Tulsa-Citing lower volumes and higher operational and environmental costs, ammonia pipeline margins at Magellan Midstream LLC were down to $442,000 for the second quarter ending June 30 on sales of $3.43 million, versus the year-ago $1.46 million and $3.5 million, respectively. Magellan noted that higher average tariffs helped offset lower volumes. Expenses were up, primarily due to an October 2004 release and higher system integrity costs. Second quarter volumes were 162,000 st, down from 186,000 st. Six-month ammonia margins remain ahead of the prior year period, at $2.9 million on sales of $8.14 million, up from $2.44 million and $6.2 million, respectively. Six-month volumes stand at 378,000 st, up from 338,000 st. Magellan-wide, second-quarter net income was up 47.2 percent, to $57.4 million ($.62 per unit) on sales of $311.5 million, compared to the year-ago $39 million ($.48 per unit) and $255.6 million, respectively. Six-month net income stands at $105.7 million ($1.17 per unit) on sales of $590.8 million, versus the year-ago $81.1 million ($1.02 per unit) and $513.9 million, respectively.