 24 compounds with high/medium hazard in influents, while the amount only decreased to 21 in effluents. The top HQ values were obtained for risperidone, lovastatin, diphenhydramine and fluoxetine (influent/effluent samples), plus caffeine (influent) and trimethoprim (effluent). Likewise, the estimation of overall hazard in WWTP samples (sum of individual HQ, ∑HQ) demonstrated that every influent and 96% of the effluents presented high hazard towards aquatic organisms. Ecotoxicological analysis (Daphnia magna, Lactuca sativa and Microtox test) revealed that 16.7% of the effluents presented toxicity towards all benchmark organisms; the phytotoxicity was particularly frequent, as inhibition values ≥20% in the germination index for L. sativa were obtained for all the effluents. The ∑HQ approach estimated the highest hazard in urban wastewater, while the ecotoxicological results showed the highest toxicity in hospital and landfill wastewater. Likewise, ecotoxicological results and ∑HQ values showed a rather poor correlation; instead, better correlations were obtained between ecotoxicological parameters and HQ values for some individual pharmaceuticals such as cephalexin and diphenhydramine. Findings from this study provide novel information on the occurrence of pharmaceuticals and the performance of WWTPs in the tropical region of Central America.